Bioequivalence Interval Research Articles

Tecarfarin, a Novel Vitamin K Reductase Antagonist, Is Not Affected by CYP2C9 and CYP3A4 Inhibition Following Concomitant Administration of Fluconazole in Healthy Participants

Comparative pharmacokinetics of vitamin K epoxide reductase antagonists tecarfarin and warfarin were assessed before and after coadministration for 21 days of the CYP450 inhibitor fluconazole in a randomized, open-label, single-center drug interaction study. Twenty healthy adult participants were randomized 1:1 to receive approximately equipotent single oral doses of tecarfarin (50 mg) or warfarin (17.5 mg). Following 7 days of baseline serial blood level collections, each participant received oral fluconazole 400 mg daily for 21 days. A second identical single oral dose of tecarfarin or warfarin was given 14 days after starting fluconazole with serial pharmacokinetic sampling. Key pharmacokinetic parameters C(max), t(max), AUC(0-168), apparent clearance, and t(1/2) demonstrated no tecarfarin-fluconazole interaction but a strong warfarin-fluconazole interaction. The ratio of log-transformed mean AUC(0-168) with versus without fluconazole for tecarfarin was 91.2% (90% confidence interval [CI]: 83.3-99.8) and for racemic warfarin was 213% (90% CI: 202-226). The 90% CI was entirely within the standard 80% to 125% bioequivalence interval for tecarfarin but well outside the bioequivalence interval for warfarin, confirming a clinically significant pharmacokinetic interaction between warfarin and fluconazole. In contrast, tecarfarin pharmacokinetics were apparently unchanged by fluconazole.

Bioequivalence between two serum-free recombinant factor VIII preparations (N8 and ADVATE®) - an open-label, sequential dosing pharmacokinetic study in patients with severe haemophilia A

Recombinant coagulation factor VIII (rFVIII) concentrates provide a safe and efficacious replacement therapy for treatment and prevention of bleeding in patients with severe haemophilia A. The aim of this study was to compare the pharmacokinetic (PK) and safety profiles of two serum-free rFVIII products: N8, a new rFVIII manufactured by Novo Nordisk and Advate(®), a marketed product. Patients with severe haemophilia A with >150 exposure days to FVIII, without current or past inhibitors, were enrolled in an open-label, first human dose (FHD), multicentre trial. Twenty-three patients first received a single dose of 50 IU kg(-1) body weight Advate(®) followed by 50 IU kg(-1) body weight N8 at the next visit. A 4-day washout period was required prior to each dosing. Blood samples for PK and safety analyses were drawn prior to dosing and at intervals up until 48 h postdosing. The PK parameters were based on FVIII clotting activity (FVIII:C) measurements. Occurrence of adverse events was closely monitored. The mean profiles of FVIII:C and all primary and secondary parameters for Advate(®) and N8 were comparable. The 90% CI for the treatment ratio (Advate(®)/N8) for all primary endpoints (incremental recovery, t(1/2), AUC and Cl), and the secondary endpoints (AUC(last) and C(max)) were within the bioequivalence interval of 0.8-1.25. There were no safety concerns in the study and no reports of inhibitor formation in the 72-h period following exposure to a single N8 dose. In conclusion, N8 is bioequivalent to Advate(®). Furthermore, N8 is well tolerated in the FHD trial.

Evaluation of bioequivalence of two oral formulations of olanzapine.

