Pharmaceutical applications of surface film studies

Study of polymers used as packaging materials and film coatings 

Packaging materials must protect the dmg without altering in any way the composition of the product. One problem is that of adsorption of constituents, for example, preservatives, from the drug product (see section 6.2.8). The permeability of the packing material to gases or liquids should also be considered, since this may result in deterioration of the product due to oxidation, hydrolysis or loss of volatile ingredients. Monolayers are useful models by which the properties of 

Several methods have been employed in the determination of the resistance of monolayers to evaporation. The evaporation rate may be determined from the increase in mass of a desiccant suspended over the monolayer, or from the loss of weight of a Petri dish containing solution and spread monolayer, under carefully controlled conditions. Such experiments are useful in determining the effect on permeability of incorporation of a plasticiser into the polymer stmcture.  

Polymer monolayers have been used as models to assess the suitability of new polymers and of polymer mixtures as potential enteric and film coatings for solid dosage 

Phospholipid monolayers provide useful models for studying dmg-lipid interactions as we can see from the following recent example which explores the interaction of the pheno-thiazine drugs trifluoperazine (TFP) and chlor-promazine (CPZ) with the anionic glycero-phospholipid dipalmitoylphosphatidylglycerol (DPPG). The surface pressure isotherms of 

---