Test Product: Telmisartan USP 40 mg Tablet, produced by Beximco pharmaceuticals Ltd in Bangladesh (Batch: SDF610).

Reference Product: Micardis^® 40 mg tablet of Boehringer Ingelheim Pharma GmbH & Co. KG Ingelheim Am Rhein, Germany (Batch No C04677).

On October 11^th, 2020; the Bangladesh Medical Research Council’s (BMRC)

National Research Ethics Committee (NREC) approved the study protocol. (Ethical approval no.: 27204022020) and by the Directorate General of Drug Administration (DGDA) on 02^nd December 2020 (Memo No.: DGDA/CTP-1/06/2016/4810).

The volunteers are aged between 20 - 30 years, with a Body Mass Index (BMI) of 17.63 - 31.60 kg/m² selected randomly from registered database and asked for a screening procedure as per inclusion exclusion criteria within 28 days prior to dosing of period 1. Each subject has given verbal & written consent before participating in the study. After passing a clinical screening procedure within 28 days prior to dosing of period-I, volunteers were enrolled. Subject were excluded if they take more than five cigarettes per day, had history of significant disorders, had hypersensitive to telmisartan, had history of consumption of alcohol, had received any prescribed medication within 28 days prior to the start of study, participated in any clinical study within 3 months prior to the screening, and donation or loss more than 500 mL of blood within 3 months prior to the screening.

All subjects were refrained to take prescribed medicines within 28 days & Over the Counter (OTC) products within 14 days before first study drug administration until the completion of study. They were also refrained from smoking, drinking alcoholic beverages and xanthine containing foods and beverages (tea, coffee, chocolate, or cola) for 48 hours before each dose, until the last blood sample was collected. Clinical screening was repeated, upon completion of the study.

This was an open label, randomized, laboratory blind study which had single dose, three periods, two treatments, three sequence, partial-replicated, in normal healthy adult 18 human subjects under fasting condition. There was 10 days’ washout period in each period of this study. The subjects were confined within the facility one night before study to ensure the fasting condition (10 hours before study drug administration). During the study, subjects were randomized to one of the three sequences (Test-Reference-Reference) (TRR); Reference-Reference-Test (RRT); Reference-Test-Reference (RTR). The randomization list was generated using Statistical Analysis Software (SAS). On dosing day of each period, each subject received a single oral dose (1 × 40 mg Tablet) of either test product or reference product with 240 of water at ambient temperature.

Subjects were in a comfortable recumbent position up to 8 hours after dosing and remained under monitoring for up to 12 hours after dosing [10].

Subjects were fasted overnight from at least 10.00 hours (hrs) before dose administration and for at least 04.00 hrs post-dose in each study period. Water intake was allowed except for one hour before and one hour after the dose. No food was allowed until 4 hours after dose administration [11].

As per “Guidance for industry-Bioavailability & Bioequivalence studies submitted in NDAS or INDS-General consideration” of USFDA; subjects were fasted for at least 10 hours before dosing & no meal was allowed till 4 hours after dosing. Considering the sedentary lifestyle of volunteers a qualified dietician prepared the meal plan of 1000 - 1200 calories through calorie breakdown of lunch, snack, dinner & breakfast. In all the periods meal distribution was uniform.

Venous blood were collected at pre dose (0.00 hour) (within 1.0 hour prior to dosing), 0.17, 0.33, 0.50, 0.67, 0.83, 1.00, 1.25, 1.50, 2.00, 2.50, 3.00, 4.00, 6.00, 9.00, 12.00, 16.00, 24.00, 48.00, 72.00 and 96.00 hrs post dose in a pre-labeled vaccutainers containing K₂EDTA at each period. Within 60 minutes after each time point of blood collection, Blood sample vacutainers were centrifuged at 3500 Revolution Per Minute (RPM) for 10 minutes at 5˚C ± 3˚C.

