Methods: Reaction conditions were studied for a lipase method using newly synthesized 2,3-dibutyrylthio-1-propyl oleate as the substrate and 5,5′-dithio-bis-(2-nitro-benzoic acid) as the chromogen.
Results: Optimum conditions, using colipase and Mg++ in aqueous hexamethyl phosphoric triamide medium at pH 9.2, were defined. The substrate was highly selective to pancreatic lipase. The reaction increased linearly with lipase concentrations up to 500 U/l. The reference interval of serum lipase concentrations was 21.5–65 U/l. Using the Passing–Bablok regression analysis, the present assay shows a slope of 0.414, an intercept of − 2.4 U/l, and r-value of 0.992 in the comparison with the chromogenic method using the 6-methylresorufin ester of 1-O,2-O-dilauryl-rac-glycero-3-glutaric acid as the substrate.
Conclusion: Because of the simple composition of the reagents, the proposed procedure may represent a significant advancement in the commercially available methods for pancreatic lipase determination.