Hydrophilic- Water loving / Oil hating
Hydrophobic- Water hating / Oil loving
Surfactants are amphiphilic molecules composed of a hydrophilic or polar moiety known as head and a hydrophobic or nonpolar moiety known as tail.
The nature and number of polar and nonpolar groups – Hydrophilic, Lipophillic or somewhere in between.
Example - Alcohols, Amines and Acids Changes from hydrophilic to Lipophillic as carbons atoms increasing in their alkyl chain.
Microemulsion is an isotropic mixture of oil, surfactant, Cosurfactant and drug.
Upon mild agitation followed by dilution in aqueous media, such as gastrointestinal (GI) fluids, the systems can form fine oil in water (O/W) Microemulsions which usually have a droplet size less than 100 nm.
Microemulsion have been successfully used to improve the solubility, chemical stability, and oral bioavailability of many poorly water soluble drugs.
They have characteristic properties such as a low interfacial tension, large interfacial area and capacity to solubilize both aqueous and oil-soluble compounds.
Hydrophilic- Water loving / Oil hating
Hydrophobic- Water hating / Oil loving
Surfactants are amphiphilic molecules composed of a hydrophilic or polar moiety known as head and a hydrophobic or nonpolar moiety known as tail.
The nature and number of polar and nonpolar groups – Hydrophilic, Lipophillic or somewhere in between.
Example - Alcohols, Amines and Acids Changes from hydrophilic to Lipophillic as carbons atoms increasing in their alkyl chain.
Microemulsion is an isotropic mixture of oil, surfactant, Cosurfactant and drug.
Upon mild agitation followed by dilution in aqueous media, such as gastrointestinal (GI) fluids, the systems can form fine oil in water (O/W) Microemulsions which usually have a droplet size less than 100 nm.
Microemulsion have been successfully used to improve the solubility, chemical stability, and oral bioavailability of many poorly water soluble drugs.
They have characteristic properties such as a low interfacial tension, large interfacial area and capacity to solubilize both aqueous and oil-soluble compounds.
Surfactants and their applications in pharmaceutical dosage formMuhammad Jamal
This presentation is very much helpful for the medical students,pharmacists, researchers and other health care providers. i hope it will provide important information regarding surfactants and their applications in pharmaceutical dosage forms.
SURFACTANT (SURFACE ACTIVE AGENT)AND CLASSIFICATION.pptxRAHUL PAL
surfactant, also called surface-active agent, substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surfactants help the dye penetrate the fabric evenly.
A micelle is an aggregate of surfactant molecules dispersed in a liquid colloid.
A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic tail regions in the micelle centre. This type of micelle is known as a normal phase micelle (oil-in-water micelle).
Inverse micelles have the head groups at the centre with the tails extending out (water-in-oil micelle).
SURFACE TENSION, INTERFACIAL TENSION, SURFACE FREE ENERGY, Measurement of surface and interfacial tension-capillary rise method, drop number method, drop weight method, Du Nuoy tensiometer method, Spreading of liquids, spreading coefficient, surface active agents, hydrophilic-lipophilic balance, soluble monolayers, Adsorption on solid surface, Isotherms
Intermediate state of mesophases & halfway between isotropic liquid &solid crystal.
In solid crystal, basic unit display translational long range order, with center of molecule located on crystal lattice &display orientational order.
In isotropic liquid, basic unit do not preset positional or orientational long rang order.
In past fifty years, there has been a tremendous growth in the field of surfactants. The term surfactants include emulsifiers, wetting agents, suspending agents, detergents, anti-foam compounds and many others.
Therefore, there classification is very important to choose suitable surfactant to give maximum effect.
William Griffin, in the late 1940s, introduced the Hydrophilic-Lipophilic Balance system (HLB) as a way of figuring out which emulsifier would work best with the oil phase of an emulsified product
Surfactants and their applications in pharmaceutical dosage formMuhammad Jamal
This presentation is very much helpful for the medical students,pharmacists, researchers and other health care providers. i hope it will provide important information regarding surfactants and their applications in pharmaceutical dosage forms.
SURFACTANT (SURFACE ACTIVE AGENT)AND CLASSIFICATION.pptxRAHUL PAL
surfactant, also called surface-active agent, substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surfactants help the dye penetrate the fabric evenly.
