In vitro release dynamics of model drugs from psyllium and acrylic acid based hydrogels for the use in colon specific drug delivery.

Psyllium is medicinally important gel forming polysaccharides. Keeping in view, the pharmacological importance of psyllium and drug delivery devices based on hydrogels, psyllium, if suitably tailored to prepare the hydrogels, can act as the double potential candidates for the novel drug delivery systems. Therefore, it is an attempt to prepared psyllium and acrylic acid based pH sensitive novel hydrogels by using N,N'-methylenebisacrylamide (N,N-MBAAm) as crosslinker and ammonium persulfate (APS) as initiator for the use in colon specific drug delivery. The present paper discusses the swelling kinetics of the hydrogels and release dynamics of model drugs (tetracycline hydrochloride, insulin and tyrosine) from drug-loaded hydrogels, for the evaluation of the swelling mechanism and drug release mechanism from the polymeric networks .The effect of pH on the swelling kinetics and release pattern of drugs have been studied by varying the pH of the release medium. It has been observed that swelling and release of drugs from the hydrogels occurred through non-Fickian or anomalous diffusion mechanism in distilled water and pH 7.4 buffer. It shows that the rate of polymer chain relaxation and the rate of drug diffusion from these hydrogels are comparable.