Absolute Purity Determination of a Hygroscopic Substance, Indocyanine Green, Using Quantitative NMR (qNMR)

Quantitative NMR (qNMR) is applied to determine the absolute quantitative value of analytical standards for HPLC-based quantification. We have previously reported optimal and reproducible sample preparation method qNMR hygroscopic reagents, such as saikosaponin a, which used an standard in assay crude drug section Japanese Pharmacopoeia (JP). In this study, we examined purity determination a substance, indocyanine green (ICG), listed Pharmaceutical Codex 2002, using standardization by focusing on adaptation ICG JP. The ICG, official non-Pharmacopoeial reference (non-PRS), had high variation (86.12 ± 2.70%) when preparing samples under non-controlled humidity (a conventional method). Additionally, residual ethanol (0.26 0.11%) was observed non-PRS ICG. Next, determined via controlled saturated sodium bromide solution. 84.19 0.47% with lower than that humidity. Moreover, signal almost disappeared. estimated replaced water Subsequently, analysis performed constant temperature box. It showed excellent results lowest (82.26 0.19%). As use box resulted variability, it recommended control if needed JP assays.