Effect of solvents on formation of disulphide bond in peptides: A comparative study to produce the peptide using solvents used for purification and therefore to reduce the introduction of chemicals or metal ions in the manufacturing process
The document describes a study that evaluated the effect of different solvent systems on the formation of disulfide bonds in peptides during oxidation reactions. Desmopressin was used as a model peptide and oxidized at various concentrations in water, water:acetonitrile, water:methanol, and water:ethanol solvent mixtures. Oxidation in water produced lower purity peptides that took longer to form compared to other solvents. Oxidation in water:acetonitrile mixtures resulted in higher purity peptides formed faster than other solvent conditions tested, with 0.5-1 mg/ml concentrations performing best. The study demonstrates water:acetonitrile is a suitable solvent system for disulfide bond formation in peptides
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document discusses various methods for analyzing antioxidant capacity, including ORAC, HORAC, CUPRAC, DPPH, PFRAP, fluorometry, FRAP, and ABTS assays. The ORAC assay measures antioxidant scavenging against peroxyl radicals using fluorescein as a fluorescent probe. The HORAC assay similarly uses a fluorescent probe to measure protection against hydroxyl radicals. CUPRAC determines antioxidant capacity based on copper ion reduction. DPPH measures hydrogen or electron donation through color change. PFRAP analyzes reducing ability through complex formation. Fluorometry quantifies antioxidants in biodiesel. FRAP detects redox potentials below 0.7 V through color change.
In Vitro Antioxidant Studies of Whole Plant Ethanolic Extract of Blepharisrep...pharmaindexing
The document describes an in vitro study of the antioxidant properties of the whole plant ethanolic extract of Blepharisrepens (Vahl) Roth. Both the ethanol and aqueous extracts showed high scavenging activity against DPPH radicals at 500 μg/ml concentration. The ethanol extract was more effective at scavenging DPPH and nitric oxide radicals, while the aqueous extract more effectively scavenged hydroxyl and superoxide radicals. Both extracts showed moderate lipid peroxidation inhibition and contained flavonoids and phenols that contribute to their antioxidant effects. The study suggests Blepharisrepens has substantial antioxidant activity through its flavonoid content.
Bioactive compounds and antioxidant capacities of fresh and canned fruit,of p...GC University Faisalabad
This document summarizes a study on the bioactive compounds and antioxidant capacities of fresh and canned pineapple fruit. The study found that fresh pineapple extracts had higher levels of total phenolics, total flavonoids, and stronger antioxidant activities compared to canned pineapple extracts based on DPPH radical scavenging, inhibition of linoleic acid peroxidation, and reducing power assays. Fresh pineapple is a richer source of natural antioxidants than canned pineapple.
This document evaluates the antioxidant activity of 15 substances that have been proposed to address problems caused by tooth bleaching procedures. It assesses antioxidant activity using the DPPH free radical assay, which measures the ability of substances to scavenge stable DPPH radicals. The substances tested included ascorbic acid, sodium ascorbate, catalase, alpha-tocopherol, mouthwashes, sodium fluoride, and natural plant extracts. The results showed that ascorbic acid, ascorbic acid gel, vitamin E, and sodium ascorbate gel exhibited the highest antioxidant activity, while chlorhexidine, commercial products, and sodium fluoride showed the lowest activity. In conclusion, ascorbic acid, ascorbic acid gel,
Evaluation of antioxidant and antiradical properties of pomegranate (punica g...Pritam Kolge
Evaluation of antioxidant and antiradical properties
of Pomegranate (Punica granatum L.) seed and defatted
seed extracts
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Abstract
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
*Important Methods used
#Moisture content
#Fat content
#Acid value
#Peroxide value
#Oxidative stability index
#Total phenols content
#Preparation of Pomegranate seed extracts and calculate extract yield
#Evaluation of antioxidant properties of Pomegranate seed extracts using
-DPPH radicals scavenging activity
-FRAP assay
#Antioxidant efficiency of seed extract (Oxidative stability extract)
#Statistical analysis
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Dr. A. J. Shinde (Assistant Professor, Department of Pharmaceutics)
This document outlines a study to screen and analyze selected plant species for their antioxidant properties. The objectives are to:
1. Screen 3-4 plant species from forest regions for antioxidant properties.
2. Identify primary and secondary metabolites in plant extracts.
3. Isolate and quantify bioactive antioxidant compounds and determine medicinal value.
4. Compare antioxidant profiles between plant species.
Plants will be extracted using solvent extraction. Phytochemical analysis will test for compounds like alkaloids, flavonoids, tannins. Total phenolic content and flavonoid content will be determined colorimetrically. Antioxidant capacity will be evaluated using DPPH, ABTS, hydroxy
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document discusses various methods for analyzing antioxidant capacity, including ORAC, HORAC, CUPRAC, DPPH, PFRAP, fluorometry, FRAP, and ABTS assays. The ORAC assay measures antioxidant scavenging against peroxyl radicals using fluorescein as a fluorescent probe. The HORAC assay similarly uses a fluorescent probe to measure protection against hydroxyl radicals. CUPRAC determines antioxidant capacity based on copper ion reduction. DPPH measures hydrogen or electron donation through color change. PFRAP analyzes reducing ability through complex formation. Fluorometry quantifies antioxidants in biodiesel. FRAP detects redox potentials below 0.7 V through color change.
In Vitro Antioxidant Studies of Whole Plant Ethanolic Extract of Blepharisrep...pharmaindexing
The document describes an in vitro study of the antioxidant properties of the whole plant ethanolic extract of Blepharisrepens (Vahl) Roth. Both the ethanol and aqueous extracts showed high scavenging activity against DPPH radicals at 500 μg/ml concentration. The ethanol extract was more effective at scavenging DPPH and nitric oxide radicals, while the aqueous extract more effectively scavenged hydroxyl and superoxide radicals. Both extracts showed moderate lipid peroxidation inhibition and contained flavonoids and phenols that contribute to their antioxidant effects. The study suggests Blepharisrepens has substantial antioxidant activity through its flavonoid content.
Bioactive compounds and antioxidant capacities of fresh and canned fruit,of p...GC University Faisalabad
This document summarizes a study on the bioactive compounds and antioxidant capacities of fresh and canned pineapple fruit. The study found that fresh pineapple extracts had higher levels of total phenolics, total flavonoids, and stronger antioxidant activities compared to canned pineapple extracts based on DPPH radical scavenging, inhibition of linoleic acid peroxidation, and reducing power assays. Fresh pineapple is a richer source of natural antioxidants than canned pineapple.
This document evaluates the antioxidant activity of 15 substances that have been proposed to address problems caused by tooth bleaching procedures. It assesses antioxidant activity using the DPPH free radical assay, which measures the ability of substances to scavenge stable DPPH radicals. The substances tested included ascorbic acid, sodium ascorbate, catalase, alpha-tocopherol, mouthwashes, sodium fluoride, and natural plant extracts. The results showed that ascorbic acid, ascorbic acid gel, vitamin E, and sodium ascorbate gel exhibited the highest antioxidant activity, while chlorhexidine, commercial products, and sodium fluoride showed the lowest activity. In conclusion, ascorbic acid, ascorbic acid gel,
Evaluation of antioxidant and antiradical properties of pomegranate (punica g...Pritam Kolge
Evaluation of antioxidant and antiradical properties
of Pomegranate (Punica granatum L.) seed and defatted
seed extracts
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Abstract
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
*Important Methods used
#Moisture content
#Fat content
#Acid value
#Peroxide value
#Oxidative stability index
#Total phenols content
#Preparation of Pomegranate seed extracts and calculate extract yield
#Evaluation of antioxidant properties of Pomegranate seed extracts using
-DPPH radicals scavenging activity
-FRAP assay
#Antioxidant efficiency of seed extract (Oxidative stability extract)
#Statistical analysis
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Dr. A. J. Shinde (Assistant Professor, Department of Pharmaceutics)
This document outlines a study to screen and analyze selected plant species for their antioxidant properties. The objectives are to:
1. Screen 3-4 plant species from forest regions for antioxidant properties.
2. Identify primary and secondary metabolites in plant extracts.
3. Isolate and quantify bioactive antioxidant compounds and determine medicinal value.
4. Compare antioxidant profiles between plant species.
Plants will be extracted using solvent extraction. Phytochemical analysis will test for compounds like alkaloids, flavonoids, tannins. Total phenolic content and flavonoid content will be determined colorimetrically. Antioxidant capacity will be evaluated using DPPH, ABTS, hydroxy
This document discusses different methods of asymmetric synthesis, which is a type of chemical reaction that produces unequal amounts of stereoisomeric products. It describes three main approaches: using a chiral starting material from natural sources (chiral pool synthesis), introducing chirality with an auxiliary group that is later removed (chiral auxiliaries), and using a chiral catalyst or reagent (external asymmetric induction). Examples of each method are provided. The document also summarizes several ways to separate enantiomers, such as preferential crystallization, biochemical separation, and forming diastereomers.
ABSTRACT- Saccharomyces cerevisiae (Family: Saccharomycetaceae) is a Basidiomycetes fungus that is used in day to day life for human welfare ranging from food to medicines depending upon the type of strains and uses. Alcohol Dehydrogenase (ADH) is an important enzyme produced by the Saccharomyces fungus that catalyzes the many oxidation-reduction reaction in nature. The present study focuses on the reduction properties of the enzyme ADH on compounds like Nicotinamide Adenine Dinucleotide (NAD+), Dicholorophenol Indophenol (DCPIP), and Acetophenone using Spectrophotometric assays. The aim and hypothesis of present study was to extract the enzyme in Crude and Immobilized form and to check the best reduction of compounds in either form. The activity of enzyme in Crude and Immobilized was mathematically calculated and was expressed in Units of enzyme activity per ml of ADH enzyme on respective compounds used for study. Successfully the ADH was extracted in both forms but reduction of compounds at best was observed in Immobilized Enzyme form.
Key-words- Saccharomyces cerevisiae, Alcohol Dehydrogenase, Nicotinamide Adenine Dinucleotide, Dicholorophenol Indophenol, Acetophenone
This document provides information on several common methods used to measure antioxidant capacity in biological samples and foods. It describes the principles, procedures, and key measurements of assays such as ORAC, DPPH, ABTS, Folin-Ciocalteu, FRAP, CAA, HPLC, UPLC, and ELISA. These assays utilize different chemical reactions and detection methods to quantify a sample's ability to inhibit oxidation initiated by free radicals.
1. The document describes various qualitative tests that can be used to identify different types of carbohydrates, including monosaccharides, disaccharides, and polysaccharides.
2. Key tests described include the Molisch test, Benedict's test, Barfoed's test, Seliwanoff's test, and the hydrolysis test for sucrose. Each test exploits a unique chemical property of carbohydrates to indicate their presence.
3. The tests allow identification of carbohydrates by the color change produced, crystalline structure of osazones formed, or ability to reduce copper or show color change with reagents like iodine. Taken together, the battery of tests can determine the identity of an unknown carbohydrate sample.
This document discusses types and sources of impurities in active pharmaceutical ingredients (APIs). It outlines various types of impurities including organic, inorganic, residual solvents, and genotoxic impurities. Synthesis and formulation related impurities are described that can arise from starting materials, degradation, byproducts, excipients, and processing methods. Special attention is given to genotoxic impurities which are potentially mutagenic and carcinogenic even in low concentrations. Examples are provided of compounds used in synthesis like alkyl halides and epoxides that can lead to genotoxic impurities.
This document describes methods for the quantitative determination and analysis of Promethazine Hydrochloride and Prasugrel Hydrochloride using Folin-Ciocalteu reagent (FCR) through spectrophotometric studies. Calibration curves were constructed for both drugs using FCR and results were validated in terms of limits of detection, quantification, accuracy and precision. The developed methods were applied to pharmaceutical formulations containing the drugs and found to give satisfactory recoveries. Various factors affecting the absorbance were also optimized.
This document discusses various color reaction tests that can be used to identify proteins and amino acids. It describes the Biuret test, which produces a purple/violet color in the presence of two or more peptide bonds. The Xanthoproteic test identifies tyrosine and tryptophan by producing a yellow color that turns orange upon adding an alkali. Rosenheim's test is specific for tryptophan and produces a violet ring. The Ninhydrin test produces a blue/purple color with primary amines like proteins and amino acids. Molisch's test identifies glycoproteins by producing a purple ring.
The document describes the synthesis of novel hydroxy naphthylchalcone compounds as potential inhibitors of the enzyme polyphenol oxidase (tyrosinase). Two of the synthesized compounds showed higher tyrosinase inhibitory activity than the positive control kojic acid. Kinetic analysis revealed the inhibition was reversible and competitive. Molecular docking studies confirmed the active inhibitors strongly interacted with residues in the active site of mushroom tyrosinase.
This document discusses various methods for asymmetric synthesis, which is a form of chemical synthesis that favors the formation of one stereoisomer over another. It begins by explaining enantioselective synthesis and its importance in pharmaceuticals. It then discusses using naturally occurring chiral compounds as starting materials, known as the "chiral pool". Examples of compounds in the chiral pool are discussed, such as amino acids and carbohydrates. Methods for using these compounds or derivatives in asymmetric synthesis are provided, such as through diastereoselective reactions. The document also discusses using chiral auxiliaries and catalysts to control stereoselectivity in reactions. Specific examples of chiral auxiliaries like oxazolidinones and catalytic reactions like asymmetric
Synthesis and pharmacological evaluation of novel imidazole derivativespharmaindexing
This document summarizes a research study that synthesized novel imidazole derivatives and evaluated their pharmacological properties. Specifically:
- Seven novel imidazole derivatives containing an imidazole-isatin scaffold were synthesized. Their structures and physical properties were characterized.
- The compounds were evaluated for anthelmintic activity using Pheretima posthuma earthworms as a model. The time taken for paralysis and death of the worms was recorded and compared to the reference drug albendazole.
- One of the synthesized compounds, 2-(1H-imidazol-1-yl)-N’-(2-oxoindolin-3-ylidene)acetohydra
The document summarizes various qualitative tests that can be used to identify carbohydrates, including monosaccharides, disaccharides, and polysaccharides. It describes tests such as the Molisch test, Benedict's test, Barfoed's test, Seliwanoff's test, a hydrolysis test for sucrose, the osazone test, Bial's test, and an iodine reaction test. For each test, it provides the principle, procedure, expected results, and how to interpret the results in order to determine what type of carbohydrate may be present in the sample being tested.
Asymmetric synthesis (As per new syllabus of PCI)
Methods of asymmetric synthesis using chiral pool
Chiral auxiliaries and catalytic asymmetric synthesis
Enantiopure seperation
Stereoselective synthesis
Recent advances
References
Glossary of staining methods, reagents, immunostaining, terminology and eponymsPravin Amabade
This document provides a glossary of terms related to biological staining methods, reagents, immunostaining, and related terminology. It contains over 150 entries defined in black bold, with cross-references in underlined blue italic. The glossary aims to define terms for researchers across sub-disciplines of microtechnique to increase understanding of staining rationales, reagents, and eponyms. It is updated periodically to expand coverage of dyes, fixatives, and other procedures.
This document discusses various modes of drug degradation, including chemical, physical, and microbial degradation. It describes common chemical degradation pathways such as hydrolysis, oxidation, isomerization, and photodegradation. It also discusses factors that can influence the rate of degradation, such as excipients, moisture, temperature, and pH. Finally, it covers different kinetic models that can be used to describe drug degradation, such as pseudo-first order, pseudo-zero order, and reversible reactions.