A micelle is an aggregate of surfactant molecules dispersed in a liquid colloid.
A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic tail regions in the micelle centre. This type of micelle is known as a normal phase micelle (oil-in-water micelle).
Inverse micelles have the head groups at the centre with the tails extending out (water-in-oil micelle).
SURFACE TENSION, INTERFACIAL TENSION, SURFACE FREE ENERGY, Measurement of surface and interfacial tension-capillary rise method, drop number method, drop weight method, Du Nuoy tensiometer method, Spreading of liquids, spreading coefficient, surface active agents, hydrophilic-lipophilic balance, soluble monolayers, Adsorption on solid surface, Isotherms
Intermediate state of mesophases & halfway between isotropic liquid &solid crystal.
In solid crystal, basic unit display translational long range order, with center of molecule located on crystal lattice &display orientational order.
In isotropic liquid, basic unit do not preset positional or orientational long rang order.
In past fifty years, there has been a tremendous growth in the field of surfactants. The term surfactants include emulsifiers, wetting agents, suspending agents, detergents, anti-foam compounds and many others.
Therefore, there classification is very important to choose suitable surfactant to give maximum effect.
William Griffin, in the late 1940s, introduced the Hydrophilic-Lipophilic Balance system (HLB) as a way of figuring out which emulsifier would work best with the oil phase of an emulsified product
The hydroxy ethelene chain, which is quite long and slightly hydrophilic is coiled in a solution and binds water due to the entropy effect.
At a given temperature and concentration, the miscelles of a surfactant are mono disperse.
When the surfactant molecules in the water-air interface become so packed in the monolayer that no more molecules can be accommodated with ease, they agglometrate in the bulk of the solution leading to the formation of aggregates , are known as Miscelles.
The Miscelle concentration increases with the total surfactant concentration.
Upon completion of module on Google classroom you will able to
1. Understand concept of Google Classroom.
2. Create your own class using Google Classroom.
3. Invite students and teachers to join Google Class.
4. Add topics and course content in Classroom.
5. Create and conduct assignments for students.
6. Post announcements and notices.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
263778731218 Abortion Clinic /Pills In Harare ,sisternakatoto
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micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
1. Surfactants
Mr. K. K. Mali
Assistant Professor,
YSPM’s Yashoda Technical Campus, Satara
2. CONTENTS
Introduction of surfactant
Classification of Surfactant
Properties of surfactant
Phase behaviour of Surfactant
3. INTRODUCTION
Surface active agents
Lowers surface tension of water
Any material that makes a surface contribution to the free energy of
the surface phase of two component system.
Surfactants is a Amphiphilic compound that
Is soluble in at least one phase of system
Forms oriented monolayers at phase interface
Exhibits equilibrium concentrations at phase interfaces higher than those in
the bulk solution & forms micelles at specific concentration.
Exhibits characters- detergency, foaming, wetting, emulsifying, solubilizing
& dispersing
Tail or hydrophobic group this group is usually hydrocarbon (alkyl)
chain
Head or hydrophilic group can be neutral or charged
4. INTRODUCTION
Their surface activity arises from
adsorption at the solution air interface –
the means by which the hydrophobic
region of the molecule ‘escapes’ from
the hostile aqueous environment by
protruding into the vapour phase above.
Adsorption at the interface between
aqueous and nonaqueous solutions
occurs in such a way that the
hydrophobic group is in the solution in
the nonaqueous phase, leaving the
hydrophilic group in contact with the
aqueous solution.
6. SURFACE AND INTERFACIAL TENSION;
SURFACE AND INTERFACIAL FREE ENERGY
‘‘surface’’ is usually reserved for the region between a condensed phase
(liquid or solid) and a gas phase or vacuum.
‘‘interface’’ is normally applied to the region between two condensed
phases.
liquid–gas interface, molecules of the liquid in the boundary can only
develop attractive cohesive forces with molecules situated below and
adjacent to them.
They can develop attractive adhesive forces with molecules of the
gaseous phase.
At the gas–liquid interface, these adhesive forces are quite small.
The net effect is that molecules at the surface of the liquid have potential
energies greater than those of similar molecules in the interior of the
liquid and experience an inward force toward the bulk of liquid.
This force pulls the molecules of the interface together and the surface
contracts.
