detection limit of 0.5%, thus showing the product to be enantiomerically pure.Solubility Determination. Ten milliliters of hot (65 ± 2 °C) distilled water was rapidly added to 10.2 mg of dry l-VHCI while rapidly magnetically stirring in a 50-mL beaker. The homogeneous solution thus obtained was diluted with hot water to 50 mL in a warm volumetric flask. This hot solution was filtered through a 0.45-µ Type HA Millipore filter into a warm 50-mL volumetric flask. The concentration of l-VHCI in the filtrate, which was maintained at 65 ± 2 °C, was then determined by HPLC analysis (2.0 mL/min 60% CH3OH in 0.03 M KH2P04; 286 nm) to be 191 mg/L. No crystallization or precipitation of L-l was observed on cooling. After 4 h, HPLC analysis indicated the concentration of l-VHCI to be 183 mg/L. Crystallization of L-l then began to occur slowly. After 94 h (22 °C), the concentration of L-l was determined to be 33 mg/L. The pH of this solution was 3.65.An identical procedure employing 10.3 mg of dl-VHCI yielded a solution having a dl-VHCI concentration of 205 mg/L. After the solution was cooled over 4 h, the concentration had dropped to 186 mg/L, and after 94 h (22 °C) a concentration of 18 mg/L was determined. The pH of this solution was 3.57.
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