Enantioselective Retention of 4‐Aryl‐1,4‐dihydropyridine Calcium‐Channel Blockers on Human Serum Albumin and α ₁ ‐Acid Glycoprotein HPLC Columns: Relationships with Different Scales of Lipophilicity

Stability-indicating methods for the enantioselective determination of dihydropyridines by high performance liquid chromatography and capillary electrophoresis

“…Nitrendipine and nimodipine. The optimization of analyses conditions of NTD and NMD were based on the method described by Barbato et al 14 Some modifications were preformed to improve the resolution of enantiomers. Several mobile phases consisting of different proportions of buffer and organic solvent were tested (Table 1).…”

“…Elution order (R)-NTD and (R)-NMD are known to be dextrorotatory while (R)-NSD is known to be levorotatory. 14 The elution order for the NTD enantiomers was established by analyzing the pure enantiomers obtained by semipreparative analysis of the 25 mL standard methanolic solution racemates on a Chiralcel OJ column 250 Â 4.6 mm id, 10 mm particle size (Daicel Chemical Industries, Tokyo, Japan) and the mobile phase consisted of nhexane : isopropanol (87.5 : 12.5, v/v) at a flow rate of 1.0 mL min À1 . 15 The two peaks corresponding to (À)-(S)-NTD and (+)-(R)-NTD were collected at the end of the column, the solvent was evaporated and the residues were analyzed under the conditions established in the present paper and the elution order established.…”

“…The elution order for the NMD enantiomers was based on the work described by Barbato et al 14 These authors employed a Chiral AGP 100 Â 4.0 mm id, 5 mm particle size (Chromtech, H€ agersten, Sweden) using a mobile phase which consisted of isopropanol: 0.01 mol L À1 phosphate-buffered saline pH 7.0 (10 : 90, v/v) and flow rate of 0.9 mL min À1 . In this condition the two peaks corresponding to (À)-(S)-NMD and (+)-(R)-NMD were collected separately at the end of the column, the solvent was evaporated and the residues were analyzed under the conditions established in the present paper and the elution order established.…”

Aplicações da eletroforese capilar na análise do biomarcadir alfa-1 glicoproteína ácida, no controle de qualidade do biofármaco interferon alfa 2a e na avaliação da estabilidade enantiosseletiva do fármaco isradipina

“…Diversos métodos, utilizando a cromatografia quiral, tem sido apresentados para a análise enantiosseletiva da IRD. Estes métodos empregaram a α1-glicoproteína ácida como fase estacionária (BARBATO et al, 2000;BOATTO et al, 2003), e derivados de polissacarídeos (OKAMOTO et al, 1990;RASK;ANGELO;CHRISTENSEN, 1998). Além disso, um método empregando cromatografia líquida acoplada a espectrometria de massas foi relatado para a determinação de produtos de degradação da IRD (BARTLETT et al, 1998).…”

“…De acordo com Barbato et al (2000), (S)-IRD é dextrógira e (R)-IRD é levógira. A ordem de migração foi estabelecida pela análise dos enantiômeros da IRD de acordo com o trabalho descrito por Rask, Angelo e Christensen (1998 (WEINBERGER, 2000).…”