preparation of buffers, buffers and isotonic systems. Methods for
adjustment of tonicity of solutions. Buffers in pharmaceutical and biological systems.
Buffer solutions resist changes in pH upon the addition of small amounts of acid or base through buffer action. A buffer is a combination of a weak acid and its conjugate base. The pH of a buffer solution depends on the ratio of the concentration of the salt to the acid. Factors like the addition of neutral salts, dilution, and temperature can impact the pH of a buffer solution. Buffers have various applications in pharmaceutical formulations to adjust pH for stability and therapeutic effects.
Here are potential responses to the study questions:
Define the following terms:
- Ionization: The process by which an atom or molecule acquires a negative or positive charge by gaining or losing electrons.
- Buffer capacity: The ability of a solution to resist changes in pH upon the addition of an acid or base. It depends on the buffer composition and concentration.
- In-vivo: Occurring or taking place inside a living organism.
Considering a practical process, illustrate the procedural significance of buffer systems in moderation of the reactions of a solution system:
Buffer systems are important in pharmaceutical formulations to maintain the pH within an optimal range for drug stability, solubility, and to minimize irritation upon administration.
This document provides an overview of acid-base titration and volumetric analysis. It defines key terms like titration, indicator, equivalence point, and standardization. It describes different types of titrations including direct, indirect, and back titration. Acid-base concepts are explained based on Arrhenius, Bronsted-Lowry, and Lewis theories. The document also discusses the ionic product of water, common ion effect, classification of indicators, and theories of indicators including Ostwald and chromophore theories.
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by providing conjugate acid-base pairs that absorb added H+ or OH- ions. There are two main types of buffers: acidic buffers use a weak acid and its salt with a strong base, while basic buffers use a weak base and its salt with a strong acid. The Henderson-Hasselbalch equation relates the pH of a buffer to the pKa of the weak acid/base and the concentrations of the conjugate acid-base pair. Buffer capacity is a measure of a buffer's resistance to pH change and depends on how close the buffer components are to their pKa. Buffers have many applications, including maintaining pH in biological
This document discusses the importance of tonicity and defines hypertonic, hypotonic, and isotonic solutions. It explains that tonicity is a measure of effective osmotic pressure between two solutions separated by a semi-permeable membrane. Hypertonic solutions have a higher concentration than body fluids and cause cells to shrink. Hypotonic solutions have a lower concentration than body fluids and cause cells to swell and burst. Isotonic solutions have the same concentration as body fluids and do not affect cell volume. The document provides examples of different concentration saline, dextrose, and lactated ringer's solutions and their classification as hypertonic, hypotonic or isotonic. It also discusses the importance of solutions being
The document discusses Hydrophilic-Lipophilic Balance (HLB), which is a numerical scale used to represent the hydrophilicity and lipophilicity of surfactants. The HLB scale ranges from 0 to 20 for non-ionic surfactants and up to 50 for ionic surfactants. Surfactants with higher HLB values are more water-soluble and hydrophilic, while those with lower values are more oil-soluble and lipophilic. The HLB concept allows emulsifiers to be selected and blended to produce stable oil-in-water or water-in-oil emulsions for a given oil based on its required HLB value. Formulas are provided to calculate required H
buffer capacity, preparation of buffer and stability of bufferTAUFIK MULLA
This document discusses buffer capacity, preparation, and stability. It defines buffer capacity as the strength to resist pH changes when acid or base is added. Greater buffer capacity means a buffer can tolerate more added acid/base before pH changes. The document provides equations to calculate buffer capacity more exactly. It also discusses how buffers are prepared by combining a weak acid and its salt, or weak base and its salt. Examples like phosphate buffer are given. Finally, it outlines factors that impact buffer stability like proper storage, temperature, and protection from light and microbes. Buffers should maintain pH and not degrade over their typical 1-2 year shelf life.
This document discusses acid-base theories and titration. It covers:
1) Arrhenius, Bronsted-Lowry, and Lewis acid-base theories.
2) Types of acids and bases as strong or weak.
3) The law of mass action and dissociation constants.
4) Neutralization curves for different types of acid-base titrations and the pH at equivalence points.
5) Choice of indicators for different titrations and mixed indicators.
Buffer solutions resist changes in pH upon the addition of small amounts of acid or base through buffer action. A buffer is a combination of a weak acid and its conjugate base. The pH of a buffer solution depends on the ratio of the concentration of the salt to the acid. Factors like the addition of neutral salts, dilution, and temperature can impact the pH of a buffer solution. Buffers have various applications in pharmaceutical formulations to adjust pH for stability and therapeutic effects.
Here are potential responses to the study questions:
Define the following terms:
- Ionization: The process by which an atom or molecule acquires a negative or positive charge by gaining or losing electrons.
- Buffer capacity: The ability of a solution to resist changes in pH upon the addition of an acid or base. It depends on the buffer composition and concentration.
- In-vivo: Occurring or taking place inside a living organism.
Considering a practical process, illustrate the procedural significance of buffer systems in moderation of the reactions of a solution system:
Buffer systems are important in pharmaceutical formulations to maintain the pH within an optimal range for drug stability, solubility, and to minimize irritation upon administration.
This document provides an overview of acid-base titration and volumetric analysis. It defines key terms like titration, indicator, equivalence point, and standardization. It describes different types of titrations including direct, indirect, and back titration. Acid-base concepts are explained based on Arrhenius, Bronsted-Lowry, and Lewis theories. The document also discusses the ionic product of water, common ion effect, classification of indicators, and theories of indicators including Ostwald and chromophore theories.
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by providing conjugate acid-base pairs that absorb added H+ or OH- ions. There are two main types of buffers: acidic buffers use a weak acid and its salt with a strong base, while basic buffers use a weak base and its salt with a strong acid. The Henderson-Hasselbalch equation relates the pH of a buffer to the pKa of the weak acid/base and the concentrations of the conjugate acid-base pair. Buffer capacity is a measure of a buffer's resistance to pH change and depends on how close the buffer components are to their pKa. Buffers have many applications, including maintaining pH in biological
This document discusses the importance of tonicity and defines hypertonic, hypotonic, and isotonic solutions. It explains that tonicity is a measure of effective osmotic pressure between two solutions separated by a semi-permeable membrane. Hypertonic solutions have a higher concentration than body fluids and cause cells to shrink. Hypotonic solutions have a lower concentration than body fluids and cause cells to swell and burst. Isotonic solutions have the same concentration as body fluids and do not affect cell volume. The document provides examples of different concentration saline, dextrose, and lactated ringer's solutions and their classification as hypertonic, hypotonic or isotonic. It also discusses the importance of solutions being
The document discusses Hydrophilic-Lipophilic Balance (HLB), which is a numerical scale used to represent the hydrophilicity and lipophilicity of surfactants. The HLB scale ranges from 0 to 20 for non-ionic surfactants and up to 50 for ionic surfactants. Surfactants with higher HLB values are more water-soluble and hydrophilic, while those with lower values are more oil-soluble and lipophilic. The HLB concept allows emulsifiers to be selected and blended to produce stable oil-in-water or water-in-oil emulsions for a given oil based on its required HLB value. Formulas are provided to calculate required H
buffer capacity, preparation of buffer and stability of bufferTAUFIK MULLA
This document discusses buffer capacity, preparation, and stability. It defines buffer capacity as the strength to resist pH changes when acid or base is added. Greater buffer capacity means a buffer can tolerate more added acid/base before pH changes. The document provides equations to calculate buffer capacity more exactly. It also discusses how buffers are prepared by combining a weak acid and its salt, or weak base and its salt. Examples like phosphate buffer are given. Finally, it outlines factors that impact buffer stability like proper storage, temperature, and protection from light and microbes. Buffers should maintain pH and not degrade over their typical 1-2 year shelf life.
This document discusses acid-base theories and titration. It covers:
1) Arrhenius, Bronsted-Lowry, and Lewis acid-base theories.
