This document discusses interfacial phenomena and surface tension. It begins with definitions of interface, surface tension, and interfacial tension. Several methods for measuring surface tension are described, including the capillary rise method, Du-Nouy ring method, and stallagmometric method. The concepts of surface free energy, spreading coefficient, and surface active agents are also introduced.
Surface and Interfacial tension [Part-3(b)](Measurement of Surface and Inter...Ms. Pooja Bhandare
This document discusses two methods for measuring surface and interfacial tension: the Wilhelmy plate method and the DuNouy ring method. The Wilhelmy plate method involves immersing a thin plate into a liquid and measuring the force required to detach the plate from the surface. The surface tension can then be calculated based on this force measurement. The DuNouy ring method similarly uses a ring immersed at an interface and measures the force needed to detach the ring, from which the interfacial tension can be derived. Both methods relate the measured detachment force to the perimeter of the liquid/interface and surface/interfacial tension.
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...
Complexation and Protein Binding [Part-2](Method of analysis, Complexation a...Ms. Pooja Bhandare
This document discusses various methods for analyzing complexes, including continuous variation (Job's) method, distribution method, solubility method, pH titration method, and spectroscopy. The continuous variation method analyzes changes in physical properties like dielectric constant when complexes form to determine stoichiometric ratios. The distribution method examines how the distribution of a solute between immiscible liquids changes with complexation to estimate stability constants. The solubility method observes whether solubility increases or decreases with the addition of a complexing agent. pH titration is reliable for complexes that affect pH upon formation. Spectroscopy techniques like UV and NMR are also used to determine rate constants and equilibrium constants.
State of matter and properties of matter (Part-3) (Eutectic mixture)Ms. Pooja Bhandare
This document discusses eutectic mixtures, which are mixtures of two or more phases that have the lowest melting point. A eutectic mixture is formed at a specific composition where the phases simultaneously crystallize from a molten solution. The term comes from the Greek word meaning "easily melted". Eutectic mixtures can be formed between APIs, APIs and excipients, or excipients. Below the eutectic temperature, the mixture exists as a solid, while above it exists as a liquid. Eutectic mixtures have various applications in the pharmaceutical industry, such as improving drug solubility and bioavailability for different routes of administration like oral, transdermal, parental, and nasal delivery.
Surface and Interfacial tension [Part-6]( Solubilization, Detergency, Adsorp...Ms. Pooja Bhandare
This document discusses three topics related to surface and interfacial tension: solubilization, detergency, and adsorption at solid interfaces. Solubilization is the process of increasing the solubility of organic compounds in water using surfactants. Detergency is the removal of dirt from surfaces using detergents, which are surfactants. Adsorption at solid interfaces is when substances deposit on the surface of solids, with the deposited substance called the adsorbate and the surface called the adsorbent. Adsorption depends on factors like the nature of the adsorbent and adsorbate, temperature, and can be physical or chemical in nature.
Sanjo College of Pharmaceutical Studies, Physical Pharmaceutics I , 3rd semester B.Pharm, Complexation & protein binding, Classification in detail, determination methods, application of complexes in pharmacy.
1. Interfacial phenomena are important in pharmacy for drug adsorption, penetration through membranes, emulsion formation and stability, and suspension of insoluble particles.
2. Surface tension is the inward force at the liquid interface, while interfacial tension exists between immiscible liquids. Temperature, additives, and molecular interactions influence surface/interfacial tensions.
3. Several methods measure these tensions, including the capillary rise, Du Nouy ring, and drop weight methods. Surface-active agents are amphiphilic molecules that adsorb at interfaces and are used as wetting, solubilizing, and emulsifying agents in pharmaceutical formulations.
Surface and Interfacial tension [Part-3(b)](Measurement of Surface and Inter...Ms. Pooja Bhandare
This document discusses two methods for measuring surface and interfacial tension: the Wilhelmy plate method and the DuNouy ring method. The Wilhelmy plate method involves immersing a thin plate into a liquid and measuring the force required to detach the plate from the surface. The surface tension can then be calculated based on this force measurement. The DuNouy ring method similarly uses a ring immersed at an interface and measures the force needed to detach the ring, from which the interfacial tension can be derived. Both methods relate the measured detachment force to the perimeter of the liquid/interface and surface/interfacial tension.
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...
Complexation and Protein Binding [Part-2](Method of analysis, Complexation a...Ms. Pooja Bhandare
This document discusses various methods for analyzing complexes, including continuous variation (Job's) method, distribution method, solubility method, pH titration method, and spectroscopy. The continuous variation method analyzes changes in physical properties like dielectric constant when complexes form to determine stoichiometric ratios. The distribution method examines how the distribution of a solute between immiscible liquids changes with complexation to estimate stability constants. The solubility method observes whether solubility increases or decreases with the addition of a complexing agent. pH titration is reliable for complexes that affect pH upon formation. Spectroscopy techniques like UV and NMR are also used to determine rate constants and equilibrium constants.
State of matter and properties of matter (Part-3) (Eutectic mixture)Ms. Pooja Bhandare
This document discusses eutectic mixtures, which are mixtures of two or more phases that have the lowest melting point. A eutectic mixture is formed at a specific composition where the phases simultaneously crystallize from a molten solution. The term comes from the Greek word meaning "easily melted". Eutectic mixtures can be formed between APIs, APIs and excipients, or excipients. Below the eutectic temperature, the mixture exists as a solid, while above it exists as a liquid. Eutectic mixtures have various applications in the pharmaceutical industry, such as improving drug solubility and bioavailability for different routes of administration like oral, transdermal, parental, and nasal delivery.
Surface and Interfacial tension [Part-6]( Solubilization, Detergency, Adsorp...Ms. Pooja Bhandare
This document discusses three topics related to surface and interfacial tension: solubilization, detergency, and adsorption at solid interfaces. Solubilization is the process of increasing the solubility of organic compounds in water using surfactants. Detergency is the removal of dirt from surfaces using detergents, which are surfactants. Adsorption at solid interfaces is when substances deposit on the surface of solids, with the deposited substance called the adsorbate and the surface called the adsorbent. Adsorption depends on factors like the nature of the adsorbent and adsorbate, temperature, and can be physical or chemical in nature.
Sanjo College of Pharmaceutical Studies, Physical Pharmaceutics I , 3rd semester B.Pharm, Complexation & protein binding, Classification in detail, determination methods, application of complexes in pharmacy.
1. Interfacial phenomena are important in pharmacy for drug adsorption, penetration through membranes, emulsion formation and stability, and suspension of insoluble particles.
2. Surface tension is the inward force at the liquid interface, while interfacial tension exists between immiscible liquids. Temperature, additives, and molecular interactions influence surface/interfacial tensions.
3. Several methods measure these tensions, including the capillary rise, Du Nouy ring, and drop weight methods. Surface-active agents are amphiphilic molecules that adsorb at interfaces and are used as wetting, solubilizing, and emulsifying agents in pharmaceutical formulations.
Surface and Interfacial tension [Part-3(a)](Measurement of Surface and Inter...Ms. Pooja Bhandare
MEASUREMENT OF SURFACE AND INTERFACIAL TENSION
Capillary Rise Method, Drop Count and Weight Method.
Wilhelmy Plate Methods ,The DuNouy Ring Method.
