Study of Crystalline Drugs by Means of Polarizing Microscope. IX

Preparation of the Charts for Simultaneous Analysis, Identification and Measurement of Thickness of Crystalline Drugs Listed in the Japanese Pharmacopoeia X

Abstract

The combined charts by which about 85 group A crystals (lamellar, scales or plates) listed in the Japanese Pharmacopoeia X can be analyzed, identified and their thicknesses can be simultaneously measured, have been prepared by use of a graph of retardation plotting by log (n₂-n₁) as the abscissa and (n₁, n₂) as well as log (D) as the ordinate, where n₁ and n₂ are the key refractive indices (refractive indices measured at the natural position by the immersion method) and D denotes the thickness of the sample. As the charts are advantageous for the estimation of optical properties of anisotropic crystals, other about 85 drugs not belonging to group A were also tried to present in the charts by using their refractive indices measured at the position parallel to the microscope stage. These charts would be useful to apply for the quality testing of poorly soluble drugs.