2) Types of acids and bases as strong or weak.
3) The law of mass action and dissociation constants.
4) Neutralization curves for different types of acid-base titrations and the pH at equivalence points.
5) Choice of indicators for different titrations and mixed indicators.
This document discusses non-aqueous titrations, including the types of solvents used, endpoint detection methods, and applications. It covers protogenic solvents like acetic acid that can act as both acids and bases, protophilic solvents with high proton affinity, and aprotic solvents like benzene that are inert. Common indicators and titrants used include crystal violet, perchloric acid, and sodium acetate. The document provides examples of using non-aqueous titrations to assay substances like sodium acetate and norfloxacin tablets that are insoluble or reactive in water.
Application of buffers,buffers equation and buffer capacityRajdeepaKundu
This document discusses buffers, buffer capacity, and buffer equations. It defines a buffer as an aqueous solution of a weak acid and its conjugate base that resists changes in pH when a small amount of strong acid or base is added. The key points are:
- Buffers work by maintaining an equilibrium between an acid and its conjugate base
- Buffer capacity is a measure of a buffer's ability to resist pH changes upon addition of acid or base
- The buffer equation relates pH, pKa, and relative concentrations of the acid and conjugate base
- Buffers have important applications in drug formulations, fermentation, blood plasma, and more to maintain stable and optimal pH levels.
Non Aqueous Titration- by Dr. A. AmsavelDr. Amsavel A
This document discusses principles of non-aqueous titration and its applications in pharmaceutical industries. It describes the limitations of aqueous titration and how non-aqueous titration overcomes them. Various types of solvents used in non-aqueous titration are defined including aprotic, protogenic, protophilic and amphiprotic solvents. Acid-base theories, choice of titrants and endpoints, indicators and potentiometric titration are also covered. The document emphasizes the importance of solvent selection and various techniques to improve accuracy in non-aqueous titration.
This document discusses pH determination methods. It defines pH as the negative logarithm of hydrogen ion concentration and describes how Sorensen developed the pH scale in 1909. A pH of 7 is neutral as hydrogen and hydroxide ion concentrations are equal. The document outlines that the glass electrode method measures potential difference using a pH meter to determine pH electrometrically. It also describes colorimetric determination where pH is estimated by comparing color changes of indicators like phenolphthalein in solutions of known pH.
Buffers in pharmaceutical and biological systemBASIT MANZOOR
1. The document discusses buffers in pharmaceutical and biological systems. It describes various buffer systems that function in the human body to maintain blood pH, including bicarbonate-carbonic acid, phosphate, and protein buffers.
2. The bicarbonate-carbonic acid buffer system regulates blood pH through reactions involving sodium bicarbonate, carbonic acid, and water. The phosphate buffer system involves the conversion between sodium dihydrogen phosphate and sodium monohydrogen phosphate through reactions with strong acids and bases.
3. Hemoglobin and proteins also act as buffers, with hemoglobin buffering pH changes during the conversion of carbon dioxide to bicarbonate and proteins buffering pH in blood plasma and within
This document discusses acids, bases, and buffers. It begins by defining acids as substances that release hydrogen ions (H+) in solution and bases as substances that release hydroxide ions (OH-). Water can form acids and bases by dissociating into hydronium and hydroxide ions. Acids and bases are classified as strong or weak based on their degree of dissociation. A buffer is a solution that resists pH changes upon addition of small amounts of acid or base, consisting of a weak acid and its conjugate base or vice versa. The Henderson-Hasselbalch equation relates the pH of a buffer solution to the concentrations and acid dissociation constant. Buffers have various applications in pharmaceutical products to control pH
This document discusses precipitation titration, which involves the formation of an insoluble precipitate during titration. It describes the Mohr, Volhard, and Fajans methods for detecting the endpoint of precipitation titrations using different indicators like chromate, iron, and fluorescein. The Volhard method, which detects the endpoint potentiometrically by titrating excess silver with thiocyanate, is highlighted as being widely used. Limitations and ways to overcome problems of precipitation titration are also outlined.
It is a type of quantitative analysis that involves weighing of the constituent under determination.
Or
It is the process of isolating and weighing an element or compound in a pure form.
Or
Gravimetric methods of analysis are based on the measurement of mass.
Electrogravimetry, we deposit the analyte as a solid film an electrode in an electrochemical cell.
Ex: The deposition as PbO2 at a Pt anode and reduction of Cu2+ to Cu at a Pt cathode is of electrogravimetry.
When thermal or chemical energy is used to remove a volatile species, such method called as Volatilization gravimetry.
Ex: In determining the moisture content of bread, for example, we use thermal energy to vaporize the water in the sample.
Particulate gravimetry we determine the analyte by separating it from the sample’s matrix using a filtration or an extraction. The determination of total suspended solids is one example of particulate gravimetry.
A gravimetric precipitating agent should react specifically, and selectively with the analyte. The ideal precipitating reagent would react with the analyte to give a product that is
Readily filtered and washed free of contaminants
Low solubility so that no significant loss of the solid occurs during filtration and washing
Un-reactive with constituents of the atmosphere
Should not alter the composition after it is dried or, if necessary, ignited.
This document discusses precipitation titration methods. It describes Mohr's method, Volhard's method and Fajan's method. Mohr's method uses potassium chromate as an indicator. Volhard's method indirectly titrates excess silver ions with thiocyanate using ferric ammonium sulfate as an indicator. Fajan's method uses adsorption indicators like fluorescein that change color upon adsorption to the precipitate formed at the endpoint. Key factors that influence precipitation titrations like solubility products, common ion effect and temperature are also discussed.
This document provides information on various types of monophasic liquid dosage forms, including their definitions, advantages, disadvantages, examples, and typical formulation methods. It discusses gargles, mouthwashes, throat paints, ear drops, nasal drops, syrups, elixirs, liniments, and lotions. For each type, it provides a brief description of its use and purpose as well as an example formulation and method.
Buffers are compounds or mixtures
of compounds that by their presence
in the solution resist changes in the
pH upon the addition of small
quantities of acid or alkali.
Buffers resist changes in pH upon the addition of acids or bases. There are two types of buffers: acidic buffers contain a weak acid and its salt, while alkaline buffers contain a weak base and its salt. The buffer equation, also called the Henderson-Hasselbalch equation, relates the pH of a buffer solution to the pKa of the acid or base and the ratio of the concentrations of the conjugate base and acid or base and conjugate acid. Specifically, for acidic buffers the pH equals the pKa plus the log of the ratio of the conjugate base to acid concentrations, and for alkaline buffers the pH equals the pKb plus the log of the ratio of the base to conjugate acid concentrations.
This document discusses precipitation titration methods. It describes the principles of precipitation titration where a titrant forms an insoluble precipitate with the analyte. Common methods like Mohr's, Volhard's, and Fajans are summarized. Factors affecting precipitate solubility and limitations of precipitation titration are also outlined. The document serves to introduce various techniques in precipitation titration.
The document describes the limit test for lead, which determines the allowable limit of heavy metal lead in a sample. The test involves reacting the sample with dithizone, which forms a violet-colored lead dithizonate complex in the presence of lead. The intensity of color in the sample is compared to that of a standard lead solution treated the same way. If the sample solution is less colored than the standard, the sample passes the lead limit test. The test is useful for detecting trace amounts of lead impurity from sources like equipment, storage containers, or packaging materials used during manufacturing or storage of medical compounds.
This document discusses theories of acid-base indicators used in titrations. It describes Ostwald's theory and the quinonoid theory, which attempt to explain the color change of indicators at different pH levels. Ostwald's theory states that indicators exist in ionized and unionized forms with different colors. The quinonoid theory proposes that indicators exist in two tautomeric forms - benzenoid and quinonoid - which are in equilibrium and have different colors. The document uses examples like phenolphthalein and methyl orange to illustrate how each theory explains the color change of common acid-base indicators during titrations.