Thus, the surface of a liquid behaves as if it were in a state of tension—
the surface tension ()—due to the contracting force acting in all
directions in the plane of the surface.
7. SURFACE AND INTERFACIAL TENSION;
SURFACE AND INTERFACIAL FREE ENERGY
In order to extend the surface of a liquid it is necessary to
bring molecules from the interior to the surface against the
inward pull.
The work required to increase the surface area by unit area is
termed the surface free energy.
At the interface between two condensed phases, the
dissimilar molecules in the adjacent layers facing each other
have potential energies greater than those of similar
molecules in the respective bulk phases.
This is due to the fact that cohesive forces between like
molecules tend to be stronger than adhesive forces between
dissimilar molecules.
The interfacial tension is the force per unit length existing at
the interface between two immiscible or partially miscible
condensed phases.
The interfacial free energy is the work required to increase
the interface by unit area.
8. SURFACTANT CLASSIFICATION
Depending on their charge characteristics the
surface-active molecules may be
Anionic: SLS
Cationic: QAC
Zwitterionic (ampholytic): N-dodecyl-N,N-
dimethylbetaine
Nonionic: Sorbitan esters, Polysorbates, Poloxamer
14. PROPERTIES OF SURFACTANT
Detergency
• Detergents are surfactants used for removal of dirt.
• Detergency involves
Wetting of the dirt particles
Removing the insoluble dirt
as a deflocculated particle or
as a emulsion (oil soluble material)
• Washing
15. PROPERTIES OF SURFACTANT
Solublisation
Process of preparing clear solution
Microemulsion
Swollen micelle
Phenolic compound such as cresol, thymol, chlorocresol chloroxylenol
stabilized to form clear solution used as disinfection.
Low solubility of steroids in water is major problem in ophthalmic formulation.
So use of non ionic surfactant produce a clear solution which are stable to
sterilization.
Polysorbate used in preparation of aqueous injection of water insoluble
vitamins A,D,E & K.
16. PROPERTIES OF SURFACTANT
Solublisation
Micelle used in targeted drug delivery system .
Micelle is used to encapsulate antibiotic and anti-cancer drug.
Amphotericin is encapsulated in a deaggregated form in micelle of
monomethoxy poly Phospholipids formed by solvent evaporation
Complex cisplatin block copolymer is used in cancer therapy.
Drug activity & absorption
Low concentration of surfactant increases absorption due to the
enhanced the contact of drug with absorbing membrane.
Concentration above the CMC either produce additional effect or
cause decrease absorption because drug held within the micelle so
that the concentration available for absorption is reduced.
17. MICELLIZATION
Micelle Formation
In dilute aqueous solution, amphiphiles tend to concentrate on
surface.
As concentration increased- surface become more crowded-till no
more space in surface layer.
Then forced to remain in aqueous solution and causes disruption
of the hydrogen bonding between water molecules.
To minimize this disruption amphiphile molecules tend to
aggregate into multiple molecular structures.
It disrupts water-water attractions.
So driving force for formation of micelles-entropy gain from
disruption of the water structure.
19. MICELLIZATION
Micellization
• As concentration of surfactant increased there is alteration in
physical properties of solution.
Self-association of the amphiphile into small aggregates
called micelles.
Concentration of surfactant at which micelles first appear in
solution is called as CMC
Reason for micelle formation is the attainment of a minimum
free energy state.
Driving force for the formation of micelles is the increase of
entropy that occurs when the hydrophobic regions of the
surfactant are removed from water and the ordered structure
of the water molecules around this region of the molecule is
lost.
Most micelles are spherical and contain between 60 and 100
surfactant molecules.
23. MICELLIZATION
Micelles Structure
Critical packing parameter
The shape of the micelle formed by a particular surfactant is
influenced to a large extent by the geometry of the surfactant
molecule, as can be seen if we consider the packing of space-filling
models of the surfactants. The dimensionless parameter of use in
these considerations is called the critical packing parameter (CPP)
and is defined as
where v is the volume of one chain,
a is the cross-sectional area of the surfactant head group
lc is the extended length of the surfactant alkyl chain
24. MICELLIZATION
Micelles Structure
Critical packing parameter
Structure of the aggregate that will be formed in solution.
