ABSTRACT
<p><b>OBJECTIVE</b>To determine the enantiomeric impurity contents of domestic timolol maleate in bulk drugs and eye drops.</p><p><b>METHODS</b>Enantiomer impurity of timolol was assayed by chiral high performance liquid chromatography. The chromatographic conditions were as follows:chiralcel OD chiral column (4.6 mm ×150 mm, 5μm), detection wavelength:297 nm, mobile phase:hexane-isopropanol-diethylamine (480:20:1), column temperature:25 ℃, flow rate:1.0 ml/min, sample injection volume:5 μl.</p><p><b>RESULTS</b>The resolution between R- and S-timolol was more than 4. The enantiomeric impurity contents were less than 0.67% on average in two batches of timolol maleate bulk drugs, and 0.31% on average in three batches of timolol maleate eye drops.</p><p><b>CONCLUSION</b>Enantiomeric impurity contents in each batch of products all meet European Pharmacopoeia criteria, which can be used as references in Chinese Pharmacopoeia criteria.</p>
Subject(s)
Chromatography, High Pressure Liquid , Methods , Drug Contamination , Ophthalmic Solutions , Reference Standards , Stereoisomerism , Timolol , Reference StandardsABSTRACT
<p><b>OBJECTIVE</b>To determine the contents of L-enantiomer impurity in valaciclovir hydrochloride.</p><p><b>METHODS</b>Valaciclovir enantiomers were separated and determined by using chiral high performance liquid chromatography. Chromatographic conditions were as follows:CROWNPAK(®) CR(+) chiral column (4 mm×150 mm, 5 μm), detection wavelength:254 nm, mobile phase:water-methanol-perchloric acid (19:1:0.1), flow rate:0.75 ml/min, sample injection volume:10 μl.</p><p><b>RESULTS</b>D-valaciclovir was completely separated from L-enantiomer impurity. The contents of L-enantiomer impurity were 0.65%-2.62% on average in 8 batches of valaciclovir hydrochloride.</p><p><b>CONCLUSION</b>Enantiomeric impurity contents in each batch of products were all meet criteria of United States Pharmacopeia, which can be used in criteria of Chinese Pharmacopeia as references.</p>
Subject(s)
Acyclovir , Chromatography, High Pressure Liquid , Methods , Stereoisomerism , ValineABSTRACT
<p><b>OBJECTIVE</b>To study the determination of desloratadine in human serum and its pharmacokinetics in healthy volunteers.</p><p><b>METHODS</b>A single oral dose of 10 mg desloratadine was given to 18 healthy volunteers. The serum concentrations of desloratadine were determined by HPLC-MS assay. The pharmacokinetics parameters of desloratadine tablets were calculated with program 3P97.</p><p><b>RESULT</b>The main pharmacokinetics parameters of desloratadine tablets were as followsút(max)(1.611 +/-0.366)h, C(max) (4.455+/-1.990)microg x L(-1), AUC(0-t) (58.50+/-21.34)microg x L(-1) x h(-1), AUC(0-infinity) (60.59+/-22.32)microg x L(-1) x h(-1), t(1/2(ke)) (20.303+/-5.833)h, Ke (0.0372+/-0.0116)h(-1) and CL(0.1838+/-0.0563)L x h(-1).</p><p><b>CONCLUSION</b>Desloratadine tablet is absorbed quicker in the 18 healthy volunteers than the reports and its peak blood concentration reached at 1.5 h after oral administration with t(1/2) 20 h.</p>