Preparation and In-Vitro Pharmacokinetic Evaluation of Compressed Kollidon® SR Based Salbutamol Sulphate Microcapsules: Effect of Pigments

Microcapsules of salbutamol sulphate were prepared with kollidon® SR by W/O emulsification solvent evaporation technique using iron oxide yellow, iron oxide red and TiO2 as pigments and light liquid paraffin oil was used as oil phase and 1% (w/w of the continuum) of span 60 as emulsifier. Salbutamol sulphate, a bronchodilator drug for asthma is suitable for designing as microcapsules to prolong its therapeutic duration. For the prepared microcapsules scanning electron microscopy (SEM) was performed to study the size and surface morphology of prepared microcapsules. UV-spectrophotometric method was applied to calculate the drug loading efficiency and the performance of the prepared dosage form was evaluated in terms of in-vitro dissolution studies according to USP XXX paddle method (type 2) in 400 ml distilled water (pH 7.4) for 8 hours at 370 ± 50 C temperature at 50 rpm. Release of salbutamol sulphate from the compressed microcapsules was found to follow Higuchi mechanism (R2=0.99 and 0.99) when iron oxide yellow and iron oxide red were used in F-1 and F-2 respectively while F-3 followed both first order and Higuchi kinetic model (R2=0.99) when TiO2 was used. Korsmeyer equation was used to calculate the release exponent value (n) which indicates the drug release behavior and the mean dissolution time (MDT) for release rate where F-2 containing iron oxide red gave the highest value (4.12 h).