Capillary Rise Method: Upward force due to surface tension: Drop count and Weight method Downward Force: Drop weight method: Drop count method
State of matter and properties of matter (Part-2) (Latent Heat, Vapour pressu...Ms. Pooja Bhandare
Latent Heat, Vapour pressure, Factor affecting vapour pressure, Surface area, Types of molecule, Temperature and Intermolecular forces, Sublimation Critical point
This document discusses pharmaceutical suspensions. It defines suspensions as dispersions of solid drug particles in a liquid vehicle. Suspensions are classified based on particle size as molecular dispersions (<1nm), colloidal dispersions (1nm-0.5um) or coarse dispersions (>0.5um). Most pharmaceutical suspensions are coarse dispersions. The document outlines factors to consider in suspension formulation including particle wetting and size, sedimentation rate, electrokinetic properties, and methods of controlling flocculation. Structured vehicles and controlled flocculation are described as methods for producing stable suspensions. Key qualities of ideal suspensions are also provided such as resistance to settling and caking.
This document discusses complexation and protein binding. It defines complexes as molecules where most bonds can be described by classical theories of valency, but one or more bonds are anomalous. Complexes result from donor-acceptor or Lewis acid-base reactions between constituents.
It describes different types of complexes including metal complexes where the metal ion is the central atom. It also discusses organic molecular complexes formed between two organic molecules via hydrogen bonds or van der Waals forces. Inclusion complexes involve one compound being trapped in the lattice structure of another.
Various methods for analyzing complexes are presented, including determining stoichiometric ratios and stability constants using methods like continuous variation, distribution, solubility, and pH titration. Applications of complex
This document provides an overview of states of matter and polymorphism. It discusses the three main states of matter - gases, liquids, and solids - and how their molecular arrangements differ. Solids can exist in crystalline or amorphous forms, with crystalline solids possessing long-range molecular order. Polymorphism, where a substance can exist in multiple crystal structures, is described. The importance of polymorphism in pharmaceutical industry is highlighted, as different solid forms can impact properties like solubility, dissolution rate, and bioavailability. Specific drug examples like carbamazepine and ritonavir and their polymorphic forms are mentioned.
This document discusses solubilization and surfactants. It defines solubilization as preparing an isotropic solution of an insoluble substance using a component or suitable method. Solubility is affected by the nature of solute and solvent, temperature, pressure, and particle size. Surfactants lower surface tension and act as detergents, wetting agents, etc. When added to water, surfactants self-assemble into micelles with hydrophilic heads facing out and hydrophobic tails inside in spherical, rod, or lamellar shapes above the critical micelle concentration. Micelle formation is driven by thermodynamics to increase entropy.
Diffusion is the net movement of molecules from an area of high concentration to lower concentration due to random molecular motion. It plays an important role in pharmaceutical sciences, including drug release from dosage forms and permeation of drugs through tissues. There are different types of diffusion such as passive diffusion down a concentration gradient, and active transport against a gradient. Fick's laws of diffusion describe diffusion as proportional to the concentration gradient. Diffusion is measured using devices like the Franz diffusion cell, where a membrane separates drug and receptor compartments to assess permeation over time. Diffusion-controlled drug release systems rely on drug diffusing out of insoluble matrices or reservoirs over time.
Dispersion system
suspensions
interfacial properties of suspensions
zeta potential
Sedimentation parameters
Settling in suspension
Formulation of suspension
Preparation of suspension
Physical Pharmaceutics-IUnit-IIISurface and Interfacial tension (Part-1)(Li...Ms. Pooja Bhandare
This document discusses liquid interfaces and surface and interfacial tension. It defines a liquid interface as the boundary between phases in contact, with surface referring specifically to the boundary between a liquid and gas. Surface tension is the force per unit length acting at right angles to the liquid surface and arises from cohesive intermolecular forces being imbalanced at the surface. Molecules in the bulk liquid experience equal attractive forces from all sides, while surface molecules only experience inward attraction. This imbalance causes the surface to contract and results in surface tension. Interfacial tension similarly describes the imbalance of forces at the boundary between immiscible liquids. Some examples of liquid surface tensions are provided.
The document discusses coarse dispersions and suspensions. It defines a suspension as an insoluble solid dispersed in a liquid medium where the particles are larger than 0.1 μm. Common types of suspensions include orally administered, ophthalmic, and injectable suspensions. Desirable qualities include minimal settling, uniform distribution, and appropriate viscosity. The document outlines factors that influence particle interactions like surface energy and interfacial tension. It also discusses strategies to achieve stability including controlled flocculation, use of surfactants, polymers, and structured vehicles.
This document provides an overview of suspensions, including their classification, properties, formulation, and stability. Key points include:
- Suspensions are heterogeneous systems with an insoluble dispersed phase distributed throughout a continuous phase. They can be classified based on their intended use, concentration of solids, particle size, and electrokinetic properties.
- Interfacial properties like surface tension affect particle flocculation and sedimentation. Surfactants can reduce surface tension to promote deflocculation.
- Particle size, concentration, and Brownian motion influence sedimentation rates. Flocculated particles settle faster but are easier to redisperse than deflocculated particles.
- Stable suspensions are formulated using vehicles to
This document provides an overview of surface and interfacial phenomena. It discusses interfaces, types of interfaces including liquid interfaces. It describes surface and interfacial tensions, and how they arise from attractive and cohesive forces between molecules. Measurement techniques for surface and interfacial tensions are presented, including the capillary rise method and DuNoüy ring method. Concepts around spreading coefficients, micelle formation, adsorption at liquid and solid interfaces, and wetting are explained. Adsorption isotherms including Langmuir and BET isotherms are also summarized.
1. An insoluble monomolecular film forms when a slightly soluble material is spread on a liquid surface, such as water. The molecules stand vertically and pack closely, with thickness equaling molecular length.
2. Film pressure is measured as the difference between the surface tension of the clean liquid and the surface tension of the liquid covered by the film. The film resists contraction of the clean surface.
3. A π-A curve plots the relationship between film pressure and film area, showing phase changes as the film is compressed, from a gas-like to liquid-like to solid-like state.
This document provides information on complexation and protein binding. It defines complexation as the association between two or more molecules to form a non-bonded entity through interactions like coordination bonds, van der Waals forces, hydrogen bonds, etc. It classifies complexes into metal complexes, organic molecular complexes, and inclusion complexes. It also discusses ligand types, methods of analyzing complexes, and applications of complexation. The document then defines protein binding and discusses factors that affect binding like drug and protein properties, drug interactions, and patient factors. It explains kinetics of protein binding and methods to determine binding constants and sites like direct plots, Scatchard plots, and others.
1. Complexation refers to the association of two or more interacting molecules or ions through coordinate bonding. This can occur between metal ions and ligands to form metal complexes, or between two organic molecules to form organic complexes.
2. Complexation has various applications in formulation such as improving physical state, reducing volatility, and enhancing solid state stability. It can also influence drug action by modifying properties like absorption, bioavailability, toxicity, and antibacterial activity.
3. Protein binding refers specifically to the formation of complexes between drug molecules and blood proteins. This binding affects the amount of free or unbound drug available to produce pharmacological effects.
This document discusses surface and interfacial phenomena. It defines interfaces and divides them into solid and liquid interfaces. Liquid interfaces deal with liquid-gas or liquid-liquid phases and have applications in infiltration, biopharmaceuticals, and suspensions/emulsions. Surface tension exists between solid-gas and liquid-gas phases, while interfacial tension exists between immiscible liquids. Various methods are described to measure surface tension, interfacial tension, and surface free energy. Surfactants are also discussed, including how they lower tensions and are used in products. Adsorption at interfaces and isotherms are briefly covered.
