Pharmacokinetics of two generic co-formulations of lopinavir/ritonavir for HIV-infected children: a pilot study of paediatric Lopimune versus the branded product in healthy adult volunteers.

Objectives: To determine the pharmacokinetic profiles of lopinavir and ritonavir in two newly developed generic co-formulations for HIV-infected children (Lopimune paediatric tablets and granules, 100/25 mg of lopinavir/ritonavir, Cipla Pharmaceuticals), and to compare these with the branded product (Kaletra).
Methods: This Phase I, comparative, open-label, three-period, single-dose, crossover study was designed as a pilot study to exclude large (>40%) differences in the exposure to lopinavir. Single doses of medication, normalized to 400 mg of lopinavir, were administered on an empty stomach, 1 week apart. A 32 h pharmacokinetic curve was recorded. In an additional part of the study, in five of the same volunteers, a pharmacokinetic curve was recorded after administration of the Lopimune granules and Kaletra oral solution, both with food.
Results: Twelve healthy subjects were enrolled (four females). The median (range) age, height and body weight were 24 (21-55) years, 1.79 (1.63-1.95) m and 72 (51-87) kg, respectively. The median [interquartile range (IQR)] AUC(0-t) of lopinavir was 71.8 (48.8-93.5), 38.7 (28.7-52.2) and 58.7 (42.5-79.4) mg.h/L with Kaletra tablets, Lopimune granules and Lopimune paediatric tablets, all taken on an empty stomach, respectively. The respective C(max) values were 7.2 (5.8-8.3), 4.6 (4.1-5.2) and 6.5 (5.0-7.1) mg/L after intake of the different formulations. When comparing the Lopimune formulations with the reference product Kaletra, for all parameters the differences were statistically significant (P <or= 0.015). Ritonavir exposure was also lower after intake of the generic formulations versus Kaletra. When the five subjects took the Lopimune granules or Kaletra solution with food, the median (IQR) AUC(0-t) of lopinavir was 58.5 (55.4-77.6) and 49.6 (39.1-58.1) mg.h/L, respectively.
Conclusions: Large differences in pharmacokinetic parameters can be excluded for Lopimune paediatric tablets when compared with the branded product and taken on an empty stomach, and also for Lopimune granules when these are taken with food.