Consideration of the packing of molecules into spheres shows that
when CPP ≤ 1/3, which is the case for surfactants having a single
hydrophobic chain and a simple ionic or large nonionic head group, a
spherical micelle will be formed.
Ionic Micelle
25. MICELLIZATION
Micelles Structure
Critical packing parameter
It is easily seen that if we double volume (v) by adding a second alkyl
chain then the value of CPP will exceed 1/3 and nonspherical
structures such as bilayers (CPP = 1) will form in solution, from which
vesicles are formed .
26. MICELLIZATION
Micelles Structure
Critical packing parameter
The ‘effective’ cross-sectional area of the surfactant molecule is
strongly influenced by the interaction forces between adjacent head
groups in the micelle surface. These forces are decreased by
addition of electrolyte, leading to a decrease of a, an increase of the
CPP, and a change of shape of the aggregate,
27. MICELLIZATION
Micelles Structure
ionic surfactants consists of:
Hydrophobic core composed of the hydrocarbon chains of the
surfactant molecule
a Stern layer surrounding the core, which is a concentric shell
of hydrophilic head groups with (1 – )N counterions, where is
the degree of ionisation and N is the aggregation number
(number of molecules in the micelle). For most ionic micelles
the degree of ionisation is between 0.2 and 0.3; that is, 70–
80% of the counterions may be considered to be bound to the
micelles
a Gouy–Chapman electrical double layer surrounding the
Stern layer, which is a diffuse layer containing the N
counterions required to neutralise the charge on the kinetic
micelle. The thickness of the double layer is dependent on the
ionic strength of the solution and is greatly compressed in the
presence of electrolyte.
29. MICELLIZATION
Micelles Structure
Nonionic surfactants
are larger than their ionic counterparts and may sometimes be
elongated into an ellipsoid or rod-like structure.
attributable to the removal of electrical work which must be done
when a monomer of an ionic surfactant is added to an existing
charged micelle.
nonionic micelles are frequently asymmetric due to its size.
have a hydrophobic core formed from the hydrocarbon chains of
the surfactant molecules surrounded by a shell (the palisade
layer) composed of the oxyethylene chains of the surfactant and
entrapping a considerable number of water molecules, which is
highly hydrated.
31. MICELLIZATION
Importance
Micelles make insoluble material soluble in water.
The structure of the micelles can affect the viscosity of the
solution.
Micelles are reservoirs of surfactants.
32. MICELLIZATION
1. Nature of hydrophilic group
2. Nature of hydrophobic group
3. Nature of counter ion
4. Effects of electrolyte
5. Effect of temperature
6. Effect of pressure
Factors
Affecting
CMC and
Micellar size
33. MICELLIZATION
Factors Affecting CMC and Micellar size
Nature of hydrophobic group
•Increase in length of the HC results
in:
• decrease in CMC, which for
compounds with identical polar
head groups is expressed by the
linear equation:
log [CMC] = A – Bm
where m is the number of
carbon atoms in the chain and A
and B
are constants for a homologous
series.
• corresponding increase in
micellar size.
•Branching of HC increases CMC
•Unsaturation of HC increases CMC
35. MICELLIZATION
Factors Affecting CMC and Micellar size
Nature of hydrophilic group
Non-ionic surfactants generally have very much lower CMC
values and higher aggregation numbers than their ionic
counterparts with similar hydrocarbon chains.
An increase in the ethylene oxide chain length of a non-ionic
surfactant makes the molecule more hydrophilic and the CMC
increases.
36. MICELLIZATION
Factors Affecting CMC and Micellar size
Type of Counterion
Micellar size increases for a particular cationic surfactant as the
counterion is changed according to the series Cl− < Br− < I−, and for
a particular anionic surfactant according to Na+ < K+ < Cs+.
Ionic surfactants with organic counterions (e.g. maleates) have
lower CMCs and higher aggregation numbers than those with
inorganic counterions.
37. MICELLIZATION
Factors Affecting CMC and Micellar size
Addition of electrolyte
Electrolyte addition to solutions of ionic surfactants decreases the
CMC and increases the micellar size. This is because the
electrolyte reduces the forces of repulsion between the charged
head groups at the micelle surface, so allowing the micelle to
grow.
At high electrolyte concentration the micelles of ionic surfactants
may become non-spherical.