Surface tension is the property of liquids that allows them to behave like an elastic membrane. It causes liquids to take up the least surface area possible and pull inward on the surface. There are several methods to measure surface and interfacial tension between liquids, including the capillary rise method, drop count/weight methods, Wilhelmy plate method, and ring detachment method. The capillary rise method measures the height liquid rises in a thin glass tube based on the balance of adhesive and cohesive forces. The drop count/weight methods compare the number or weight of drops of a test liquid to a reference liquid in a stalagmometer. The Wilhelmy plate and ring detachment methods apply a calibrated force to detach a
Surface and Interfacial tension [Part-3(a)](Measurement of Surface and Inter...Ms. Pooja Bhandare
MEASUREMENT OF SURFACE AND INTERFACIAL TENSION
Capillary Rise Method, Drop Count and Weight Method.
Wilhelmy Plate Methods ,The DuNouy Ring Method.
Capillary Rise Method: Upward force due to surface tension: Drop count and Weight method Downward Force: Drop weight method: Drop count method
State of matter and properties of matter (Part-2) (Latent Heat, Vapour pressu...Ms. Pooja Bhandare
Latent Heat, Vapour pressure, Factor affecting vapour pressure, Surface area, Types of molecule, Temperature and Intermolecular forces, Sublimation Critical point
This document discusses pharmaceutical suspensions. It defines suspensions as dispersions of solid drug particles in a liquid vehicle. Suspensions are classified based on particle size as molecular dispersions (<1nm), colloidal dispersions (1nm-0.5um) or coarse dispersions (>0.5um). Most pharmaceutical suspensions are coarse dispersions. The document outlines factors to consider in suspension formulation including particle wetting and size, sedimentation rate, electrokinetic properties, and methods of controlling flocculation. Structured vehicles and controlled flocculation are described as methods for producing stable suspensions. Key qualities of ideal suspensions are also provided such as resistance to settling and caking.
This document discusses complexation and protein binding. It defines complexes as molecules where most bonds can be described by classical theories of valency, but one or more bonds are anomalous. Complexes result from donor-acceptor or Lewis acid-base reactions between constituents.
It describes different types of complexes including metal complexes where the metal ion is the central atom. It also discusses organic molecular complexes formed between two organic molecules via hydrogen bonds or van der Waals forces. Inclusion complexes involve one compound being trapped in the lattice structure of another.
Various methods for analyzing complexes are presented, including determining stoichiometric ratios and stability constants using methods like continuous variation, distribution, solubility, and pH titration. Applications of complex
This document provides an overview of states of matter and polymorphism. It discusses the three main states of matter - gases, liquids, and solids - and how their molecular arrangements differ. Solids can exist in crystalline or amorphous forms, with crystalline solids possessing long-range molecular order. Polymorphism, where a substance can exist in multiple crystal structures, is described. The importance of polymorphism in pharmaceutical industry is highlighted, as different solid forms can impact properties like solubility, dissolution rate, and bioavailability. Specific drug examples like carbamazepine and ritonavir and their polymorphic forms are mentioned.
This document discusses solubilization and surfactants. It defines solubilization as preparing an isotropic solution of an insoluble substance using a component or suitable method. Solubility is affected by the nature of solute and solvent, temperature, pressure, and particle size. Surfactants lower surface tension and act as detergents, wetting agents, etc. When added to water, surfactants self-assemble into micelles with hydrophilic heads facing out and hydrophobic tails inside in spherical, rod, or lamellar shapes above the critical micelle concentration. Micelle formation is driven by thermodynamics to increase entropy.
Diffusion is the net movement of molecules from an area of high concentration to lower concentration due to random molecular motion. It plays an important role in pharmaceutical sciences, including drug release from dosage forms and permeation of drugs through tissues. There are different types of diffusion such as passive diffusion down a concentration gradient, and active transport against a gradient. Fick's laws of diffusion describe diffusion as proportional to the concentration gradient. Diffusion is measured using devices like the Franz diffusion cell, where a membrane separates drug and receptor compartments to assess permeation over time. Diffusion-controlled drug release systems rely on drug diffusing out of insoluble matrices or reservoirs over time.
Dispersion system
suspensions
interfacial properties of suspensions
zeta potential
Sedimentation parameters
Settling in suspension
Formulation of suspension
Preparation of suspension
Physical Pharmaceutics-IUnit-IIISurface and Interfacial tension (Part-1)(Li...Ms. Pooja Bhandare
This document discusses liquid interfaces and surface and interfacial tension. It defines a liquid interface as the boundary between phases in contact, with surface referring specifically to the boundary between a liquid and gas. Surface tension is the force per unit length acting at right angles to the liquid surface and arises from cohesive intermolecular forces being imbalanced at the surface. Molecules in the bulk liquid experience equal attractive forces from all sides, while surface molecules only experience inward attraction. This imbalance causes the surface to contract and results in surface tension. Interfacial tension similarly describes the imbalance of forces at the boundary between immiscible liquids. Some examples of liquid surface tensions are provided.
The document discusses coarse dispersions and suspensions. It defines a suspension as an insoluble solid dispersed in a liquid medium where the particles are larger than 0.1 μm. Common types of suspensions include orally administered, ophthalmic, and injectable suspensions. Desirable qualities include minimal settling, uniform distribution, and appropriate viscosity. The document outlines factors that influence particle interactions like surface energy and interfacial tension. It also discusses strategies to achieve stability including controlled flocculation, use of surfactants, polymers, and structured vehicles.
This document provides an overview of suspensions, including their classification, properties, formulation, and stability. Key points include:
- Suspensions are heterogeneous systems with an insoluble dispersed phase distributed throughout a continuous phase. They can be classified based on their intended use, concentration of solids, particle size, and electrokinetic properties.
- Interfacial properties like surface tension affect particle flocculation and sedimentation. Surfactants can reduce surface tension to promote deflocculation.
- Particle size, concentration, and Brownian motion influence sedimentation rates. Flocculated particles settle faster but are easier to redisperse than deflocculated particles.
- Stable suspensions are formulated using vehicles to
This document provides an overview of surface and interfacial phenomena. It discusses interfaces, types of interfaces including liquid interfaces. It describes surface and interfacial tensions, and how they arise from attractive and cohesive forces between molecules. Measurement techniques for surface and interfacial tensions are presented, including the capillary rise method and DuNoüy ring method. Concepts around spreading coefficients, micelle formation, adsorption at liquid and solid interfaces, and wetting are explained. Adsorption isotherms including Langmuir and BET isotherms are also summarized.
1. An insoluble monomolecular film forms when a slightly soluble material is spread on a liquid surface, such as water. The molecules stand vertically and pack closely, with thickness equaling molecular length.
2. Film pressure is measured as the difference between the surface tension of the clean liquid and the surface tension of the liquid covered by the film. The film resists contraction of the clean surface.
3. A π-A curve plots the relationship between film pressure and film area, showing phase changes as the film is compressed, from a gas-like to liquid-like to solid-like state.
This document provides information on complexation and protein binding. It defines complexation as the association between two or more molecules to form a non-bonded entity through interactions like coordination bonds, van der Waals forces, hydrogen bonds, etc. It classifies complexes into metal complexes, organic molecular complexes, and inclusion complexes. It also discusses ligand types, methods of analyzing complexes, and applications of complexation. The document then defines protein binding and discusses factors that affect binding like drug and protein properties, drug interactions, and patient factors. It explains kinetics of protein binding and methods to determine binding constants and sites like direct plots, Scatchard plots, and others.
1. Complexation refers to the association of two or more interacting molecules or ions through coordinate bonding. This can occur between metal ions and ligands to form metal complexes, or between two organic molecules to form organic complexes.
2. Complexation has various applications in formulation such as improving physical state, reducing volatility, and enhancing solid state stability. It can also influence drug action by modifying properties like absorption, bioavailability, toxicity, and antibacterial activity.
