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 investigate the chemical constituents of the herbs of Taraxacum mongolicum.</p><p><b>METHOD</b>The chemical constituents were isolated by various column chromatographic methods and their structures elucidated mainly by NMR and MS evidences.</p><p><b>RESULT</b>Forty-four components were obtained and identified were as artemetin (1), quercetin (2), quercetin-3', 4', 7-trime-thyl ether (3), luteolin (4), luteolin-7-O-beta-D-glucopyranoside (5), luteolin-7-O-beta-D-galactopyranoside (6), genkwanin (7), isoetin (8), hesperetin (9), genkwanin-4'-O-beta-D-lutinoside (10), hesperidin (11), quercetin-7-O-[beta-D-glucopyranosyl (1-->6) -beta-D-glucopyranoside (12), quercetin-3, 7-O-beta-D-diglucopyranoside (13), isoetin-7-O-beta-D-glucopyranosyl- 2'-O-alpha-L-arabinopyranoside (14), isoetin-7-O-beta-D-glucopyranosyl-2'-O-alpha-D-glucopyranoside (15), isoetin-7- O-beta-D-glucopyranosyl-2'-O-beta-D-xyloypyranoside (16), caffeic acid (17), furulic acid (18), 3-O-caffeoylquinic acid (19), 3, 5-di-O-caffeoylquinic acid (20), 3, 4-di-O-caffeoylquinic acid (21), 4, 5-di-O-caffeoylquinic acid (22), 1-hydroxymethyl-5-hydroxy-phenyl-2-O-beta-D-glucopyranoside (23), p-hydroxybenzoic acid (24), p-coumaric acid (25), 3, 5-dihydroxylbenzoic acid (26), gallic acid (27), gallicin (28), syringic acid (29), 3, 4-dihydroxybenzoic acid (30), caffeic acid ethyl ester (31), esculetin (32), rufescidride (33), mongolicumin A [6, 9, 10-trihydroxy-benzoxanthene-1, 2-dicarboxylic acid] (34), mongolicumin B [1 l-hydroxy-2-oxo-guaia-1 (10), 3, 5-trien-8, 12-lactone] (35), isodonsesquitin A (36), taraxacin (37), sesquiterpene ketolactone (38), taraxasteryl acetate (39), phi-taraxasteryl acetate (40) and lupenol acetate (41), palmitic acid (42), beta-sitosterol (43), and stigmasterol (44).</p><p><b>CONCLUSION</b>Four compounds (14, 15, 34 and 35) were new compounds, compounds 1, 3, 6-13, 20-22, 30 and 31 were isolated from this genus for the first time, while compounds 18, 23-29, 32 and 37-42 were obtained from this species for the first time.</p>