In Vitro Dissolution Enhancement Studies on Binary Solid Dispersions of Lornoxicam

The poor solubility and wettability of a non steroidal anti-inflammatory drug, Lornoxicam leads to poor dissolution and hence, low bioavailability after oral administration. The objective of the study was to formulate solid dispersions of Lornoxicam to improve the aqueous solubility and dissolution rate to facilitate faster onset of action. Lornoxicam is a BCS class II drug having low aqueous solubility and therefore low bioavailability. In the present study, solid dispersions of Lornoxicam with three different hydrophilic polymers and one superdisintegrant in 4 drug-carrier ratios were prepared by solvent evaporation and common solvent methods. Solid dispersions were characterized by infrared spectroscopy (IR) and evaluated for drug content, dissolution rate constant, regression coefficient. The dissolution rate and dissolution efficiency of the prepared solid dispersions were evaluated in comparison to the corresponding pure drug. The invitro dissolution studied showed increased drug release rates compared to that of pure API alone. The increasing order of dissolution rate of solid dispersions Lornoxicam with various polymers was HPMC > PVP > PEG. The solid dispersions in combined carriers gave much higher rates of dissolution than superdisintegrants alone. Finally, in-vitro dissolution studies showed that Lornoxicam release was greatly improved by formation of solid dispersion. A 170.2 fold increase in the dissolution rate of Lornoxicam was observed with solid dispersions prepared using combined carriers such as HPMC, MCC whereas only a 15.78 fold increase was observed with solid dispersions prepared using only MCC. Thus, the solid dispersion technique can be successfully used for enhancement of dissolution rate.