This document discusses pharmaceutical emulsions. It defines an emulsion as consisting of two immiscible liquids, one dispersed as droplets in the other. Emulsions are stabilized by emulsifying agents. Pharmaceutical applications of emulsions include oral, rectal, topical, and intramuscular administration. Different types of emulsions like O/W and W/O are described. Factors affecting emulsion stability and types of instabilities are outlined. Methods for emulsification, preservation, and packaging are also summarized.
Suspension, interfacial properties of suspended particles, settling in suspensions, formulation of flocculated and deflocculated suspensions. Emulsions and theories of emulsification, microemulsion and multiple emulsions; Stability of emulsions, preservation of emulsions, rheological properties of emulsions.
Suspension, interfacial properties of suspended particles, settling in suspensions, formulation of flocculated and deflocculated suspensions. Emulsions and theories of emulsification, microemulsion and multiple emulsions; Stability of emulsions, preservation of emulsions, rheological properties of emulsions.
INCLUDES SPREADING COEFFICIENT AND ITS THEORY AND ALSO FEW OF ITS APPLICATION IN PHARMACEUTICAL FIELD
WILL BE HELPFUL FOR B PHARMACY STUDENTS
INCLUDES HOW IT IS DERIVED AND ALSO HOW IT IS RELATED TO SPREADING OF A CREAM OR OINTMENT ON OUR SKIN
IMPORTANCE OF SPREADING COEFFICIENT
Semisolid dosage forms: Definitions, classification, mechanisms and factors influencing dermal penetration of drugs. Preparation of ointments, pastes, creams and gels. Excipients used in semi solid dosage forms. Evaluation of semi solid dosages forms
INCLUDES SPREADING COEFFICIENT AND ITS THEORY AND ALSO FEW OF ITS APPLICATION IN PHARMACEUTICAL FIELD
WILL BE HELPFUL FOR B PHARMACY STUDENTS
INCLUDES HOW IT IS DERIVED AND ALSO HOW IT IS RELATED TO SPREADING OF A CREAM OR OINTMENT ON OUR SKIN
IMPORTANCE OF SPREADING COEFFICIENT
Semisolid dosage forms: Definitions, classification, mechanisms and factors influencing dermal penetration of drugs. Preparation of ointments, pastes, creams and gels. Excipients used in semi solid dosage forms. Evaluation of semi solid dosages forms
4th (30.10.2014) on eutectic mixture by Diptarco SinghaDiptarco Singha
this ppt is very simple and has immence importance in physical pharmacy. it has been prepared based on the syllabus of WBUT & consists of informations of elimentary label...
Discussion on the 2 kinds of Disperse Systems 1. Suspensions 2. Emulsions. The principles of emulsification, types and examples of emulsifying agents used.
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Emulsions
Definition
These are homogenous, transparent and thermodynamically stable dispersion of water and oil stabilized by surfactant and co-surfactants
Consists of globules less than 0.1 μm in diameter
Types
Oil dispersed in water (o/w) - oil fraction low
Water dispersed in oil (w/o) - water fraction low
Bicontinuous (amount of oil and water are same)
Advantages
Thermodynamically stable, long shelf life
Potential reservoir of lipophilic or hydrophilic drug
Enhance the absorption and permeation of drugs through biological membranes
Increased solubility and stability of drugs
Ease and economical scale-up
Greater effect at lower concentration
Enhances the bioavailability of poorly soluble drugs
Theories of microemulsion
Interfacial or mixed film theory
Microemulsions are formed spontaneously due to formation of complex film at the interface by a mixture of surfactant and co-surfactant, As a result of which the interfacial tension reduces
Solubilization theory
Microemulsions are considered to be thermodynamically stable solutions of water swollen (w/o) or oil swollen (o/w) spherical micelles
Thermodynamic theory
The free energy of microemulsion formation is dependent on the role of surfactant in lowering the surface tension at the interface and increasing the entropy of the system
Multiple emulsions are complex polydispersed systems where both oil in water and water in oil emulsion exists simultaneously which are stabilized by lipophilic and hydrophilic surfactants respectively
