Solubility and dissolution improvement of Rofecoxib using solid dispersion technique.

Rofecoxib (RXB) is a potent and selective cyclo-oxygenase-2 (COX-2) inhibitor, highly effective in the treatment of various pains, inflammatory condition, post-operative pain, rheumatoid arthritis, other musculo-skeletal and joint disorders. Although they are completely absorbed upon oral administration, the peak plasma concentration is reached 2-3 hours after oral ingestion. The reason for delay being slow rate of absorption due to poor aqueous solubility. An attempt has been made to enhance solubility and dissolution of rofecoxib by solid dispersion(SD) technique using various hydrophilic excipients like PEG 4000, PEG 6000, PVP at different ratios by melting method and solvent evaporation method. The prepared SD of RXB were characterized to various physico-chemical properties and in vitro drug dissolution studies in 0.1N HCl with 0.25% SLS (pH 1.1) media for a period of 90 min using USP XXIII electro lab 8 basket tab dissolution test apparatus using paddle. The result of study indicated that there was no drug-polymer interaction found. The drug dissolution was found to enhance percent in PEG 4000, PEG 6000 and PVP, after 90 mins of dissolution study 79.02%, 88.02%, 98.57% respectively. On comparison of various polymers used at varied concentrations PVP at 75:25 ratio by fusion method was found to be best suitable for the enhancement of dissolution and solubility of RXB.