ABSTRACT
A capillary electrophoresis method was developed and validated for the first time for the analysis of clopidogrel and its carboxylic acid metabolite. Prior to method optimization, the pH dependence of effective mobility of both compounds was determined in order to define the initial pH of the running buffer. The optimized method demonstrated to be selective, and linear in the concentration range of 2-100 microM for both compounds. The method limits of detection and quantification were, respectively, 1.2 and 3.7 microM for clopidogrel and 1.1 and 3.2 microM for the carboxylic acid metabolite. Moreover, method validation demonstrated acceptable results for method repeatability (RSD<7%), intermediate precision (RSD<7%) and accuracy (85-96%) and is suitable for the quantitative analysis of clopidogrel and its metabolite in serum samples. The validated method was also applied to the determination of the kinetic parameters of the enzymatic hydrolysis of clopidogrel. An apparent K(m) of 145+/-30 microM and V(max) of 0.4, 1.5 and 3.4 microM/min, respectively for the enzyme concentrations 1.0, 2.0 and 4.0 U/ml, were obtained.
Subject(s)
Carboxylic Acids/analysis , Electrophoresis, Capillary/methods , Ticlopidine/analogs & derivatives , Carboxylic Acids/chemistry , Carboxylic Acids/metabolism , Clopidogrel , Hydrogen-Ion Concentration , Least-Squares Analysis , Reproducibility of Results , Sensitivity and Specificity , Sodium Dodecyl Sulfate , Temperature , Ticlopidine/analysis , Ticlopidine/chemistry , Ticlopidine/metabolismABSTRACT
Glucocorticoids are used in the treatment of inflammatory bowel disease. A limitation to their use is that they undergo absorption from the GIT before reaching the colon causing severe systemic side effects. We report here on a novel prodrug approach to targeting corticosteroids to the colon. The design involves attaching a 21-ester group that suppresses absorption during transit to the colon. The prodrug is designed to be primed by colonic microflora liberating an amino ester that cyclizes releasing the steroid. One of the prodrugs 5b was as efficacious as prednisolone in the murine DSS model but did not cause thymic atrophy, a marker for systemic steroid effects.
Subject(s)
Adrenal Cortex Hormones/administration & dosage , Colon/metabolism , Drug Carriers/chemical synthesis , Inflammatory Bowel Diseases/drug therapy , Prodrugs/chemical synthesis , Animals , Bacteria/metabolism , Colon/microbiology , Cyclization , Drug Delivery Systems , Esters , Intestinal Absorption/drug effects , Mice , Prodrugs/chemistry , Prodrugs/metabolismABSTRACT
The volatiles emitted by fresh whole flowers and isolated flower organs of male, female, and hermaphrodite carob trees (Ceratonia siliqua L.; Leguminosae) were analyzed by headspace solid-phase microextraction followed by capillary gas chromatography and mass spectrometry. The headspace of carob flowers is mainly constituted of high amounts of monoterpenes and sesquiterpenes, and more than 25 compounds were identified. The gender and cultivar affected both the qualitative profile and the relative abundances of the volatiles of whole flowers and isolated floral organs. Linalool and its derivatives (cis-linalool furan oxide, 2,2,6-trimethyl-3-keto-6-vinyltetrahydropyran, cis-linalool pyran oxide, and trans-linalool furan oxide), alpha-pinene, and alpha-farnesene were the dominant volatiles. Female flowers had a higher diversity of volatile compounds than males and hermaphrodites, but a lower abundance of the major ones. Similarly, the floral scent of female flowers of cv. Mulata had a higher content of volatiles but a lower abundance of the major ones, when compared to cv. Galhosa. In each of the three gender types of flowers, the nectary disks seemed to be the major source of volatiles.
