Fluoxetine hydrochloride (CAS 59333-67-4) is a selective serotonin reuptake inhibitor (SSRI) widely used as antidepressant drug. The aim of the present trial was to assess the bioequivalence of a new formulation of the drug (test formulation) as compared to a reference product from the Swiss market. Both drugs were available as 20 mg dispersible tablets. The trial was performed according to a two-period, two-sequence, balanced, randomised, single-dose design with a wash-out phase of at least 56 days. The two formulations were tested in 30 male healthy volunteers. A specific highly sensitive bioassay in tandem mass spectrometry allowed to set the limit of quantification to 100 pg/ml for fluoxetine and norfluoxetine. Average t(max) was 5.4 h for fluoxetine and 71-80 h for norfluoxetine. The peak concentration was on average 14 ng/ml for fluoxetine and 10.5 ng/ml for norfluoxetine. Half-life was on average 48-50 h for fluoxetine and 130-138 h for norfluoxetine. AUC infinity for fluoxetine and norfluoxetine were on average 790 and 2800 ng x ml(-1) x h, respectively. All these figures demonstrate that plasma concentration-time profiles of fluoxetine and norfluoxetine are quite different. Applied statistical tests, suggested by operating guidelines, demonstrated bioequivalence of the test formulation and the reference formulation. The conclusion on bioequivalence was based on both fluoxetine and norfluoxetine results. 90 % confidence Intervals for Cmax, AUCt and AUC infinity (fluoxetine and norfluoxetine) were within the acceptance range (0.80-1.25) and t(max), processed with a non-parametric test, did not show any statistically significant difference between test and reference formulation. Safety and tolerability proved to be similarly good with both test and reference formulation. In conclusion, the present trial has demonstrated bioequivalence of the test and the reference formulation, both consisting of fluoxetine hydrochloride dispersible tablets.

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This paper deals with a crossover trial on healthy volunteers performed to obtain combined pharmacodynamic, safety and pharmacokinetic data in order to assess the bioequivalence of formoterol fumarate (CAS 43229-80-7) delivered by mono-dose dry powder inhalers, as test and reference. The trial was carried out on 24 Caucasian healthy male and female volunteers treated with 12 micrograms formoterol fumarate bihydrate capsules for inhalation route. Pharmacodynamics was evaluated through a challenge test with methacholine on the forced expiratory volume in 1 s (FEV1). Safety was achieved from glucose and potassium serum levels assayed on timed samples over a 12-h period cost-dosing and from blood pressure, heart rate and ECG recording. Pharmacokinetics was obtained from urinary excretion of formoterol, assessed by a highly sensitive analytical method (LC-MS-MS). Pharmacodynamic, safety and pharmacokinetic results evidenced the bioequivalence of the two formulations investigated. This investigation is an interesting approach how to assess bioequivalence when the classical approach based on the similarity of plasma concentrations can not be applied.

Amlodipine (CAS 88150-42-9) is a 1,4-dihydropyridine derivative, one of the most widely used drugs for the management of essential hypertension. In developing manidipine (CAS 120092-68-4), a new antihypertensive drug, amlodipine was selected as the reference comparator drug in a Phase III double blind clinical trial. However, manidipine is formulated in hard gelatin capsules, whereas amlodipine is presented as a tablet. In order to respect the double blind design of the study, it was necessary to insert the amlodipine tablet into hard gelatin capsules matching those of the new test product. This called for an amlodipine bioequivalence study on two halves of one tablet inserted into a capsule (test formulation) and two halves of one tablet ingested as such (reference formulation). The bioequivalence trial was carried out on 18 healthy volunteers (9 males and 9 females). Subjects were administered a single 10 mg dose of test and reference products according to a two-treatment, two-period, two-sequence crossover design, with a wash-out period of three weeks. Plasma concentrations of the parent compound were monitored over a period of 6 days, considering the long half-life of amlodipine. The drug was quantified with a very sensitive, robust bioassay, which was set up and validated in our laboratory. Peak concentration and area under the curve of plasma concentrations were log-transformed and analyzed to obtain 90% confidence intervals which proved to be 0.94-1.06, and thus within the acceptable bioequivalence range of 0.80-1.25. Time to peak, analyzed according to a non-parametric test, did not show any statistically significant difference between the test and reference. Both the test and reference products showed a similar and very good safety profile. The conclusion is that one amlodipine tablet broken into two halves and administered as such (reference formulation) is bioequivalent with one amlodipine tablet broken into two halves and encapsulated (test formulation).