The Biuret test detects the presence of peptide bonds in proteins. Peptide bonds form when amino acids link together to make proteins. The test involves adding a protein sample to an alkaline solution of copper sulfate and sodium hydroxide. In an alkaline environment, the copper ions will form a coordination complex with the nitrogen atoms from any peptide bonds present. This complex is purple in color, so a color change from blue to purple indicates that proteins containing peptide bonds are present in the sample.
1. The document discusses degradation kinetics and mechanisms of drugs. It defines kinetics, order of reaction, and half-life and describes zero, first, second and third order degradation pathways.
2. Common chemical degradation mechanisms for drugs include hydrolysis, dehydration, isomerization, racemization, decarboxylation, elimination, oxidation, and photodegradation. Specific drug examples are provided for each.
3. Amines can also degrade through the Maillard reaction with reducing sugars, browning the products. This document provides an overview of important concepts in drug degradation kinetics and mechanisms.
Imidazole Derivatives Biological Activity And Synthetic ApproachesBalmukund Thakkar
This document summarizes biological activity and synthetic approaches for imidazole derivatives. It discusses the biological importance of natural imidazoles and synthetic imidazoles used as drugs, including antifungals, antithyroid drugs, and drugs affecting the sympathetic nervous system. It also reviews conventional imidazole synthesis methods and their limitations, and modern catalytic and non-catalytic methods that offer better yields, selectivity, and green chemistry profiles.
Evaluation of antioxidant properties of pomegranate peel extract in compariso...Pritam Kolge
Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract.....
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Highlights
#Introduction
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
Important Methods used
1)Antioxidants extraction
2)Determination of total phenolics content
3)FRAP Assay
4)Determination of content of phenolic compounds in the
extract
5)Superoxide radical scavenging activity (DPPH)
6)Hydroxyl radical (OH) prevention activity
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Mr. D. P. Mali Assistant Professor, Pharmaceutical Chemistry
1. The document provides an overview of qualitative analysis methods for proteins. It discusses different types of proteins and how they can be classified.
2. Several precipitation tests are described to identify proteins, including precipitation by salts, adjusting pH to the isoelectric point, using organic solvents, heavy metals, alkaloidal reagents, and heat.
3. Color reaction tests are also summarized that can identify proteins and specific amino acids. These include the Biuret, Ninhydrin, Xanthoproteic, Modified Millon's, and Hopkins and Cole tests. The document outlines the principles and observations for each qualitative analysis method.
ClipperTelemed+ provides remote medical services for superyacht crews, owners, and guests via telephone, email, and video. They offer 24/7 emergency and primary care from physicians anywhere in the world. Services include enhanced medical care, emergency and primary care consultations, and flexible contract terms tailored to the needs of individual yachts.
This document discusses different methods of asymmetric synthesis, which is a type of chemical reaction that produces unequal amounts of stereoisomeric products. It describes three main approaches: using a chiral starting material from natural sources (chiral pool synthesis), introducing chirality with an auxiliary group that is later removed (chiral auxiliaries), and using a chiral catalyst or reagent (external asymmetric induction). Examples of each method are provided. The document also summarizes several ways to separate enantiomers, such as preferential crystallization, biochemical separation, and forming diastereomers.
ABSTRACT- Saccharomyces cerevisiae (Family: Saccharomycetaceae) is a Basidiomycetes fungus that is used in day to day life for human welfare ranging from food to medicines depending upon the type of strains and uses. Alcohol Dehydrogenase (ADH) is an important enzyme produced by the Saccharomyces fungus that catalyzes the many oxidation-reduction reaction in nature. The present study focuses on the reduction properties of the enzyme ADH on compounds like Nicotinamide Adenine Dinucleotide (NAD+), Dicholorophenol Indophenol (DCPIP), and Acetophenone using Spectrophotometric assays. The aim and hypothesis of present study was to extract the enzyme in Crude and Immobilized form and to check the best reduction of compounds in either form. The activity of enzyme in Crude and Immobilized was mathematically calculated and was expressed in Units of enzyme activity per ml of ADH enzyme on respective compounds used for study. Successfully the ADH was extracted in both forms but reduction of compounds at best was observed in Immobilized Enzyme form.
Key-words- Saccharomyces cerevisiae, Alcohol Dehydrogenase, Nicotinamide Adenine Dinucleotide, Dicholorophenol Indophenol, Acetophenone
This document provides information on several common methods used to measure antioxidant capacity in biological samples and foods. It describes the principles, procedures, and key measurements of assays such as ORAC, DPPH, ABTS, Folin-Ciocalteu, FRAP, CAA, HPLC, UPLC, and ELISA. These assays utilize different chemical reactions and detection methods to quantify a sample's ability to inhibit oxidation initiated by free radicals.
1. The document describes various qualitative tests that can be used to identify different types of carbohydrates, including monosaccharides, disaccharides, and polysaccharides.
2. Key tests described include the Molisch test, Benedict's test, Barfoed's test, Seliwanoff's test, and the hydrolysis test for sucrose. Each test exploits a unique chemical property of carbohydrates to indicate their presence.
3. The tests allow identification of carbohydrates by the color change produced, crystalline structure of osazones formed, or ability to reduce copper or show color change with reagents like iodine. Taken together, the battery of tests can determine the identity of an unknown carbohydrate sample.
This document discusses types and sources of impurities in active pharmaceutical ingredients (APIs). It outlines various types of impurities including organic, inorganic, residual solvents, and genotoxic impurities. Synthesis and formulation related impurities are described that can arise from starting materials, degradation, byproducts, excipients, and processing methods. Special attention is given to genotoxic impurities which are potentially mutagenic and carcinogenic even in low concentrations. Examples are provided of compounds used in synthesis like alkyl halides and epoxides that can lead to genotoxic impurities.
This document describes methods for the quantitative determination and analysis of Promethazine Hydrochloride and Prasugrel Hydrochloride using Folin-Ciocalteu reagent (FCR) through spectrophotometric studies. Calibration curves were constructed for both drugs using FCR and results were validated in terms of limits of detection, quantification, accuracy and precision. The developed methods were applied to pharmaceutical formulations containing the drugs and found to give satisfactory recoveries. Various factors affecting the absorbance were also optimized.
This document discusses various color reaction tests that can be used to identify proteins and amino acids. It describes the Biuret test, which produces a purple/violet color in the presence of two or more peptide bonds. The Xanthoproteic test identifies tyrosine and tryptophan by producing a yellow color that turns orange upon adding an alkali. Rosenheim's test is specific for tryptophan and produces a violet ring. The Ninhydrin test produces a blue/purple color with primary amines like proteins and amino acids. Molisch's test identifies glycoproteins by producing a purple ring.
The document describes the synthesis of novel hydroxy naphthylchalcone compounds as potential inhibitors of the enzyme polyphenol oxidase (tyrosinase). Two of the synthesized compounds showed higher tyrosinase inhibitory activity than the positive control kojic acid. Kinetic analysis revealed the inhibition was reversible and competitive. Molecular docking studies confirmed the active inhibitors strongly interacted with residues in the active site of mushroom tyrosinase.
This document discusses various methods for asymmetric synthesis, which is a form of chemical synthesis that favors the formation of one stereoisomer over another. It begins by explaining enantioselective synthesis and its importance in pharmaceuticals. It then discusses using naturally occurring chiral compounds as starting materials, known as the "chiral pool". Examples of compounds in the chiral pool are discussed, such as amino acids and carbohydrates. Methods for using these compounds or derivatives in asymmetric synthesis are provided, such as through diastereoselective reactions. The document also discusses using chiral auxiliaries and catalysts to control stereoselectivity in reactions. Specific examples of chiral auxiliaries like oxazolidinones and catalytic reactions like asymmetric
Synthesis and pharmacological evaluation of novel imidazole derivativespharmaindexing
This document summarizes a research study that synthesized novel imidazole derivatives and evaluated their pharmacological properties. Specifically:
- Seven novel imidazole derivatives containing an imidazole-isatin scaffold were synthesized. Their structures and physical properties were characterized.
