This study is prospective, open-label, randomized, crossover, single dose, with 02 treatments, 02 sequences and 02 periods. The volunteers received, in each period, the reference or the test formulation, according to the randomization list, under fasting conditions, in order to evaluate if the reference and test formulations are bioequivalent.
This study is prospective, open-label, randomized, crossover, single dose, with 02 treatments, 02 seuqences and 02 periods. The objective is to confirm if two formulations of topiramate 100 mg, coated tablet, are bioequivalent, after oral, single-dose administration under fasting conditions. The test product is topiramate 100 mg produced by Dr. Reddy's Laboratories Ltd. and the reference product is Topamax® marketed by Janssen-Cilag Farmacêutica Ltda. Twenty-eight healthy male volunteers were evaluated. The volunteers received, in each period, the test or the reference formulation, according to the randomization list. In each period, blood samples are collected in the following times: 00:00 (prior to the administration of medication); 00:20; 00:40; 01:00; 01:30; 02:00; 02:30; 03:00; 03:30; 04:00; 05:00; 06:00; 08:00; 12:00; 16:00; 20:00; 24:00; 48:00; 72:00; 96:00; 120:00; 144:00; 168:00; 192:00. The comparative bioavailability of the two formulations was evaluated based in statistical comparisons of relevant pharmacokinetic parameters, obtained from data of drug concentrations in blood.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
26
Test formulation
Reference formulation
GSK Investigational Site
Campinas, São Paulo, Brazil
Area under curve of plasma concentration of drug from time 0 (zero) from time t (last measurable concentration)
The area under the plot of plasma concentration of drug against time (non-compartimental method), after drug administration, defined as the area under the curve (AUC). The AUC 0-t is calculated from time 0 (prior to administration of medication) to time t (the time of the last quantifiable concentration), by linear trapezoidal rule. The AUC is of particular use in estimating the bioavailability of drugs, by measuring the extent of absorption.
Time frame: Collection points from time 0 to 192 hours evaluated in two periods
Maximum observed concentration of drug through time (Cmax)
Cmax is defined as the maximum or "peak" concentration of a drug observed after its administration. Cmax is one of the parameters of particular use in estimating the bioavailability of drugs, by measuring the total amount of drug absorbed. Measurement obtained directly of the plasma concentration curve of the drug (non-compartimental method). Occurring at Tmax.
Time frame: Collection points from time 0 to 192 hours evaluated in two periods
Area under curve of plasma concentration of drug from the time 0 (zero) extrapolated to infinity (AUC0-inf)
Measurement obtained directly from the plasma concentration curve of drug against time (non-compartimental method). AUC0-inf is calculated from time 0 (prior to administration of medication) extrapolated to infinity, by formula AUC0-inf=AUClast +Clast/Kel, where Clast is the Last measurable concentration and Kel is the first order rate constant associated with the terminal portion of the curve.
Time frame: Collection points from time 0 to 192 hours evaluated in two periods
Time of maximum observed concentration (Tmax)
Time when Cmax is obtained
Time frame: Collection points from time 0 to 192 hours evaluated in two periods
Terminal half-life - T1/2
Calculated by formula: T1/2\_Kel= Ln(2)/Kel.
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Time frame: Collection points from time 0 to 192 hours evaluated in two periods
First order rate constant associated with the terminal portion of the curve (Kel)
This parameter is estimated by the angular coefficient of the regression line, calculated by the minimum squares method, of the natural logarithm of the concentration versus time for the last four concentrations values (or at least three) above the quantification limit
Time frame: Collection points from time 0 to 192 hours evaluated in two periods