The ratio of these surfactants is important in achieving stable multiple emulsions
They are also known as “Double emulsion” or “emulsion-within-emulsion”
Types
Oil-in-water-in-oil (O/W/O)
An o/w emulsion is dispersed in an oil continuous phase
Water-in-oil-in-water (W/O/W)
a w/o emulsion is dispersed in a water-continuous phase
MONOMOLECULAR ADSORPTION THEORY
MULTIMOLECULAR ADSORPTION THEORY
SOLID PARTICLE ADSORPTION THEORY
ELECTRICAL DOUBLE LAYER THEORY
ORIENTED WEDGE THEORY
Surfactants adsorb at the oil-water interface and form a monomolecular film
This film rapidly envelopes the droplets
They are very compact, elastic, flexible, strong and cannot be easily broken
For getting better stable emulsions combination of surfactants [surfactant blend] are used rather than a single one
The surfactant blend consists of both water soluble and oil soluble surfactants in order to approach the interface from aqueous and oil phase sides
At interface the surfactant blend interact to form a complex and condense a monomolecular film
Ex: A combination of Sodium cetyl sulfate (hydrophilic) and Cholesterol (lipophilic) forms a close packed complex film at the interface that produces an excellent emulsion
This is the pdf of Emulsions, types, emulsifying agent and stability of emulsions.
Definition:-The emulsion is a biphasic liquid preparation containing two immiscible liquids one of which is dispersed as minute globules into the other with the help of an emulsifying agent.
The liquid that is broken up into globules is called the dispersed phase & the liquid in which the globules are dispersed is known as the continuous phase.
Types of emulsion:
They are two types
1. Oil in water:-
In the O/w type, oil is a dispersed phase & water is the continuous phase. In oil in water type, oil is surrounded by water. So the unpleasant taste & odor of the oil is masked. Therefore o/w type of emulsion is preferable for internal use.
2. Water in oil type:-
In w/o type water is the dispersed phase & oil is in the continuous phase. In w/o type, water is surrounded by oil. So application on the skin may be easier. Therefore w/o type of emulsion is preferable for external use.
Examples for natural emulsion:
Milk is an example for o/w emulsion. Butter is an example for w/o emulsion.
Emulsifying agent/ surfactants
Surfactants are materials get adsorbed at the interface between the two phases. The surface adsorption lowers or decreases the tension between the two phases. It causes the inter mix of the phases with each other. Hence to reduce surface tension surfactants are used.
They are classified as follows:
1. Natural Emulgents from vegetable sources: These are anionic in nature & produce o/w type emulsions. They act as primary emulgents & stabilizers. Ex: acacia, tragacanth, agar, pectin
2. Natural emulsifying agents from animal sources:
a) Gelatin: It occurs in two forms Pharmagol A- used in acidic PH Pharmagol B-used in alkaline PH
b) Egg Yolk
c) Wool Fat
3. Semi synthetic polysaccharides: These produce o/w type of emulsion
Ex: Methyl cellulose, sodium CMC
4. Synthetic Emulgents:
a) Anionic: Its anionic part is responsible for emulsifying activity.
Ex: - Soaps & sodium lauryl sulphate
b) Cationic: Its cationic part is responsible for emulsification. Ex: - Cetrimide, Benzalkonium chloride.
They produce o/w type emulsion.
c) Non-Ionic: They do not ionize in aqueous solution. These are stable at wide range of pH & are not affected by addition of acids & electrolytes.
5. In-organic Emulgents: Ex: - Milk of magnesia, magnesium oxide, magnesium aluminium silicate & bentonite.
6. Alcohols: Ex: - Cetyl alcohol, stearyl alcohol, glycerol mono- stearate. Carbo waxes.
Stability of Emulsions:
1. Creaming:
Creaming is defined as the upward movement of the dispersed phase towards the surface and forms a thick layer at the surface of the emulsion.
2. Sedimentation:
Definition: It is defined as the downward movement of the dispersed phase towards the bottom & forms a separate layer over the sediment particles.