- The compounds were evaluated for anthelmintic activity using Pheretima posthuma earthworms as a model. The time taken for paralysis and death of the worms was recorded and compared to the reference drug albendazole.
- One of the synthesized compounds, 2-(1H-imidazol-1-yl)-N’-(2-oxoindolin-3-ylidene)acetohydra
The document summarizes various qualitative tests that can be used to identify carbohydrates, including monosaccharides, disaccharides, and polysaccharides. It describes tests such as the Molisch test, Benedict's test, Barfoed's test, Seliwanoff's test, a hydrolysis test for sucrose, the osazone test, Bial's test, and an iodine reaction test. For each test, it provides the principle, procedure, expected results, and how to interpret the results in order to determine what type of carbohydrate may be present in the sample being tested.
Asymmetric synthesis (As per new syllabus of PCI)
Methods of asymmetric synthesis using chiral pool
Chiral auxiliaries and catalytic asymmetric synthesis
Enantiopure seperation
Stereoselective synthesis
Recent advances
References
Glossary of staining methods, reagents, immunostaining, terminology and eponymsPravin Amabade
This document provides a glossary of terms related to biological staining methods, reagents, immunostaining, and related terminology. It contains over 150 entries defined in black bold, with cross-references in underlined blue italic. The glossary aims to define terms for researchers across sub-disciplines of microtechnique to increase understanding of staining rationales, reagents, and eponyms. It is updated periodically to expand coverage of dyes, fixatives, and other procedures.
This document discusses various modes of drug degradation, including chemical, physical, and microbial degradation. It describes common chemical degradation pathways such as hydrolysis, oxidation, isomerization, and photodegradation. It also discusses factors that can influence the rate of degradation, such as excipients, moisture, temperature, and pH. Finally, it covers different kinetic models that can be used to describe drug degradation, such as pseudo-first order, pseudo-zero order, and reversible reactions.
The Biuret test detects the presence of peptide bonds in proteins. Peptide bonds form when amino acids link together to make proteins. The test involves adding a protein sample to an alkaline solution of copper sulfate and sodium hydroxide. In an alkaline environment, the copper ions will form a coordination complex with the nitrogen atoms from any peptide bonds present. This complex is purple in color, so a color change from blue to purple indicates that proteins containing peptide bonds are present in the sample.
1. The document discusses degradation kinetics and mechanisms of drugs. It defines kinetics, order of reaction, and half-life and describes zero, first, second and third order degradation pathways.
2. Common chemical degradation mechanisms for drugs include hydrolysis, dehydration, isomerization, racemization, decarboxylation, elimination, oxidation, and photodegradation. Specific drug examples are provided for each.
3. Amines can also degrade through the Maillard reaction with reducing sugars, browning the products. This document provides an overview of important concepts in drug degradation kinetics and mechanisms.
Imidazole Derivatives Biological Activity And Synthetic ApproachesBalmukund Thakkar
This document summarizes biological activity and synthetic approaches for imidazole derivatives. It discusses the biological importance of natural imidazoles and synthetic imidazoles used as drugs, including antifungals, antithyroid drugs, and drugs affecting the sympathetic nervous system. It also reviews conventional imidazole synthesis methods and their limitations, and modern catalytic and non-catalytic methods that offer better yields, selectivity, and green chemistry profiles.
Evaluation of antioxidant properties of pomegranate peel extract in compariso...Pritam Kolge
Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract.....
This is Journal Club activity Presentation with the reference of various research papers.
This Presentation Contain following...
#Info about Paper
#Highlights
#Introduction
#Materials
#Methods
#Results
#Discussion
#Conclusion
#References
Important Methods used
1)Antioxidants extraction
2)Determination of total phenolics content
3)FRAP Assay
4)Determination of content of phenolic compounds in the
extract
5)Superoxide radical scavenging activity (DPPH)
6)Hydroxyl radical (OH) prevention activity
Journal Club Presentation at Bharati Vidyapeeth College of Pharmacy, Kolhapur.
Thanks for Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Mr. D. P. Mali Assistant Professor, Pharmaceutical Chemistry
1. The document provides an overview of qualitative analysis methods for proteins. It discusses different types of proteins and how they can be classified.
2. Several precipitation tests are described to identify proteins, including precipitation by salts, adjusting pH to the isoelectric point, using organic solvents, heavy metals, alkaloidal reagents, and heat.
3. Color reaction tests are also summarized that can identify proteins and specific amino acids. These include the Biuret, Ninhydrin, Xanthoproteic, Modified Millon's, and Hopkins and Cole tests. The document outlines the principles and observations for each qualitative analysis method.
ClipperTelemed+ provides remote medical services for superyacht crews, owners, and guests via telephone, email, and video. They offer 24/7 emergency and primary care from physicians anywhere in the world. Services include enhanced medical care, emergency and primary care consultations, and flexible contract terms tailored to the needs of individual yachts.
Dr. Aziz is the Manifestation of E.M. Forster's Prejudiced towards the British.inventionjournals
E. M Forster’s novel A Passage to India where English characters are presented as superior ‘we’,
Indians remain ‘other’. The author’s prejudiced interruption in portrayal the characters actually diminish the
oriental values and upgrade the superior ideologies of the English. The central character in A Passage to India
becomes the victim of the bigotry and prejudice attitude of the writer. Forster portrays his protagonist Aziz who
is showered by all the ordinary features of oriental values that make the whole nation inferior along with him.
Aziz is a middle class Muslim with Indian social values under British environment. Again, he is not drawn as a
nationalistic hero of extraordinary qualities. Rather he is stereotyped with falsehood, superstitious, lazy,
flatterer, illogical, confused, suffering from fake superiority complex (result inferiority complex), his inborn
religious prejudices and intellectual shallowness. Apart from European characters (Mrs. Moore, Adela
Quested, Cyril Fielding and Ronny Heslop), Aziz is marginalized because of his typical Indianness. The article
concentrates on the inferior features of Orientals that proves Forster’s bias attitude towards the main character
comparing other four English characters Cyril Fielding, Mrs. Moore, Adela Quested and Ronny Heslop in the
novel.
Keywords: prejudice, Indianness, immobilization, peculiarities
JC Economics highlights the latest microeconomics and macroeconomics news events which will give students real-world knowledge so that they can apply their content knowledge to answer examination questions on these issues.
This document discusses the importance of respecting nature. It is presented as a speech asking the audience who they are and what they want for themselves. It notes that nature provides beautiful scenery and living creatures, but these gifts are not respected in return as nature is given back death instead. The speech encourages the audience to do something for nature, for themselves, and for everyone, asking who will protect nature if not them and wondering when it will be done if not now. It concludes by thanking the audience and asking them to share the message with others.
Connell Mott MacDonald designed and engineered three major sporting facilities in Melbourne since 2000: the 52,000-seat Colonial Stadium featuring a unique moving roof; the Vodafone Arena, a multipurpose venue with retractable seating that can be lowered to reveal an Olympic-standard velodrome; and the VRC Members Grandstand with frameless glass and cantilevered seating overlooking the racetrack. Each facility presented innovative engineering solutions such as thermal modeling of the stadium roof's movements, access through the velodrome track, and fire engineering techniques that reduced protection needs for steel beams.
