Alfredo Piñeyro López

Tissue culture ofKarwinskia humboldtiana—a plant producing toxins with antitumoural effects

Isolated embryos ofKarwinskia humboldtiana were cultured in vitro. The growth of embryos and development to plantlets on woody plant medium supplemented with indole-3-acetic acid 6.10-2 μmol l−1, gibberellic acid (GA3) 3.10-2 μmol l−1, and 6-benzylaminopurine (BA) 2 μmol l−1 was obtained. Multiplication of shoots and rooting of excised shoots has been achieved. Callus formation on modified Murashige-Skoog medium supplemented with 1-naphthaleneacetic acid 10 μmol l−1, GA3 14 μmol l−1, and kinetin 5 μmol l−1 on hypocotyls, or on root cultures on medium supplemented with 2.4-dichlorophenoxyacetic acid 10 μmol l−1 and BA 10 μmol l−1 was induced.

Simultaneous Determination of Anticonvulsants and Their Principal Metabolites by HPLC

Abstract A rapid, precise, and sensitive method has been developed for the simultaneous determination of five antiepileptic drugs (carbamazepine, phenobarbital, diphenylhydantoin, primidone, and oxcarbazepine) and six metabolites (from carbamazepine, carbamazepin‐10,11‐epoxide; from phenobarbital, p‐hydroxyphenobarbital; from primidone, 2‐phenyl‐2‐ethylmalonamide; from diphenylhydantoin, 5‐(p‐hydroxyphenyl)‐5‐phenylhydantoin) in human serum. Separation was achieved by means of liquid chromatography with a diode array detector (DAD) using reverse‐phase ODS‐Hypersil columns (100 × 2.1 mm) with particle size of 5 µm, flow‐rate 0.6 mL/minute, column temperature 40°C, wavelength: 210 nm. Mobile phase was a gradient consisting of solvent A: phosphate buffer pH 5.7, solvent B: MeOH. Two procedures were tested for the serum treatment: protein precipitation with acetonitrile and solid‐phase extraction with C18 cartridges. The best recoveries were found by means of protein precipitation. Solid‐phase extraction gave poor recoveries for phenobarbital and its metabolite. The results obtained are suitable in terms of precision, linearity, and accuracy for the simultaneous determination of serum levels of the mentioned drugs in the usual therapeutic ranges.

PURITY DETERMINATION OF PEROXISOMICINE A1 BY HPLC WITH A DIODE ARRAY DETECTOR

ABSTRACT A simple and reliable method for determination of isoperoximicine in peroxisomicine-contaminated batches was developed. The method consists of mathematical derivatization of zero order chromatograms, plus a standard addition technique required to increase the sensitivity of the method due to the small amounts of impurity present. Combination of both techniques offers a simple generalized methodology for determination of the final quality product, with potential application in the pharmaceutical field.