Assessment of membrane type effects on in vitro performance of topical semi-solid products

In vitro release tests have been widely used to assess performance of topical products. Any interaction should not be observed between drug and synthetic membrane, but there is no conclusive information about relationship of membrane type and properties of drug substances. In this study, four types of membranes (regenerated cellulose, cellulose acetate, mixed cellulose ester, silicone) were used to evaluate in vitro release of hydrophilic, moderately lipophilic and highly lipophilic drug substances from their topical preparations. The relationship between membrane type and drug characteristics was investigated using Strat-MTM membrane resembling to human skin, and excised porcine skin for in vitro permeation studies. The release data revealed that acceptor/donor groups in drug substance and synthetic membrane could hinder drug release through membrane. Mixed cellulose ester or cellulose acetate membranes should be opted for in vitro release studies of drugs consisting of abundant, strong acceptor/donor groups. In vitro permeation data showed that drug lipophilicity might come into prominence for these studies. Strat-MTM membrane could be more useful to estimate permeability of lipophilic molecules rather than hydrophilic ones. The results suggest that molecular structure and lipophilicity of drug could be considered to select synthetic membrane used for in vitro release and permeation studies.

Automated summary

This study investigated the relationship between different types of synthetic membranes and drug characteristics in in vitro release and permeation studies. The results showed that mixed cellulose ester or cellulose acetate membranes are suitable for drugs containing abundant, strong acceptor/donor groups, while drug lipophilicity may play a prominent role in these studies. Strat-MTM membrane was found to be more useful for estimating permeability of lipophilic molecules rather than hydrophilic ones. The molecular structure and lipophilicity of the drug should be considered when selecting a synthetic membrane for in vitro release and permeation studies.