ABSTRACT
The proton-catalyzed hydrolytic decomposition of prostacyclin was assayed by UV spectroscopic and HPLC methods. Changes of the absorbance in aqueous solutions were measured at 220 nm. HPLC studies were performed on C18 column using NH4Cl (0.03 mol X l-1)/NH4OH (0.03 mol X l-1)/methanol (1 : 1 : 4) eluent. Temperature and pH dependence of the hydrolytic process was determined. Effects of alcohol and glycols on the degradation rate were studied.
Subject(s)
Epoprostenol/analysis , Chromatography, High Pressure Liquid , Drug Stability , Hydrogen-Ion Concentration , Kinetics , Solutions , Spectrophotometry, Ultraviolet , TemperatureSubject(s)
Adrenergic beta-Antagonists , Amino Alcohols , Chromatography, Thin Layer , Drug Stability , Heart/drug effects , Hot Temperature , Humans , Kinetics , PolarographyABSTRACT
A sensitive, specific high-performance liquid chromatographic procedure was developed for the determination of plasma drotaverine levels. Basic plasma samples were adjusted to pH 1.5 and extracted with chloroform. HPLC [n-heptane-dichloromethane-diethylamine (50:25:2)] on a microporous silica column, with a variable-wavelength UV detector set at 302 nm allowed the measurement of drotaverine at the 50-ng/mL level. The utility of this method for determination of drotaverine in dog and rat plasma was demonstrated.
Subject(s)
Papaverine/analogs & derivatives , Parasympatholytics/blood , Animals , Chromatography, High Pressure Liquid/methods , Dogs , Papaverine/blood , Rats , Spectrophotometry, UltravioletABSTRACT
Pharmacokinetics of 3-phenyl-6-(1, 2, 3, 4-tetrahydro-2-isoquinolyl)-methyl-4H-5,6-dihydro-1,2,4, -oxadiazine (I) in rat were studied. Plasma levels following a single oral dose were determined by HPLC method. Basic plasma samples were partitioned with chloroform. The organic layers were evaporated to dryness under reduced pressure. The residues were redissolved in chloroform and chromatographed on a microporous silica column with chloroform-isopropanol (7:3) eluent. Pharmacokinetics of (I) obeyed the one-compartment open model adequately. Constructed the plasma level curve, absorption and elimination rate constants were calculated by linear regression analysis. Rate of absorption proved to be significantly higher compared to that of elimination. The time of plasma level peak (tmax) was 35 min. After 20 h only traces of (I) could be found in the plasma.
Subject(s)
Isoquinolines , Oxazines/metabolism , Tetrahydroisoquinolines , Vasodilator Agents/metabolism , Animals , Chromatography, High Pressure Liquid/methods , Intestinal Absorption , Kinetics , Oxazines/blood , Rats , Rats, Inbred StrainsABSTRACT
A sensitive high performance liquid chromatographic procedure was developed for the determination of 3-phenyl-6-(1,2,3,4-tetrahydro-2-isoquinolyl)methyl-4H-5,6-dihydro -1,2, 4-oxadiazine a new vasodilator, in plasma. Rat plasma samples were made alkaline with ammonia and partitioned with chloroform. The extracts were dried with anhydrous sodium sulphate and evaporated to dryness under reduced pressure. The residues were redissolved in chloroform, and then chromatographed on silica column with chloroform/isopropanol (7:3, v/v). Detection was performed with a variable-wavelength UV detector set at 265 nm. Limit of identification was 10 ng, that of quantitative determination 50 ng 1/ml of plasma. The utility of the method for pharmacokinetic studies in the rat was demonstrated.
