Characterization and evaluation of tenoxicam coprecipitates.

Tenoxicam is a nonsteroidal anti-inflammatory drug belonging to the oxicam group. The drug is slightly soluble in water. In a trial to increase its dissolution, different commonly used excipients were selected to prepare coprecipitates with tenoxicam. The coprecipitates were prepared using the solvent evaporation method, and the ratio used was 1:3 drug to additive. The prepared coprecipitates were subjected to a dissolution study, and they were characterized using infrared (IR) and differential scanning calorimetry (DSC) techniques. Dissolution profiles of most of the prepared coprecipitates demonstrated higher dissolution than pure tenoxicam. The characteristic peaks of tenoxicam in the IR spectrum disappeared in the spectra of all the prepared coprecipitates except those prepared with sodium chloride, for which the IR spectrum was identical to that of the pure drug. The characteristic peaks of tenoxicam disappeared in the DSC thermograms of the coprecipitates under study, indicating a change in structure from pure tenoxicam. Characterization of the coprecipitates by IR and DSC techniques revealed structural changes in the prepared coprecipitates from the plain drug, which may account for increased dissolution rates.