SummaryThe development and subsequent validation of an isocratic high-performance liquid chromatographic (HPLC) procedure employing ultraviolet (UV) detection for the determination of degradation products in Dipyridamole Injection is reported. The development of this assay involved the evaluation of several factors including buffer type, ionic strength, pH, organic composition, and column type. The described method is simple, reproducible, accurate, and selective. The precision, relative standard deviation (RSD), amongst five sample preparations for total degradation products was not more than (NMT) 10.2 %, while the individual degradation products were NMT 12.1 %. Intermediate precision, as determined from fifteen sample preparations, generated by two Analysts on different HPLC systems over three days, exhibited an RSD for total and individual degradation products of 8.2 % and NMT 27.5 %, respectively. The mean absolute recovery of dipyridamole using the described method is 102.1 + 1. 9 %, (mean + SD, n = 12) over the concentration range of 0.03 % to 5.0 % of its label claim of 5 mg mL -1. The limit of detection and limit of quantitation were 0.1 and 0.3 ~tg mL -1, respectively. The linearity of the peak response was verified with respect to dipyridamole concentration over a range of 0.3 and 50 ~tg mL -1 (0.03 % to 5.0 % label claim). The Standard and Assay Preparations are stable for up to 48 hours at room temperature. The selectivity was evaluated by subjecting the finished product (Dipyridamole Injection) to thermal, acidic, basic, oxidative and fluorescent radiation stress conditions. No interference in the analysis of degradation products was observed, showing the method is stabilityindicating.

A reversed-phase chiral liquid chromatographic method had been developed and validated for resolution of the enantiomers of racemic fudosteine. The effects on the separation of the amounts of anhydrous cupric sulfate and L-phenylalanine, the methanol content, mobile phase pH, and temperature were investigated. The method was validated for linearity, repeatability, intermediate precision, sample recovery, solution stability, and limits of detection (LOD). L-Phenylalanine and anhydrous cupric sulfate as chiral ligand-exchange complexes were used for separation, isomer identification, related substance investigation, and analysis of fudosteine enantiomers in fudosteine bulk drugs and fudosteine tablets.