3. Cracking:
Cracking can be defined as the separation of the dispersed phase and continuous phase as two separate layers. They cannot be re-dispersed on shaking.
This presentation consists of the info about the pharmaceutical emulsions , definition, types,preparations,methods,formulation,emulsifying agents ....
this presentation is very useful for the b.pharm students for a brief idea ...
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
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.
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
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.
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
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.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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.
Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
2. Emulsion
An emulsion consists of two immiscible liquids one of which is
uniformly dispersed through the other as droplets of
diameter greater than 0.1 mm.
The system is stabilized by the presence of emulsifying agent.
The particle diameter of the disperse phase extends from 0.1
to 100 mm.
09/19/14 PHT 312 2
4. Pharmaceutical application of emulsions:
- Oral, rectal and topical administration of oils and oil-soluble
drugs.
- The unpleasant taste or odor can be masked by
emulsification
- The absorption and penetration of medicament are
enhanced by emulsification
- Intramuscular injections of water-soluble drugs or
vaccine to provide slow release.
- The use of sterile stable i.v emulsion containing fats,
carbohydrates and vitamins as a potential nutrition
09/19/14 PHT 312 4
6. DIFFERENCE BETWEEN O/W AND W/O EMULSIONS
Oil in ( water emulsion (o/w (Water in oil emulsion (w/o
Water is the dispersion medium and oil is the
dispersed phase
Oil is the dispersion medium and water is the
dispersed phase
They are non greasy and easily removable from
the skin surface
They are greasy and not water washable
They are used externally to provide cooling
effect e.g. vanishing cream
They are used externally to prevent evaporation
of moisture from the surface of skin e.g. Cold
cream
Water soluble drugs are more quickly released
from o/w emulsions
Oil soluble drugs are more quickly released from
w/o emulsions
They are preferred for formulations meant for
internal use as bitter taste of oils can be
.masked
They are preferred for formulations meant
. for external use like creams
O/W emulsions give a positive conductivity test
as water is the external phase which is a good
.conductor of electricity
W/O emulsions go not give a positive conductivity
test as oil is the external phase which is a poor
. conductor of electricity
09/19/14 PHT 312 6
7. • Test for identification of emulsion type:
• Dilution test (miscibility test)
• Staining test (dye solubility test)
• Conductivity measurement
09/19/14 PHT 312 7
9. Conductivity Test
This test is based on the basic principle that water is a good conductor of
electricity. Therefore in case of o/w emulsion , this test will be positive as
water is the external phase. In this test. An assembly consisting of a pair
of electrodes connected to a lamp is dipped into an emulsion. If the emulsion
is o/w type, the lamp glows.
09/19/14 PHT 312 9
10. Dye Solubility Test
In this test, when an emulsion is mixed with a water soluble dye such as
amaranth and observed under the microscope, if the continuous phase
appears red, then it means that the emulsion is o/w type as water is the
external phase and the dye will dissolve in it to give color but if the scattered
globules appear red and continuous phase colorless, then it is w/o type.
Similarly if an oil soluble dye such as Scarlet red C or Sudan III is added to an
emulsion and the continuous phase appears red, then it w/o emulsion.
09/19/14 PHT 312 10
11. • Theories of emulsification:
• Δ F = g Δ A
• The smaller Δ F is, the more thermodynamically stable system.
Δ F = g 6 V / d
• The system attempts to lose this excess free surface energy to
its surrounding by coalescence of the droplets. Addition of
emulsifier which concentrates at an interface, thereby altering
the surface free energy.
09/19/14 PHT 312 11
12. Instabilities In Emulsions
• An emulsion is a thermodynamically unstable
preparation so care has to be taken that the chemical as
well as the physical stability of the preparation remains
intact throughout the shelf life.
• There should be no appreciable change in the mean
particle size or the size distribution of the droplets of the
dispersed phase and secondly droplets of the dispersed
phase should remain uniformly distributed throughout the
system. Instabilities seen in emulsion can be grouped as:
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13. Creaming
An emulsion is said to cream when the oil or fat rises to the
surface, but remains in the form of globules, which may be
redistributed throughout the dispersion medium by shaking.
