ABSTRACT
The separation and determination of amiloride, metoprolol, deacetylmetipranolol, labetalol and furosemide in human serum and urine by capillary isotachophoresis were investigated. Amiloride and beta-blockers were separated by cationic isotachophoresis in the electrolyte system sodium morpholinoethanesulfonate buffer (pH 5.5) (cL = 10 mM)-glutamic acid. Furosemide was separated using the anionic electrolyte system histidine hydrochloride buffer (pH 6.2) (cL = 10 mM)-morpholinopropanesulfonic acid. Endogenous and the possible exogenous compounds were almost totally removed from serum and urine by solid-phase extraction using a Separon SGX C18 cartridge. The recovery of compounds varied from 98.2 to 103.2%. The linearity range for the compounds was 50-1000 ng/ml. The relative standard deviations varied from 0.1 to 5.6%. The overall limits of determination ranged from 32 to 46 ng/ml of urine and from 39 to 46 ng/ml of serum, depending of the type of drugs.
Subject(s)
Cardiovascular Agents/blood , Cardiovascular Agents/urine , Electrophoresis, Capillary , Adrenergic beta-Antagonists/blood , Adrenergic beta-Antagonists/urine , Amiloride/blood , Amiloride/urine , Electrophoresis, Capillary/statistics & numerical data , Furosemide/blood , Furosemide/urine , Humans , Hydrogen-Ion Concentration , Labetalol/blood , Labetalol/urine , Metipranolol/analogs & derivatives , Metipranolol/blood , Metipranolol/urine , Metoprolol/blood , Metoprolol/urine , Reproducibility of ResultsABSTRACT
A high-performance liquid chromatographic (HPLC) method is described for direct separation of the enantiomers of metipranolol and its principal degradation product and main metabolite, desacetylmetipranolol. Separations are performed on a chiral stationary phase of cellulose tris-3,5-dimethylphenyl carbamate (Chiralcel OD), with hexane-propan-2-ol-diethylamine elution and UV detection at 278 nm. The method affords identification and determination of the optical purity of the bulk drug and its formulated ophthalmic products.
Subject(s)
Adrenergic beta-Antagonists/isolation & purification , Carbamates , Cellulose/analogs & derivatives , Metipranolol/analogs & derivatives , Metipranolol/isolation & purification , Phenylcarbamates , 1-Propanol , Chromatography, High Pressure Liquid/methods , Diethylamines , Ethanol , Radiation , StereoisomerismABSTRACT
Concentrations of metipranolol were determined in the aqueous humour of patients undergoing cataract surgery. At 30 min before the operation, patients were given 20- or 30 microliters drops of 0.1% or 0.3% metipranolol solutions with a viscosity of 7.5 cP or drops (20 or 30 microliters) of a 0.3% solution with a viscosity of 1.5 cP. Samples of the aqueous humour were obtained at the beginning of the cataract operation, and desacetyl-metipranolol content was determined by means of gas chromatography and mass spectroscope. The Wilcoxon signed-rank test and Jonckheere's method were used for evaluation of the results. A 3-fold increase in the strength of metipranolol was associated with an approx. 8-fold increase in the concentration of metabolite found in the aqueous humour. Drop size had no apparent effect on the concentration of this substance in the aqueous humour, but viscosity had a significant influence when large drops were applied. An increase in the amount of metipranolol applied as eye-drops was associated with an increase in the intraocular concentration of the metabolite.
Subject(s)
Aqueous Humor/metabolism , Metipranolol/pharmacokinetics , Administration, Topical , Adrenergic beta-Antagonists/analysis , Adult , Aged , Aged, 80 and over , Cataract Extraction , Dosage Forms , Dose-Response Relationship, Drug , Female , Gas Chromatography-Mass Spectrometry , Humans , Male , Metipranolol/analogs & derivatives , Metipranolol/analysis , Middle Aged , ViscosityABSTRACT
The concentration of the metabolite of the beta-blocker metipranolol was determined in the aqueous humour of 89 cataract patients. At 1, 2 or 5 h before surgery, they received one drop (30 microliters) of a 0.1% or 0.3% solution of the drug. At 1, 2 or 5 h after the application of 0.1% metipranolol eye drops, desacetyl-metipranolol concentrations of 624.55, 235.29 and 88.02 ng/ml, respectively, were measured. At the same intervals after the instillation of 0.3% metipranolol eye drops, the respective values of 1289.20, 1120.88 and 327.36 ng/ml were found. The metabolite concentration in the eye drops and the values measured show no consistent correlation.
Subject(s)
Aqueous Humor/metabolism , Metipranolol/pharmacokinetics , Adrenergic beta-Antagonists/analysis , Aged , Aged, 80 and over , Cataract Extraction , Cornea/drug effects , Dosage Forms , Female , Gas Chromatography-Mass Spectrometry , Humans , Male , Metipranolol/administration & dosage , Metipranolol/analogs & derivatives , Metipranolol/analysis , Middle Aged , Ophthalmic Solutions , Timolol/pharmacokineticsABSTRACT
A sensitive high-performance liquid chromatographic method with electro-chemical detection is developed for the determination of deacetylmetipranolol (DMP), an active metabolite of beta-sympatholytic drug metipranolol (MP). DMP is extracted from the plasma after basifying with dichloromethane. After evaporation, the residue is reconstituted in the mobile phase, injected onto the reversed-phase ODS column and chromatographed at 50 degrees C. The sensitivity of the method is 2 ng of DMP in 1 ml plasma. Pindolol, another beta-blocking agent is used as internal standard. The method is used for a pharmacokinetic investigation of MP in healthy volunteers and in the patients with liver cirrhosis.
