FORMULATION AND PREPARATION OF CONTROLLED-RELEASE PELLETS OF SALBUTAMOL BY THE AIR SUSPENSION TECHNIQUE

A controlled release preparation of salbutamol may improve patient com pliance, minimise side effects and be valuable in the treatment of noc turnal asthma by extending drug action throughout the night. The aim o f the study was therefore to formulate a controlled release pellet pre paration of salbutamol via the air suspension technique. The study est ablished that curing for 24 h at 38 +/- 0.5 degrees C was necessary fo r homogeneous film coats of Eudragit(R) RS30D and hence stable drug re lease characteristics. Pellets coated with 6% Eudragit(R) RS30D (polym er), 12.5% triethyl citrate (plasticiser) and 0.5% magnesium stearate (antitackiness agent) displayed desirable controlled drug release char acteristics over the 8 h testing period. The manufacturing conditions employed in the study were shown to be reproducible thus ensuring repr oducibility of drug release characteristics between batches of salbuta mol controlled release pellets. Short term stability testing on the ne wly formulated pellets indicated no significant change in drug release characteristics relative to the initial drug release data when stored for 8 weeks at room temperature 20 +/- 2 degrees C or 37 degrees C wi th 80% Relative Humidity or at low temperature (5 +/- 1 degrees C). Ho wever, pellets stored at 40 degrees C, showed a slower in-vitro drug r elease after 8 weeks of storage and therefore failed to maintain their initial drug release profile.