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by neutralizing added acid or base through chemical reactions. There are two main types of buffers - acidic buffers which use a weak acid and its salt, and basic buffers which use a weak base and its salt. The pH of buffer solutions can be calculated using the Henderson-Hasselbalch equation. Buffer capacity is a measure of a buffer's ability to resist pH changes and depends on the buffer components and their concentrations. Buffers have many important applications, including maintaining the pH of blood and pharmaceutical products.
Buffer solutions resist changes in pH upon addition of small amounts of acid or base. They are made up of a weak acid and its conjugate base. Buffers have important applications in pharmaceutical manufacturing and drug formulations. The pH of buffer solutions and how much they resist pH changes can be calculated using the Henderson-Hasselbalch equation. Factors like temperature, dilution, and addition of salts can impact buffer solutions. Biological fluids also use buffer systems, like bicarbonate buffers in blood and phosphate buffers in tears, to maintain optimal pH ranges.
This document discusses acid-base balance and pH. It defines pH as the negative log of the hydrogen ion concentration. The pH scale ranges from 0 to 14, with values below 7 being acidic and above 7 being basic. The body maintains acid-base balance through buffer systems like bicarbonate and proteins, and respiratory and renal compensation mechanisms. Disturbances in acid-base balance can cause metabolic acidosis, metabolic alkalosis, respiratory acidosis, or respiratory alkalosis.
This document discusses buffer solutions and their properties. It begins by defining a buffer as a solution that resists changes in pH when small amounts of acid or base are added. It then describes the common types of buffer solutions and illustrates buffer action using acetic acid/sodium acetate as an example. The mechanism and function of acidic and basic buffers is explained. It also covers the Henderson-Hasselbalch equation for calculating buffer pH, buffer capacity, and important buffer systems in pharmaceutical and biological contexts like the bicarbonate buffer system in blood.
This document discusses non-aqueous titrations, including the types of solvents used, endpoint detection methods, and applications. It covers protogenic solvents like acetic acid that can act as both acids and bases, protophilic solvents with high proton affinity, and aprotic solvents like benzene that are inert. Common indicators and titrants used include crystal violet, perchloric acid, and sodium acetate. The document provides examples of using non-aqueous titrations to assay substances like sodium acetate and norfloxacin tablets that are insoluble or reactive in water.
Application of buffers,buffers equation and buffer capacityRajdeepaKundu
This document discusses buffers, buffer capacity, and buffer equations. It defines a buffer as an aqueous solution of a weak acid and its conjugate base that resists changes in pH when a small amount of strong acid or base is added. The key points are:
- Buffers work by maintaining an equilibrium between an acid and its conjugate base
- Buffer capacity is a measure of a buffer's ability to resist pH changes upon addition of acid or base
- The buffer equation relates pH, pKa, and relative concentrations of the acid and conjugate base
- Buffers have important applications in drug formulations, fermentation, blood plasma, and more to maintain stable and optimal pH levels.
Non Aqueous Titration- by Dr. A. AmsavelDr. Amsavel A
This document discusses principles of non-aqueous titration and its applications in pharmaceutical industries. It describes the limitations of aqueous titration and how non-aqueous titration overcomes them. Various types of solvents used in non-aqueous titration are defined including aprotic, protogenic, protophilic and amphiprotic solvents. Acid-base theories, choice of titrants and endpoints, indicators and potentiometric titration are also covered. The document emphasizes the importance of solvent selection and various techniques to improve accuracy in non-aqueous titration.
This document discusses pH determination methods. It defines pH as the negative logarithm of hydrogen ion concentration and describes how Sorensen developed the pH scale in 1909. A pH of 7 is neutral as hydrogen and hydroxide ion concentrations are equal. The document outlines that the glass electrode method measures potential difference using a pH meter to determine pH electrometrically. It also describes colorimetric determination where pH is estimated by comparing color changes of indicators like phenolphthalein in solutions of known pH.
Buffers in pharmaceutical and biological systemBASIT MANZOOR
1. The document discusses buffers in pharmaceutical and biological systems. It describes various buffer systems that function in the human body to maintain blood pH, including bicarbonate-carbonic acid, phosphate, and protein buffers.
2. The bicarbonate-carbonic acid buffer system regulates blood pH through reactions involving sodium bicarbonate, carbonic acid, and water. The phosphate buffer system involves the conversion between sodium dihydrogen phosphate and sodium monohydrogen phosphate through reactions with strong acids and bases.
3. Hemoglobin and proteins also act as buffers, with hemoglobin buffering pH changes during the conversion of carbon dioxide to bicarbonate and proteins buffering pH in blood plasma and within
This document discusses acids, bases, and buffers. It begins by defining acids as substances that release hydrogen ions (H+) in solution and bases as substances that release hydroxide ions (OH-). Water can form acids and bases by dissociating into hydronium and hydroxide ions. Acids and bases are classified as strong or weak based on their degree of dissociation. A buffer is a solution that resists pH changes upon addition of small amounts of acid or base, consisting of a weak acid and its conjugate base or vice versa. The Henderson-Hasselbalch equation relates the pH of a buffer solution to the concentrations and acid dissociation constant. Buffers have various applications in pharmaceutical products to control pH
This document discusses precipitation titration, which involves the formation of an insoluble precipitate during titration. It describes the Mohr, Volhard, and Fajans methods for detecting the endpoint of precipitation titrations using different indicators like chromate, iron, and fluorescein. The Volhard method, which detects the endpoint potentiometrically by titrating excess silver with thiocyanate, is highlighted as being widely used. Limitations and ways to overcome problems of precipitation titration are also outlined.
It is a type of quantitative analysis that involves weighing of the constituent under determination.
Or
It is the process of isolating and weighing an element or compound in a pure form.
Or
Gravimetric methods of analysis are based on the measurement of mass.
Electrogravimetry, we deposit the analyte as a solid film an electrode in an electrochemical cell.
Ex: The deposition as PbO2 at a Pt anode and reduction of Cu2+ to Cu at a Pt cathode is of electrogravimetry.
When thermal or chemical energy is used to remove a volatile species, such method called as Volatilization gravimetry.
Ex: In determining the moisture content of bread, for example, we use thermal energy to vaporize the water in the sample.
Particulate gravimetry we determine the analyte by separating it from the sample’s matrix using a filtration or an extraction. The determination of total suspended solids is one example of particulate gravimetry.
A gravimetric precipitating agent should react specifically, and selectively with the analyte. The ideal precipitating reagent would react with the analyte to give a product that is
Readily filtered and washed free of contaminants
Low solubility so that no significant loss of the solid occurs during filtration and washing
Un-reactive with constituents of the atmosphere
Should not alter the composition after it is dried or, if necessary, ignited.
This document discusses precipitation titration methods. It describes Mohr's method, Volhard's method and Fajan's method. Mohr's method uses potassium chromate as an indicator. Volhard's method indirectly titrates excess silver ions with thiocyanate using ferric ammonium sulfate as an indicator. Fajan's method uses adsorption indicators like fluorescein that change color upon adsorption to the precipitate formed at the endpoint. Key factors that influence precipitation titrations like solubility products, common ion effect and temperature are also discussed.
This document provides information on various types of monophasic liquid dosage forms, including their definitions, advantages, disadvantages, examples, and typical formulation methods. It discusses gargles, mouthwashes, throat paints, ear drops, nasal drops, syrups, elixirs, liniments, and lotions. For each type, it provides a brief description of its use and purpose as well as an example formulation and method.
Buffers are compounds or mixtures
of compounds that by their presence
in the solution resist changes in the
pH upon the addition of small
quantities of acid or alkali.