Olanzapine is an atypical antipsychotic drug, used for the management of schizophrenia and for the treatment of moderate to severe mania associated with bipolar disorder. The objective of the present randomised, crossover study was to compare the bioavailability of olanzapine 10 mg/5 ml powder for oral suspension with olanzapine 10 mg orally disintegrating tablet. Eighteen healthy male volunteers were randomly assigned to crossover, single-dose treatment regimens. Serial blood samples were collected, and plasma concentrations of olanzapine were analysed using the LC-MS/MS technique. Pharmacokinetic parameters and bioequivalence limits were calculated using non-compartmental methods. Average Cmax following administration of the single 10 mg disintegrating tablet formulation and 10 mg/5 ml suspension were 14.47±4.25 ng/ml and 13.56±3.99 ng/ml respectively. Corresponding median Tmax were 5.0 h and 6.0 h, respectively. The average AUC0–t values and AUC0–inf values were similar following each of the olanzapine preparations. Overall, the 90% Confidence Interval for the intra-individual ratios of the log-transformed Cmax and AUC values of the two formulations were within the bioequivalence interval of 80–125%. The study has demonstrated the bioequivalence of the 10 mg tablet and the 10 mg/5 ml oral suspension of olanzapine.

Bioequivalence studies for three formulations of a recombinant human growth hormone: Challenges and lessons learned

Two bioequivalence (BE) studies in healthy volunteers comparing new formulations of the recombinant human growth hormone (rhGH) Nutropin AQ (somatropin [rDNA origin] injection; Genentech, Inc., South San Francisco, CA) with the currently marketed formulation (5 mg/mL) were conducted to extend available dosing options. All formulations were administered by subcutaneous (SC) injection ranging in volume from 0.25 to 1.0 mL depending on the formulation concentration. Study A was a 2-period crossover design to assess the BE of 5 and 10 mg/mL. The estimate for relative bioavailability (AUC 0–24 h ) was within the prespecified BE interval (0.80–1.25). However, while the C max estimate (1.17) was contained within the range for BE, the 90% CI (0.986–1.38) extended beyond the prespecified BE interval. As a result, Study A failed to show BE between the 5 and 10 mg/mL formulations. Review of the data showed unexpected increased variability in the observed C max. Further review of individual data suggested that in 4 subjects, the GH concentration profile of 1 of the 2 injections closely resembled the absorption kinetics of an intramuscular injection rather than an SC injection. Because study conduct may have contributed to these results, we performed a second study, Study B. This study incorporated injection technique training, a defined injection site, and a larger sample size to accommodate variability. It also included a third formulation, creating a 3-period crossover design to assess the BE of 2.5, 5, and 10 mg/mL. Study B results demonstrated BE of the new 2.5- and 10-mg/mL formulations to the reference 5-mg/mL formulation, and BE to each other, with all 90% CIs within the BE range of 0.80 to 1.25. Thus the challenge of recognizing that design issues could affect outcomes gave us the tools to perform a second study, and the positive results taught us that demonstrating BE is an issue not only of pharmacology, but also of study methodology and execution.

Bioavailability of a controlled-release cyclobenzaprine tablet and influence of a high fat meal on bioavailability

To evaluate the systemic bioavailability of a new controlled release cyclobenzaprine tablet, and the influence of a high fat meal on its bioavailability. 24 and 12 healthy male subjects were recruited for the bioavailability and influence of diet studies, respectively. Experimental design for both studies was an open randomized, 2-period, single dose, crossover study. In the bioavailability study, each subject received in different occasions, a single oral dose of cyclobenzaprine of immediate (10 mg) or controlled release (20 mg) tablet, followed by a 2-week washout period. In the influence of diet study, the volunteers received the controlled-release tablet concomitantly with a high fat meal or in a state of fasting. In the bioavailability study, plasma cyclobenzaprine profiles were in agreement with a controlled release system. This formulation presented a 92.8% of relative bioavailability (IC 85.5 - 105%) and a significant reduction in Cmax (IC 58 - 65.5%), when compared with equal dose of the immediate release tablet. The presence of food increased AUC (11.6%) and Cmax (48%). For both parameters the calculated 90% confidence interval was not in the bioequivalence interval, 97.4 - 125.8% for AUC and 111.7 - 184.2% for Cmax. The controlled release tablet showed a relative bioavailability comparable with equal dose of the immediate release product and produced a significantly lower Cmax, as expected in a controlled release formulation. The concomitant administration of the tablet with a high fat meal produced an increase on its bioavailability, mainly in Cmax, with no evidence of dose-dumping.

