Evaluation of the relationship between a pharmaceutical compound's distribution coefficient, log D and adsorption loss to polypropylene in urine and CSF.

PMID 21083273


The distribution coefficient, D, is a physicochemical property used to determine the partitioning of compounds between aqueous and hydrophobic media at a given pH. A clear relationship was observed between the calculated pH-dependent distribution coefficient of six representative pharmaceutical probe compounds and their propensity to partition between a relatively hydrophobic polypropylene surface and the aqueous matrices, human urine or human cerebrospinal fluid (CSF). Compound log D cut-off values of 1.5 and 3.8 for urine and CSF, respectively, were determined using a threshold of less than 20% adsorption to the polypropylene surface. The ability to forecast the adsorption of a given compound to a polypropylene container with urine and CSF offers an effective means for screening potential issues and identifying when additional testing and corrective measures may need to be applied.