38. MICELLIZATION
Factors Affecting CMC and Micellar size
Effect of Temperature
•Aqueous solutions of many non-
ionic surfactants become turbid at a
characteristic temperature called
the cloud point.
•At temperatures up to the cloud
point there is an increase in
micellar size and a corresponding
decrease in CMC.
•Temperature has a comparatively
small effect on the micellar
properties of ionic surfactants.
39. MICELLIZATION
Factors Affecting CMC and Micellar size
Effect of Pressure
•Increase in CMC with pressure
upto 150 Mpa followed by a CMC
decreases at high pressure.
40. MICELLIZATION
Thermodynamics of Micelle Formation
Mass action model
Micelles are in equilibrium with unassociated surfactant.
For nonionic surfactant, n [the aggregation number] molecules
of the monomeric un ionised surfactant (S) react in a single step
to form a micelle, M
nS M
Equilibrium constant for micelle formation Km is given as
Term in bracket refers molar concentration of species.
nm
S
M
K
][
][
41. MICELLIZATION
Thermodynamics of Micelle Formation
Mass action model
When n is large – the free energy of micellization at the CMC is
G0
m represents the standard free energy change for transferring 1
mol of S from the aqueous solution into its micellar form.
CMCm SRTG ]ln[0
42. MICELLIZATION
Thermodynamics of Micelle Formation
Mass action model
For ionised surfactant, ionic micelle derived from an anionic
surfactant is formed by the association of n surfactant ions S- and
of [n-p] firmly bound counterions (X+) as follows:
nS- + (n-p)X+ M-p
Equilibrium constant for micelle formation is given by
When aggregation number n is large, the free energy of
micellization at or near the CMC reduces to
CMCm SRT
n
p
G ]ln[20
pnn
p
m
XS
M
K
][][
][2
43. MICELLIZATION
Thermodynamics of Micelle Formation
Phase –Separation model
considers micelles as a separate phase at CMC.
Hence s and m
0 are defined as the chemical potentials [per mol]
of the free surfactant in the aqueous phase and of the associated
surfactant in the micellar phase respectively
At equilibrium s = m
0
If activity coefficients are ignored, s is related to the surfactants
standard state s
0 by
SRTss ln0
44. MICELLIZATION
Thermodynamics of Micelle Formation
Phase –Separation model
On the other hand, micellar material is in standard state, and m =
m
0
The standard free energy of micellization is
The analogous approach for an ionized surfactant yields
CMCm SRTpnG ]ln[)](1[0
000
smmG
45. PHASE BEHAVIOUR
Equilibrium phase structures
As the concentration of a surfactant solution is increased,
different structures encount ered.
At concentrations well above the CMC, a more ordered
structuring of the solution occurs.
Two main types of liquid crystalline phases
Middle phase, M, exhibiting a hexagonal array of indefinitely long,
mutually parallel rods; and the neat phase, G, with a lamellar
structure.
The liquid crystalline hexagonal phase, like the micellar phase,
can exist either in a normal or reverse orientation.
The order of phase structures formed upon increasing surfactant
concentration generally follows a well defined sequence with a
‘‘mirror plane’’ through the lamellar phase in such a way that
normal phase structures can be considered to be ‘‘oil-in-water’’
and the reverse structures to be ‘‘water-in-oil.
46. PHASE BEHAVIOUR
Modified phase structures
Vesicular forms of surfactants are generally formed by
dispersing lamellar phases in an excess of water (or non-
aqueous polar solvents such as ethylene glycol or
dimethylformamide) or, in the case of reversed vesicles, in an
excess of oil.
With most surfactants, vesicles are non-equilibrium structures
that will eventually re-equilibrate back into the lamellar phases
from which they originated.
Vesicles are structural analogs of liposomes; they are
approximately spherical structures and have the ability to
‘‘solubilize’’ both lipid soluble and water soluble agents.
47. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Lyotropic liquid crystals
The liquid crystalline phases that occur on increasing
the concentration of surfactant solutions are referred to
as lyotropic liquid crystals.
48. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Lyotropic liquid crystals
Increase of concentration of a surfactant solution frequently
causes a transition from the typical spherical micellar structure
to a more elongated or rod-like micelle.
Further increase in concentration may cause the orientation
and close packing of the elongated micelles into hexagonal
arrays; this is a liquid crystalline state termed the middle phase
or hexagonal phase.
