Attenuated total reflection infrared spectroscopy (ATR-IR) as an in situ technique for dissolution studies

Dissolution studies are critical tests for measuring the performance of a drug product. We have developed a novel technique using in situ ATR-IR spectroscopy to monitor dissolutions of pharmaceutical drug products. The accuracy of this technique is ±3% relative to HPLC using salicylic acid calibrator tablets and acetaminophen OTC tablets. This novel approach also gives the research laboratory the capability of analyzing individual ingredients in multiple tablets; for example, individual components of salicylic acid and acetaminophen tablets are easily distinguished. In addition, the individual ingredients of a multi-component tablet containing acetylsalicylic acid and acetaminophen are readily distinguished. The ATR-IR system was found to have good sensitivity and can analyze samples as low as 0.03 mg/ml. With improved sensitivity, this is a promising method for monitoring dissolution of pharmaceutical tablets with an excellent in situ capability for distinguishing individual components.