3. Protein binding refers specifically to the formation of complexes between drug molecules and blood proteins. This binding affects the amount of free or unbound drug available to produce pharmacological effects.
This document discusses surface and interfacial phenomena. It defines interfaces and divides them into solid and liquid interfaces. Liquid interfaces deal with liquid-gas or liquid-liquid phases and have applications in infiltration, biopharmaceuticals, and suspensions/emulsions. Surface tension exists between solid-gas and liquid-gas phases, while interfacial tension exists between immiscible liquids. Various methods are described to measure surface tension, interfacial tension, and surface free energy. Surfactants are also discussed, including how they lower tensions and are used in products. Adsorption at interfaces and isotherms are briefly covered.
Surface tension is the property of liquids that allows them to behave like an elastic membrane. It causes liquids to take up the least surface area possible and pull inward on the surface. There are several methods to measure surface and interfacial tension between liquids, including the capillary rise method, drop count/weight methods, Wilhelmy plate method, and ring detachment method. The capillary rise method measures the height liquid rises in a thin glass tube based on the balance of adhesive and cohesive forces. The drop count/weight methods compare the number or weight of drops of a test liquid to a reference liquid in a stalagmometer. The Wilhelmy plate and ring detachment methods apply a calibrated force to detach a
The document discusses surface and interfacial phenomena. It begins by defining an interface as the boundary between two phases that exist together, such as solid-liquid or liquid-gas. Interfaces can be divided into liquid interfaces and solid interfaces. Liquid interfaces deal with liquid-gas or liquid-liquid phases and have applications in processes like emulsification. Solid interfaces involve solid-gas or solid-liquid boundaries. Several methods are described for measuring properties at interfaces like surface tension, interfacial tension, and surface free energy. Surfactants are introduced as agents that can lower surface tension and interfacial tension. Their structures allow them to concentrate at interfaces.
In this presentation:
Surface Tension
Interfacial Tension
Definition of inerfacial tension in different ways
Measurement of interfacial and surface tesion
This document discusses surface and interfacial phenomena. It defines interfaces and surfaces, and describes different types of interfaces including liquid interfaces. It explains concepts such as surface tension, interfacial tension, and surface free energy. Methods for measuring surface and interfacial tensions like the capillary rise method, Du Nouy ring method, and drop weight method are summarized. The document also discusses spreading coefficients and adsorption at liquid interfaces.
The document discusses the design of a steel pipeline submerged in moving water. It analyzes the forces on the pipeline from the flowing water, including drag force. Experiments using a wind tunnel were conducted to determine the coefficient of drag on cylindrical objects at different flow velocities. This was then used to calculate the drag force on the 10-inch diameter pipeline placed 200 inches below the surface of water flowing at 10 in/s. The calculated drag force and weight of the pipeline and water above it were then used to design the pipeline to withstand these forces.
The document summarizes concepts related to surface and interfacial phenomena. It defines interfaces as boundaries between phases, such as solid-liquid or liquid-gas. It describes measurement methods for surface tension and interfacial tension, such as the capillary rise, drop weight, and spinning drop methods. It also discusses the role of surfactants in lowering surface and interfacial tensions and their applications in products like detergents.
This document discusses heat transfer via forced convection. It begins by outlining key topics like boundary layer thickness, skin surface coefficient, and dimensional relationships involving Reynolds and Prandtl numbers. It then discusses specific heat transfer processes like boiling and condensation. The majority of the document focuses on deriving the Blasius exact solution for laminar boundary layer flows over a flat plate through defining stream functions and solving the boundary layer equations and continuity equation to obtain the velocity profile. Key parameters like boundary layer thickness and skin friction coefficient are also defined and related to the dimensionless velocity profile.
This document discusses fluid mechanics and hydraulics concepts including:
1. Definitions of density, specific gravity, atmospheric pressure, absolute and gauge pressure.
2. Descriptions of viscosity, laminar flow, turbulent flow, continuity equation, and steady vs unsteady flow.
3. Explanations of surface tension, capillarity, hydrostatic pressure, buoyancy, and center of pressure.
4. Discussions of manometers, energy equations, forces on submerged surfaces, and fluid static forces.
This document discusses various topics related to fluid mechanics including:
1. Fluid statics, hydrostatic pressure variation, and Pascal's law.
2. Different types of pressures like atmospheric pressure, gauge pressure, vacuum pressure, and absolute pressure.
3. The hydrostatic paradox and how pressure intensity is independent of the weight of fluid.
4. Different types of manometers used to measure pressure like piezometers, U-tube manometers, single column manometers, differential manometers, and inverted U-tube differential manometers.
5. How bourdon tubes and diaphragm/bellows gauges can be used to measure pressure by converting pressure differences into mechanical displacements.
When phases exist together, the boundary between two of them is known as interface.
When the phase is in contact with atmosphere it is termed as surface.
This document provides information about a course on mechanics of fluids. It outlines the course objectives, which are to impart understanding of key fluid concepts and principles, provide knowledge to analyze and design engineering systems involving fluids, and enhance student interest in fluid phenomena. It also lists the expected course outcomes, which include describing fluid properties and solving problems, computing hydrostatic forces, analyzing fluid flow using principles of kinematics and dynamics, and applying dimensional analysis. The document further provides details of various modules that will be covered related to fluid properties, pressure measurement, and fluid flow concepts.
The document discusses key concepts in fluid mechanics including:
1. Pressure is defined as force per unit area and its units are Pascal (SI) or dynes/cm2 (CGS). Atmospheric pressure at sea level is 101,325 Pa.
2. Density is defined as mass per unit volume and has units of kg/m3 (SI) or g/cc (CGS). Specific weight is weight per unit volume and specific gravity is the ratio of a fluid's density to that of water.
3. Viscosity describes a fluid's resistance to flow and is measured by dynamic viscosity in N·s/m2 or kinematic viscosity in m2/s.
The document defines key concepts in fluid mechanics including pressure, density, viscosity, surface tension, continuity equation, and Bernoulli's equation. It provides the definitions and formulas for these terms, as well as explanations of related concepts like manometers, hydrostatic forces, stability of floating bodies, and equations of motion. The summary focuses on introducing the broad topics covered rather than specific details or values.
This presentation covers concepts such as surface tension, surface energy, liquid drops and bubbles, wetting, capillarity at the elementary school level. Comment down in a box for improvement.
The document discusses several concepts related to fluid mechanics, including:
1. Pressure exerted by fluids on surfaces according to the equation P=F/A. Hydrostatic pressure and pressure variations in vertical planes are also covered.
2. Pascal's principle which states that pressure changes are transmitted undiminished throughout a fluid. This allows applications like hydraulic presses.
This document describes several common methods for measuring surface tension of liquids:
1. The capillary rise method measures the height liquid rises in a thin capillary tube based on surface tension.
2. The stalagmometric or drop weight method weighs drops detached from a capillary tip, relating drop size to surface tension.
3. The Wilhelmy plate and ring method measures the force needed to detach a thin plate or ring from the liquid surface, relating this force to surface tension.
This document discusses various parameters used to characterize drug release from pharmaceutical formulations, including diffusion parameters described by Higuchi's equation, dissolution parameters like the effects of agitation and pH, and pharmacokinetic parameters like Cmax, Tmax, and AUC. It also covers models like the Heckel equation that can be applied to understand powder compaction and the Korsmeyer-Peppas model for characterizing drug release mechanisms.
This document discusses optimization techniques used in pharmaceutical development. It defines optimization as choosing the best alternative from available options to make something as perfect or effective as possible. It discusses various optimization parameters like problem type (constrained vs unconstrained), variables (independent vs dependent), and methods like response surface methodology, factorial designs, evolutionary operations, and search methods. Response surface methodology uses statistical experimental designs like central composite designs to determine the relationship between independent and dependent variables and find the optimum formulation.