With some surfactants, further increase of concentration
results in the separation of a second liquid crystalline state –
the neat phase or lamellar phase.
In some surfactant systems another liquid crystalline state, the
cubic phase, occurs between the middle and neat phases
49. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Lyotropic liquid crystals The lyotropic liquid crystals are
anisotropic, that is, their physical
properties vary with direction of
measurement.
The middle phase, for example,
will only flow in a direction
parallel to the long axis of the
arrays. It is rigid in the other two
directions.
The neat phase is more fl uid and
behaves as a solid only in the
direction perpendicular to that of
the layers.
Plane-polarised light is rotated
when travelling along any axis
except the long axis in the middle
phase and a direction
perpendicular to the layers in the
neat phase.
50. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Thermotropic liquid crystals
Thermotropic liquid crystals are produced when certain
substances, for example the esters of cholesterol, are heated.
The arrangement of the elongated molecules in thermotropic
liquid crystals is generally recognisable as one of three
principal types
Nematic liquid crystals:
Groups of molecules orientate spontaneously with their
long axes parallel, but they are not ordered into layers.
Because the molecules have freedom of rotation about
their long axis, the nematic liquid crystals are quite mobile and
are readily orientated by electric or magnetic fields.
51. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Thermotropic liquid crystals
Smectic liquid crystals:
Groups of molecules are arranged with their long axes
parallel, and are also arranged into distinct layers.
As a result of their two-dimensional order the smectic
liquid crystals are viscous and are not orientated by magnetic
fields.
52. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Thermotropic liquid crystals
Cholesteric (or chiral nematic) liquid crystals:
Are formed by several cholesteryl esters.
Can be visualised as a stack of very thin two-dimensional nematic-like
layers in which the elongated molecules lie parallel to each other in the
plane of the layer.
The orientation of the long axes in each layer is displaced from that in
the adjacent layer and this displacement is cumulative through successive
layers so that the overall displacement traces out a helical path through the
layers.
The helical path causes very pronounced rotation of polarised light,
which can be as much as 50 rotations per millimeter.
The pitch of the helix (the distance required for one complete rotation)
is very sensitive to small changes in temperature and pressure and
dramatic colour changes can result from variations in these properties.
The cholesteric phase has a characteristic iridescent appearance when
illuminated by white light due to circular dichroism.
53. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Vesicles
Vesicles are formed by phospholipids and other surfactants
having two hydrophobic chains. There are several types:
Liposomes
Liposomes are formed by naturally occurring phospholipids such as
lecithin (phosphatidyl choline).
They can be multilamellar (composed of several bimolecular lipid
lamellae separated by aqueous layers) or unilamellar (formed by
sonication of solutions of multilamellar liposomes).
They may be used as drug carriers; water-soluble drugs can
be entrapped in liposomes by intercalation in the aqueous
layers, whereas lipid-soluble drugs can be solubilised within
the hydrocarbon interiors of the lipid bilayers.
54. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Surfactant vesicles and niosomes
Formed by surfactants having two alkyl chains.
Sonication can produce single-compartment vesicles.
Vesicles formed by ionic surfactants are useful as
membrane models.
Vesicles formed from non-ionic surfactants are called
niosomes and have potential use in drug delivery.
55. PHASE BEHAVIOUR
Formation of liquid crystals and vesicles
Monoolein vesicles
Polar amphiphilic lipids such as glyceryl monooleate (monoolein)
form bilayers, the nature of which depends on the temperature
and concentration.
phase formed at monoolein concentrations of 60–80% w/w is the
bicontinuous cubic phase.
The structure of this phase is unique and consists of a curved
bicontinuous lipid bilayer extending in three dimensions,
separating two networks of water channels with pores of about 5
nm diameter.
On dilution, these structures coexist with excess water and there
is the formation of dispersed cubic phase vesicles or cubosomes.
Cubic phases have been shown to incorporate and deliver small
molecule drugs and large proteins by oral and parenteral routes,
in addition to local delivery in vaginal and periodontal cavities.
61. APPLICATIONS
Surfactant as emulsifying agent.
Surfactant for contact lenses cleaning.
Surfactant in drug absorption from rectal suppositories.
Surfactant as flocculating agent