Valproic acid, a branched short-chain fatty acid, has numerous action mechanisms which turn it into a broad spectrum anticonvulsant drug and make its use possible in some other pathologies such as bipolar disorder. It is extensively metabolized in liver, representing β-oxidation in the mitochondria one of its main metabolic route (40%). Carnitine is responsible for its entry into the mitochondria as any other fatty acid. Long-term high-dose VPA therapy or acute VPA overdose induces carnitine depletion, resulting in high levels of ammonia in blood. As a high correlation between salivary valproic acid levels and plasma ultrafiltrate levels was found in humans, saliva becomes a promising monitoring fluid in order to study valproic acid pharmacokinetics and its toxic effect. Extended-release (twice daily) formulations of valproic acid or carnitine supplementation are the proposed two therapeutic strategies in order to reverse hyperammonemia.

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R-to-S conversion rate could be mainly associated with several passages of the drug through the intestinal mucosa. The concentration-time profiles of ketoprofen in plasma after the administration of both formulations evidenced R-to-S conversion of recirculating drug following meal intakes.

Sixteen healthy volunteers (8 women and 8 men) participated in a 2-period, 2-treatment crossover study. A delayed-release gastroresistant formulation of ketoprofen was administered under fasting and fed conditions. Cmax , AUC, Cmax /AUC, and kel obtained after food coadministration did not differ from those calculated under fasting administration. Ninety-five percent confidence intervals for fed/fasting geometric mean ratio of Cmax /AUC and AUC were 0.80-1.14 and 0.80-1.23, respectively. A significant difference (P < .01) was found between lag-time medians (T0 ), with a longer T0 after food intake (5.5 vs 2.5 hours). Also, a significant difference between the medians of Tmax was found (P < .01), being 7.0 hours after food coadministration and 4.0 hours under fasting administration, but this difference disappeared once T0 was subtracted from Tmax . Cmax /AUC, which is related to drug absorption rate, showed significant differences between sexes. Men showed higher (P =.006) Cmax /AUC means (0.468 ± 0.094 vs 0.361 ± 0.087 h(-1) . Tmax was also significantly different (P < .05), being 4.0 (3.0-5.0) hours for men and 8.0 (5.0-10.0) hours for women. In conclusion, men showed a faster intestinal absorption rate with earlier time-to-peak plasma concentration of ketoprofen. Food coadministration extended the gastric residence time of formulation but exerted no effect on its intestinal absorption pattern.

The aim of this work was to study the effect of the sex and the smoking status on the pharmacokinetics and the bioequivalence assessment of a branded and a generic cyclosporine A microemulsion formulation in soft-gelatin capsule. Sixteen healthy volunteers (eight women and eight men) participated in a CyA bioequivalence study, with nine of the volunteers being smokers. Sandimmun Neoral® (brand formulation; Reference) and Sigmasporin Microral® (generic formulation; Test) were administered under fasting conditions. Pharmacokinetic parameters were calculated through non compartmental analysis. Bioequivalence was declared based on the 90% confidence intervals (90% CI) for the T/R ratio of the geometric means for each parameter. In vitro determination of the capsules opening time was performed in simulated gastric fluid without enzyme with USP Apparatus 2. The extent of absorption was similar between both products for all subjects or each sex-group. The absorption rate was similar for both products when considering all subjects, whereas a significant difference in the TMAX between the two products was observed for the male subjects only, which relates to its slower capsule opening time observed in vitro (12.4 versus 6.0 min). No differences were observed in women that could relate to their slower gastric emptying. Differences in drug exposure were observed between smokers and non-smokers. Sex- and smoke-related differences in the gastrointestinal transit should be considered when the on-set time would be determinant for the treatment success of a drug.