Similar to Effect of solvents on formation of disulphide bond in peptides: A comparative study to produce the peptide using solvents used for purification and therefore to reduce the introduction of chemicals or metal ions in the manufacturing process
The effect of addition NaCI 150 mOsmol pH 7 on liposomes Tetraether Lipid (EP...IjcmsdrJournal
As a drugs carrier, liposome can alter the pharmacokinetics of the entrapped drugs. Thus, drugs can act directly on the targeted cell while their systemic side effects are reduced. To become an effective drugs carrier, liposome must reach its stability in chemical, physical, and biological conditions. Liposome stability can be achieved by changing the lipid composition, such as EPC-TEL 2,5 which is made from the combination of Egg Yolk Phosphatydyl Coline (EPC) and TEL 2,5 mol % that is extracted from Thermoplasma acidofilum. The aim of this study is to test the chemical stability of liposome EPC-TEL 2,5 with sonication by addition of NaCI 150 mOsmol pH 7 solution. The increase in number of liposome larger than 100 nm is the stability parameter in this study. After observation at day 0, 7, 30, 60, 90, there was no significant increase in the number of liposome larger than 100 nm after addition of NaCI 150 mOsmol pH 7 compared with control.
This document summarizes a seminar presentation on liposomes and niosomes. It discusses various types of liposomes and methods for preparing liposomes, including solvent dispersion methods like ethanol injection, ether injection, and reverse phase evaporation. Characterization techniques for liposomes like size, shape, encapsulation efficiency, and drug release are also outlined. Finally, the document notes therapeutic applications of liposomes for drug delivery and discusses characterization of liposomes through parameters like vesicle shape, size, surface charge, and drug entrapment efficiency.
The document discusses using the solvent N-methylmorpholine-N-oxide (NMMO) to dissolve cellulose for enzymatic hydrolysis. Key findings include:
1) Enzymatic hydrolysis rates were higher for cellulose dissolved in NMMO compared to regenerated cellulose. This supports conducting pretreatment and hydrolysis in a single step.
2) Among ionic liquids tested, enzymatic activity was highest in NMMO and gradually decreased in two other ionic liquids.
3) Preliminary experiments in a twin screw reactor demonstrated the potential to process high cellulose loads and achieve higher sugar yields in a continuous process.
In-vitro evaluation techniques of anticancer, anti oxidant, anti microbial ZakiyaUsmani
This document discusses various in vitro methods used to evaluate potential anti-cancer and antioxidant compounds, as well as antimicrobial activity. It describes cytotoxicity assays such as MTT, SRB, clonogenic assays and dye exclusion tests that are used to study anti-cancer activity against cell lines. Methods to evaluate antioxidant activity in vitro include DPPH radical scavenging, hydrogen peroxide and superoxide radical scavenging assays. Diffusion and dilution methods are discussed for determining antimicrobial activity of compounds in vitro prior to animal studies.
1) Phenolic disinfectants like phenol, 2,4-dichlorophenol, and p-tert-amylphenol bound to Micrococcus lysodeikticus cells, with higher percentages binding to cells for more potent disinfectants.
2) Protoplasts bound slightly less (around 20%) of the phenolic disinfectants compared to whole cells, suggesting cell walls contribute to binding.
3) Binding of 2,4-dichlorophenol decreased with increasing pH, while binding of phenol and p-tert-amylphenol was constant over the pH range tested, relating to differences in ionization properties.
This document discusses liposomes, which are spherical vesicles made of phospholipid bilayers that can encapsulate aqueous content. It defines liposomes and describes their mechanisms of action and various classifications. The document also outlines several common methods for preparing, purifying, and evaluating liposomes, such as solvent dispersion, detergent removal, mechanical dispersion, and freeze drying. Finally, it lists some applications of liposomes like enzyme replacement therapy and delivery of drugs, antibodies, and vaccines.
Introduction,Drug- Excipient Compatibility Experimental Design ,Excipient role in drug destabilization,DRUG EXCIPIENT COMPATIBILTY IN PARENTERAL PRODUCTS.This topic are described.
The document provides an overview of solid phase synthesis. It describes how solid phase synthesis involves coupling reagents to an inert solid support to perform multi-step organic synthesis. The key steps include attaching the starting material to a resin via a linker, performing sequential reactions on the bound intermediate, then cleaving the final product from the resin. The Merrifield method from 1963 pioneered this technique by automating the synthesis of peptides on an insoluble polystyrene resin, enabling efficient purification and the potential for parallel reactions.
Colloidal drug delivery system (Nano formulation)pratik9527088941
This document discusses various colloidal drug delivery systems including liposomes, niosomes, solid lipid nanoparticles, polymeric nanoparticles, and carbon nanotubes. It provides details on the composition, advantages, methods of preparation, and drug incorporation for each system. The key points are that nanocarriers can improve drug solubility and stability, target drug delivery, and reduce toxicity. The document outlines various fabrication techniques for each nanocarrier type such as homogenization, solvent evaporation, and polymerization.
The document summarizes research on enzymatic hydrolysis of cellulose in the ionic liquid NMMO. Key findings include:
1) A twin screw extruder was modified to produce high cellulose loading solutions of up to 13% in NMMO/H2O. Enzymatic hydrolysis reactions were then performed in the extruder.
2) Reaction conditions like cellulose loading, enzyme loading, pH, and agitation method significantly impacted sugar yields and conversion rates. The highest yield was obtained at 10% cellulose, 122 FPU/g enzymes, and acidic pH in a stirred tank reactor.
3) A stirred tank reactor provided better mixing than a shaker bath and achieved near complete conversion of cell
This document discusses various techniques for preparing and characterizing liposomes. It describes common methods for passive loading of drugs into liposomes, such as freeze drying, ethanol injection, ether injection, and reverse-phase evaporation. It also discusses remote loading using pH gradients or electrical potentials. Characterization techniques discussed include measuring particle size, surface charge, drug encapsulation efficiency, transition temperature, and drug release rate. Methods are provided for determining important chemical characteristics like phospholipid and cholesterol content.
The effect of conjugation on different polymers in bioadhesive films of losartanSriramNagarajan18
The document summarizes a study that investigated the effect of conjugating different polymers on the properties of buccal films containing the drug losartan potassium. Sodium alginate and chitosan were conjugated with cysteine and thioglycolic acid respectively, and films containing plain or conjugated polymers were prepared and evaluated. The conjugation was confirmed using FTIR and the polymers were found to contain thiol groups. Films were evaluated for properties like thickness, drug content, swelling, bioadhesion and drug permeation. Formulations containing conjugated polymers showed higher bioadhesion, swelling and longer drug permeation compared to films with plain polymers. The optimized formulations were found to be stable.
In vitro and in vivo evaluation of positively charged liposaccharide derivati...Adel Abdelrahim, PhD
This document describes a study evaluating positively charged liposaccharide derivatives as oral absorption enhancers for delivering anionic drugs. Positively charged liposaccharide derivatives were synthesized and combined with the anionic model drug piperacillin through ion pairing. The conjugates were evaluated in vitro and in vivo to assess antimicrobial activity, plasma stability, permeability across Caco-2 cell monolayers, and oral absorption. Results showed that ion pairing the liposaccharide derivatives with piperacillin improved permeability in Caco-2 cells without altering antimicrobial activity, indicating potential as oral absorption enhancers.
CHE235L4Spring2017.pdf
FW
(g/mol)
mp (
o
C) bp (
o
C) mmol mass (g)
density
(g/mL)
volume
(mL)
N/A
N/A
bismuth(III) nitrate pentahydrate N/A N/A N/A N/A
sodium chloride, saturated (brine) N/A N/A N/A N/A N/A
ethyl acetate N/A N/A
cis -1,2-cyclohexanediol N/A N/A N/A
trans -1,2-cyclohexanediol, (±) N/A N/A N/A
Prelab 4: Green Lewis Acid-Catalyzed Hydrolysis of Cyclohexene Oxide
Name:
Reaction equation:
Note: For those reagents that are in solution, the FW, mmol, and mass columns refer to the solute in the
solution.
