Module 1: Introduction to Physical Pharmacy PDF

Module 1: Introduction to Physical Pharmacy By: Cyruschad Tutor,RPh,MBA  Physical Pharmacy is a branch of pharmaceutical science that focuses on the physical and chemical properties of drugs and drug delivery systems It involves the study of how drugs interact...

Module 1: Introduction to Physical Pharmacy By: Cyruschad Tutor,RPh,MBA  Physical Pharmacy is a branch of pharmaceutical science that focuses on the physical and chemical properties of drugs and drug delivery systems It involves the study of how drugs interact with their environment, including the human body, and how these interactions affect drug efficacy, safety, and stability. Physical pharmacy also encompasses the development of drug delivery systems that optimize drug delivery and patient outcomes. ctutorPhysPhar2024  Physical Pharmacy One of the key areas of focus in physical pharmacy is drug solubility and dissolution. The solubility of a drug is the amount of drug that can dissolve in a given solvent at a given temperature, while dissolution refers to the process by which a solid drug dissolves in a solvent. (Factor for Bioavailability) Another important area of physical pharmacy is drug stability. The stability of a drug refers to its ability to maintain its physical, chemical, and biological properties over time and under different conditions. ctutorPhysPhar2024  Physical Pharmacy Physical pharmacy also encompasses drug delivery systems, which are designed to optimize drug delivery and patient outcomes. Drug delivery systems can be classified into several categories, including oral, transdermal, inhalation, and parenteral. ctutorPhysPhar2024 DENSITY AND SPECIFIC GRAVITY ctutorPhysPhar2024  DENSITY Density is a measure of mass per unit of volume. In general, gases have the lowest densities, and solids have the highest but these densities are highly dependent on the pressure and temperature. Density is an essential characteristic of a substance, a measure that affects medicines too. Density is the name given to a relationship; a relationship between the mass of a substance and the space that that mass occupies. Substance of its mass per unit volume (g/ml) ctutorPhysPhar2024  DENSITY At a certain temperature – for example – 20 degrees C – 100 grams of water occupies a volume of 100mL, a 1:1 relationship. This proportional relationship is, however, not the same for all liquids, solids and semi-solids. Given that different substances do not have this 1:1 ratio of mass:volume, it is necessary for the formulator to convert either mass or volume. A liquid may, for example, be easier to measure by volume rather than by mass. ctutorPhysPhar2024  DENSITY COMPUTATION ctutorPhysPhar2024  SPECIFIC GRAVITY Density of a sample/Density of a standard/It is the ratio of a substance to the density of a standard Ratio of weight of a substance over the weight of an equal volume of a standard Standard: water No unit; Numerically equivalent to density Temperature: 25 °C; alcohol=15.56 °C ctutorPhysPhar2024  SPECIFIC GRAVITY This is a figure depicting the layering of immiscible liquids in a test tube, with mineral oil being lighter than water and chloroform being heavier. When temperatures change, substances expand or contract at various rates, therefore accurate work must account for differences in specific gravity. The standard temperature for specific gravities in the US Pharmacopeia is 25°C, except for alcohol, which is 15.56°C under government regulation. ctutorPhysPhar2024  SPECIFIC GRAVITY The specific gravity of a liquid can be calculated when its weight and volume are known using the following equation: Specific gravity = weight of substance weight of equal volume of water ctutorPhysPhar2024  1. SPECIFIC GRAVITY OF USING PYCNOMETER ctutorPhysPhar2024 ANSWER ME A 50 mL pycnometer is found to weigh 120 g when empty, 171 g when filled with water and 160 g when filled with an unknown liquid. Calculate the sp. gr of the unknown liquid. ctutorPhysPhar2024  2. DISPLACEMENT METHOD Archimedes' principle states that the “upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces”. Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by Archimedes of Syracuse. Apparent loss of water ctutorPhysPhar2024  2. DISPLACEMENT METHOD We can weigh a plummet when suspended in water and when suspended in a liquid the specific gravity of which is to be determined, weight of displaced water = Weight of plummet (in air– in water). weight of displaced liquid = Weight of plummet (in air - in liquid) sp. gr. of oil =wt of displaced oil wt of displaced water ctutorPhysPhar2024 ANSWER ME A glass plummet weighs 12.64 g in air, 8.57 g when immersed in water, and 9.12g when immersed in an oil. Calculate, the specific gravity of the oil. ctutorPhysPhar2024  3. SOLIDS HEAVIER THAN AND INSOLUBLE IN WATER simply divide the weight of the solid in air by the weight of water that it displaces when immersed in it. The weight of water displaced (apparent loss of weight in water) is equal to the weight of an equal volume of water. ctutorPhysPhar2024  3. SOLIDS HEAVIER THAN AND INSOLUBLE IN WATER A piece of glass weighs 38.525 g in air and 23.525 g when immersed in water. What is its specific gravity? answer: 38.525 g - 23.525 g = 15.000 g of displaced water (weight of an equal volume of water) Specific gravity of glass = 38.525 g/15.000 = 2.568 ctutorPhysPhar2024  3. SPECIFIC GRAVITY OF SOLIDS Solids Heavier Than and Soluble in Water. The weights of equal volumes of any two substances are proportional to their specific gravities. Therefore, given a solid heavier than and soluble in water, we may use the method just discussed, but substituting some liquid of known specific gravity in which the solid is insoluble. ctutorPhysPhar2024  3. SPECIFIC GRAVITY OF SOLIDS A crystal of a chemical salt weighs 6.423g in air and 2.873g when immersed in an oil having a specific gravity of 0.858. What is the specific gravity of the salt? Answer 6.423 g - 2.873 g = 3.550 g of displaced oil 3.55 (𝑔 𝑜𝑓 𝑜𝑖𝑙) 6.423 (𝑔 𝑜𝑓 𝑠𝑎𝑙𝑡) = 0.858 (𝑠𝑝.𝑔𝑟.𝑜𝑓 𝑜𝑖𝑙) 𝑥 (𝑠𝑝.𝑔𝑟.𝑜𝑓 𝑠𝑎𝑙𝑡) = so x = 1.55 ctutorPhysPhar2024  PHARMACEUTICAL APPLICATIONS Specific gravity is employed when a pharmacist wishes to convert the weight of an ingredient or preparation to volume or vice versa. Specific gravity is also used to calculate the equivalent strength of a preparation on the basis of either weight or volume. Specific gravity is in automated pharmaceutical equipment used by pharmacists to prepare total parenteral nutrition (TPN) admixtures. The purpose of the specific gravity of the large-volume liquids being mixed is to determine the weights of components (e.g., dextrose, amino acids, and water). Based on the admixture's solutions' specific gravity, volume, and percentage concentration (e.g., 70% dextrose injection), component weights are automatically determined. ctutorPhysPhar2024 CONCENTRATIONS ctutorPhysPhar2024  CONCENTRATION EXPRESSIONS In the pharmaceutical sciences, liquid homogenous aqueous systems are termed solutions, having a solute and a solvent. Concentration units are independent to the volume of a solution. ctutorPhysPhar2024  CONCENTRATION EXPRESSIONS Each of these concentration expressions is used in different applications in the pharmaceutical sciences. Molarity is a concentration expression based on moles of solute in a specific volume of solution. ctutorPhysPhar2024 Calculations of Moles To calculate moles from grams, molecular weight converts the weight to moles: ctutorPhysPhar2024  CONCENTRATION EXPRESSIONS ctutorPhysPhar2024  Molarity formula Molality formula ctutorPhysPhar2024  Normality formula Mole Fraction formula ctutorPhysPhar2024 % weight in volume formula % volume in volume formula ctutorPhysPhar2024 % weight in weight formula ctutorPhysPhar2024  Thank You GET READY FOR MODULAR QUIZ ctutorPhysPhar2024