PHYSICAL PHARMACY STUDY NOTES

PHYSICAL PHARMACY STUDY NOTES

Module Breakdown

• Module 5: Pharmaceutics (17%)
  • Competency:
  • Manufacturing: No. of Questions: 29 (K: 6, C: 6, Ap: 12, An: 2, S: 2, E: 1)
  • Pharmaceutical Dosage Forms: No. of Questions: 29 (K: 6, C: 6, Ap: 12, An: 2, S: 2, E: 1)
  • Physical Pharmacy: No. of Questions: 25 (K: 5, C: 5, Ap: 10, An: 2, S: 2, E: 1)
  • Jurisprudence and Ethics: No. of Questions: 17 (K: 3, C: 3, Ap: 6, An: 2, S: 2, E: 1)

Overview of Physical Pharmacy

• Physical Pharmacy is a branch of pharmacy that integrates physical and chemical principles to understand drug properties, dosage forms, and drug delivery systems.
• It deals with quantitative and theoretical principles that are essential for practicing pharmacy and requires knowledge across various scientific disciplines, including biopharmaceutics, biochemistry, and pharmacology.
• Its applications include understanding and developing dosage forms and drug delivery systems.

Importance of Understanding Physical Properties of Substances

• Understanding physical properties is crucial for:
  • Determining identity and purity of substances.
  • Formulation of pharmaceutical products.
  • Understanding pharmacokinetic and pharmacodynamic properties.
  • Proper storage and handling of materials based on their properties.
  • Managing cleanup and disposal of accidental spills based on the substances' properties.

Classification of Physical Properties of Matter

1. Intensive Properties:

   • Do not depend on the amount of substance.
   • Examples include: temperature, pressure, density, viscosity, surface tension, specific gravity.

2. Extensive Properties:

   • Depend on the quantity of matter in the system.
   • Examples include: mass, length, volume.

Forms of Physical Properties

• Additive Properties: Depend on the sum of individual properties in a system. Example: Molecular Weight and Molar Volume.
• Constitutive Properties: Dependent on the arrangement and type of components in the system.
• Colligative Properties: Dependent on the collective number of particles. Examples: Vapor Pressure Lowering, Boiling Point Elevation, Freezing Point Depression, and Osmotic Pressure.

Molecular Weight and Molar Volume

• Molecular Weight Determination:
  • Sum atomic weights in the chemical formula.
  • Molar Volume Equation:
    $ext{Molar Volume} = ext{Sum of Atomic Volumes}$

Solubility and Complexation

• Solubility: Ability of a substance to dissolve in a solvent, heavily influenced by temperature, pH, and polarity of the solvent and solute.
• Complexation: Reaction between two different substances resulting in complex formation through various interactions such as hydrogen bonds, Van der Waals forces, covalent interactions.

Kinetics of Reactions

• Reaction Rate: Velocity with which a reaction proceeds is influenced by reactant concentration, temperature, and pH.
• Orders of Reaction: Zero-order reactions where the rate is constant, and first-order reactions where the rate is dependent on reactant concentration.
• Shelf Life Calculation:
  • For zero-order:
    $t_{90} = 0.1C_0/k_0$
  • For first order:
    $t_{90} = 0.105/k$

Phase Equilibria and the Phase Rule

• Phase Rule (Gibbs):
  $F = C - P + 2$
  where:

  • F = degrees of freedom
  • C = number of components
  • P = number of phases present

• Phases and their interactions are critical for determining stability and various physical properties of chemical systems.

Summary of Key Concepts

• Understanding physical properties deeply impacts pharmaceutical formulations and drug delivery efficiency.
• Familiarizing with the physical pharmacy principles aids in resolving complex pharmaceutical challenges.
• Continuous exploration of kinetics, solubility, and complexation enhances practical applications of pharmacy.