Comparative pharmacokinetic profiles of a novel isotretinoin formulation (isotretinoin-Lidose) and the innovator isotretinoin formulation: a randomized, 4-treatment, crossover study.

Abstract

A high-fat meal is needed for optimal absorption of isotretinoin. A new formulation of isotretinoin, which enhances absorption of isotretinoin in the absence of dietary fat, has recently been approved by the Food and Drug Administration (FDA). We sought to compare the pharmacokinetic profiles of a new formulation of isotretinoin (isotretinoin-Lidose) with the innovator isotretinoin formulation. This study was an open-label, single-dose, randomized, 4-treatment, crossover comparative trial between a new and innovator formulation of isotretinoin in the fasting and fed states. Both formulations were bioequivalent under fed conditions. As expected in a fasting state, absorption of both formulations was reduced. A considerable difference between the 2 drugs occurred under fasted conditions-there was a marked improvement in overall bioavailability of the isotretinoin-Lidose formulation. Mean plasma levels of the isotretinoin-Lidose formulation during fasting reached 66.8% of that observed with a fatty meal, and those of the isotretinoin formulation only reached 39.6% of that observed with a fatty meal. Only the FDA-stipulated standard high-fat, high-calorie meal of 50-g fat was studied in the fed state. Isotretinoin-Lidose formulation is bioequivalent to the innovator formulation under fed conditions with regard to its pharmacokinetic profile but delivers twice as much isotretinoin and 4-oxo-isotretinoin when administered after an overnight fast.