The influence of swelling capacity of superdisintegrants in different pH media on the dissolution of hydrochlorothiazide from directly compressed tablets

The purpose of this study was to investigate the efficiency of superdisintegrants in promoting tablet disintegration and drug dissolution under varied media pH. Significant reductions in the rate and extent of water uptake and swelling were observed for both sodium starch glycolate (Primojel) and croscarmellose sodium (Ac-Di-Sol) in an acidic medium (0.1 N HCl) but not for crospovidone NF (Polyplasdone XL10), a nonionic polymer. When Primojel and Ac-Di-Sol were incorporated in model formulations, a significant increase in tablet disintegration time was observed for slowly disintegrating tablets (lactose-based tablets) but not for the rapidly disintegrating tablets (dicalcium phosphate-based tablets). The dissolution rate of the model drug, hydrochlorothiazide, was found highly dependent on both tablet disintegration efficiency and the solubility of base material(s) in the testing medium. A laser diffraction particle size analyzer proved to be an effective tool for determining the intrinsic swelling of disintegrant particles in different media. Water uptake and swelling were confirmed as 2 important functions of superdisintegrants. The reduced water uptake and swelling capacity of disintegrants containing ionizable substituents in an acidic medium can potentially jeopardize their efficiency in promoting tablet disintegration and the drug dissolution rate

Double-layered mucoadhesive tablets containing nystatin

The objective of this work was to design a mucoadhesive tablet with a potential use in the treatment of oral candidosis. A 2-layered tablet containing nystain was formulated. Lactose CD (direct compression), carbomer (CB), and hydroxypropylmethylcellulose (HPMC) were used as excipients. Tablets were obtained through direct compression. Properties such as in vitro mucoadhesion, water uptake, front movements, and drug release were evaluated. The immediate release layer was made of lactose CD (100 mg) and nystatin (30 mg). The CB:HPMC 9∶1 mixture showed the best mucoadhesion properties and was selected as excipient for the mucoadhesive polymeric layer (200 mg). The incorporation of nystatin (33.3 mg) in this layer affected the water uptake, which, in turn, modified the erosion front behavior. Nystatin showed a first-order release. The polymeric layer presented an anomalous kinetic (n=0.82) when this layer layer was individually evaluated. The mucoadhesive tablet formulated in this work releases nystatin quickly from the lactose layer and then in a sustained way, during approximately 6 hours. from the polymeric layer. The mixture CB:HPMC 9∶1 showed good in vitro mucoadhesion. A swelling-diffusion process modulates the release of nystatin from this layer. A non-Fickian (anomalous) kinetic was observed