Kotecha Jignesh, Shah Shailesh, Rathod Ishwarsinh, Subbaiah Gunta
Department of Quality Assurance, L.M. College of Pharmacy, P.O. Box 4011, Navrangpura, Ahmedabad 380009, India.
Int J Pharm. 2007 Mar 21;333(1-2):127-35. doi: 10.1016/j.ijpharm.2006.10.010. Epub 2006 Oct 11.
Capacity factors are determined for a set of drugs for which human oral absorption (HOA) data are available, using immobilized artificial membrane (IAM) chromatography. The compound set represented acidic, basic, neutral and amphoteric drugs from various structure classes and having low to high human oral absorption. Effect of mobile phase pH on retention was investigated to determine the optimal condition for better correlation with HOA. The retention (capacity factor, k'(IAM) of each drug was measured by reverse phase HPLC using an IAM.PC.DD2 (1 cm x 3 mm i.d., 12 microm) column with an eluent of acetonitrile - 0.01 M phosphate buffer at pH 4.5-7.4. The pH dependent k'(IAM) was in accordance with pH partition theory. Using non-linear regression analysis the obtained log k'(IAM) values were compared with published data on HOA in order to establish correlation. The better correlation with HOA was observed when the highest log k'(IAM) value selected among pH 4.5-7.4 (R(2)=0.8566) for each drug rather than obtained at more traditional pH 7.4 (R(2)=0.7403). Finally, it was confirmed by Cook's D outlier test that there was no influential observation in the model that affect the relationship between IAM capacity factor and HOA. The assay conditions were optimized and validated to make it suitable for routine analysis and for compound characterization in early discovery where permeability may be an issue.
利用固定化人工膜（IAM）色谱法，为一组有人类口服吸收（HOA）数据的药物测定容量因子。该化合物集代表了来自各种结构类别的酸性、碱性、中性和两性药物，且具有低至高的人类口服吸收。研究了流动相pH对保留的影响，以确定与HOA有更好相关性的最佳条件。使用IAM.PC.DD2（1 cm×3 mm内径，12微米）柱，以乙腈 - 0.01 M pH 4.5 - 7.4的磷酸盐缓冲液为洗脱剂，通过反相高效液相色谱法测量每种药物的保留（容量因子，k'(IAM)）。pH依赖性k'(IAM)符合pH分配理论。使用非线性回归分析，将获得的log k'(IAM)值与已发表的HOA数据进行比较，以建立相关性。当为每种药物选择pH 4.5 - 7.4之间的最高log k'(IAM)值时（R(2)=0.8566），观察到与HOA有更好的相关性，而不是在更传统的pH 7.4时获得的值（R(2)=0.7403）。最后，通过库克距离异常值检验证实，该模型中不存在影响IAM容量因子与HOA之间关系的有影响力的观测值。对分析条件进行了优化和验证，使其适用于常规分析以及早期发现中可能存在通透性问题的化合物表征。