An oil of low viscosity tends to cream more readily than one
of high viscosity.
Increasing the viscosity of the medium decreases the tendency
to cream.
Creaming is a reversible phenomenon which can be corrected
by mild shaking.
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14. The factors affecting creaming are best described by stoke’€€s
law:
V= 2r2 (d1-d2) g/9h
• Where V= rate of creaming
• r=radius of globules
• d1= density of dispersed phase
• d2= density of dispersion medium
• g= gravitational constant
• h = viscosity of the dispersion medium
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15. • The following approaches can be used for decreasing
Creaming
• Reduction of globule size: According to stoke’€€s law, rate of
creaming is directly proportional to the size of globules.
Bigger is the size of the globules, more will be the creaming.
Therefore in order to minimize creaming, globule size should
be reduced by homogenization.
• Increasing the viscosity of the continuous phase: Rate of
creaming is inversely proportional to the viscosity of the
continuous phase i.e. more the viscosity of the continuous
phase, less will the problem of creaming. Therefore to avoid
creaming in emulsions, the viscosity of the continuous phase
should be increased by adding suitable viscosity enhancers
like gum acacia, tragacanth etc.
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16. Cracking
• Occasionally, it happens that an emulsion cracks during
preparation, i.e., the primary emulsion does not become white
but acquires an oily translucent appearance.
• In such a case, it is impossible to dilute the emulsion nucleus
with water and the oil separates out (irreversible process)
• Cracking of emulsion can be due to:
• addition of an incompatible emulsifying agent,
• chemical or microbial decomposition of emulsifying agent,
• addition of electrolytes,
• exposure to increased or reduced temperature or change in pH.
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17. A. Two immiscible liquids, not yet emulsified.
B. An emulsion of Phase II dispersed in Phase I.
C. The unstable emulsion progressively separates.
D. The surfactant positions itself on the interfaces between
Phase II and Phase I, stabilizing the emulsion
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18. Phase Inversion
• In phase inversion o/w type emulsion changes into w/o type
and vice versa.
• It is a physical instability.
• It may be brought about by the addition of an electrolyte or
by changing the phase volume ratio or
• by temperature changes.
• Phase inversion can be minimized by using the proper
emulsifying agent in adequate concentration,
• keeping the concentration of dispersed phase between 30 to 60
percent
• and by storing the emulsion in a cool place.
•
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19. Points to be considered during formulations of emulsions
• Stability of the active ingredient
• Stability of the excipients
• Visual appearance
• Color
• Odor (development of pungent odor/loss of fragrance)
• Viscosity, extrudability
• Loss of water and other volatile vehicle components
• Concentration of emulsifier
• Order of addition of ingredients
• Particle size distribution of dispersed phases
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20. • pH
• Temperature of emulsification
• Type of equipment
• Method and rate of cooling
• Texture, feel upon application (stiffness, grittiness,
greasiness, tackiness, spreadibility)
• Microbial contamination/sterility (in the unopened container
and under conditions of use)
• Release/bioavailability (percutaneous absorption)
• Phase distribution, Phase Inversion (homogeneity/phase
separation, bleeding
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21. Packaging, Labeling and Storage of Emulsions
• Depending on the use, emulsions should be packed in suitable
containers. Emulsions meant for oral use are usually packed
in well filled bottles having an air tight closure.
• Light sensitive products are packed in amber coloured bottles.
• For viscous emulsions, wide mouth bottles should be used.
The label on the emulsion should mention that these
products have to be shaken thoroughly before use.
• External use products should clearly mention on their label
that they are meant for external use only.
• Emulsions should be stored in a cool place but refrigeration
should be avoided as this low temperature can adversely
effect the stability of preparation.
•09/19/14 PHT 312 21
22. Preservation of Emulsions
• Preservation from microorganisms:
• It is necessary to preserve the emulsions from microorganisms as these can
proliferate easily in emulsified systems with high water content,
particularly if carbohydrates, proteins or steroidal materials are also
present.