A New Formulation of Recombinant Human Factor IX Is Bioequivalent to BeneFIX: A Double-Blind, Randomized, Crossover Pharmacokinetic and Open-Label Safety and Efficacy Study.

A new formulation (rFIX-R) of BeneFIX has been developed to reduce the possibility of RBC agglutination, a phenomenon associated with the low ionic strength of the reconstituted drug product. The new formulation contains NaCl to increase the ionic strength and the recombinant factor IX concentration is increased for the 1000 IU strength and a new 2000 IU strength by reconstituting all strengths in 5 mL, facilitating the administration of larger doses in decreased volumes. Thirty-four (34) previously treated (≥150 exposure days [EDs]) males (≥12 years) with moderately severe/severe hemophilia B (FIX:C ≤2%) were enrolled and treated in this 2 part study. In the randomized, double-blind, crossover pharmacokinetic (PK) period of the study, the PK characteristics of rFIX-R were compared with those of the currently available formulation of BeneFIX. Subjects received either rFIX-R or BeneFIX as a 75 IU/kg bolus infusion over 10 minutes after a suitable washout. Blood samples were collected at defined times over 72 hours to measure pre-/post-infusion plasma factor IX activity. Subjects then received the alternate treatment following the same procedure. The mean plasma factor IX activity-versus-time profile after the infusion of rFIX-R was essentially identical to that seen with BeneFIX. From the 26 evaluable subjects, the mean PK parameter estimates of factor IX activity establish bioequivalence of the products since the 90% confidence intervals for rFIX-R to BeneFIX ratios of the geometric means of Cmax and AUCs fell within the bioequivalence interval of 80% to 125%. [Display omitted] In the open-label treatment period, subjects used rFIX-R for on-demand control of bleeding, routine prophylaxis, and/or surgical prophylaxis for 6- to 12-months to achieve at least 30 EDs. The plasma factor IX activity-versus-time profile was recharacterized after 6 months of rFIX-R treatment and was unchanged compared with the baseline rFIX-R PK profile. Over 1000 infusions (>3,500,000 IU of rFIX-R) have been administered with no serious adverse events related to rFIX-R. No clinically significant adverse events related to rFIX-R have been reported, including FIX inhibitor development, allergic-type manifestations, or thrombotic complications. One subject, with a prior history of frequent RBC agglutination, reported two instances without any associated adverse events. The overall results of this study demonstrate the safety of rFIX-R and the bioequivalence of the new formulation and BeneFIX. Since bioequivalence is the most important surrogate endpoint for efficacy, these data predict a favorable rFIX-R efficacy profile, consistent with that of BeneFIX, but with increased convenience in that larger doses can be administered using decreased volumes relative to BeneFIX.

Bioequivalence Study of Two Formulations (Sachet and Tablet) of Cefixime after Single Oral Doses of 200mg in Healthy Male Volunteers

The comparative bioavailability of two oral formulations of cefixime, the Oroken® 200mg tablet (reference formulation) and the novel Oroken® 200mg sachet (test formulation), was investigated in a single-dose crossover study in 18 healthy male volunteers. The data obtained in this study demonstrated bioequivalence of the two formulations. No statistical differences were observed for either maximum serum drug concentrations (Cmax) or areas under serum drug concentration versus time curves (AUC). 90% confidence intervals for mean Cmax and mean AUC (logarithmically transformed data) of the sachet as compared with the tablet were within the bioequivalence interval of 0.8 to 1.25. No differences between formulations in time to reach Cmax (tmax) or serum elimination half-life (t00BDβ) were evident. Moreover, after administration of either formulation, comparable amounts of unchanged cefixime were excreted in urine over similar time-frames. Clinical and biological tolerability was excellent for both formulations. The results of the present study show bioequivalence in terms of rate and extent of absorption of the tablet and sachet formulations of cefixime. The novel sachet formulation appears of considerable use for patients who are unable or unwilling to take tablets and for whom therapy with cefixime is recommended.