Rapid liquid chromatographic assay for the determination of acetaminophen in plasma after propacetamol administration: application to pharmacokinetic studies.

A simple method for the rapid estimation of acetaminophen in plasma is described here. p-Propionamidophenol was used as internal standard. The assay involved a single ethyl acetate extraction and liquid chromatographic analysis at a wavelength of 242 nm using a reversed-phase encapped column, with a mobile phase of acetonitrile and 0.005 M potassium dihydrogen phosphate adjusted at pH 3.00. The limit of quantitation of acetaminophen by this method was 0.05 microg ml(-1), only 0.1 ml of the plasma sample was required for the determination. The calibration graph was linear from 0.05 to 100 microg ml(-1). Intra and inter-day precision (CV) did not exceed 8.93%. Mean recoveries of 90.31% with a CV of 1.38% were obtained. Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received 2 mg propacetamol.

Enantiomeric separation of tramadol and its active metabolite in human plasma by chiral high-performance liquid chromatography: application to pharmacokinetic studies.

A sensitive and stereoselective high-performance liquid chromatographic assay for the quantitative determination of the analgesic tramadol and O-demethyltramadol, an active metabolite, is described in this work. Ketamine was used as internal standard. The assay involved a single tert-butymethylether extraction and liquid chromatography analysis with fluorescence detection. Chromatography was performed at 20 degrees C on a Chiracel OD-R column containing cellulose tris-(3,5-dimethylphenylcarbamate) as stationary phase, preceded by an achiral end-capped C18 column. The mobile phase was a mixture of phosphate buffer (containing sodium perchlorate (0.2 M) and triethylamine (0.09 M) adjusted to pH 6) and acetonitrile (80:20). The method developed was validated. The limit of quantitation of each enantiomer of tramadol and its active metabolite by this method was 0.5 ng/mL; only 0.5 mL of the plasma sample was required for the determination. The calibration curve was linear from 0.5 to 750 ng/mL for tramadol enantiomers, and from 0.5 to 500 ng/mL for O-demethyltramadol enantiomers. Intra and interday precision [coefficient of variation (CV)] did not exceed 10%. Mean recoveries of 95.95 and 97.87% for (+)R,R- and (-)S,S-tramadol and 97.70 and 98.79% for (+)R,R- and (-)S,S-O-demethyltramadol with CVs < 2.15% were obtained. Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received 100 mg of tramadol by the intravenous route.

Rapid high-performance liquid chromatographic determination of cefepime in human plasma.

A simple, rapid and reproducible high-performance liquid chromatographic method for the quantitative determination of cefepime in human plasma was developed. Ceftazidime was used as internal standard. Chromatography was performed on a reversed-phase encapped column (Hypersil BDS C18). The samples, after protein precipitation, were eluted with a mobile phase of acetonitrile-acetate buffer, pH 4 (2.8:97.2, v/v). The detection wavelength was 254 nm. The limit of quantitation of cefepime was 0.5 microgram/mL and only 0.5 mL of plasma sample was required for the determination. The average cefepime recoveries over a concentration range of 0.5-500 micrograms/mL ranged from 98 to 104%. Precision and accuracy did not exceed 5%.

Renal failure after upper gastrointestinal bleeding in cirrhosis: incidence, clinical course, predictive factors, and short-term prognosis.

To assess the incidence, clinical course, predictive factors, and prognosis of renal failure in patients with cirrhosis and gastrointestinal bleeding, 175 consecutive episodes of gastrointestinal bleeding in 161 patients were analyzed. Renal failure occurred in 20 (11%) episodes and was transient in 8 episodes and nontransient in 12. Renal failure was more common in patients with cirrhosis than in a control population of bleeding patients without cirrhosis matched by age and severity of the bleeding episode. Among 39 clinical and laboratory variables obtained at admission or during hospitalization related with the bleeding episode or with liver and renal function, the presence of hypovolemic shock, number of packed red blood cells transfused, Child-Pugh class at admission, and baseline platelet count were independent predictors of renal failure. The development of renal failure and hypovolemic shock was the only independent predictors of in-hospital mortality. Mortality rate among the 20 episodes with renal failure was 55% (11 deaths) as compared with only 3% (5 deaths) in the 155 episodes without renal failure (P <.01). The development of nontransient renal failure entailed a much greater mortality as compared with transient renal failure (10 of 12 [83%] vs. 1 of 8 [12%]; P <.01). In conclusion, renal failure is a common event in patients with cirrhosis and gastrointestinal bleeding, the occurrence of which is mainly related to the severity of bleeding and baseline liver function. Renal failure is a strong predictor of mortality in patients with cirrhosis and gastrointestinal bleeding.

Vasoconstrictores en el tratamiento del síndrome hepatorrenal / Vasoconstrictors in the hepatorenal syndrome treatment

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