Buffers resist changes in pH upon the addition of acids or bases. There are two types of buffers: acidic buffers contain a weak acid and its salt, while alkaline buffers contain a weak base and its salt. The buffer equation, also called the Henderson-Hasselbalch equation, relates the pH of a buffer solution to the pKa of the acid or base and the ratio of the concentrations of the conjugate base and acid or base and conjugate acid. Specifically, for acidic buffers the pH equals the pKa plus the log of the ratio of the conjugate base to acid concentrations, and for alkaline buffers the pH equals the pKb plus the log of the ratio of the base to conjugate acid concentrations.
This document discusses precipitation titration methods. It describes the principles of precipitation titration where a titrant forms an insoluble precipitate with the analyte. Common methods like Mohr's, Volhard's, and Fajans are summarized. Factors affecting precipitate solubility and limitations of precipitation titration are also outlined. The document serves to introduce various techniques in precipitation titration.
The document describes the limit test for lead, which determines the allowable limit of heavy metal lead in a sample. The test involves reacting the sample with dithizone, which forms a violet-colored lead dithizonate complex in the presence of lead. The intensity of color in the sample is compared to that of a standard lead solution treated the same way. If the sample solution is less colored than the standard, the sample passes the lead limit test. The test is useful for detecting trace amounts of lead impurity from sources like equipment, storage containers, or packaging materials used during manufacturing or storage of medical compounds.
This document discusses theories of acid-base indicators used in titrations. It describes Ostwald's theory and the quinonoid theory, which attempt to explain the color change of indicators at different pH levels. Ostwald's theory states that indicators exist in ionized and unionized forms with different colors. The quinonoid theory proposes that indicators exist in two tautomeric forms - benzenoid and quinonoid - which are in equilibrium and have different colors. The document uses examples like phenolphthalein and methyl orange to illustrate how each theory explains the color change of common acid-base indicators during titrations.
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by neutralizing added acid or base through chemical reactions. There are two main types of buffers - acidic buffers which use a weak acid and its salt, and basic buffers which use a weak base and its salt. The pH of buffer solutions can be calculated using the Henderson-Hasselbalch equation. Buffer capacity is a measure of a buffer's ability to resist pH changes and depends on the buffer components and their concentrations. Buffers have many important applications, including maintaining the pH of blood and pharmaceutical products.
Buffer solutions resist changes in pH upon addition of small amounts of acid or base. They are made up of a weak acid and its conjugate base. Buffers have important applications in pharmaceutical manufacturing and drug formulations. The pH of buffer solutions and how much they resist pH changes can be calculated using the Henderson-Hasselbalch equation. Factors like temperature, dilution, and addition of salts can impact buffer solutions. Biological fluids also use buffer systems, like bicarbonate buffers in blood and phosphate buffers in tears, to maintain optimal pH ranges.
This document discusses acid-base balance and pH. It defines pH as the negative log of the hydrogen ion concentration. The pH scale ranges from 0 to 14, with values below 7 being acidic and above 7 being basic. The body maintains acid-base balance through buffer systems like bicarbonate and proteins, and respiratory and renal compensation mechanisms. Disturbances in acid-base balance can cause metabolic acidosis, metabolic alkalosis, respiratory acidosis, or respiratory alkalosis.
This document discusses buffer solutions and their properties. It begins by defining a buffer as a solution that resists changes in pH when small amounts of acid or base are added. It then describes the common types of buffer solutions and illustrates buffer action using acetic acid/sodium acetate as an example. The mechanism and function of acidic and basic buffers is explained. It also covers the Henderson-Hasselbalch equation for calculating buffer pH, buffer capacity, and important buffer systems in pharmaceutical and biological contexts like the bicarbonate buffer system in blood.
1. This unit covers acid-base chemistry including solutions containing a common ion, buffered solutions, and titrations.
2. Buffered solutions contain relatively large concentrations of a weak acid and its conjugate base or a weak base and its conjugate acid. They resist changes in pH when small amounts of acid or base are added.
3. Titration curves are generated by plotting pH versus volume of titrant added. The pH changes slowly until near the equivalence point, where a small change in titrant produces a large pH change as the ratio of [H+]/[OH-] changes dramatically.
This document discusses buffer solutions, including their definition, examples, and mechanisms of action. It defines a buffer as a solution that resists changes to its pH when small amounts of acid or base are added. Common buffer systems include carbonic acid/sodium bicarbonate and monosodium phosphate/disodium phosphate. The Henderson-Hasselbach equation relates the pH of a buffer solution to the ratio of its conjugate acid and base forms and their pKa values. Buffers in the body include bicarbonate, phosphate, and protein buffers that help maintain blood pH within a narrow range.
Here are the ratios [HA]/[A-] required for each system to yield a pH of 4.30:
Acetic acid (pKa = 4.76): [HA]/[A-] = 1
Benzoic acid (pKa = 4.19): [HA]/[A-] = 1
Phthalic acid (pKa = 2.89): [HA]/[A-] is not possible since the pKa is too low.
The optimal system is acetic acid/sodium acetate since it has a pKa closest to the desired pH of 4.30. This system allows a ratio of [HA]/[A-] = 1, which provides maximum buffering
The document discusses pH and buffers. It defines pH as the negative log of the hydrogen ion concentration. pH is measured on a scale from 0 to 14, with values below 7 being acidic and above 7 being basic. Buffers resist changes in pH when acids or bases are added by using an equilibrium between a weak acid and its conjugate base or vice versa. Common methods for measuring pH include pH strips, pH indicators, and pH meters. The most important buffer system in the body is the carbonic acid-hydrogen carbonate buffer system, which helps maintain pH levels in body fluids.
The document defines key terms related to acid-base balance including acids, bases, pH, buffers, and acidosis and alkalosis. It then discusses the major blood buffer systems that help regulate pH, including the protein, hemoglobin, phosphate, and bicarbonate-carbonic acid systems. The bicarbonate-carbonic acid system functions through the reversible reaction of carbon dioxide and water to form carbonic acid which dissociates into bicarbonate and hydrogen ions. The document also covers respiratory and renal compensation mechanisms that help return pH to normal levels in response to acid-base imbalances through lung and kidney functions.
The document defines key terms related to acid-base balance such as acids, bases, pH, buffers, and acidosis and alkalosis. It describes the four major blood buffer systems - protein, hemoglobin, phosphate, and bicarbonate/carbonic acid. The relationship between pH, bicarbonate, and carbonic acid is explained using the Henderson-Hasselbalch equation. The roles of the lungs and kidneys in regulating pH through respiratory and renal compensation are discussed. The document outlines the characteristics of uncompensated, partially compensated, compensated, and mixed acid-base imbalances.
This document discusses acid-base balance and disorders. It covers 3 key mechanisms to maintain blood pH: 1) blood buffers, 2) respiratory regulation, and 3) renal regulation. The blood's bicarbonate buffer system uses carbonic acid, while tissues also use phosphate and protein buffers. Respiration controls pH by regulating CO2 exhalation. The kidneys compensate for acid-base imbalances over hours by regulating bicarbonate reabsorption and acid excretion. Acid-base disorders include respiratory and metabolic acidosis and alkalosis.
The document discusses pH, buffers, and acid-base balance in the body. It provides information on:
- The definition of pH and how it relates to hydrogen ion concentration. pH ranges from 0-14 with lower values being more acidic and higher more basic.
- Common buffers in the body including the bicarbonate buffer system, hemoglobin buffer system, and phosphate buffer system which help regulate pH.
- How the body maintains acid-base balance through buffering, respiratory compensation, and renal regulation of bicarbonate and acid excretion.
- The four main types of acid-base imbalances: metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alk
Buffers in chemical analysis, types of buffersChirag Patel
- A buffer solution resists changes in pH when small amounts of acid or base are added due to the equilibrium between a weak acid and its conjugate base. Commonly used buffers include a weak acid and the salt of its conjugate base or a weak base and the salt of its conjugate acid.
- Buffers work best when the concentrations of the weak acid and its conjugate base are equal and the pH is within 1 unit of the pKa. Their buffering capacity depends on their concentration and is highest when the pH equals the pKa.