Limiting reagent:
Reagent Table
water
Theoretical yield:
Chemical
cyclohexene oxide
EXPERIMENT #4
GREEN LEWIS ACID-CATALYZED HYDROLYSIS OF CYCLOHEXENE OXIDE
Introduction:
Epoxides are three-membered ethers. They are special because unlike most ethers, they can react
with nucleophiles to form a new bond between carbon and the nucleophile and break a bond
between that carbon and oxygen. This ring-opening reaction makes epoxides versatile functional
groups for organic synthesis. (In fact epoxide is the functional group that makes epoxy resins
possible.)
Scheme 1. Ring opening of an epoxide in the presence of a nucleophile.
Ring-opening of the epoxide can occur under basic or acidic conditions. Under basic conditions,
the reaction is similar to an SN2 reaction so that the nucleophile attacks the less substituted carbon
of an unsymmetrical epoxide by backside attack. Sodium ethoxide reacts with this epoxide in the
following reaction.
Scheme 2. Ring opening of an unsymmetrical epoxide under basic conditions.
Under acidic conditions, the reaction is more complicated. It is similar to an SN2 reaction because
the nucleophile reacts by backside attack. However, because there is partial positive charge on the
Reference Material:
MAHHS Chapter 1: Safety in the Laboratory
MAHHS Chapter 2: Protecting the Environment
MAHHS Chapter 3: Laboratory Notebooks and Prelaboratory Information
MAHHS Chapter 4: Laboratory Glassware
MAHHS Chapter 5: Measurements and Transferring Reagents
MAHHS Chapter 10: Filtration
MAHHS Chapter 11: Extraction
MAHHS Chapter 12: Drying Organic Liquids and Recovering Reaction Products
MAHHS Chapter 17: Thin-Layer Chromatography, especially section 17.8
MAHHS Chapter 20: Infrared Spectroscopy
Klein Chapter 14: Ethers and Epoxides; Thiols and Sulfides
three atoms of the epoxide ring, the nucleophile attacks where the partial positive charge is more
stabilized, the more substituted carbon of an unsymmetrical epoxide. Ethanol in the presence of
sulfuric acid reacts with this epoxide in the following reaction.
Scheme 3. Ring opening of an unsymmetrical epoxide under acidic conditions.
While sulfuric acid is an inexpensive acid catalyst, it is difficult to handle. It is very corrosive and
can cause severe burns. In addition, it is viscous, which makes it difficult to handle on the scale of
the reactions perfor ...
Final Photocatalysis Lab Report (1) (1)Henry Hsieh
The document summarizes an experiment analyzing the effect of hydrogen peroxide concentration on the methylene blue degradation kinetic constant. When 5mL and 10mL of hydrogen peroxide were added, kinetic constants of 0.07 min-1 and 0.12 min-1 were obtained, respectively, indicating faster degradation with more hydrogen peroxide. However, decreasing kinetics from excess hydrogen peroxide was not observed due to the limited concentration range studied. Absorbance measurements and kinetic plots were used to determine the degradation constants.
The document discusses oxidative stress and antioxidants. It defines reactive oxygen species and their sources inside and outside the body. ROS can cause damage but the body has an antioxidant defense system like SOD and glutathione. Oxidative stress occurs when ROS levels overwhelm antioxidants and can lead to diseases. The document describes several markers of oxidative stress and health effects like cancer, cardiovascular and neurodegenerative diseases. It also discusses antioxidants from foods and lifestyle factors that influence oxidative stress.
Buffers resist changes in pH and consist of a conjugate acid-base pair where the ratio of proton acceptor to proton donor is near unity. A webinar discusses how biological buffers can impact reproducibility and explores considerations for buffer selection and use to improve reproducibility. Key factors include how buffers may interact with metals and biological materials and tips for proper buffer selection and use. [END SUMMARY]
it provide a brief note on the drug excipient interaction and various technique to find it which is a part of preformulation studies. it gives help to mpharm(pharmaceutics) students. i.
This document presents a kinetic model for the lipase-catalyzed conversion of ascorbic acid and oleic acid to the liposoluble vitamin C ester ascorbyl oleate. Experimental data were fitted to a ping-pong bi-bi kinetic model with substrate inhibition by excess ascorbic acid. Kinetic constants were determined under optimized reaction conditions. The model was then expanded to include terms describing ester hydrolysis, and kinetic constants for the reverse reaction were estimated. The calculated constants revealed that lipase has the highest affinity for ascorbyl oleate and slightly lower activity for ascorbic acid, with the lowest activity for oleic acid.
The document presents a kinetic model for the acid-catalyzed delignification of sugarcane bagasse by aqueous acetic acid (AcH). The model introduces the concept of "potential degree of delignification (dD)" to account for the multilayered structure of plant cell walls and the inhibitory effect of dissolved lignin. Experimental results showed that delignification rate followed first-order kinetics with respect to sulfuric acid concentration but had a high reaction order with respect to AcH concentration. The activation energy for delignification was determined to be 64.41 kJ/mol. Mechanism analysis found that cleavage of α-aryl ether bonds in lignin was mainly responsible for lignin fragment formation, and increasing AcH
Similar to Effect of solvents on formation of disulphide bond in peptides: A comparative study to produce the peptide using solvents used for purification and therefore to reduce the introduction of chemicals or metal ions in the manufacturing process (20)
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
10 Benefits an EPCR Software should Bring to EMS Organizations Traumasoft LLC
The benefits of an ePCR solution should extend to the whole EMS organization, not just certain groups of people or certain departments. It should provide more than just a form for entering and a database for storing information. It should also include a workflow of how information is communicated, used and stored across the entire organization.
5-hydroxytryptamine or 5-HT or Serotonin is a neurotransmitter that serves a range of roles in the human body. It is sometimes referred to as the happy chemical since it promotes overall well-being and happiness.
It is mostly found in the brain, intestines, and blood platelets.
5-HT is utilised to transport messages between nerve cells, is known to be involved in smooth muscle contraction, and adds to overall well-being and pleasure, among other benefits. 5-HT regulates the body's sleep-wake cycles and internal clock by acting as a precursor to melatonin.
It is hypothesised to regulate hunger, emotions, motor, cognitive, and autonomic processes.
DECLARATION OF HELSINKI - History and principlesanaghabharat01
This SlideShare presentation provides a comprehensive overview of the Declaration of Helsinki, a foundational document outlining ethical guidelines for conducting medical research involving human subjects.
Promoting Wellbeing - Applied Social Psychology - Psychology SuperNotesPsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Travel vaccination in Manchester offers comprehensive immunization services for individuals planning international trips. Expert healthcare providers administer vaccines tailored to your destination, ensuring you stay protected against various diseases. Conveniently located clinics and flexible appointment options make it easy to get the necessary shots before your journey. Stay healthy and travel with confidence by getting vaccinated in Manchester. Visit us: www.nxhealthcare.co.uk
- Video recording of this lecture in English language: https://youtu.be/Pt1nA32sdHQ
- Video recording of this lecture in Arabic language: https://youtu.be/uFdc9F0rlP0
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
Osteoporosis - Definition , Evaluation and Management .pdf
Effect of solvents on formation of disulphide bond in peptides: A comparative study to produce the peptide using solvents used for purification and therefore to reduce the introduction of chemicals or metal ions in the manufacturing process
1. International Journal of Pharmaceutical Science Invention
ISSN (Online): 2319 – 6718, ISSN (Print): 2319 – 670X
www.ijpsi.org Volume 4 Issue 7 ‖ July 2015 ‖ PP.20-27
www.ijpsi.org 20 | P a g e
Effect of solvents on formation of disulphide bond in peptides: A
comparative study to produce the peptide using solvents used for
purification and therefore to reduce the introduction of chemicals
or metal ions in the manufacturing process.
