Investigation of drug partition property in artificial sebum

Abstract Targeted delivery of a therapeutic agent into the hair and sebaceous follicles greatly depends on the extent of drug partitioning/diffusion in the sebum. The objective of the present research was to develop a method to determine the sebum partition coefficient in order to facilitate the selection of sebum-targeted drug candidates. Partition coefficients of model drugs with different chemical structures and 4-hydroxybenzoate series compounds were measured in artificial sebum/water ( K sebum ) and human stratum corneum/water ( K sc ) at 37 °C. The relationship was evaluated between log  K sebum , log  K sc and clog  P . The results of the partition coefficient studies indicate that the K sebum of some drugs was significantly higher than the K sc , whereas some drugs showed lower or similar K sebum when compared with K sc . Overall, a relatively poor correlation was observed between log  K sebum , log  K sc and clog P . However, a linear relationship exists between log  K sebum and clog P in the 4-hydroxybenzoate series compounds, indicating that K sebum depends on the lipophilicity and chemical structure of the compounds. The results of the present study demonstrate that K sebum is different from K sc and calculated P and is likely to be a critical parameter reflecting drug delivery into hair and sebaceous follicles.