- Common applications of buffers include controlling pH in chemical reactions, biological systems, pools, and more. The carbonic acid-bicarbonate buffer system is particularly important for maintaining
The document discusses pH, buffers, and their importance in maintaining blood pH homeostasis and gastric juice pH. It defines pH as a measure of hydrogen ion concentration and describes the pH scale. It explains how buffers work by achieving resistance to pH change through an equilibrium between a weak acid and its conjugate base. Important buffers mentioned are the bicarbonate buffer system, which maintains blood pH, and the acidic gastric juices, with a pH of 1-3 maintained by secreted hydrochloric acid.
buffers action acids and bases mechanism.pptxsalman91742
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by neutralizing added acid or base. There are two main types of buffers: acidic buffers which use a weak acid and its salt with a strong base, and basic buffers which use a weak base and its salt with a strong acid. The Henderson-Hasselbalch equation can be used to calculate the pH of a buffer solution based on the pKa of the weak acid/base and the concentrations of the components. Buffer capacity is a measure of a buffer's ability to resist pH changes and depends on factors like concentrations. Buffers have many applications including maintaining pH in biological systems like blood and in pharmaceutical formulations.
pH, pH measurement, and buffer solutions can be summarized as follows:
1) pH is a measure of how acidic or basic a solution is, measured on a scale from 0-14. It is determined by the concentration of hydrogen ions [H+] in the solution.
2) pH can be measured using pH strips, pH indicators, or a pH meter. Common pH indicators change color depending on the pH range and can indicate if a solution is acidic or basic.
3) Buffer solutions help maintain pH when small amounts of acid or base are added. They use a weak acid or base combined with its salt. The Henderson-Hasselbalch equation can be used to calculate the pH of buffer solutions
This document discusses acids and bases including definitions, the pH scale, dissociation of weak acids and bases, buffers, and buffering in biological systems. Key points covered include the ionization of water, proton hopping, the definition of pH and pKa, acid-base reactions and conjugate pairs, Henderson-Hasselbalch equation, and examples of buffers in the body.
This document discusses titrations, buffers, and strong-weak acid-base reactions. It defines the equivalence point and endpoint in a titration. It explains how indicators work and which indicators to use for different titration reactions. It also discusses buffer solutions, how they maintain pH, and their importance in biological systems. Key buffer reactions and equations are provided. Finally, it examines the effects of adding a strong acid or base to a buffer solution and defines the buffer capacity.
The document discusses acid-base balance and pH regulation in the blood. It explains that bicarbonate buffering and the roles of the lungs and kidneys are key to maintaining pH. The lungs regulate blood pH through controlling carbon dioxide levels, while the kidneys excrete excess hydrogen ions and help regenerate bicarbonate. Abnormal pH can lead to acidosis or alkalosis, which are stabilized through multiple compensatory mechanisms working together.
Buffers resist changes in pH upon the addition of small amounts of acid or base. They work by providing conjugate acid-base pairs that absorb added H+ or OH- ions. Common buffer systems include acetic acid/sodium acetate and phosphoric acid/sodium phosphate. The Henderson-Hasselbalch equation relates a buffer's pH to the pKa of the acid/base pair and the concentrations of the components. Buffers have important applications in biological systems like blood and pharmaceutical products where a stable and precise pH is required.
This document discusses acid-base balance and buffers. It defines pH and describes strong and weak acids and bases. The key physiological buffers - bicarbonate, phosphate, hemoglobin and proteins/amino acids - are explained in terms of how they maintain blood pH during the addition of acids or bases. The document also covers acid-base imbalance disorders like acidosis and alkalosis, their causes and compensation mechanisms. Arterial blood gases are described as a way to diagnose acid-base disorders. An example case of metabolic acidosis in an infant with diarrhea is analyzed.
A buffer is a solution of a weak acid and its conjugate base (salt) that resists changes in pH in both directions—either up or down, when small quantities of an acid and a base(alkali) are added to it.
Vitamins & vitamin containing drugs manikImran Nur Manik
Vitamins are organic compounds that are essential nutrients for the human body. There are 13 essential vitamins that must be obtained through diet as the body cannot synthesize them. Vitamins play important roles in growth, development, and metabolic processes. Deficiencies can lead to specific diseases. Vitamins can be fat-soluble like A, D, E and K which are stored in the body, or water-soluble like the B vitamins and C which are not stored. Dietary sources and functions of several key vitamins are discussed.
Standardization of Acids and bases.
2. Determination of pKa and pKb values
3. Preparation of solutions of different pH & buffer capacities.
4. Determination of phase diagram of binary systems.
Determination of distribution coefficients.
6. Determination of molecular weight by Victor Meyer’s Method.
7. Determination of heats of solutions by measuring solubility as a function of temperature
(Van’t Hoff equation.)
A. Qualitative analysis of metal ions and acid radicals:
Na+, K+, Ca+2, Ag+, Mn+4, Fe+2, Fe+3, Co+2, Mg+2, Al+3, Cu+2 and acid radicals CO3,
halides, Citrate
SO4-2, NO3-, SO3-2, etc.
B. Identification of inorganic drugs in their formulation:
1. Ca+2, from supplied preparations
2. Fe+2 from supplied preparations
3. Al+3 from supplied preparations
4. Mg+2 from supplied preparations
5. K+ from supplied reparations
6. Na+ from supplied preparations
C. Conversion of different water insoluble or sparingly soluble drugs into water soluble
forms:
1. Na/ K – salicylate from salicylic acid
2. Na/ K – benzoate from benzoic acid
3. Na/ K – citrate from citric acid
Plants in complimentary and traditional systems of medicine MANIKanikImran Nur Manik
Plants in complimentary and traditional systems of medicine: Introduction-different types of
alternative systems of treatments (e.g. Ayurvedic, Unani and Homeopathic medicine). Contribution
of traditional drugs to modern medicines. Details of some common indigenous traditional drugs:
Punarnava, Vashaka, Anantamul, Arjuna, Chirata, Picrorhiga, Kalomegh, Amla, Asoka, Bahera,
Haritaki, Tulsi, Neem, Betel nut, Joan, Karela, Shajna, Carrot, Bael, Garlic, Jam and Madar.
This document provides information about various lipids (fats and oils) obtained from plants and animals. It discusses the basic chemistry of lipids, describing them as esters of fatty acids and alcohols. Specific lipids are then outlined, including their source, composition, properties, and some uses. Key lipids discussed include olive oil, coconut oil, castor oil, linseed oil, peanut oil, chaulmoogra oil, and beeswax.
Pharmacognosy is the study of medicinal plants and natural products. The term was introduced in 1815 and comes from Greek roots meaning "drug" and "knowledge." It involves the study of plants as potential drug sources from pre-historic use through various civilizations like Chinese, Babylonian, Egyptian, Indian, and Greek. Modern pharmacognosy has broad applications in medicine, agriculture, cosmetics, and other industries and offers career opportunities in academia, private industry, and government.
Crude drugs: A general view of their origin, distributions, cultivation, collection, drying and
storage, commerce and quality control.
a) Classification of drugs.
b) Preparation of drugs for commercial market
c) Evaluation of crude drugs.
d) Drug adulteration.
Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen. They play a vital role in life and include monosaccharides (simple sugars), disaccharides, and polysaccharides. Common monosaccharides are glucose and fructose. Sucrose is a prevalent disaccharide composed of glucose and fructose. Starch and cellulose are examples of polysaccharides. Carbohydrates serve important functions and some like glucose are used as nutrients. Tests can identify the presence of carbohydrates and their type.
