Development of salbutamol sulphate sustained release pellets using acrylic polymer and polyvinyl acetate polymer and evaluation of in vitro release kinetics

Abstract

The nuclei of sustained-release pellets of salbutamol sulphate were prepared using extrusionspheronization technique followed by coating with the aqueous dispersion of methacrylic acid esters (Eudragit RS® 30 D) and commercial aqueous polyvinyl acetate dispersion (30% dispersion) (Kollicoat SR® 30 D). The coating polymers were applied to obtain a theoretical polymer load of 5%, 10%, 15%, 20% & 25%(w/w) on the nuclei. Invitro dissolution studies of the coated pellets were performed in a USP paddle apparatus (type-2). Dissolution media was distilled water (500 ml), paddle speed was 50 rpm and it was preformed for 8 hours at 37°C (±0.5°C) temperature. Scanning Electron Micrographs (SEMs) of the nuclei & coated pellets were taken to study their surface morphology. The kinetics of the dissolution process was determined by analyzing the dissolution data using zeroorder, first order, Higuchi and Korsmeyer equations. The kinetic modeling of the dissolution profiles revealed that drug release mechanism ranged from diffusion controlled or Fickian transport to anomalous type or non-Fickian transport. T50% (MDT) and T90% values were calculated for each formulation. The higher MDT values were obtained with Eudragit® RS 30D where as Kollicoat® SR 30D showed comparatively low MDT values. MDT values were also increased with increasing polymer load on the nuclei.