Permeation of indomethacin from semisolid preparations through various semipermeable membranes.

The aim of this study was to evaluate and compare the permeation of model drug indomethacin (IND) from various types of gels through several semipermeable membranes. Permeation of IND from gels based on carbomer (CA), hydroxyethylcellulose (HEC), and polyacrylamid/laureth-7/isoparaffin was performed via diffusion cell method through membranes: shed snake skin, full thickness chicken skin, mucosa of pork small intestine, and cellophane. The least permeation of IND was observed in the case of shed snake skin and full thickness chicken skin. It did not exceed 5.4% of original amount in the preparation after 3 h of measurement regardless the type of gel. In the case of mucosa of pork small intestine and cellophane the permeated amount of IND ranged from 9.4 to 55.4% depending on the type of gelling agent used. There was also quite a significant influence of a gelling agent on the permeation of IND observed. The permeation of IND was highest from CA gel, where it ranged from 0.6 to 52.2% of original amount in the preparation depending on the type of membrane used. Gelling agent inhibiting the permeation the most was HEC, where the permeated amount of IND did not exceed 12.3% regardless the type of membrane used. In general the permeated amount of IND through biological membranes containing stratum corneum represented just a small part of the amount in original preparation. Gelling agent has significant effect on the extent and rate of permeation.