Controlled release - recent progress in polymeric drug delivery systems

Release of DNA and surfactant from gel particles: the receptor solution effect and the dehydration-hydration aspects

DNA and cetyltrimethylammonium bromide (CTAB) have been used to prepare gel particles for controlled release studies. This article reports on the release of DNA and CTAB in four different solutions: in sodium bromide, in strong acid, pH 2 and pH 9 solutions for salmon testes DNA-CTAB gel particles. Also, compares results at extreme acid media and 10 mM NaBr solution with higher molecular weight DNA gel particles. The direct surfactant release was followed for the first time and shows the need of using biocompatible surfactants for the preparation of these gel particles. The release behavior depends on the receptor solution pH and the molecular weight of DNA. The first stage of the release corresponds to the so-called normal release profile and after this period, the release changed to a slow release profile. Also, the effect of dehydration and rehydration on the gel particles structure has been studied for the first time. The last process was observed visually and by SAXS measurements as a function of time. This process maintains the particle membrane integrity, structure and barrier function. The rehydration of dry gel particle in water occurs in only a few hours.