Content » Vol 100, February

Investigative Report

Comparative Pharmacokinetic Profiles of a Novel Low-dose Micronized-isotretinoin 32 mg Formulation and Lidose-isotretinoin 40 mg in Fed and Fasted Conditions: Two Open-label, Randomized, Crossover Studies in Healthy Adult Participants

Sumit Madan, Sudershan Kumar, Jeanett Segal
DOI: 10.2340/00015555-3381


Two open-label, crossover studies compared the bioavailability of Micronized-isotretinoin 32 mg and Lidose-isotretinoin 40 mg in healthy adults. In the fed bioequivalence/food-effect study, participants (n = 71) received single doses of fed-state Micronized-isotretinoin 32 mg, fed-state Lidose-isotretinoin 40 mg and fasted-state Micronized-isotretinoin 32 mg. In the fasting study, participants (n = 18) received single doses of fasted-state Micronized-isotretinoin 32 mg and fasted-state Lidose-isotretinoin 40 mg. Bioavailability was assessed by isotretinoin LnAUC0–t, LnAUC0–∞ and LnCmax in blood samples taken pre-dosing and over 96 h post-dosing. The 90% confidence intervals for baseline-adjusted least squares geometric mean ratios for LnAUC0–t, LnAUC0–∞ and LnCmax fell within the 80–125% range for bioequivalence for fed-state Micronized-isotretinoin 32 mg vs. fed-state Lidose-isotretinoin 40 mg. Fasted-state Micronized-isotretinoin 32 mg had ~2 times higher bioavailability than fasted-state Lidose-isotretinoin 40 mg. Food had no effect on the rate and a marginal effect on the extent of absorption of Micronized-isotretinoin 32 mg.


For the treatment of acne, Lidose-isotretinoin does not need to be taken with a high-fat meal. Two studies compared the absorption of a novel form of isotretinoin (Micronized-isotretinoin 32 mg) and Lidose-isotretinoin 40 mg in healthy adults following either a fast or a high-fat meal. Absorption of Micronized-isotretinoin 32 mg was superior to Lidose-isotretinoin 40 mg, as demonstrated by the equivalent blood levels achieved when both were taken with food. Under fasted conditions, Micronized-isotretinoin 32 mg was absorbed approximately twice as much as Lidose-isotretinoin 40 mg. Micronized-isotretinoin 32 mg could be an alternative acne therapy without stringent food intake requirements.

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