The document discusses ethics in computing in pharmaceutical research and computer use in market analysis. It addresses key ethical issues like privacy, liability, ownership, and power related to use of computers. It also discusses relevant codes of conduct for computer use and how computers can be used in market analysis to facilitate collection and dissemination of market information. A survey was conducted of industry participants to assess potential acceptance of computer-aided marketing systems. The advisory committee concluded such a system should be developed to complement existing marketing practices.
Quality by Design (QbD) is a systematic approach to pharmaceutical development that begins with predefined objectives and emphasizes product and process understanding based on sound science and quality risk management. Key aspects of QbD include establishing a Quality Target Product Profile (QTPP) that identifies critical quality attributes (CQAs), understanding critical material attributes (CMAs) and critical process parameters (CPPs), and implementing a control strategy for CQAs and CPPs. The ICH Q8 guideline introduced QbD, and it has been further developed through guidelines like ICH Q9 and Q10. Examples show how QbD has been applied scientifically in different pharmaceutical development and manufacturing processes.
This document discusses the application of computer-aided techniques in developing pharmaceutical emulsions and microemulsions. It provides several examples of how experimental design and artificial neural networks have been used to optimize emulsion formulations and processing parameters. Specifically, researchers have used factorial design, response surface methodology, and artificial neural networks to determine the ideal concentrations of formulation components, processing conditions, and emulsifier mixtures to produce emulsions with desirable properties like stability, viscosity, and particle size. These computer-aided approaches allow for simultaneous optimization of multiple formulation parameters and provide a way to shorten product development time compared to traditional trial-and-error methods.
This document discusses various solubilization techniques for improving the solubility of poorly soluble drugs, including physical and chemical modifications. Under physical modifications, it covers crystal modification techniques like polymorphism and salt formation. It also discusses particle size reduction methods like micronization, nanonization, and production of nanosuspensions. Other techniques covered are drug dispersion in carriers through solid solutions, eutectic mixtures and solid dispersions. It also discusses solubilization using surfactants, complexation, and chemical modifications. The techniques discussed aim to improve drug dissolution rates and oral absorption of class II drugs limited by solubility.
This document discusses factors that affect drug absorption in the gastrointestinal (GI) tract. It covers pharmaceutical factors like a drug's solubility, particle size, salt form, and polymorphism/amorphism, which can impact dissolution rate and absorption. It also discusses patient-related factors like age, GI pH, transit time, and disease status. Key pharmaceutical factors that influence drug absorption are solubility, dissolution rate, and factors that impact effective surface area like particle size.
This document provides an overview of parenterals (injectable drugs). It discusses:
- Definitions and routes of administration including subcutaneous, intramuscular, intravenous, and others
- Formulation components like vehicles, buffers, antioxidants, and preservatives
- Manufacturing facilities and processes including design of aseptic areas, environmental controls, and personnel requirements
- Quality control tests for parenterals including clarity, leakage, sterility, and pyrogen testing
This document discusses the three common states of matter - gases, liquids, and solids. It provides details on the properties and behaviors of each state. Gases have widely separated molecules and are compressible. Liquids have more tightly packed molecules and are relatively incompressible. Solids have molecules in close contact that do not move and are nearly incompressible. The document then focuses more on properties of solids, including crystalline and amorphous structures. It also discusses phase equilibria, liquid crystals, and properties of gases including gas laws and the ideal gas equation.
This document discusses rheology, which is the branch of physics dealing with the deformation and flow of liquids. It provides definitions and examples of different types of fluid flow, including Newtonian, plastic, pseudoplastic, and dilatant flow. Key aspects covered include viscosity, shear stress, yield value, and the effects of temperature, particle concentration, and other factors on rheological properties. Common instruments used to measure viscosity, such as capillary, falling sphere, cup and bob, and cone and plate viscometers are also described.
1. The document discusses colloidal dispersions, which are systems where particles between 1 nm and 1000 nm are dispersed uniformly throughout a dispersion medium.
2. Colloidal systems are classified based on particle size into molecular dispersions, colloidal dispersions, and coarse dispersions. They are also classified based on particle-medium interactions into lyophilic, lyophobic, and association colloids.
3. The key properties of colloidal systems discussed are electrical properties (surface charge, zeta potential, electrophoresis), optical properties (Tyndall effect, turbidity), and kinetic properties (Brownian motion, diffusion, viscosity).
1. The document discusses regulatory requirements for drug approval, including non-clinical and clinical studies that must be conducted and submitted to regulatory agencies like the FDA.
2. It describes the various teams involved in drug development, including discovery, preclinical, clinical, manufacturing, and marketing teams. The responsibilities and roles of each team are provided.
3. The approval process is outlined, including requirements for an Investigational New Drug (IND) application to the FDA. The IND must provide data from animal and other preclinical studies. It allows clinical trials to proceed if approved by the FDA within 30 days.
Total quality management (TQM) is a management approach focused on customer satisfaction through continual improvement. It involves all employees and emphasizes strategic planning, fact-based decision making, and effective communication. TQM aims to hold all parties accountable for quality and can improve profitability, customer satisfaction, productivity, and employee morale. Quality by design (QbD) is a concept where quality is planned and designed into products and processes from the development stage to reduce issues and meet customer needs.
This document discusses emulsions and self-emulsifying drug delivery systems (SEDDS). It defines emulsions as mixtures of two immiscible liquids stabilized by an emulsifying agent. The main types of emulsions described are oil-in-water, water-in-oil, multiple emulsions, and microemulsions. SEDDS are defined as isotropic mixtures of oils, surfactants, and co-solvents/co-surfactants that spontaneously form emulsions when exposed to aqueous media and can improve drug solubility and bioavailability. Key factors in developing SEDDS like choice of oils, surfactants, and evaluation methods are also summarized.
The document discusses suspensions, which are two-phase systems composed of solid particles dispersed in a liquid. Suspensions can be classified based on particle size as molecular, colloidal, or coarse dispersions. They can also be classified as flocculated or deflocculated based on how the particles interact. Factors like particle size, viscosity, density, and interfacial properties affect suspension stability. Common methods for producing suspensions include precipitation, dispersion, and controlled flocculation. The stability of suspensions is evaluated through sedimentation volume, degree of flocculation, and zeta potential measurements. Equipment like colloid mills and ultrasonic devices can be used to formulate suspensions.
This document discusses various parameters used to characterize drug release from pharmaceutical formulations. It describes diffusion parameters defined by Higuchi's equation and plots. Dissolution parameters like the effects of agitation, pH, temperature, and medium properties are outlined. Pharmacokinetic parameters including Cmax, Tmax, and AUC are defined. The Heckel equation is presented as a method to analyze powder compaction. Similarity factors f1 and f2 are introduced to compare dissolution profiles. The Higuchi and Korsmeyer-Peppas models for drug release are presented.
The document discusses kinetics of stability and accelerated stability testing. It provides details on zero order, first order and second order reactions. It explains the determination of rate constants, half life and time for 90% degradation using kinetic equations. The document also discusses Arrhenius equation for predicting shelf life from accelerated stability studies conducted at elevated temperatures. It summarizes the guidelines for stability testing of active pharmaceutical ingredients and finished pharmaceutical products as per ICH.
The document discusses different analytical techniques used to analyze drug-excipient interactions, including thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and FT-IR spectroscopy. Each technique is described in one to two sentences. TGA measures mass changes as temperature changes and provides information on physical and chemical phenomena like decomposition. DTA and DSC measure the temperature and heat flow differences between a sample and reference to determine endothermic and exothermic reactions like melting. XRD analyzes diffraction patterns to characterize crystal structure and polymorphism. FT-IR identifies functional groups and structures by analyzing absorption peaks.
