Johansson M, Lenngren S
Research and Development Department, ACO Läkemedel AB, Solna, Sweden.
J Chromatogr. 1988 Nov 18;432:243-52. doi: 10.1016/s0378-4347(00)80649-0.
Extraction of the hydrophobic tertiary amine bromhexine from plasma using cyclohexane-heptafluorobutanol (99.5:0.5, v/v) was studied at different pH values. The extraction yield from buffer solutions was quantitative at pH greater than 4.1, but from plasma the extraction yield decreased with increasing pH. Furthermore, at pH 8.4 the extraction yield varied greatly (56-99%) in different human plasma. The addition of lipoproteins to phosphate buffer, at pH 8.1, decreased the extraction yields considerably. Quantitative extraction from plasma was obtained by using a very long extraction time at pH 8.4 or by decreasing the pH to 5.4. The chromatographic system consisted of a reversed-phase column (Nucleosil C18, 5 microns) with an acidic mobile phase (methanol-phosphate buffer, pH 2) containing an aliphatic tertiary amine. UV detection at 308 or 254 nm was used. The limit of quantitation was 5 ng/ml using 3.00 ml of plasma and detection at 254 nm. The intra-assay precision for bromhexine was better than 3.6% at 5 ng/ml.
研究了在不同pH值下，使用环己烷 - 七氟丁醇（99.5:0.5，v/v）从血浆中提取疏水性叔胺溴己新的情况。在pH大于4.1时，从缓冲溶液中的提取率是定量的，但从血浆中提取率随pH升高而降低。此外，在pH 8.4时，不同人血浆中的提取率差异很大（56 - 99%）。在pH 8.1时，向磷酸盐缓冲液中添加脂蛋白会显著降低提取率。通过在pH 8.4使用很长的提取时间或通过将pH降至5.4，可以从血浆中进行定量提取。色谱系统由反相柱（Nucleosil C18，5微米）组成，流动相为酸性（甲醇 - 磷酸盐缓冲液，pH 2），含有脂肪族叔胺。使用308或254 nm的紫外检测。使用3.00 ml血浆并在254 nm检测时，定量限为5 ng/ml。溴己新的批内精密度在5 ng/ml时优于3.6%。