Using a validated liquid chromatography-mass spectrometry (LC-MS/MS) analytical technique, the amount of telmisartan in plasma was determined in a blind fashion without reference to the treatment plan. The linearity range was (10.000 - 1200.0) ng/mL according to method validation.

At pre dose, 01.00, 03.00, 05.00, 08.00, 12.00, and 24.00 hours, check-in, check-out, and throughout each ambulatory post-dose in each session, the subjects’ well-being & vital parameters were assessed. Up until the very conclusion of the research, the individuals were regularly observed for adverse events and concurrent medication use during the entire confinement durations. Safety evaluation was done on the basis of outcomes of physical examination, vital signs measurement and clinical laboratory results which were performed during the study period.

The following pharmacokinetic variables were determined for Telmisartan using a non-compartmental model.

Among 18 Subjects, 17 subjects completed all the three periods of the study and that was evaluated. Demographic data of all evaluable subjects are presented in Table 1.

Good linearity was obtained for all standard curves (correlation coefficient r > 0.999). The standard calibration curve for telmisartan was linear from 10 - 1200 ng/mL. Table 2 shows the precision and accuracy of the quality control samples

SD: Standard Deviation, CV: Coefficient of Variance.

during pre-study validation.

The bioanalytical method has been validated according to the Guideline on Bioanalytical Validation, EMA 2011 [12].

Administration of a single oral dose of either the test or reference formulation was found to be safe in healthy subjects. No severe, serious, or life-threatening side effects were reported throughout the study.

Data from total 17 subjects completed the study was used in calculation of pharmacokinetic parameters and statistical analysis for calculation of intra-subject variability of Reference Product and to assess the bioequivalence.

The mean telmisartan concentration versus time profiles Untransformed and log-transformed data for both formulations are presented in Figure 2 & Figure 3.

Descriptive statistics of the pharmacokinetic parameters for telmisartan test and reference are summarized in Table 3.

AUC_% Extrapolation

The mean AUC_% Extrapolation was 22.410% (range: 8.929% to 40.258%) for reference product (R) and 25.652% (range: 9.718% to 54.168%) for test product (T), respectively.

Analysis of Variance (ANOVA)

There were no sequence and formulation effects observed for pharmacokinetic parameters C_max, AUC0-t and AUC0-inf.

The 90% geometric ratios confidence intervals and intra-subject CVs of reference product for primary parameters are shown in Table 4.

C_max: The mean C_max obtained was 122.270 ng/mL in Reference Product (R) and Test Product (T) was 122.606 ng/mL respectively. AUC_0−t: The mean area under the curve from zero to last measurable concentration was 825.619 (ng.hr/mL) in Reference Product (R) and test product (T) was 852.698 (ng.hr/mL) respectively. AUC_0−∞: The mean area under the curve from zero to infinity was 1072.310 (ng.hr/mL) in Reference Product (R) and test product (T) was 1159.513 (ng.hr/mL) respectively. T_max: The median of Tmax was 2.500 hour (range = 0.585 to 6.000 hours) for reference product (R and 2.500 hour (range = 0.670 to 4.000 hours) for test product (T), respectively. Terminal Half Life (T_1/2): The mean terminal half-life was 11.141 (range: 1.067 to 28.292) for reference product (R) and 13.700 hour (range: 1.237 to 36.811 hours) for test product (T), respectively. Elimination Rate Constant K_el: The mean elimination rate constant was 0.172 hrs⁻¹ (range: 0.025 to 0.651 hrs⁻¹) for reference product (R) and 0.105 hrs⁻¹ (range: 0.019 to 0.560 hrs⁻¹) for test product (T), respectively.

The intra-subject CV of telmisartan for C_max was 22.86% (<30%), hence wider acceptance criteria were not applicable for this study. The 90% Confidence Intervals (CI) of C_max, AUC_0−t and AUC_0−∞ were found 84.88% - 107.79%, 89.76% - 109.55%, and 91.20% - 114.52% respectively which included into the range of bioequivalence acceptance limit of 80.00% - 125.00%.