[Features of chemical and toxicological study of 1,4-dihydropyridine derivatives].

Objective: To investigate the features of 1.4-dihydropyridine derivatives' determination in biological material in chemical and toxicological studies.

Material and methods: Liquid-liquid extraction, semi-preparative column chromatography, thin-layer chromatography (TLC) and gas chromatography with mass spectrometric detection (GC-MS) were used as analysis methods.

Results: It has been established that extraction of 1.4-dihydropyridine derivatives from biomaterial is most appropriate to be carried out by consecutive (by 30 min) infusion with two portions of acetone-acetonitrile (7.5:2.5) mixture at a mass ratio of the extracting liquid and bioactive matrix equal 2:1. The optimum regimen of 1.4-dihydropyridine derivatives chromatography in C-18 «Silasorb» sorbent column using acetonitrile-aqua (7:3) eluant was determined, that was realized in combined purification including the extraction with ethyl acetate from aqua-acetonitrile medium and column chromatography of analytes. Butanol-acetone (5:5) eluant may be used to identify analytes by TLC method («Sorbfil» plates). Additionally, the identification of 1.4-dihydropyridine derivatives can be performed using GC-MS (HP-5 ms Ultra inert (30 000×0.25 mm) column, immobilized phase is 5% phenyl-95% dimethylpolysiloxane, mobile phase is helium by characteristic retention time and ion sets in the analytes' mass-spectra. The same method was used for quantitative determination of studied compounds. Methods for the determination of amlodipine, nifedipine, nimodipine and felodipine were developed by GC-MS method in biomatrix model (liver tissue), that showed suitability to validation requirements by a number of key criteria. The maximum detectable and quantitatively determinable content levels of studied substances in biomatrix did not exceed 0.04-0.14 and 0.08-0.24 mg/g, respectively.