The document discusses alkaloids, which are nitrogen-containing plant compounds. It defines alkaloids and explains that they are difficult to define precisely due to overlapping properties with other amines. It then covers the distribution of various alkaloids in different plant parts, their chemical properties, pharmacological actions, classification based on ring structure, extraction methods, and chemical tests to identify alkaloids.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
Students should calculate the time allotted per mark on their exam to help manage their time efficiently. For example, a 40 mark exam in 2.25 hours means each mark is worth 3 minutes and 22 seconds. Students should also practice solving previous years' exam questions and ensure they have the proper stationaries like pens, pencils, erasers and papers like admit cards for their exam. Proper preparation of time management and materials can help students complete their written exams successfully.
Volatile oils and related terpenoids-Methods of obtaining volatile oils,
chemistry, their medicinal and commercial uses, biosynthesis of some important
volatile oils used as drugs.
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7shruti jagirdar
Unit 4: MRA 103T Regulatory affairs
This guideline is directed principally toward new Molecular Entities that are
likely to have significant use in the elderly, either because the disease intended
to be treated is characteristically a disease of aging ( e.g., Alzheimer's disease) or
because the population to be treated is known to include substantial numbers of
geriatric patients (e.g., hypertension).
BBB and BCF
control the entry of compounds into the brain and
regulate brain homeostasis.
restricts access to brain cells of blood–borne compounds and
facilitates nutrients essential for normal metabolism to reach brain cells
Congestive Heart failure is caused by low cardiac output and high sympathetic discharge. Diuretics reduce preload, ACE inhibitors lower afterload, beta blockers reduce sympathetic activity, and digitalis has inotropic effects. Newer medications target vasodilation and myosin activation to improve heart efficiency while lowering energy requirements. Combination therapy, following an assessment of cardiac function and volume status, is the most effective strategy to heart failure care.
Pictorial and detailed description of patellar instability with sign and symptoms and how to diagnose , what investigations you should go with and how to approach with treatment options . I have presented this slide in my 2nd year junior residency in orthopedics at LLRM medical college Meerut and got good reviews for it
After getting it read you will definitely understand the topic.
Allopurinol, a uric acid synthesis inhibitor acts by inhibiting Xanthine oxidase competitively as well as non- competitively, Whereas Oxypurinol is a non-competitive inhibitor of xanthine oxidase.
Discover the benefits of homeopathic medicine for irregular periods with our guide on 5 common remedies. Learn how these natural treatments can help regulate menstrual cycles and improve overall menstrual health.
Visit Us: https://drdeepikashomeopathy.com/service/irregular-periods-treatment/
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)MuskanShingari
Statistics- Statistics is the science of collecting, organizing, presenting, analyzing and interpreting numerical data to assist in making more effective decisions.
A statistics is a measure which is used to estimate the population parameter
Parameters-It is used to describe the properties of an entire population.
Examples-Measures of central tendency Dispersion, Variance, Standard Deviation (SD), Absolute Error, Mean Absolute Error (MAE), Eigen Value
Giloy in Ayurveda - Classical Categorization and SynonymsPlanet Ayurveda
Giloy, also known as Guduchi or Amrita in classical Ayurvedic texts, is a revered herb renowned for its myriad health benefits. It is categorized as a Rasayana, meaning it has rejuvenating properties that enhance vitality and longevity. Giloy is celebrated for its ability to boost the immune system, detoxify the body, and promote overall wellness. Its anti-inflammatory, antipyretic, and antioxidant properties make it a staple in managing conditions like fever, diabetes, and stress. The versatility and efficacy of Giloy in supporting health naturally highlight its importance in Ayurveda. At Planet Ayurveda, we provide a comprehensive range of health services and 100% herbal supplements that harness the power of natural ingredients like Giloy. Our products are globally available and affordable, ensuring that everyone can benefit from the ancient wisdom of Ayurveda. If you or your loved ones are dealing with health issues, contact Planet Ayurveda at 01725214040 to book an online video consultation with our professional doctors. Let us help you achieve optimal health and wellness naturally.
CLASSIFICATION OF H1 ANTIHISTAMINICS-
FIRST GENERATION ANTIHISTAMINICS-
1)HIGHLY SEDATIVE-DIPHENHYDRAMINE,DIMENHYDRINATE,PROMETHAZINE,HYDROXYZINE 2)MODERATELY SEDATIVE- PHENARIMINE,CYPROHEPTADINE, MECLIZINE,CINNARIZINE
3)MILD SEDATIVE-CHLORPHENIRAMINE,DEXCHLORPHENIRAMINE
TRIPROLIDINE,CLEMASTINE
SECOND GENERATION ANTIHISTAMINICS-FEXOFENADINE,
LORATADINE,DESLORATADINE,CETIRIZINE,LEVOCETIRIZINE,
AZELASTINE,MIZOLASTINE,EBASTINE,RUPATADINE. Mechanism of action of 2nd generation antihistaminics-
These drugs competitively antagonize actions of
histamine at the H1 receptors.
Pharmacological actions-
Antagonism of histamine-The H1 antagonists effectively block histamine induced bronchoconstriction, contraction of intestinal and other smooth muscle and triple response especially wheal, flare and itch. Constriction of larger blood vessel by histamine is also antagonized.
2) Antiallergic actions-Many manifestations of immediate hypersensitivity (type I reactions)are suppressed. Urticaria, itching and angioedema are well controlled.3) CNS action-The older antihistamines produce variable degree of CNS depression.But in case of 2nd gen antihistaminics there is less CNS depressant property as these cross BBB to significantly lesser extent.
4) Anticholinergic action- many H1 blockers
in addition antagonize muscarinic actions of ACh. BUT IN 2ND gen histaminics there is Higher H1 selectivitiy : no anticholinergic side effects
The Children are very vulnerable to get affected with respiratory disease.
In our country, the respiratory Disease conditions are consider as major cause for mortality and Morbidity in Child.
Nutritional deficiency Disorder are problems in india.
It is very important to learn about Indian child's nutritional parameters as well the Disease related to alteration in their Nutrition.
Storyboard on Acne-Innovative Learning-M. pharm. (2nd sem.) CosmeticsMuskanShingari
Acne is a common skin condition that occurs when hair follicles become clogged with oil and dead skin cells. It typically manifests as pimples, blackheads, or whiteheads, often on the face, chest, shoulders, or back. Acne can range from mild to severe and may cause emotional distress and scarring in some cases.
**Causes:**
1. **Excess Oil Production:** Hormonal changes during adolescence or certain times in adulthood can increase sebum (oil) production, leading to clogged pores.
2. **Clogged Pores:** When dead skin cells and oil block hair follicles, bacteria (usually Propionibacterium acnes) can thrive, causing inflammation and acne lesions.
3. **Hormonal Factors:** Fluctuations in hormone levels, such as during puberty, menstrual cycles, pregnancy, or certain medical conditions, can contribute to acne.
4. **Genetics:** A family history of acne can increase the likelihood of developing the condition.
**Types of Acne:**
- **Whiteheads:** Closed plugged pores.
- **Blackheads:** Open plugged pores with a dark surface.
- **Papules:** Small red, tender bumps.
- **Pustules:** Pimples with pus at their tips.
- **Nodules:** Large, solid, painful lumps beneath the surface.
- **Cysts:** Painful, pus-filled lumps beneath the surface that can cause scarring.
**Treatment:**
Treatment depends on the severity and type of acne but may include:
- **Topical Treatments:** Such as benzoyl peroxide, salicylic acid, or retinoids to reduce bacteria and unclog pores.
- **Oral Medications:** Antibiotics or oral contraceptives for hormonal acne.
- **Procedures:** Such as chemical peels, extraction of comedones, or light therapy for more severe cases.
**Prevention and Management:**
- **Cleanse:** Regularly wash skin with a gentle cleanser.
- **Moisturize:** Use non-comedogenic moisturizers to keep skin hydrated without clogging pores.
- **Avoid Irritants:** Such as harsh cosmetics or excessive scrubbing.
- **Sun Protection:** Use sunscreen to prevent exacerbation of acne scars and inflammation.
