[Application of thermogravimetry to loss on drying test and water-content determination of drugs].

Thermogravimetry, one of the techniques of thermal analysis, was applied to the quality control of drug raw materials as a "Loss on Drying" or for "Water Content Determination". Twenty two kinds of drugs were selected for the comparison of the applicability of thermogravimetry with that of Loss on Drying Test and/or Water Content Determination by the Karl-Fisher method. In all kinds of drugs, it was ascertained that the results with thermogravimetry agreed well with those obtained by Loss on Drying test and/or Karl-Fisher method. In conclusion, thermogravimetry can be used as a substitute for the Loss on Drying test in cases where drug possess a water bound strongly. Further, thermogravimetry can be utilized for some drugs to which the Karl-Fisher method cannot be applied due to their insolubility in Karl-Fisher reagents.