1992 Volume 40 Issue 12 Pages 3340-3342
In vitro release tests were investigated in single-layered and double-layered film systems. Sodium guaiazurene-3-sulfonate (GAS) was chosen as the drug for local use. Hydroxypropylcellulose (HPC), hydroxypropylmethyl-cellulose phthalate (HPMCP) and polyvinylacetaldiethylaminoacetate (AEA) were used to make films, and the tests were done with films made of various ratios of these two polymers.The drug rekease from the HPC single-layered films was independent of pH, and showed a zero order release. The apparent release rate constants, ka of the double-layered film varied according to the nature of the polymers and the drug as well as with the pH of the testing solutions.The results suggest the possibility of sustained release from double-layered films.