• Contamination due to microorganisms can result in problems such as color
and odor change, gas production, hydrolysis, pH change and eventually
breaking of emulsion.
• Therefore is necessary that emulsified systems be adequately preserved.
An ideal preservative should be nonirritant, nonsensitizing and nontoxic in
the concentration used.
• It should be physically as well as chemically compatible with other
ingredients of the emulsions and with the proposed container of the
product.
• It should not impart any taste, color or odor to the product.
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23. • It should be stable and effective over a wide range of pH and
temperature.
• It should have a wide spectrum of activity against a range of
bacteria, yeasts and moulds. The selective preservative
should have high water solubility and a low oil/water partition
coefficient.
• It should have bactericidal rather than bacteriostatic activity.
09/19/14 PHT 312 23
24. • Examples of antimicrobial preservatives used to preserve
emulsified systems include
• parahydroxybenzoate esters such as methyl, propyl and butyl
parabens,
• organic acids such as ascorbic acid and benzoic acid,
• organic mercurials such as phenylmercuric acetate and
phenylmercuric nitrate,
• quarternary ammonium compounds such as cetrimide,
• cresol derivatives such as chlorocresol
• and miscellaneous agents such as sodium benzoate,
chloroform and phenoxyethano
09/19/14 PHT 312 24
25. Preservation from oxidation:
• Oxidative changes such as rancidity and spoilage due to
atmospheric oxygen and effects of enzymes produced by
micro-organisms is seen in many emulsions containing
vegetables and mineral oils and animal fats.
• Antioxidants can be used to prevent the changes occurring
due to atmospheric oxygen.
• Antioxidants are agents having a high affinity for oxygen and
compete for it with labile substances in the formulation.
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26. • The ideal antioxidant should be:
• nontoxic, nonirritant,
• effective at low concentration under the expected conditions
of storage and use,
• soluble in the medium and stable.
• Antioxidants for use in oral preparation should also be
odorless and tasteless.
• Some of the commonly used antixidants for emulsified
systems include alkyl gallate such as ethyl, propyl or dodecyl
gallate, butylated hydroxyanisole (BHT), butylated
hydroxytoluene (BHT)
09/19/14 PHT 312 26
27. Preparation of Emulsions
• Preparation Of Emulsions
• Preparation of emulsions depends on the scale at which it is produced.
• On small scale mortar and pestle can be used but its efficiency is limited.
To overcome these drawback small electric mixers can be used although
care must be exercised to avoid excessive entrapment of air.
• For large scale production mechanical stirrers are used
to provide controlled agitation and shearing stress
to produce stable emulsions.
09/19/14 PHT 312 27
28. • The methods commonly used to prepare emulsions can be
divided into two categories:
A- Trituration Method
This method consists of dry gum method and wet gum method.
1- Dry Gum Method
In this method the oil is first triturated with gum with a little
amount of water to form the primary emulsion. The trituration
is continued till a characteristic ‘clicking’ sound is heard and a
thick white cream is formed. Once the primary emulsion is
formed, the remaining quantity of water is slowly added to
form the final emulsion.
09/19/14 PHT 312 28
29. 2- Wet Gum Method
As the name implies, in this method first gum and water are
triturated together to form a mucilage. The required quantity
of oil is then added gradually in small proportions with
thorough trituration to form the primary emulsion.
Once the primary emulsion has been formed remaining
quantity of water is added to make the final emulsion.
09/19/14 PHT 312 29
30. B- Bottle Method
This method is employed for preparing emulsions containing
volatile and other non-viscous oils. Both dry gum and wet gum
methods can be employed for the preparation.
As volatile oils have a low viscosity as compared to fixed oils,
they require comparatively large quantity of gum for
emulsification.
In this method, oil or water is first shaken thoroughly and
vigorously with the calculated amount of gum. Once this has
emulsified completely, the second liquid (either oil or water) is
then added all at once and the bottle is again shaken
vigorously to form the primary emulsion. More of water is
added in small portions with constant agitation after each
addition to produce the final volume.
