Effect of hydrocarbon surfactants on dexamethasone solubilization into silicone surfactant micelles in aqueous media and its release from agar films as carriers

Abstract Silicone surfactant (SS) micelles are one of the unexplored systems especially for drug solubilization. SS are increasingly becoming important as pharmaceutical additives because, the polydimethylsiloxane part of it is very permeable to the diffusion of active drugs. In the present work, the effect of hydrocarbon surfactants (HS) namely sodium dodecyl sulfate (SDS), or dodecyltrimethylammonium bromide (DTAB), or polyoxyethylene octyl phenyl ether (TX-100), as additives on the solubilization of dexamethasone (dex), a poorly water soluble drug into the micelles of a nonionic trisiloxane silicone surfactant in water was measured. The dex loaded micellar solutions were uniformly dispersed in the agar hydrogels as carriers. The release of dex (by simple dilution) from the dry cast gel films was monitored at different time intervals and the release data were analyzed mathematically in terms of diffusion models. The drug diffusion coefficients, D drug were calculated and it was found that D drug values linearly decreased with the concentration of HS or SS and while the addition of HS increased the D drug in SS micellar solutions indicating that HS facilitate not only release of dex but also enhance its rate of release. The enhancement of dex release from SS micelles are closely related to the dissolution of SS micelles.