This document provides an overview of pharmaceutical packaging. It discusses the functions of packaging including protection, storage, identification and information provision. It describes common packaging materials like glass, plastic, metal and rubber and how they are used. Different dosage forms like solids, liquids, and parenterals are outlined along with their typical packaging. Recent trends in the industry toward devices like prefilled syringes and regulations from the FDA are also summarized.
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Main Java[All of the Base Concepts}.docxadhitya5119
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How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
1. INTERFACIAL PHENOMENA
Presented by
(Dr) Kahnu Charan Panigrahi
Asst. Professor, Research Scholar,
Roland Institute of Pharmaceutical Sciences,
(Affiliated to BPUT)
Web of Science Researcher ID: AAK-3095-2020
12/14/2021 INTERFACIAL PHENOMENON BY KC 1
2. INTRODUCTION
• Interface is the boundary between two phases.
• Surface is a term used to describe either a gas-
solid or a gas- liquid interface.
• Definition: Surface tension is the force per
unit length that must be applied parallel to the
surface to counterbalance the net inward pull. It
has the units of dynes/cm or N/m.
• Interfacial tension is the force per unit length
existing at the interface between two
immiscible phases (units are dynes/cm or N/m).
𝜸= F/L
12/14/2021 INTERFACIAL PHENOMENON BY KC 2
3. • Surface tension maintains the surface area of liquid to a minimum value.
• If the surface of the liquid increases the energy of the liquid also increases.
• Because this energy is proportional to the size of the free surface, it is called
as surface free energy.
• Surface free energy is defined as the work required to increase the surface
area by 1 sq cm.
INTERFACIAL PHENOMENON BY KC
12/14/2021 3
Surface Free Energy
𝑾 = 𝜸 ∆ 𝑨
𝑾 Surfacefree energy(ergs)
𝜸 surface tension (dynes/cm)
∆ 𝑨increase in area (cm2).
4. • Let’s consider a ABCD rectangular wire as shown in figure.
• The side AD of length L is movable.
• A drop of soap solution is placed on frame so that it will form a film within
the frame.
• The side AD remain stable until a downward force f is applied.
• After applying force side AD move to a distance d as shown in figure.
• The work done is given by:
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
4
W = F X d
The soap film has two surface each having length L
F = γ X 2 L
γ = F X 2L
By putting this in equation 1
W = γ X 2L X d
W = γ X dA
6. METHODS OF SURFACE TENSION MEASUREMENTS:-
INTERFACIAL PHENOMENON BY KC
12/14/2021 6
There are several methods of surface tension measurements:
1. Capillary rise method
2. Dunouy’sring method
2. Stallagmometer method
7. CapillaryRiseMethod
𝜸
𝒓
𝒉
𝒑
𝒈
surface tension
radius of capillary
height
density of the liquid
acceleration of gravity
This method cannot be used to obtain interfacial tensions.
When a capillarytube is placed in a liquid contained in a beaker, the liquid rises
up in the tube to a certain distance. By measuring this rise in the capillary, it is
possible to determine the surface tension of the liquid using the formula:
𝜸 = ½ 𝒓𝒉𝒑𝒈
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
7
a
b
𝜽
8. Upward Component:-
For this purpose, a thin circular capillary is dipped into the tested liquid. If the interaction
forces of the liquid with the capillary walls (adhesion) are stronger than those between the
liquid molecules (cohesion), the liquid wets the walls and rises in the capillary to a defined
level and the meniscus is hemi spherically concave.
In the opposite situation the forces cause decrease of the liquid level in the capillary below
that in the chamber and the meniscus is hemi spherically convex.
If the cross-section area of the capillary is circular and its radius is sufficiently small, then
the meniscus is hemispherical. Along the perimeter of the meniscus there acts a force due to the
surface tension presence. 𝒄𝒐𝒔𝜽 = a / 𝜸
a= 𝟐𝝅𝒓𝜸𝒄𝒐𝒔𝜽
[r= the capillary radius, 𝜸 = the liquid surface tension, ⱺ= the wetting contact angle]
The upword force a is equilibrated by the mass of the liquid raised in the capillary to the
height h, that is the gravity force b.
INTERFACIAL PHENOMENON BY KC
12/14/2021 8
9. INTERFACIAL PHENOMENON BY KC
12/14/2021 9
Downward Component:-
In the case of non-wetting liquid , it is lowered to a distance h.
At equilibrium: a = b
𝟐𝝅𝒓𝜸𝒄𝒐𝒔𝜽 = 𝝅𝒓𝟐hpg
𝜸 =
𝒓𝒉𝒑𝒈
𝟐𝒄𝒐𝒔𝜽
For liquid completely wetting wall of capillary ⱺ = 0 so equation becomes 𝛄 =
𝐫𝐡𝒑𝐠
𝟐
b= 𝝅𝒓𝟐hpg
Method:-
A clean dry capillary is fixed on a stand horizontally.
Microscope & cross wire are adjusted to measure internal diameter(d).from which r is
estimated
50 ml water is taken in a 100ml beaker.
Then capillary is dipped in it such that pointer just touches the water surface.
10. h1=Height of water level in capillary during attachment of beaker
h2=Height of water in capillary after removal of beaker
Rise of liquid in capillary (h)= h2-h1
Density (p) of liquid is estimated by a specific gravity or pychnometer method.
Using the value of r, h, p surface tension can be estimated.
INTERFACIAL PHENOMENON BY KC
12/14/2021 10
𝜸 = ½ 𝒓𝒉𝒑𝒈
11. The Du-Nouy Ring Method
This method is used to measure both surface &
interfacial phenomena.
it is a rapid process of determination & only a small
amount of liquid can be determined.
A platinum ring can be used, which is submerged in the
liquid.
As the ring is pulled out of the liquid, the force required
to detach it from the liquid surface is precisely measured.
The force necessary to detach a platinum–iridium
ring immersed at the surface or interface is
proportional to the surface or interfacial tension.
INTERFACIAL PHENOMENON BY KC
12/14/2021 11
12. UPWARD PULL=>
When ring is pulled upward then some liquid rises from its level. And force is recorded (in
dyne)by help of torsion wire.
Upward pool =dial reading in dynes
DOWNWARD PULL=>
Weight of the liquid under ring & also interfacial tension makes a downward pool to balance the
upward pool.
Downward pool =mg = 𝜸 ∗ 𝟐𝝅𝒓 ∗ 𝟐
At equilibrium Upward pool = Downward pool
Dial reading in dynes = 𝜸 ∗ 𝟐𝝅𝒓 ∗ 𝟐
INTERFACIAL PHENOMENON BY KC
12/14/2021 12
13. Method
• A cleaned platinum-iridium ring is attached to the hook at the end of the torsion lever arm.
• A more dense liquid is transferred into a clean glass vessel and placed on the table.
• The table is moved beneath the ring and raised until the ring is immersed in the liquid.
• The torsion arm is released by rotating the torsion adjusting knob. The instrument is
adjusted to zero reading.
• The torsion knob is adjusted until the index and its image is exactly in line with the
reference mark on the mirror.
• The light liquid is poured on the surface of the heavier liquid.
• During the next step, two operations are done simultaneously.
(l) The sample table is lowered and therefore, the lever (ring) is pulled down.
(2) The torsion knob is adjusted so as to induce upward-pull.
• The ring at the interface between two liquids will become distended, but the index is kept
on the reference.
• These two adjustments are continued until the distended film at the interface ruptures.
