Monash University

Leader(s): Suzanne Caliph

Offered

Sunway Second semester 2009 (Day)
Parkville Second semester 2009 (Day)

Synopsis

This unit aims to provide students with a firm understanding of the fundamental physicochemical principles that underpin the science behind pharmacy as a discipline. This understanding sets the foundation for students to build upon in drug delivery units in the second, third and fourth years of the course. The understanding of these principles will also assist students in their understanding in some areas of chemistry, physiology and biology.

Objectives

At the end of this unit students will be able to:

1. Understand the physicochemical principles that underpin the important processes of pharmaceutical solids dissolving to form a solution. In particular an understanding of dissolution, solubility and distribution are critical in many areas of pharmacy and pharmaceutical science;
2. Describe the various forms of pharmaceutical solids, both drug forms and other components (excipients) and to understand their role and impact when used to produce solution-based dose forms in the pharmacy field;
3. Understand the basic physical chemistry of solutions once formed, including: understanding the terms solution, supersaturation, solubility (ideal and non-ideal), solubility parameter, dissolution, distribution (in a physical chemistry sense) and partitioning, the influence of ionizable functional groups and structure on solution behaviour, the properties of polymers in solution and their rheological aspects, to describe the physical chemical concepts of solutions of non-electrolytes in terms of vapour pressure, Raoult's Law and Henry's Law, and of solutions of electrolytes in terms of molar conductivity, Kohlrausch's Law, activity and ionic strength;
4. Have the ability to undertake calculations concerning the physico-chemical properties of drug solutions, including: Calculate changes in solubility with pH for ionisable compounds, Calculate and express solution concentrations in molarity, molality, mol fraction and equivalents. Use Kohlrausch's Law to calculate molar conductivities using the van't Hoff Factor. Calculate partial pressures for ideal and non-ideal systems given concentrations and activity coefficients. Calculate ionic strength using activity coefficients, Debye-Hckel approximation and the extended Debye-Hckel theory;
5. Describe strategies typically used to improve drug solubility, and to outline the theories for prediction of drug solubility from solid state properties;
6. Outline the common colligative properties and perform simple calculations to quantify these properties;
7. Describe the meaning and importance of isotonicity in pharmacy, and perform simple calculations of isotonicity. Describe methods of determination of tonicity of pharmaceutical solutions;
8. Understanding of how drug transport across biological membranes is influenced by various physicochemical factors, in particular dissolution, ionization and distribution characteristics. Competences will include: Calculating the percentage of ionized and unionized species of a drug molecule at different pH values and describe the impact of such pH changes on overall drug absorption across a biological membrane. Describe the characteristics of passive diffusion, active uptake and active efflux of drugs, in relation to drug permeability across biological membranes. Describe each component of Fick's first law of diffusion in relation to drug transport across biological membranes.

Students should also gain some experience in the ability to measure fundamental solution properties through practical exercises.

Assessment

written test on tutorial/workshop content: 10%; MCQ on practical work: 10%; end of year exam: 80%

Contact hours

72 hours of formal study per semester

Additional information on this unit is available from the faculty at:

http://www.monash.edu.au/muso/support/