Bioequivalence, safety, and tolerability of imatinib tablets compared with capsules.
ABSTRACT Imatinib (Glivec) has been established as a highly effective therapy for chronic myeloid leukemia and gastrointestinal tumors. The recommended daily dosage of 400-600 mg requires simultaneous intake of up to six of the current 100-mg capsules. Due to the need to swallow multiple capsules per dose, there is a potential negative impact on treatment adherence; therefore, a new imatinib 400-mg film-coated tablet has been developed. To improve dosing flexibility, particularly with regard to the pediatric population and the management of adverse events, a scored 100-mg film-coated tablet has also been introduced.
A group of 33 healthy subjects were randomly assigned to one of six treatment sequences, in which they received imatinib as 4 x 100-mg capsules (reference), 4 x 100-mg scored tablets (test), and 1 x 400-mg tablet (test). Blood sampling was performed for up to 96 h after dosing, followed by a 10-day washout period prior to the next sequence. After the third dosing, subjects were monitored to assess delayed drug-related adverse events. Pharmacokinetic parameters were assessed using concentration-time curves for plasma imatinib and its metabolite CGP74588.
Median Tmax was 2.5 h for capsules and tablets. Mean AUC((0-inf)) values were 27,094, 26,081 and 25,464 ng.h/ml for 4 x 100-mg capsules, 4 x 100-mg tablets, and 1 x 400-mg tablets, respectively. Cmax values were 1748, 1638 and 1606 ng/ml, and t(1/2) values were 15.8, 15.9 and 15.7 h. The test/reference ratios for AUC((0-inf)), AUC((0-96) (h)), and C(max) were 0.98, 0.98 and 0.95 for 4 x 100-mg tablets versus 4 x 100-mg capsules, and 0.95, 0.95 and 0.92 for 1 x 400-mg tablet versus 4 x 100-mg capsules. The 95% confidence intervals were fully contained within the interval (0.80, 1.25). Eight mild and one moderate adverse event considered to be drug related were reported. These events showed no clustering by type of dosage form and were of little to no clinical significance.
Film-coated 100-mg (scored) and 400-mg tablet dose forms of imatinib are bioequivalent to the commercial 100-mg hard-gelatin capsule, and are as safe and well tolerated.
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ABSTRACT: Cytochrome P450 (CYP) 3A4 is considered the most important enzyme in imatinib biotransformation. In a randomized, crossover study, 10 healthy subjects were administered gemfibrozil 600 mg or placebo twice daily for 6 days, and imatinib 200 mg on day 3, to study the significance of CYP2C8 in imatinib pharmacokinetics. Unexpectedly, gemfibrozil reduced the peak plasma concentration (Cmax) of imatinib by 35% (P < 0.001). Gemfibrozil also reduced the Cmax and area under the plasma concentration-time curve (AUC0-∞) of N-desmethylimatinib by 56% and 48% (P < 0.001), while the AUC0-∞ of imatinib was unaffected. Furthermore, gemfibrozil reduced the Cmax/C24 h ratios of imatinib and N-desmethylimatinib by 44% and 17%, (P < 0.05), suggesting diminished daily fluctuation of imatinib plasma concentrations during concomitant use with gemfibrozil. Our findings indicate significant participation of CYP2C8 in the metabolism of imatinib in humans, and support involvement of an intestinal influx transporter in imatinib absorption.Clinical Pharmacology & Therapeutics (2013); accepted article preview online 8 May 2013 doi:10.1038/clpt.2013.92.Clinical Pharmacology & Therapeutics 05/2013; · 6.85 Impact Factor
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ABSTRACT: A specific and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed for the quantification of imatinib and its primary metabolite N-desmethyl imatinib in human plasma. Protein precipitation with methanol was used for sample preparation. High-performance liquid chromatographic separation was performed on a Thermo BDS Hypersil C18 column (4.6 × 100 mm, 2.4 µm) with methanol-water (55:45, v/v) containing 0.1% formic acid and 0.2% ammonium acetate as the mobile phase, using isocratic elution at a flow rate of 0.7 mL/min. Detection was conducted with positive electrospray ionization multiple reaction monitoring of the ion transitions at m/z 494 → 394 for imatinib, 480 → 394 for N-desmethyl imatinib and 297 → 110 for the internal standard (palonosetron). The assay was validated in the concentration ranges of 8-5,000 ng/mL for imatinib and 3-700 ng/mL for N-desmethyl imatinib. The quantification limits for imatinib and N-desmethyl imatinib were 8 and 3 ng/mL, respectively. The intra-day and inter-day precision values of the assay (expressed as percentage relative standard deviation) were less than 15% at all concentration levels within the tested range, and the accuracy values were between 85 and 115%. The established method was successfully applied to the pharmacokinetic study of imatinib mesylate capsules in 24 healthy Chinese volunteers.Journal of chromatographic science 04/2013; · 0.79 Impact Factor
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ABSTRACT: Imatinib mesylate is used to treat chronic myeloid leukemia and advanced gastrointestinal stromal tumors. The purpose of this study was to compare the pharmacokinetics of 2 different strengths of the imatinib formulation containing 100 mg (reference) and 400 mg (test) to satisfy the regulatory requirement for marketing. A single-center, randomized, single-dose, open-label, 2-period, 2-sequence, comparative crossover study with a 14-day washout period was conducted in 30 healthy male volunteers. Plasma samples for the drug analysis were collected up to 72 hours after drug treatment. Participants received either the reference (4 tablets of 100-mg imatinib) or the test (1 tablet of 400-mg imatinib) formulation during the first period and the alternative formulation during the second period. The safety profiles and tolerability of the 2 formulations were also assessed based on physical examinations, laboratory tests, a 12-lead ECG, and vital signs. Thirty participants were initially enrolled; their mean (SD) age, height, weight, and body mass index were 24.9 (2.0) years (range, 23-30 years), 174 (5) cm (range, 164-185 cm), 69.9 (2.0) kg (range, 54.1-87.4 kg), and 23.0 (2.0) kg/m(2) (range, 18.5-26.9 kg/m(2)); 28 healthy participants completed both treatment periods. Two subjects did not complete the study because they withdrew consent for personal reasons. The observed mean (SD) Cmax, AUC0-last, and AUC0-∞ values for the reference formulation were 1792 (357) ng/mL, 28,485 (6274) ng · h/mL, and 29,079 (6371) ng · h/mL, respectively. Corresponding values for the test formulation were 1710 (312) ng/mL, 27,222 (4624) ng · h/mL , and 27,872 (4751) ng · h/mL. The geometric mean ratios (90% CIs) between the 2 formulations at the 400-mg dose of imatinib were 0.9579 (0.9054-1.0136) for Cmax, 0.9652 (0.9174-1.0155) for AUC0-last, and 0.9679 (0.9203-1.0179) for AUC0-∞, respectively. During the study period, 6 adverse events (3 for the reference and 3 for the test formulation) were reported; all were transient, mild, and resolved completely during the treatment period. There were 4 cases of nausea and 1 case each of dizziness and oropharyngeal pain. Four adverse events were considered related to the study drugs. The results showed that despite the different strengths of the 2 imatinib formations, the test and reference formulations both met the regulatory criteria for pharmacokinetic equivalence at a dose of imatinib 400 mg in these healthy Korean male subjects. Both imatinib formulations seemed to be generally well tolerated. ClinicalTrials.gov identifier: NCT01270984.Clinical Therapeutics 09/2013; · 2.23 Impact Factor