A Systematic Analysis of the Effect of Extraction Solvents on the Chemical Composition of Extraction Solutions and the Analytical Implications in Extractables and Leachables Studies

Abstract

Assessment of extractables and leachables (E&L) released from the pharmaceutical container closure systems (CCS), single-use polymeric processing materials (PPM), and medical devices is one of regulatory requirements in the submission and approval of pharmaceutical products and medical devices. The analytical activities involved in E&L studies are the solvent extraction of test articles, followed by instrumental analysis to determine both concentration and identities. Most E&L publications today are centered around the latter part, and the effect of extraction solvents on the chemical composition of extracts in the number, concentration and molecular weight (MW) has not been systematically delineated and conceptualized to the best of our knowledge. The focus of this study is on a systematic review and analysis of the effect of solvents on the composition of extracts based on an extensive collection and study of relevant publications. The details of the discussions include: (1) the solvent extraction processes; (2) the degree of solvent-material interactions; (3) the material swelling and diffusion rate of material constituents; (4) the MW impact from swelling; and (5) finally, the conclusion of the dependency of chemical compositions in final extracts on solvent. Experimental data have also been collected and presented to support the conclusions of the study. The implications of the solvent-dependent chemical composition on analytical measurements of E&L by using both chromatography-based and gravimetric methods are briefly and critically discussed at the end.