• The scale reading at the breaking point of the interfacial film is the apparent interfacial
tension.
INTERFACIAL PHENOMENON BY KC
12/14/2021 13
14. Stallagmometric Method:-
INTERFACIAL PHENOMENON BY KC
12/14/2021 14
• For this purpose fixed volume of test liquid and standard liquid is
leaked out from glass capillary of the stalagmometer and then
were weighed.
• By using the value of w1& w2,the surface tension of liquid can be
determined.
• This method was first time described by Tate in 1864 who formed
an equation, which is now called theTate’s law.
15. INTERFACIAL PHENOMENON BY KC
12/14/2021 15
v1 = F/L
v1 = w1 / 2ח r
w1 = 2ח r v1……………………….. (1)
[w= drop weight, r = the capillary radius, v1 = surface tension of the standard liquid]
v2 = F/L
v2 = w2 / 2ח r
w2 = 2ח r v2……………………….. (1)
[w= drop weight, r = the capillary radius, v2 = surface tension of the test liquid]
By solving both the equation
16. Spreading of liquid
• When Oleic acid dropped on water, it immediately spreads on
the surface of water
• Oleic Acid – Spreading Liquid (L)
• Water – Sub-layer Liquid (S)
• Generally spreading occurs when adhesive force is more
than cohesive force
12/14/2021
INTERFACIAL PHENOMENON BY KC
PANIGRAHI
16
17. • Work of Cohesion (W ) may be
c
defined as the surface free energy
increased by separating a column of
pure liquid into two halves
• Surface free energy increase = γ dA
• Wc = γL (dA+dA) = 2 γLdA
• Here the column is of cross sectional
area is 1cm2 (dA= 1cm2)
• Wc = 2 γL
12/14/2021 INTERFACIAL PHENOMENON BY KC 17
18. • Work of Adhesion (Wa) may be defined
as the surface free energy increased by
separating a column of two immiscible
liquids at its boundary into two sections
• As two sections of immiscible liquids
are already separated by a boundary, the
energy requirement will be less by an
amount γLS dA
• Wa= γLdA + γS dA - γLS dA
• Here the columns are of cross sectional
area 1cm2
• Wa = γL + γS - γLS
12/14/2021 INTERFACIAL PHENOMENON BY KC 18
19. • Spreading coefficient (S) is the difference between work of adhesion
and work of cohesion
S = Wa –Wc
= (γL + γS – γLS) - 2γL
= γS – γL – γLS
• S = γS – (γL + γLS)
• γL - Surface tension of spreading liquid
• γS - Surface tension of sublayer liquid
• γLS - Interfacialtension
12/14/2021 INTERFACIAL PHENOMENON BY KC 19
20. • Spreading occurs when spreading coefficient S is positive i.e., γS > (γL+
γLS). When free energy of the spreading liquid and the interfacial tension
with the sub layer is less than that of sublayer the spreading becomes
spontaneous to reduce free energy of sublayer.
• If spreading coefficient S is negative ie, (γL+ γLS) > γS Spreading liquid
forms globules or floating lens means spreading will not take place
12/14/2021 INTERFACIAL PHENOMENON BY KC 20
21. Surface ActiveAgents
• Molecules and ions that are adsorbed at interfaces are termed
surface-active agents or surfactants.
• Surfactants have two distinct functional groups in their chemical
other of
structure, one of which is water-liking (hydrophilic) and the
which is lipid-liking (lipophilic).
• These molecules are referred to as amphiphile.
12/14/2021 INTERFACIAL PHENOMENON BY KC 21
22. Surface ActiveAgents
• When such molecule is placed in an air-water or
oil-water system, the polar groups are oriented
toward the water, and the nonpolar groups are
oriented toward the air or oil.
• When surfactants are dissolved in water they can
reduce surface tension by replacing some of the
water molecules in the surface so that the forces
of attraction between surfactant and water
molecules are less than those between water
molecules themselves, hence the contraction
force is reduced.
12/14/2021 INTERFACIAL PHENOMENON BY KC 22
23. Classification of surface active agents
• Non-ionic surfactants
Have low toxicity and high stability and compatibility
,
e.g. Sorbitan esters (spans) and Polysorbates (tweens).
• Anionic surfactants
Have bacteriostatic action
e.g. Sodium Lauryl Sulphate
• Cationic surfactants
Have bactericidal activity
e.g. benzalkonium chloride
• Ampholytic Surfactants
Phospholipids
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
23
24. HLB System
hydrophile-lipophile balance
• Definition: The
(HLB) system is an arbitrary scale for
expressing the hydrophilic and lipophilic
characteristics of an emulsifying agent.
• Agents with HLB value of 1-8 are lipophilic and
suitable for preparation of w/o emulsion,
• Those with HLB value of 8-18 are hydrophilic
and good for o/w emulsion.
12/14/2021 INTERFACIAL PHENOMENON BY KC 24
27. • HLB = Σ (Hydrophilic group) – Σ (Lipophilic group) + 7
• Polyhydric Alcohol Fatty Acid Esters (Ex. Glyceryl monostearate)
HLB = 20 ( 1 – S / A )
S = Saponification number of the ester
A = Acid number of the fatty acid
• Surfactants with no Saponification no (Ex. Bees wax and lanolin)
HLB = (E + P) / 5
E = The percent by weight of ethylene oxide
P=The percent by weight of polyhydric alcohol group in the molecules
• Surfactants with hydrophilic portion have only oxyethylene groups
HLB =E / 5
INTERFACIAL PHENOMENON BY KC
12/14/2021 27
Method of estimation
28. Micellar solubilization
• Surfactants can lower surface tension & improve the
dissolution of lipophilic drugs in the aqueous
medium.
• A surfactant, when present at low concentrations in
a system, adsorbs onto surfaces or interfaces
significantly reducing the surface or interfacial free
energy.
• When the concentration of surfactants exceeds their
critical micelle concentration (CMC), micelle
formation occurs, entrapping the drugs within the
micelles.
• This process is known as micellisation and generally
results in enhanced solubility of poorly soluble drugs.
INTERFACIAL PHENOMENON BY KC
12/14/2021 28
29. Detergency
• Detergency is a process by which soil is removed from a surface and
undergoes solubilization or dispersion.
• The HLB requirement for detergency is about 13-16.
• It result of several physicochemical phenomenon at the interface of three
phases : surface/soil/detergent.
Wetting of surface
Solubilisation of dirt
Removing soluble dirt as deflocculated particle
Suspending particle in detergent solution
Removing oil soluble material as emulsion
Converting dirt into foam
Avoiding re-deposition of soil on surface
INTERFACIAL PHENOMENON BY KC
12/14/2021 29
31. Wetting phenomenon
• Wettability is defined as the tendency of one fluid to spread on or adhere to
a solid surface in the presence of other immiscible fluids.
• The tendency of a liquid to spread over the surface of a solid is an indication
of the wetting characteristics of the liquid for the solid.
• Contact angle is the angle between liquid droplet and surface over which it
spreads.
12/14/2021 INTERFACIAL PHENOMENON BY KC 31
32. • As the contact angle decreases, the wetting characteristics of the liquid
increase.
• Complete wettability would be evidenced by a zero contact angle, and
complete nonwetting would be by a contact angle of 180° .
• Surface active agent decrease the interfacial tension and also lower the contact
angle.
• The HLB requirement to act as wetting agent is 6 to 9.
γs= γSL + γL cos ϴ
• Weknow that spreading coefficient ‘S’
S= γS – γL – γLS
• Combining both these equations, substituting value of γs in second equation
S = γL (cos ϴ-1)
• The surface tension obtained at cos ϴ =1 or ϴ = 0 is critical surface tension.
