Biomedical subjects

P Modamio

Publications and source records attributed to P Modamio.

6 recordsLinked to original sources

PubMed2000

Two reproducible and sensitive liquid chromatographic methods to quantify atenolol and propranolol in human plasma and determination of their associated analytical error functions.

Two liquid chromatography (LC) methods with fluorimetric detection have been developed to measure atenolol and propranolol in human plasma. The same 5 microm Nucleosil RP-18 column, extraction procedure and mobile phase (containing acetonitrile, water, triethylamine and phosphoric acid, pH 3) were used. The linearity ranges were 25-800 ng/ml for atenolol and 3.13-100 ng/ml for propranolol. The coefficients of variation for validation assays were lower than 15% at the concentration assayed. The functions of the analytical error were linear: SD (ng/ml)=7.698+0.037C for atenolol and SD (ng/ml)=0.126+0.036C for propranolol.

Adrenergic beta-Antagonists↗

PubMed2000

A comparative in vitro study of percutaneous penetration of beta-blockers in human skin.

In vitro diffusion experiments with propranolol, oxprenolol, metoprolol and atenolol were carried out using excised human abdominal skin. The main permeation parameters (permeability coefficient, flow and lag time) were calculated and compared as measurement of intrinsic permeability across human skin. A long lag time and a low steady-state flow were found for all drugs assayed. Skin permeability predicted at steady state did not reach therapeutic concentrations, which indicated the need for appropriate chemical penetration enhancers or vehicles to overcome limiting factors. The results, including those of celiprolol and bisoprolol reported previously, correlated with physicochemical properties, especially with lipophilicity, one of the main factors in drug permeability prediction through human skin.

Administration, Cutaneous↗

PubMed1998

Determination of celiprolol and oxprenolol in human plasma by high-performance liquid chromatography and the analytical error function.

Two reversed-phase HPLC methods with UV detection to quantify celiprolol and oxprenolol in human plasma are described. The analytical methods for the determination of both drugs used the same reversed-phase HPLC column, mobile phase and extraction procedure. Linearity was obtained in the ranges 15.63-1000 and 25-800 ng/ml for celiprolol and oxprenolol, respectively. Intra-day and inter-day variation was lower than 14%. After validation of the methods, analytical error functions were established as S.D. (ng/ml)=3.096+0.041C for celiprolol and S.D. (ng/ml)=8.906+8.075x10(-8)C3 for oxprenolol.

Adrenergic beta-Antagonists↗

PubMed1998

Error structure for the HPLC analysis for atenolol, metoprolol and propranolol: a useful weighting method in parameter estimation.

Three reversed-phase high performance liquid chromatography (HPLC) methods with UV detection were developed and fully validated for the quantification of three beta-blockers: atenolol, metoprolol and propranolol. After validation, error structures for the HPLC analysis were established using a convenient and practical procedure. The mean percentage of relative standard deviation (RSD) of the experimental concentrations (C), were less than 4.29% for proportionality and less than 3.68% for precision for any of the drugs, which allowed the quantitation of beta-blockers assayed at concentrations in the range 25-0.78 micrograms.ml-1. The error structures for the HPLC analysis were: SD (micrograms.ml-1) = 5.02 x 10(-2) C for atenolol, SD (micrograms.ml-1) = 4.55 x 10(-2) + 0.63 x 10(-2) C - 7.58 x 10(-6) C3 for metoprolol and SD (micrograms.ml-1) = 2.73 x 10(-2) C - 3.49 x 10(-4) C2 for propranolol. The reciprocal of the square of the SD of the drug concentrations measured within the calibration curve could be used as weighting methods in parameter estimation by non-linear regression.

Adrenergic beta-Antagonists↗

PubMed1996

Determination of analytical error function for beta-blockers as a possible weighting method for the estimation of the regression parameters.

Three analytical methods have been developed and validated for the quantification of beta-blockers (celiprolol, bisoprolol and oxprenolol) using high performance liquid chromatography (HPLC) with UV detection. The methods were determined to be linear, precise and accurate (RSDs were lower than 5%), which allowed the quantitation of beta-blockers assayed at concentrations in the range 25-0.78 micrograms ml-1. After validation of reversed-phase HPLC methods, their analytical error functions were established by a rapid, simple and economical procedure. The discrimination of the best function for each active principle was performed by an appropriate polynomial statistical analysis, yielding SD (microgram ml-1) = 0.0295 + 0.0124C - 3.88 x 10(-4)C2 for celiprolol, 0.0199 + 0.011C - 1.27 x 10(-5)C3 for bisoprolol; and 0.0183 + 0.0089C - 9.68 x 10(-6)C3 for oxprenolol. These analytical error functions are an alternative to the weighting methods used in parameter estimation of beta-blockers.

Adrenergic beta-Antagonists↗

PubMed1994

Stability of an oral midazolam solution for premedication in paediatric patients.

The objectives of this study were to assess the stability of a 1 mg/ml oral midazolam solution elaborated by our Hospital Pharmacy Service, and to confirm its clinical effect in presurgical paediatric patients. The solution's stability was tested by determining its pH and its UV-visible absorption spectrum at room temperature for up to 60 days. A high performance liquid chromatography method was used to confirm it. There was no significant change in pH value of either the test or a control solution. No loss of midazolam could be detected during the test. The Anaesthesiology Service assessed the sedation quality (very good, good, bad) and the venous puncture response, 20 minutes after the administration of 0.3 mg/kg of an oral midazolam solution. Twenty children were examined (age: 4-7 years). In addition, the haemodynamic and ventilatory functions were evaluated.

Administration, Oral↗