Abstract
Indomethacin is a non-steroidal anti-inflammatory drug used in the treatment of rheumatoid arthritis, osteoarthritis, spondylitis and other disorders. The objective of this study was to enhance the dissolution rate of the drug by the formulation of microcrystalline cellulose (Avicel PH 101) pellets using extrusion/spheronization technique. Different cosolvents were incorporated in the pellet forming liquid (water), PEG 400, propylene glycol and ethanol. Mix torque rheometer was used to quantitatively determine the suitable moisture content in the pastes before the extrusion process. The produced pellets were characterized for their lndomethacin content, particle size, shape and dissolution profile. In addition, differential scanning calorimetry studies were carried out on indomethacin-avicelcosolvent (1:1:1) physical mixtures and the individual components. The studies on the effect of additives on Avicel rheological properties revealed that the magnitude of torque for the system was not as high as that determined where water alone was used as the wet-massing liquid. It was found that pellets manufactured by adding different concentrations of PEG 400 (20, 40 and 60% w/w of water) released the drug faster than those containing the corresponding concentrations of other cosolvents. The relative dissolution rate of indomethacin at 30 minutes (RDR30) using 60 % concentrations of PEG, propylene glycol and ethanol was enhanced to be 8.44, 4.46 and 3.22, respectively.
In conclusion, the addition of cosolvents to the manufactured pellets enhanced drug dissolution rates which might be beneficial in lowering the risk of side effects as an advantage of the pellets as drug delivery system.