S.V.Tillu1
, R.S.Lokhande2
, J. Bacardit3
1,2,3
Department of Chemistry, Jaipur National University, Jaipur-302017, India.
Abstract: A novel approach to the formation of disulphide bonds in peptides is developed by doing a series of
experiments to evaluate effect of solvents on the disulphide bond formation in peptides in terms of time required,
recovery, ease of processing during reaction working up and use of solvents. For evaluating the effect,
experiments were setup using Water:Acetonitrile, Water:Methanol and Water:Ethanol for disulphide bond
formation of Desmopressin and the results were compared with the aerial oxidation conducted in water. For
each solvent, a set of oxidation reactions was studied at 0.5 mg/ml, 1 mg/ml and 5 mg/ml concentration. The
acetonitrile water combination at concentration of either 0.5mg/ml or 1 mg/ml proved to deliver the best result
in terms of purity, yield and time required to complete reaction.
Keywords: Acetonitrile, Desmopressin Bis-SH, Ethanol, Methanol Peptide
I. Introduction:
Disulfide bridges play a crucial role in the folding and structural stabilization of many important
extracellular peptides and proteins. In addition, the artificial introduction of extra disulfide bond into peptides
or proteins allows the creation of conformational constraints that can improve biological activity or thermo
stability. Due to that, disulfide bond containing peptides or proteins are very challenging to manufacture. Now
a-days biologically active molecules that are natural in sources or mimic of natural source are playing an
important role in curing/treating life threatening conditions. Scientists are working on peptide based
formulations which can lead to less aggressive treatment for those conditions, and as peptides are the naturally
occurring chemical entities in the body and therefore it is easier to control the diseases without too many side
effects.
Methods of disulphide bridge formation (1, 3 to12)
Lot of efforts have been put towards developing cyclisation strategies of Cysteine containing peptide. A review
of summarized work can be summarized as follows: (1, 3 to12)
1. Cyclisation of SH containing precursor by Aerial oxidation: In this method during the synthesis
protecting groups are removed by side chain deprotection reagent and the resulting Bis-SH peptide is
subjected to aerial oxidation in presence of molecular oxygen or oxygen bubbling. In this method the
peptide is oxidized typically at low concentration (0.1 mg/ml to 1 mg/ml).
That method is easy and straightforward to apply and also very mild for other amino acids in the molecule
(i.e fewer chances of side reaction happening) but being in diluted state it introduces for use of additional
concentration step such as reverse osmosis or adsorption on synthetic resins. Sometimes reactions take
days to complete.
2. Symmetrical Cyclisation from S-protected precursor:
Cyclisation of cysteine protected by Acm-group (i.e acetamidomethyl –CH2-NH-CO-CH3) is done by using
iodine, thallium (III) Trifluoroacetate and a variety of alkyl trichlorosilanesulphoxide combinations. This
approach is used for intramolecular or intermolecular disulfide bond formation and it has the drawback that
side reaction are frequent specially on residues susceptible of entering redox reactions (e.g. Tryptophan).
Following are some protocols for oxidation of peptide containing cysteine:
1. Air oxidation
2. Oxidation by I2, Tl (III) Trifluoroacetate
3. Oxidation by potassium ferricyanide
4. Oxidation mediated by Charcoal
5. DMSO oxidation both in acidic and basic condition.
2. Effect of solvents on formation of disulphide…
www.ijpsi.org 21 | P a g e
Every protocol has its advantages and disadvantages. Air oxidation is very clean and doesn’t contain any harsh
chemical apart from the buffer, however some reaction take long time to complete (e.g. 40-72 days) even at
highly alkaline pH which might hydrolyse the peptide. In other protocols metal ions and high boiling solvents
are used as oxidizing agent are not easy to remove. So overall the cyclisation reaction of Cysteine containing
peptide is a key step in the manufacturing process, the quality and the quantity of peptide is dependent on the
outcome of this reaction. On industrial scale if we cannot get good yields with best quality then the resulting
product becomes difficult to process therefore in cyclic peptides oxidation is the key reaction and can affect the
quality and quantity of the product obtained.
II. Materials and Methods:
Cyclisation of desmopressin Bis-SH was studied at 3 different concentration i.e 0.5mg/ml, 1mg/ml, 5 mg/ml
using Water, 50% ACN+50%WATER or 50% MEOH+50%WATER or 50% ETOH+50%WATER as follows:
Concentration: 0.5 mg/ml,
50 mg Desmopressin Bis-SH were weighed and dissolved separately in 100 ml of water, 50% ACN+WATER,
50% MEOH+WATER or 50% ETOH+WATER to perform reaction at 0.5 mg/ml concentration.
1. pH of the reaction was checked at the start and samples injected on HPLC as Before pH.
2. pH of the reaction was adjusted to 9.5±0.5 using ammonia solution.
3. Progress of reaction was checked by HPLC and pH was checked at regular interval.
4. After achieving a consume of the % of Desmopressin Bis-SH higher than 98.5% the reaction was
stopped by addition of acetic acid.
Concentration: 1 mg/ml,
100 mg Desmopressin Bis-SH weighed and dissolved separately in 100 ml of water, 50% ACN+WATER, 50%
MEOH+WATER or 50% ETOH+WATER to perform oxidation at 1 mg/ml concentration.
1. pH of the reaction was checked at the start and samples injected on HPLC as Before pH.
2. pH of the reaction was adjusted to 9.5±0.5 using ammonia solution.
3. Progress of reaction was checked by HPLC and pH was checked at regular interval.
4. After achieving a consume of the % of Desmopressin Bis-SH higher than 98.5% the reaction was
stopped by addition of acetic acid.
Concentration: 5 mg/ml,
500 mg Desmopressin Bis-SH weighed and dissolved separately in 100 ml of water, 50% ACN+WATER, 50%
MEOH+WATER or 50% ETOH+WATER to perform reaction at 5 mg/ml concentration.
1. pH of the reaction was checked at the start and samples injected on HPLC as Before pH.
2. pH of the reaction was adjusted to 9.5±0.5 using ammonia solution.
3. Progress of reaction was checked by HPLC and pH was checked at regular interval.
4. After achieving a consume of the % of Desmopressin Bis-SH higher than 98.5% the reaction was
stopped by addition of acetic acid.
Progress of reactions as follows:
50%ACN+50%Water, 1 mg/ml concentration
12.5 15.0 17.5 20.0 22.5 25.0 27.5 min
0
250000
500000
750000
1000000
1250000
1500000
1750000
2000000
2250000
2500000
uV
5. Effect of solvents on formation of disulphide…
www.ijpsi.org 24 | P a g e
Water, 5 mg/ml concentration
18.0 19.0 20.0 21.0 22.0 min
0
250000
500000
750000
1000000
uV
The overlapped chromatograms above are showing the progress of the oxidation in each reaction condition. The
overlap is followed in the sequence from top to bottom as desmopressin std, desmopressin Bis-SH standard,
reaction at 0 hours to completion of reaction. The first graph in each is overlap is of desmopressin std, second is
of desmopressin bis-SH std, third is of 0 hours and then subsequent hours, the last graph is after acetic acid
addition.
Details of Analytical Method used for Monitoring the Reaction:
1. Buffer A: Dissolve 9.08 gm of Potasium dihydrogen phosphate in 1 L water and add 5 ml of
Trifluoroacetic acid and 5 ml Triethyl amine mix well and adjust pH to 5.01 with 10N NaOH.
2. Buffer B: 500 ml Buffer A+425 ml Acetonitrile+75ml Tetrahydrofuran.
3. Preparation of Desmopressin Standard Solution: Desmopressin Working Standard Vial dissolved in 25
ml of Milli-Q water.