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31. • Methods for preparing Emulsions for External use:
• Emulsions meant for external application such as creams,
lotions and liniments contain in their formula waxy solids
which require melting before mixing.
• Such emulsions may be prepared by melting the oily
components separately at 60 0C.
• Similarly in another vessel, the aqueous components are mixed
and are warmed gently to 60 0C.
• The aqueous phase is then added to the oily phase at the same
temperature and stirred until cold.
•
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32. Table: 1 Proportions of Oil, Water and Gum required for formation of
primary emulsion'
Type of Oil Oil Water Gum
Fixed Oil 4 2 1
Mineral Oil 3 2 1
Volatile Oil 2 2 1
09/19/14 PHT 312 32
33. • Emulsifying Agents are the substances added to an
emulsion to prevent the coalescence of the globules of the
dispersed phase.
• They are also known as emulgents or emulsifiers.
• They act by reducing the interfacial tension between the two
phases and forming a stable interfacial film.
• The choice of selection of emulsifying agent plays a very
important role in the formulation of a stable emulsion.
• No single emulsifying agent possesses all the properties
required for the formulation of a stable emulsion therefore
sometimes blends of emulsifying agents have to be taken.
09/19/14 PHT 312 33
34. • Criteria For The Selection of Emulsifying Agents
• An ideal emulsifying agent should posses the following
characteristics:
• It should be able to reduce the interfacial tension between
the two immiscible liquids.
• It should be physically and chemically stable , inert and
compatible with the other ingredients of the formulation.
• It should be non irritant and non toxic in the conc., used.
• It should be organoleptically inert i.e. should not impart any
color , odour or taste to the preparation.
• It should be able to produce and maintain the required
viscosity of the preparation.
• It should be able to form a coherent film around the globules
of the dispersed phase and should prevent the coalescence of
the droplet of the dispersed phase.
• 09/19/14 PHT 312 34
35. 1-Natural emulsifying agents from vegetable sources
• These consist of agents which are carbohydrates and include
gums and mucilaginous substances. Since these substances
are of variable chemical composition,
• these exhibit considerable variation in emulsifying properties.
They are anionic in nature and produce o/w emulsions. They
act as primary emulsifying agents as well as
secondary emulsifying agents (emulsion stabilizers).
• Since carbohydrates acts a good medium for the growth of
microorganism, therefore emulsions prepared using these
emulsifying agents have to be suitable preserved in order to
prevent microbial contamination.
• E.g. tragacanth, acacia, agar, pectin and starch.
09/19/14 PHT 312 35
36. 2-Natural emulsifying agents from animal source
The examples include gelatin, egg yolk and wool fat (anhydrous
lanolin). Type A gelatin (Cationic) is generally used for
preparing o/w emulsion while type B gelatin is used for o/w
emulsions of pH 8 and above.
Lecithin and cholesterol present in egg yolk also act as
emulsifying agent. They show surface activity and are used for
formulating o/w emulsions.
However they are used only for extemporaneous preparation
and not for commercial preparation as it darken and degrade
rapidly in unpreserved systems.
Wool fat is mainly used in w/o emulsions meant for external
use. They absorb large quantities of water and form stable
w/o emulsions with other oils and fats.
09/19/14 PHT 312 36
37. 3- Semi-synthetic polysaccharides
• Includes mainly cellulose derivatives like sodium carboxy
methyl cellulose, hydroxyl propyl cellulose and methyl
cellulose.
• They are used for formulating o/w type of emulsions.
• They primarily act by increasing the viscosity of the system.
e.g., methyl cellulose, hydroxypropyl cellulose and sodium
carboxy methyl cellulose.
09/19/14 PHT 312 37
38. 4- Synthetic emulsifying agents
• This group contains surface active agents which act by getting
adsorbed at the oil water interface in such a way that the
hydrophilic polar groups are oriented towards water and
lipophillic non polar groups are oriented towards oil, thus
forming a stable film.
• This film acts as a mechanical barrier and prevents
coalescence of the globules of the dispersed phase.
