CHARACTERIZATION OF POLYMORPHS OF A NEW ANTIINFLAMMATORY DRUG

The present study demonstrates the utility of a diversified analytical approach for the characterization and quantitative analysis for two p olymorphs of a new anti-inflammatory agent, -3,4-dihydro-8-propyl-2H-1 -benzopyran-2-carboxylic acid (SC-41930). The existence of two distinc t crystal polymorphs of SC-41930 was qualitatively indicated through m icroscopy and application of thermal methods of analysis. The applicat ion of TGA was important for establishing that the two solid forms wer e, in fact, polymorphs, as opposed to solvated and unsolvated drug sub stances. The application of IR spectrometry revealed spectral features in the carbonyl stretching region, which were characteristic and uniq ue to the two SC-41930 polymorphs. DRIFT spectrometry was implemented as the sampling method of choice to eliminate the possibility of polym orphic transformations during conventional mulling or KBr pellet sampl ing procedures. The DRIFT spectrometry procedure permitted development of a quantitative assay for detection of the low-melting polymorph (a s an impurity) in high-melting samples. Calibration plots showed accep table linearity of response from 0 to 25% (w/w) low-melting samples sp iked into the high-melting polymorph. The performance characteristics of the method indicated good run-to-run and day-to-day consistency for its intended use.