Dasatinib anhydrate containing oral formulation improves variability and bioavailability in humans.

Dasatinib monohydrate indicated for the treatment of chronic myeloid leukemia displays pH-dependent solubility. The aim of reported development program of novel dasatinib anhydrate containing formulation was to demonstrate improved absorption and lower pharmacokinetic variability compared to dasatinib monohydrate. In a bioavailability study comparing formulations containing 110.6 mg and 140 mg of dasatinib as anhydrate and monohydrate, respectively, both Cmax and AUC of dasatinib were within standard 80.00-125.00% range, while the intra- and inter-subject variability for AUC0-inf after the test product was approximately 3-fold and 1.5-fold less than after the reference, respectively.In a drug-drug interaction study, omeprazole 40 mg reduced the mean AUC0-inf of dasatinib by 19%, when the test was ingested 2 h before the 5th omeprazole dose. This decrease of exposure is clinically irrelevant and substantially less than after the reference. Co-prescription analysis supports the importance of pH-dependent solubility of dasatinib, as >21% of patients were treated concomitantly with a PPI and dasatinib despite warnings against this co-medication in the SmPC.The novel dasatinib anhydrate containing formulation demonstrated improved absorption and less pharmacokinetic variability compared to dasatinib monohydrate product, which may translate into improved clinical outcomes, although this needs to be proven by an appropriate trial.

Pharmacokinetic Variability in Pre-Clinical Studies: Sample Study with Abiraterone in Rats and Implications for Short-Term Comparative Pharmacokinetic Study Designs.

One of the major concerns for all in vivo experiments is intra- and inter-subject variability, which can be a great source of inaccuracy. The aim of this study is, therefore, to estimate the ability of parallel vs. cross-over design studies in order to describe the relative pharmacokinetic performance of the studied drug formulations. We analyzed the data from a drug development program that examined the performance of innovative abiraterone acetate formulations against the identical reference product in three stages. In stages 1-3, groups A-F were dosed with the reference product once in a parallel manner. Stage 4 was performed to evaluate the intra-individual variability (IIV) by repeated administration of the reference product to the same animals. Although the geometric mean (90% CI) values of abiraterone AUClast in groups A-F were similar to the IIV group (24.36 (23.79-41.00) vs. 26.29 (20.56-47.00) mg/mL·min·g), the results generated in the isolated parallel groups provided imprecise estimates of the true AUClast values ranging from 9.62 to 44.62 mg/mL·min·g due to chance. Notably, in 4 out of 15 possible pair comparisons between the parallel groups, the confidence intervals did not include 100%, which is the true ratio for all comparisons tested after identical formulation administration to all groups. A cross-over design can significantly improve the methodology in short-term comparative pre-clinical pharmacokinetic studies, and can provide more precise and accurate results in comparison to more traditional pre-clinical study designs.

Nabumetone and 6-MNA Pharmacokinetics, Assessment of Intrasubject Variability and Gender Effect.

In this open-label, laboratory-blinded, 2-way single dose study in 24 volunteers of both sexes we found that (1) nabumetone reaches mean Cmax ± SD of 0.56 ± 0.20 mg·L at mean tmax of 8.63 ± 7.05 hours, and mean area under the curve (AUC)last of 18.07 ± 7.19 h·mg·L; (2) there are no statistically significant differences between both sexes in pharmacokinetics of nabumetone; (3) 6-methoxy-2-naphthylacetic acid (6-MNA) reaches higher AUClast in men compared with women (mean ± SD, 721.23 ± 185.53 h·mg·L and 545.27 ± 97.69 h·mg·L, respectively; P = 0.013); (4) there is lower 6-MNA clearance in men (0.65 ± 0.22 L·h) in comparison with women (0.88 ± 0.18 L·h, P = 0.019), (5) intersubject variability of nabumetone and 6-MNA is between 35%-45% and 10%-30% for all assessed pharmacokinetics parameters (AUClast, Cmax, partial AUC values); (6) intrasubject variability (ISCV) for AUClast is low, 15.59% and 6.40% for nabumetone and 6-MNA, respectively, (7) ISCV for Cmax is 13.66% and 5.42% for nabumetone and 6-MNA, respectively. Nabumetone thus belongs to compounds with low to moderate ISCV and therefore this product is expected to produce consistent effects in clinical practice.

Single-dose, 2-way crossover, bioequivalence study of two rosuvastatin formulations in normal healthy subjects under fasting conditions.

BACKGROUND: Rosuvastatin, a synthetic lipid-lowering agent acts selectively by competitive inhibition of 3-hydroxy- 3-methylglutaryl-coenzyme A. It is indicated as an adjunct to diet in patients with hypercholesterolemia and mixed dyslipidemia. OBJECTIVE: The purpose of this study was to demonstrate bioequivalence between a generic rosuvastatin 40 mg tablet (Zentiva, Prague, Czech Republic) and a reference product (Crestor, AstraZeneca, Luton, UK), under fasting conditions as required by the European Medicinal Agency. METHODS: A single-oral 40 mg-dose, randomized, open-label, 2-way crossover design study was conducted in 42 healthy volunteers under fasting conditions. Rosuvastatin was administered following an overnight-fast in two occasions with a 14-day washout period in-between. Blood samples were collected in EDTA-K2 tubes prior to dosing and over a 96-hour period. Rosuvastatin was measured in plasma using an automated LC-MS/MS assay (range 81.02 - 40,512.00 pg/ml). Pharmacokinetics were performed using non-compartmental analyses approach to evaluate AUC(last), AUC∞ and C(max). ANOVA was performed on the ln-transformed data and the 90% Confidence Interval (CI) was determined. Bioequivalence will be concluded if the 90% CI falls within 80.00 - 125.00% for AUC(last) and C(max). Safety and tolerability were also evaluated. RESULTS: 39 volunteers completed the study and were considered for the pharmacokinetic and statistical analyses. Descriptive safety data analyses were performed on all subjects. All pharmacokinetic parameters met the acceptance criteria as the 90% CI were within 80.00 - 125.00%. Both formulations were well tolerated and no serious adverse events were reported. CONCLUSION: This study showed that the test and reference products met the regulatory criteria for bioequivalence following a 40 mg oral dose under fasting conditions.