The results of animal studies with ciprofibrate, a new orally effective hypolipidemic drug.

Findings are given to show that ciprofibrate, a new orally active phenoxyisobutyrate, is significantly more hypolipidemic than is the reference clofibrate. In hyperlipidemic rats ciprofibrate suppresses the increase in blood lipids 33% at a daily dosage of 0.6--3 mg/kg. The corresponding dosage for clofibrate is 125--460 mg/kg. Based on studies with cholesterol pools pre-labeled with [14C]mevalonate or with cholesterol-labeled pools in ciprofibrate-treated normolipidemic rats, ciprofibrate was shown to inhibit cholesterol biosynthesis. No evidence of the presence of 7- or 24-dehydrocholesterol was obtained in the sera of ciprofibrate-treated rats as shown by gas chromatography examination. The order of hypolipidemic effectiveness of ciprofibrate in hyperlipidemic rats provides a basis for anticipating that ciprofibrate will be hypolipidemic in hyperlipoproteinemic subjects who are considered at high risk of acquiring coronary artery disease.