• They are classified according to the ionic charge possessed by
the molecules of the surfactant e.g., anionic, cationic, non-ionic
and ampholytic.
09/19/14 PHT 312 38
39. 4.1. Anionic Surfactants
• The long anion chain on dissociation imparts surface activity,
while the cation is inactive.
• These agents are primarily used for external preparations
and not for internal use as they have an unpleasant bitter
taste and irritant action on the intestinal mucosa.
• e.g., alkali soaps, amine soaps, metallic soaps, alkyl sulphates
and phosphates and alkyl sulphonates.
•
09/19/14 PHT 312 39
40. 4.2. Cationic surfactants
• The positive charge cations produced on dissociation are
responsible for emulsifying properties.
• They are mainly used in external preparations such as lotions
and creams.
• Quaternary ammonium compounds such as cetrimide,
benzalkonium chloride and benzethonium chloride are
examples of important cationic surfactants.
• These compounds besides having good antibacterial activity
are also used in combination with secondary emulsifying
agents to produce o/w emulsions for external application.
09/19/14 PHT 312 40
41. 4.3. Non-ionic surfactants
• They are the class of surfactants widely used as emulsifying
agents.
• They are extensively used to produce both o/w and w/o
emulsions for internal as well as external use. The emulsions
prepared using these surfactants remain stable over a wide
range of pH changes and are not affected by the addition of
acids and electrolytes.
• They also show low irritancy as compared to other
surfactants.
• E.g. glyceryl esters such as glyceryl monostearate, propylene
glycol monostearate, macrogol esters such as polyoxyl
stearates and polyoxyl-castor oil derivatives, sorbitan fatty
acid esters such as spans and their polyoxyethylene
derivatives such as tweens (polysorbates).
09/19/14 PHT 312 41
42. 5- Finely Divided Solids
• This group consist of finely divided solids having balanced
hydrophilic lipophillic properties.
• They accumulate at the oil/water interface and form a
coherent interfacial film around the droplets of dispersed
phase globules and prevent coalescence.
• If the solid particles are preferentially wetted by oil, a w/o
emulsion is formed while if wetting is done by water then o/w
emulsion is seen.
• e.g., bentonite, aluminium magnesium stearate, attapulgite,
colloidal anhydrous silica and hectorite. The emulsions
formed using finely divided solids are stable and less prone to
microbial contamination.
09/19/14 PHT 312 42
43. • Quality control tests for Emulsions
The following are the quality control tests done for emulsions:
• 1. Determination of particle size and particle count: Determination of
changes in the average particle size or the size distribution of droplets is
an important parameter used for the evaluation of emulsions. It is
performed by optical microscopy, sedimentation by using Andreasen
apparatus and Coulter counter apparatus.
• 2. Determination of viscosity: Determination of viscosity is done to assess
the changes that might take place during aging. Emulsions exhibit non-newtonian
type of flow characterstics.
• The viscometers which should be used include cone and plate
viscometers.
09/19/14 PHT 312 43
44. 3. Determination of phase separation: This is another parameter used for
assessing the stability of the formulation.
Phase separation may be observed visually or by measuring the volume of
the separated phases.
4. Determination of electrophoretic properties: Determination of
electrophoretic properties like zeta potential is useful for assessing
flocculation since electrical charges on particles influence the rate of
flocculation.
O/W emulsion having a fine particle size will exhibit low resistance but if
the particle size increase, then it indicates a sign of oil droplet aggregation
and instability.
09/19/14 PHT 312 44
45. Stability testing
Stability of emulsions is an important parameter for the formulator.
Stability testing of emulsions involves determining stability at long term
storage conditions, accelerated storage conditions, freezing and thawing
conditions. Stress conditions are applied in order to speed up the stability
testing.
The stress conditions used for speeding up instability of emulsions include:
• Centrifugal force, Agitational force, Aging and temperature
• The following physical parameters are evaluated to assess the effect of any
of the above stress conditions:
Phase separation
Viscosity
Electrophoretic properties
Particle size and particle count
09/19/14 PHT 312 45