4. Preparation of Desmopressin Bis-SH Standard Solution: 12.5 mg of desmopressin Bis-SH were
dissolved in 25 ml of water.
5. Resolution Solution: Oxytocin Desmopressin validation mixture dissolved in water to obtain a
concentration of 0.25mg/ml
6. Test Solution: 1 ml of sample diluted to 10 ml Milli-Q water.
Chromatographic condition:
Column C18, 250X4.6mm, 5 µ
Flow rate 1.5ml/min
Injection volume 50 µL for Blank, Std solution ( Desmopressin and Desmopressin Bis-SH)
50 µL for Test solution
Run time 50 min
System Suitability: Details of Analysis
Sample Solution Retention Time of Principal Peak
Desmopressin Std Solution Around 19 min
Desmopressin Bis-SH Std Solution Around 20 min
Resolution between main peak due to Desmopressin
and main peak due to Oxytocin
NLT 1.5
6. Effect of solvents on formation of disulphide…
www.ijpsi.org 25 | P a g e
III. Result and Discussion:
Cyclisation reaction in water:
In terms of purity: The cyclized desmopressin obtained by aerial oxidation at three different concentration of
0.5mg/ml, 1 mg/ml, 5 mg/ml showed purities of 62.71%, 56.06% and 61.51% respectively which is lower as
compared to other experiments done with other solvents.
In terms of Time: The cyclisation reaction of desmopressin by aerial oxidation, at three different
concentration of 0.5mg/ml, 1 mg/ml, 5 mg/ml took 17 hours, 33 hours and 35 hours respectively. The time at 1
mg/ml and 5 mg/ml is the longest time taken by reaction for completion as compared to other reaction
conditions.
In terms of Yield: Yield of the cyclisation reaction of desmopressin by aerial oxidation, at three different
concentrations of 0.5mg/ml, 1 mg/ml, 5 mg/ml was 107.68%, 113.30% and 18.42% respectively.
From the above observation it is clear that even though water is the cleanest way to do the cyclisation of
peptides, due to solubility issues of peptides in water there are chance of low reaction yield. As the reaction
takes longer time for completion therefore there are more chances of disulphide scrambling and thus more
unwanted dimers or polymers can form during cyclisation reaction, which leads to low yields and poor purity
levels, purity. Therefore it is clear that the water alone is not a suitable medium for cyclisation reaction of
peptides.
Cyclisation reaction in Water: Acetonitrile:
In terms of purity: The cyclized desmopressin obtained by Water:Acetonitrile oxidation and at three different
concentrations of 0.5mg/ml, 1 mg/ml and 5 mg/ml showed purity by HPLC of 76.61%, 74.76% and 72.92%
respectively which is comparably higher when as compared to other experiments done with other solvents.
In terms of Time: The cyclisation reaction of desmopressin by Water: Acetonitrile oxidation, at three different
concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) took 8 hours, 11 hours and 18 hours respectively. Even though
the reaction took comparably similar time with respect to reaction in Water: Methanol, Water: Ethanol in terms
of purity and yield it was higher in acetonitrile: water mixtures than in any of the other experimental conditions.
In terms of Yield: Yield of the cyclisation reaction of desmopressin by Water: Acetonitrile oxidation, at three
different concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) was 133.81%, 106.07% and 133.81% respectively.
Considering overall Yield, time taken for completion of reaction and purity then the Water:Acetonitrile
reaction condition is comparatively cleaner and therefore preferred over Water:Methanol and Water:Ethanol
solvent conditions
Cyclisation reaction in Water: Methanol:
In terms of purity: The cyclized desmopressin obtained by Water:Methanol oxidation and at three different
concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) was having purity of 76.82%, 77.68% and 76.25% respectively
which is comparably high at all three concentration conditions when compared with results for other solvents
In terms of Time: The cyclisation reaction of desmopressin by Water: Methanol oxidation, at three different
concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) took 18 hours, 10 hours and 22 hours respectively. Even though
the purity of desmopressin using this condition is better than the previous, The time required for reaction is
higher as compared to other conditions and that can lead to lower yield.
In terms of Yield: Yield of the cyclisation reaction of desmopressin by Water: Methanol oxidation, at three
different concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) was 136.89%, 114.74% and 102.29% respectively.
7. Effect of solvents on formation of disulphide…
www.ijpsi.org 26 | P a g e
Even though Reaction at 0.5mg/ml was having comparable yield and purity with cyclisation reaction using
Water: Acetonitrile at 0.5 mg/ml and 1mg/ml, Still time taken to complete the reaction in Water: Methanol
media at 0.5mg/ml was 18 hours which longer than the Water: Acetonitrile (8 hours). Reaction at 1 mg/ml took
only 10 hours to complete. The yield was only 114.74% which is 18.07 % lower than Water: Acetonitrile
reaction at 0.5mg/ml. Reaction at 5 mg/ml took 22 hours to complete and had lower yields due to longer
reaction times.
Cyclisation reaction in Water: Ethanol:
In terms of purity: The cyclized desmopressin obtained by Water:Ethanol aerial oxidation and at three
different concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) was having purity of 72.82%, 73.23% and 76.25%
respectively which was comparably lower as compared to experiments done in Water:Acetonitrile and
Water:Methanol.
In terms of Time: The cyclisation reaction of desmopressin by Water:Ethanol aerial oxidation, at three
different concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) took 7 hours, 17 hours and 7 hours respectively. The
reaction time in Water: Ethanol is comparable to that of Water: Acetonitrile mixtures. Yields are also
comparable but purities are slightly lower (76.61% in Water: Acetonitrile and 72.82% in Water: Ethanol).
In terms of Yield: Yield of the cyclisation reaction of desmopressin by Water: Ethanol oxidation, at three
different concentrations (0.5mg/ml, 1 mg/ml, 5 mg/ml) was 134.94%, 124.26% and 88.93% respectively.
Conclusion:
The results of the above experiments are tabulated in following table in order of decreasing yield.
Medium of reaction
concentration
of reaction in
mg/ml
Time
required
for
completion
in Hours
% yield as compared to
area of desmopressin Bis-
SH at start and
Desmopressin at end of
reaction
Purity of
desmopressin
50%MEOH +50% Water 0.5 18 136.89% 76.82%
50%ETOH + 50%Water 0.5 7 134.94% 72.82%
50%Acetonitrile+50%Water 0.5 8 133.81% 76.61%
50%Acetonitrile+50%Water 5 18 132.01% 72.92%
50%ETOH + 50%Water 1 17 124.26% 73.23%
50%MEOH +50% Water 1 10 114.74% 77.68%
Water 1 33 113.30% 56.06%
Water 0.5 17 107.68% 62.71%
50%Acetonitrile+50%Water 1 11 106.07% 74.76%
50%MEOH +50% Water 5 22 102.29% 76.25%
50%ETOH + 50%Water 5 7 88.93% 66.25%
Water 5 35 18.42% 61.51%
From above observation it is clear that reaction in acetonitrile and water as a medium is one of the best
combination for disulphide bond formation in peptides. Higher yields of the reaction are indicating towards an
improved solubility of peptides in the Water: solvent mixtures. The time required for reactions is comparably
less as compared to reactions in water. Due to lower reaction times and higher yields the concentration
condition of 0.5 mg/ml and 1 mg/ml in Water: Acetonitrile are selected as suitable for cyclisation of
desmopressin at industrial scale. Similarly this can be applied to other peptides to improve the yields and
lowering the time of processing by using organic solvents for oxidation compatible with those used during the
purification step.
Acknowledgement:
We are thankful to Hemmo Pharmaceuticals Pvt. Ltd. for the support provided for research.