Abstract

The objective of the present study was to develop theophylline and salbutamol sulphate matrix tablet for sustained release combined dosage form, for treatment of chronic obstructive pulmonary disease. Simultaneous equations were formed to calculate the concentration values of theophylline and salbutamol sulphate and drug compatibility studies were established through Infrared and Differential Scanning Calorimetry studies. The matrix tablets were prepared by wet granulation method using hydroxypropyl methylcellulose K4M and K15M in various percentages. The granules showed satisfactory flow properties and compressibility. All the five tablet formulations showed acceptable pharmacotechnical properties and complied with the in-house specifications for tested parameters. The results of formulation FH-3 (20% hydroxypropylmethylcellulose of grade K15M and K4M in 1:2 ratio) could extend the release of theophylline and salbutamol sulphate up to 12 h and was found comparable to marketed sustained release tablet. Model fitting analysis for formulation FH-3, theophylline fitted in the Zero order and Korsmeyer-Peppas model, while salbutamol sulphate fitted in the Zero order model. Scanning Electron Microscopy studies of FH-3 indicates good swelling and gel formation property of hydroxy propyl methyl cellulose, supporting the drugs release followed both diffusion and erosion mechanism. Successful formulation was found stable after evaluation for physicochemical parameters, kept for 30 d at 25° /60% RH and 40°/75% RH.