[Changes in Test Methods for Internationalization in the Japanese Pharmacopoeia (Part 3): Establishment of a Quantitative Method for Sodium Cromoglicate and Trihexyphenidyl Hydrochloride Using HPLC Analysis]

The Japanese Pharmacopoeia (JP) is an official normative publication for establishing the authenticity and properties and maintaining the quality of pharmaceutical products in Japan. The JP is revised every five years and partially revised in order to respond to the progress of science and technology, the demand for medical care, and international harmonization. Thus, "Internationalization of the JP" is one of the most important issues to address for the revision of the JP, which is also referred to the basic principles for the preparation of the JP 19th edition. For instance, the incorporation of the test methods that have been used in other pharmacopeias, such as the European Pharmacopoeia (EP) and the United States Pharmacopeia (USP), into the JP is one of promising approaches. From this perspective, we have recently reported changes in test methods, establishment of a quantitative test method for the JP-listed clonidine hydrochloride as well as lorazepam from using a potentiometric titration method to using HPLC method. As our ongoing study to change test methods for internationalization, we selected sodium cromoglicate and trihexyphenidyl hydrochloride. Each pharmaceutical product is analyzed using a potentiometric titration method as listed in the 18th JP; however, both the EP and the USP use HPLC method for quantitative analysis of these drugs. In this study, we synthesized the related impurities of sodium cromoglicate and trihexyphenidyl hydrochloride listed in the EP and determined their purities using quantitative NMR. The separation conditions of these compounds were examined using HPLC and simultaneous analyses were performed.