Acne treatment can take time, and consistency in skincare routines and treatments is crucial. Consulting a dermatologist can help tailor a treatment plan that suits individual needs and reduces the risk of scarring or long-term skin damage.
Storyboard on Acne-Innovative Learning-M. pharm. (2nd sem.) Cosmetics
Buffer capacity MANIK
1.
2. An unbuffered solution
or a buffered solution
acid added base added
acid added base added
Md. Imran Nur Manik
3. A buffer solution is a solution which resists changes in pH when a
small amount of acid or base is added.
The resistive action is the result of equilibrium between the weak acid
(HA) and its conjugate base (A-).
HA(aq) + H2O(l) → H3O+
(aq) + A-
(aq)
Typically a mixture of a weak acid and a salt of its conjugate base or weak base and a salt of its
conjugate acid.Md. Imran Nur Manik
4. Two types :
ACIDIC BUFFERS –
Solution of a mixture of a weak acid and a salt of this
weak acid with a strong base.
e.g. CH3COOH + CH3COONa
( weak acid ) (Salt )
BASIC BUFFERS –
Solution of a mixture of a and a
e.g +
( Weak base) ( Salt)
Md.ImranNurManik
5. HOW BUFFERS WORK
Equilibrium between acid and base.
Example: ACETATE BUFFER
CH3COOH⇌CH3COO ⎯ +H+
CH3COONa⇌CH3COO⎯+Na+
If more H+ is added to this solution, it simply shifts the equilibrium
to the left, absorbing H+, so the [H+] remains unchanged.
If H+ is removed (e.g. by adding OH ⎯) then the equilibrium shifts to
the right, releasing H+ to keep the pH constant
Md.ImranNurManik
6. Equilibrium between acid and base.
Example: Basic Buffer
NH4OH⇌NH4
++ OH⎯
NH4Cl ⇌NH4
++ Cl⎯
If more OH⎯ is added to this solution, it simply shifts the equilibrium
to the left, absorbing OH⎯ , so the [OH⎯] remains unchanged.
If OH⎯ is removed (e.g. by adding H+) then the equilibrium shifts to
the right, releasing OH⎯ to keep the pH constant
HOW BUFFERS WORK (CONT..)
Md.ImranNurManik
7. HANDERSON HASSELBALCH EQUATION
Lawrence Joseph Henderson wrote an
equation, in 1908, describing the use
of carbonic acid as a buffer solution.
Karl Albert Hasselbalch later re-expressed
that formula in logarithmic terms, resulting in
the Henderson–Hasselbalch equation.
Md.ImranNurManik
8. Ka =
[H+] [A-]
[HA]
Take the -log on both sides
The Henderson-Hasselbalch Equation derivation
-log Ka = -log [H+] -log
[A-]
[HA]
pH = pKa + log
[A-]
[HA] = pKa + log
[Salt]
[Acid]
HA H+ + A-
pKa = pH-log
[A-]
[HA]
Apply p(x) = -log(x)
And finally solve for pH…
Md.ImranNurManik
9. Problem: Find the pH of a buffer solution containing 0.20 mole per litre CH3COONa
and 0.15 mole per litre CH3COOH. Ka for acetic acid is 1.8 10–5.
Problem: Calculate the concentration of acetic acid to be added to a 0.1 M solution of
sodium acetate to give a buffer of pH 5 (pKa of acetic acid=4.66).
Problem: The Ka of propionic acid is 1.34×10–5. What is the pH of a solution containing
0.5M propionic acid, C2H5COOH, and 0.5 sodium propionate, C2H5COONa. What
happens to the pH of this solution when volume is doubled by the addition of water?
Problem: A buffer solution contains 0.015 mole of ammonium hydroxide and 0.025 mole
of ammonium chloride. Calculate the pH value of the solution. Dissociation constant of
NH4OH at the room temperature is 1.80×10–5
Problem: Estimate the pH at 25°C containing 0.10 M sodium acetate and 0.03 M
acetic acid pKa for CH3COOH = 4.57.
10. Buffer capacity is a measure of the efficiency of a buffer, in resisting
changes in pH. The buffer capacity is defined as
It is also known as buffer efficiency,
buffer index, and buffer value.
Conventionally, the buffer capacity (β) is expressed as
A buffer solution can resist a small amount of change of pH on adding acid
or alkali to the solution. Buffer capacities ranging from 0.01-0.1 are usually
adequate for most pharmaceutical solutions.
11. In 1922, Van Slyke first introduced an approximate equation to determine the buffer capacity by
the following equation:
In which β = Buffer capacity, delta Δ=a finite change, and ΔB =the small increment in gram
equivalents (gEq)/litre of strong base added to the buffer solution to produce a pH change of ΔpH.
According to equation, the buffer capacity of a solution has a value of 1 when the addition of 1 g
Eq of strong base (or acid) to 1 litre of the buffer solution results in a change of 1 pH unit.
The higher the buffer capacity the less the buffer solution changes its pH.
A more exact equation for buffer capacity: The buffer capacity calculated from above
equation is only approximate. It gives the average buffer capacity over the increment of base added.
Koppel and Spiro and Van Slyke developed a more exact equation,
Where, C = the total buffer concentration (i.e. the sum of the molar concentrations of acid and
salt).
12. Body fluids contain buffering agents and buffer systems that maintain pH
at or near pH=7.4. Important endogenous (natural) buffer systems include
carbonic acid/sodium bicarbonate and sodium phosphate in the
plasma and haemoglobin, and potassium phosphate in the cells.
An in vivo value of pH < 6.9 or pH > 7.8 can be life threatening.
Pharmaceutical solutions generally have a low buffer capacity in order to
prevent overwhelming the body’s own buffer systems and significantly
changing the pH of the body fluids. Buffer concentrations of between 0.05
and 0.5 M and buffer capacities between 0.01 to 0.1 are usually sufficient
for pharmaceutical solutions.
14. H2CO3⇌ H++HCO3
–
The pH of blood is controlled by a bicarbonate (H2CO3/HCO3
–) buffer system. When the pH gets too
high (high OH concentration), the OH– reacts with carbonic acid (H2CO3) to form HCO3
–) and H2O.
When the pH gets too low (high H+ concentration), the H+ reacts with HCO3
– to form H2CO3. Because
H2CO3 is a weak acid, the H+ stays associated with the H2CO3. Since pH is an important factor in
many physiological processes, a change in the blood pH is a potentially life threatening condition
requiring immediate regulation.
The pH of blood:
The HCO3
-/H2CO3 buffer system is present in blood in greatest concentration and is very important in
maintaining the pH of blood within normal limit. The concentration of HCO3
- and H2CO3 in blood are
0.02M and 0.00125M respectively and hence the [HCO3
-]/[H2CO3] ratio is 20/1. In blood, the pKa
value for first ionization stage at body temperature is 6.1.
pH = pKa + Log [salt]/[Acid]
= 6.1+ Log20/1= 6.1+1.2=7.4
The phosphoric and protein buffers of plasma are of relatively little important as compared with
bicarbonate buffer in regulating pH.
15. Buffer is very important for biological system. Some of the pictures are as follows
1. Buffer maintains constant [H+] in the body required for optimum cellular activity.
2. The pH of blood (around 7.4) is controlled by a bicarbonate (H2CO3/HCO3
–) buffer system.
3. The phosphate buffer system (HPO4
2-/H2PO4
-) plays a role in plasma and erythrocytes.
H2PO4
-+H2O⇌H3O++HPO4
2-
M/A: Any acid reacts with monohydrogen phosphate to form dihydrogen phosphate
HPO4
2- + H3O+ H2PO4
- + H2O
monohydrogen phosphate dihydrogen phosphate
The base is neutralized by dihydrogen phosphate
H2PO4
- + OH- HPO4
2- + H3O+
dihydrogen phosphate monohydrogen phosphate
4. Proteins as a buffer: Proteins contain –COO- groups, which, like acetate ions (CH3COO-), can act as proton
acceptors. Proteins also contain –NH3
+ groups, which, like ammonium ions (NH4
+), can donate protons.
