Physical Pharmacy (LEC) PDF

PHYSICAL PHARMACY (LEC) ARELLANO UNIVERSITY BS Pharmacy | Semi-Finals | 2nd Year, 1st sem COMPONENTS OF A SOLUTIONS SOLUBILITY Solubility in physical pharmacy refers to the...

PHYSICAL PHARMACY (LEC) ARELLANO UNIVERSITY BS Pharmacy | Semi-Finals | 2nd Year, 1st sem COMPONENTS OF A SOLUTIONS SOLUBILITY Solubility in physical pharmacy refers to the SOLUTE maximum amount of a solute that can dissolve in a solvent at a given temperature The substance that is dissolved in the and pressure, resulting in a saturated solvent (e.g., a drug, salt, sugar). solution. It's a critical concept in drug formulation and SOLVENT delivery because the solubility of a drug affects its bioavailability, efficacy, and how The substance that dissolves the solute it's formulated into different (e.g., water, alcohol, oil). In most dosage forms. pharmaceutical applications, water is the primary solvent due to its biocompatibility. DISSOLUTION TRANSFER of molecules or ions from a solid state into solution. Is described by the Noyes-Whitney Equation. SOLUBILITY EXTENT to which the dissolution TYPES OF SOLUTIONS ACCORDING proceeds under a given set of TO THE SOLUBILITY OF THE experimental conditions. SOLUTE FORMULA: Solubility = amount of solute / volume of SATURATED SOLUTIONS Solvent A solution in which no more solute can dissolve at a given temperature and SOLUTIONS pressure. Maximum amount of solute that can In physical pharmacy, a solution refers to dissolve in a solvent. a homogeneous mixture of two or more A solution that contains the maximum substances, where a solute is dissolved in concentration of a solute that can dissolve a solvent. at a given temperature. Solutions are vital in drug formulation as they affect drug delivery, absorption, and SUPERSATURATED bioavailability. Understanding their SOLUTIONS properties and classifications helps in designing effective pharmaceutical A solution that contains more solute than Products. the equilibrium solubility, usually DAN ♡  PHYSICAL PHARMACY (LEC) ARELLANO UNIVERSITY BS Pharmacy | Semi-Finals | 2nd Year, 1st sem achieved by changing the conditions (e.g., temperature) and then cooling the Solution. Contains more solute than can PH OF THE SOLUTIONS theoretically dissolve at a given temperature and is unstable. Many drugs are weak acids or bases, so their solubility can depend on the pH of the medium. Ionized forms of drugs are more UNSATURATED SOLUTIONS soluble in aqueous solutions than their unionized counterparts. A solution that contains less solute than pH can thus be manipulated to enhance the equilibrium solubility. Solubility. Additional solute can still dissolve. Many drugs are weak acids or bases, so Contains less solute than the amount that their solubility can depend on the pH of can dissolve at a given temperature. the medium. Ionized forms of drugs are more soluble in aqueous solutions than FACTORS AFFECTING their unionized counterparts. SOLUBILITY pH can thus be manipulated to enhance solubility. NATURE OF THE SOLUTE PRESSURE AND SOLVENT For gasses, increased pressure increases "Like dissolves like" is a basic principle of solubility. This is described by Henry's Law. solubility. Polar solutes dissolve well in polar solvents (e.g., salts in water), and non- polar solutes dissolve well in non-polar solvents (e.g., oils in organic solvents). Solubility - maximum amount of solute expressed in grams that can be dissolved in 100g of water. Miscibility - ability of one substance to PARTICLE SIZE mix with another substance. (ex: liquid liquid, liquid-gas) Smaller particles have a larger surface area relative to their volume, which can lead TEMPERATURE to faster dissolution rates and, in some cases, increased solubility due to surface energy effects. For many substances, solubility increases with temperature. However, for gases, solubility typically decreases as temperature increases. PRESENCE OF SALTS Salting out --> presence of salt decreases solubility Salting in --> presence of salt increases solubility DAN ♡  PHYSICAL PHARMACY (LEC) ARELLANO UNIVERSITY BS Pharmacy | Semi-Finals | 2nd Year, 1st sem CLASSIFICATION OF DISPERSED interact to an appreciable extent with the (PARTICULATE) SYSTEM dispersion medium MOLECULAR DISPERSION LYOPHOBIC (TRUE SOLUTIONS) solvent-hating colloids is defines as a mixture of two or more composed of material that have little components that form a homogeneous attraction for the dispersion medium, due molecular dispersion or one phase system. primarily to the absence of a solvent sheath around the particles Range of Particle Size Less than 1nm ASSOCIATION Examples: Oxygen Molecules, Ordinary Ions, Glucose amphiphilic colloids characterized by having two distinct regions of opposing solution affinities COLLOIDAL DISPERSION PROPERTIES OF COLLOIDS represents a system having a particle size intermediate between that of a true solution OPTICAL and a coarse dispersion. Range of Particle Size Faraday-Tyndall Effect 1 nm to 0.5 nm (100 angstrom or 10-5 cm) ability to scatter or disperse light. It describes the rotation of the plane of Examples: Colloidal Silver Solutions, polarization of light (or other Natural and Synthetic Polymers electromagnetic waves) when it passes through a material that is under the influence of a magnetic field parallel to the COARSE DISPERSION direction of the light. diameter of particles being larger KINETIC than 0.5 μm Range of Particle Size Brownian Motion Greater than 0.5 μm (10-5000 angstrom) colloidal particles appear as tiny points of light in constant motion when examined Examples: Grains of Sand, Red Blood Cells, under an ultra microscope. Most emulsions & Suspension Diffusion --> spontaneous movement of TYPES OF COLLOIDAL SYSTEMS particles from a region of higher concentration to one of lower concentration until equilibrium is achieved. LYOPHILIC solvent-loving colloids systems containing colloidal particles that DAN ♡  PHYSICAL PHARMACY (LEC) ARELLANO UNIVERSITY BS Pharmacy | Semi-Finals | 2nd Year, 1st sem ELECTRIC Nernst Potential aka “Electro Thermodynamic Potential” difference in potential between the actual surface of the particle & the electroneutral region of the dispersion ELECTRIC Zeta Potential aka “Electrokinetic Potential” difference in potential between the surface of the tightly-bound layers & the electroneutral region of the dispersion has more application in pharmacy (example: decreased zeta potential, results to flocculation) DAN ♡