INTERFACIAL PHENOMENON BY KC
12/14/2021 32
33. Electrical properties
Surface charge – zeta potential :-
Let’s consider solid particle are dispersed in an aqueous solution containing
electrolyte .
Distribution of charges are shown in the fallowing fig.
Assuming the cation are absorbed at interface
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
33
34. The interface:
• aa’ the actual plane is the solid liquid interface and it is assumed that the
cation are adsorbed in the interface and impart +ve charges.
Tightly bound layer:
• Immediately adjacent to the interface aa’ is the region of tightly bound
layer and it extend up to bb’.
• Once the adsorption is complete the cation attract few anion and repel the
approaching cation.
• Thus at equilibrium some excess anion are present at this region however
their number is less than adsorbed cation. Therefore bb’ the shear plane
still impart +ve charge.
• The degree of attraction of certain molecule and counter ion is such that
shear plane is bb’ rather than aa’.
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
34
35. Diffused 2nd layer:
• This is the region bound by the line bb’ and cc’.
• In the layer excess –ve ion are present.
• At and beyond cc’ the charge is electrically neutral.
• As a whole the system is electrically neutral.
• Thus the electrical distribution at the interface is equivalent to the double
layer which consist of tightly bound layer and diffused 2nd layer.
• When the interface adsorbed –ve ion than aa’ is negative, bb’ is negative and
cc’ is neutral.
Nernst potential and zeta potential:
• Nernst potential is the potential at actual surface itself i.e. aa’ due to presence
of potential determining ion. It is denoted as E and also called electrodynamic
potential.
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
35
36. • It is defined as the potential difference between the actual surface and the
electro neutral region of the solution.
• Zeta potential is the potential observed at the shear plane i.e. bb’.
• Zeta potential is also known as electrokinetic potential.
• It is defined as the potential difference between surface of tightly bound layer or
shear plane and electroneutral region.
• Zeta potential also defined as the work required to bring unit charge from
infinite to surface of particle.
12/14/2021 INTERFACIAL PHENOMENON BY KC
PANIGRAHI
36
38. • Adsorption is a surface phenomenon whereas absorption is a bulk
phenomenon.
• Desorption (evaporation) is the reverse of adsorption
• Physical adsorption, in which the adsorbate is bound to the surface
through the weak van der Waals forces.
• Chemical adsorption or chemisorption, which involves the stronger
electrostatic forces.
• Adsorbate: material which get adsorb (Gas/solute) (x moles)
• Adsorbent: material on which adsorption takes place (m grams)
12/14/2021 INTERFACIAL PHENOMENON BY KC 38
Introduction
39. • The graph between gas adsorbed per unit area or unit mass of solid vs pressure
at constant temperature is called adsorption isotherm.
• Freundlich isotherm is expressed as:
y = x/m = 𝒌𝒑𝟏/𝒏
x = weight of gas adsorbed per unit weight of adsorbent,m
p = equilibrium pressure
k and n = constants
• The equation can be converted to logarithmic form as:
𝐥𝐨𝐠
𝐱
𝐦
= 𝐥𝐨𝐠 𝐤 +
𝟏
𝒏
𝐥𝐨𝐠 𝑷
INTERFACIAL PHENOMENON BY KC
12/14/2021 39
Freundlich isotherm
40. Freundlich isotherm
y = x
= kp1/n
m
Log x
m n
= Log k + 1
Log p
y =
x
m
= kp1/n
12/14/2021 INTERFACIAL PHENOMENON BY KC 40
41. Langmuiradsorptionisotherm
Fallowing are the assumption for this isotherm:
• The surface of solid has fixed no of site for adsorption
• The thickness of layer is uni molecular
• Rate of adsorption proportional to number of site unoccupied
• Rate evaporation proportional to number of site occupied
Let’s consider at a particular pressure P,
Fraction of active sites occupied = ϴ
Fraction of un-occupied sites = 1- ϴ
Rate of adsorption r1=k1(1-ϴ)p
Rate of desorption r2=k2ϴ
12/14/2021 INTERFACIAL PHENOMENON BY KC 41
42. ϴ =
k1p
k2+k1p
ϴ = (k1/k2)p
k
k2
1+( 1)p
Replacing(k1/k2) with b and ϴ with y/ym
• y= mass of gas adsorb per gram of adsorbent at pressure p
• ym= mass of gas that 1 gram of adsorbent adsorb when
monolayer is formed
k2ϴ = k1(1-ϴ)p
12/14/2021 INTERFACIAL PHENOMENON BY KC 42
At equilibrium r2=r1
k1p– k1pϴ= k2ϴ
(𝑦/𝑦𝑚) = bp/(1+bp)
y = 𝑦𝑚𝑏𝑝/(1 + 𝑏𝑝)
p/y =
1
𝑦𝑚𝑏
+
𝑝
𝑦𝑚
Inverting above equation and multiplying with p we get
1/y =
1
𝑦𝑚𝑏𝑝
+
𝑏𝑝
𝑦𝑚𝑏𝑝
43. 12/14/2021 INTERFACIAL PHENOMENON BY KC 43
• Above equation represent Langmuir isotherm.
• The plot of p/y against p gives straight line.
• ym can be obtained from slop and b can be obtained from intercept
𝒑
𝒚
=
𝟏
𝒚𝒎𝒃
+
𝒑
𝒚𝒎
44. BET Equation:
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Sometime gas adsorbed as multimolecular layer on solid. The expression
for this was derived by Brunaer, Ennet and Teller and termed as BET
equation which is given by
𝒑
y(po−p)
=
𝟏
ymb
+
𝒃−𝒑
ymb
𝒑
po
where,po = saturated vapour pressure
b = constant alpha heat of adsorption
y= mass of gas adsorbe per gram of adsorbant at pressure p
ym=mass of gas that 1 gram of adsorbent adsorb when monolayer is formed
45. INTERFACIAL PHENOMENON BY KC
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APPLICATION OF BET :
• The surface area per unit weight i.e specific surface area can be predicted.
• The type of isotherm can be determined. If b > 2.0 then type 2 and if b<2.0
then type-1 isotherm.
• The point of monolayer formation can be identified from the graph.
46. Adsorption Isotherm
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Adsorption isotherm are defined as the plot drawn between the amount of gas
adsorbed on a solid (y- axis) against the equilibrium pressure(x – axis) at constant
temperature. There are 5 different type of adsorption isotherm:
47. Type I :
• This adsorption isotherm represents a significant increase in the adsorption
with increasing pressure and fallowed by levelling off.
• This levelling off is due to saturation of available specific chemical groups
on the entire surface.
• This is same as Freundlich or Langmuir adsorption isotherm.
• e.g: Adsorption of nitrogen gas on charcoal.
Type II :
• This isotherm is ssigmoidal in shape and occur when gas undergo physical
adsorption on non-porous solid.
• The first inflection point represent formation of monolayer.
• When pressure increases multilayer formation observed.
• Described by BET equation. Constant b is greater than 2.
• Eg: Adsorption of nitrogen on platinum catalyst.
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48. Type III:
• The heat of adsorption of gas in first layer is less than latent heat of
condensation in successive layers.
• Described by BET equation. Constant b is less than 2.
• e.g.: Adsorption of bromine on silica.
Type IV:
• This plot represents the adsorption of gas on porous solid.
• The first inflection point represent formation of monolayer.
• Condensation within the pore results multi molecular layer formation.
• E.g: Adsorption of benzene on silica.
Type V:
• Represented by capillary condensation.
• Adsorption reaches a limiting value before P0
• e.g: Adsorption of water vapour on charcoal.
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