M/A: If acid comes into blood, hydronium ions can be neutralized by the –COO- groups
-COO- + H3O+- COOH + H2O
If base is added, it can be neutralized by the –NH3
+ groups
-NH3
+ + OH-- NH2 + H2O
16. PROTEIN BUFFER SYSTEM
Proteins are very large, complex molecules in
comparison to the size and complexities of acids or
bases
Proteins are surrounded by a multitude of negative
charges on the outside and numerous positive charges
in the crevices of the molecule
-
-
-
- - - -
-
-
-
-
-
----------
---
-
-
-
-
- - - -
+
+++
+
+
+
+
++
+
+
+
++ +
+
+
+
+
+
+
+ +
+
Md. Imran Nur Manik
17. PROTEIN BUFFER SYSTEM
H+ ions are attracted to and held from chemical
interaction by the negative charges
-
-
-
- - - -
-
-
-
-
-
----------
---
-
-
-
-
- - - -
+
+++
+
+
+
+
++
+
+
+
++ +
+
+
+
+
+
+
+ +
+
H+
H+
H+
H+ H+ H+ H+ H+ H+ H+
H+
H+
H+
H+
H+H+H+H+H+H+H+
Md. Imran Nur Manik
18. PROTEIN BUFFER SYSTEM
OH- ions which are the basis of alkalosis are attracted
by the positive charges in the crevices of the protein
-
-
-
- - - -
-
-
-
-
-
----------
---
-
-
-
-
- - - -
+
+++
+
+
+
+
++
+
+
+
++ +
+
+
+
+
+
+
+ +
+
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-OH-
OH-
OH-
Md. Imran Nur Manik
20. To prepare a pharmaceutical buffer solution having definite pH and capacity, the pharmacist should maintain the
following steps:
1. Select a weak acid having a pKa approximately equal to the pH at which the buffer is to be used. This will
ensure maximum buffer capacity.
2. From the buffer equation, calculate the ratio of salt and weak acid required to obtain the desired pH. (4-10)
3. Consider the individual concentrations of buffer salt and acid needed to obtain a suitable buffer capacity.
(A concentration of 0.05 to 0.5M is usually sufficient; and a buffer capacity of 0.01 to 0.1 is generally adequate.)
4. Other factors of some importance in the choice of a pharmaceutical buffer include-
• Availability of chemicals
• Sterility of the final solution
• Stability of the drug and buffer on aging
• Cost of materials
• Freedom from toxicity
e.g. a borate buffer, because of its toxic effects cannot be used to stabilize a solution to be administered orally or
parenterally.
5. Finally, one should determine the pH and buffer capacity of the completed buffer solution using a reliable pH
meter.
21. Osmotic Pressure
The flow of the solvent through a semipermeable membrane
from pure solvent to solution or from a dilute solution to
concentrated solution is termed osmosis (Greek Osmos means
“to push”.)
Osmotic pressure may be defined as the external pressure
applied to the solution in order to stop the osmosis of the solvent
into the solution separated by a semipermeable membrane.
A membrane which is permeable to solvent and not to solute is
called semipermeable membrane.
Animal and vegetable membranes are not completely semipermeable. Cupric
ferrocyanide, Cu2Fe(CN)6, membrane deposited in the walls of porous pot is
perfectly a semipermeable membrane.
Md. Imran Nur Manik
22. The flow of the solvent through a semipermeable membrane from pure solvent to solution or
from a dilute solution to concentrated solution is termed osmosis.
Osmotic pressure (π) may be defined as the external pressure applied to the solution in
order to stop the osmosis of the solvent into the solution separated by a semipermeable
membrane.
Isotonic Solutions
Solutions having the same osmotic pressure are said to be isotonic. In terms of physiological
fluids, the solutions having osmotic pressure equal to the osmotic pressure of intracellular
fluid is called isotonic solution.
(πsoln = πcell)
In pharmacy and medical science, isotonic solution is that solution; which have equal tonicity
with body fluid i.e. blood, serum, plasma or lacrimal fluid. 0.9% NaCl solution is also
regarded as isotonic solution.
23. Hypertonic Solutions
As compared to the blood plasma if a solution has higher osmotic pressure is said to be hypertonic
solution. (πsoln >πcell).
Physiological solutions having a greater osmotic pressure than that of body fluid or 0.9% NaCl
solution is referred to as hypertonic solution.
Hypotonic Solutions
As compared to the blood plasma if a solution has lower osmotic pressure is said to be hypotonic
solution. (πsoln <πcell).
Physiological solutions with an osmotic pressure lower than that of body fluid or 0.9% NaCl solution
is referred to as hypertonic solution.
Paratonic Solutions
The solution that is not isotonic that means both the hypertonic and hypotonic solutions are
called paratonic solution.
24. Effect of tonicity on body( Injection on blood)
The solutions which are not isotonic with plasma may be harmful to use. On
injecting the hypotonic solutions into blood stream, it may enter the blood cells
in an attempt to produce equilibrium, the cells swells rapidly until they
burst leading to hemolysis. As this damage is irreversible may lead to serious
danger to RBC.
When hypertonic solution is injected into the blood stream, the water comes
out of the membrane of RBC in order to reach equilibrium. The cells shrink
leading to crenulation which is only a temporary damage. When the osmotic
pressure of two solutions becomes equal the damaged cells will come to its
original position. Hence hypertonic solutions may therefore be administered
without permanent damage to the blood cells. They should be injected slowly
to ensure rapid dilution into the blood stream and to minimize the crenulation
of blood cells.
25. Calculation for the Preparation of Isotonic Solutions
For the preparation of isonotic solutions, the quantities of substances to be added may
be calculated by the following methods:
1. Based on the freezing point data (Freezing point depression).
2. Based on molecular concentration.
3. Based on Sodium Chloride equivalents.
4. Graphical method based on vapor pressure and freezing point determinations.
Method: Based on freezing point depression.
The freezing point is a colligative property often used in the calculation of the isotonic
solution as it can be measured easily and accurately. The temperature at which blood
plasma and tears (Lacrhrymal secretions) freeze is –0.52ºC which is the same value
of a 0.9% solution of NaCl. All solutions which freeze at –0.52ºC will be isotonic with
blood plasma and lachrymal fluid.
The freezing points are usually expressed in terms of 1% solutions.
26. The quantity of needed for making the solutions isotonic with
blood plasma may be calculated from the general formula given below:
Percentage W/V of needed=
Where, a= freezing point depression of unadjusted solution.
b= freezing point depression of 1% W/V of the .
Problem: Find out the concentration of required to render or make a
1% solution of cocaine hydrochloride isotonic with blood plasma. The freezing point of 1%
W/V solution of cocaine hydrochloride is –0.090ºC and that of NaCl is
–0.576ºC.
Problem: Find out the concentration of required to render or make a
1.5% solution of proocaine hydrochloride isotonic with blood plasma. The freezing
point of 1% W/V solution of proocaine hydrochloride is –0.122ºC and that of is
–0.576ºC.
27. Method: Based on Sodium Chloride Equivalents
This method has gained popularity. NaCl method is defined as the
weight of solution chloride which will produce the same osmotic
effect as 1 g of the drug to prepare an isotonic solution.
Formulla: Percentage of NaCl for adjustment to
isotonicity=0.9–Percent strength of drug solutionNaCl eqivalent of
the the drug.
Problem: Calculate the percentage of KNO3 required to make
a 0.5% isotonic solution of AgNO3.The NaCl equivalent of KNO3
is 0.56 and NaCl equivalent of AgNO3 is 0.33.
Hints: 0.9-(0.50.33)=0.735÷0.56=1.313%
Md. Imran Nur Manik