Bioequivalence of two commercial preparations of escitalopram oxalate/clonazepam using a liquid chromatography-electrospray mass spectrometry method

OBJECTIVE

A randomized, two-way crossover study was conducted in 24 fasting healthy male volunteers of Indian origin to compare the bioavailability of two brands of a fixed dose combination of escitalopram oxalate (CAS 219861-08-2) 10 mg and clonazepam (CAS 1622-61-3) 0.5 mg tablets, using Estomine-zee as test and a commercially available formulation as the reference product. The pharmacokinetics of escitalopram oxalate and clonazepam individually after oral administration of tablet formulation has been extensively evaluated in adult volunteers. However, no published data are available regarding the pharmacokinetics and bioavailability of this particular fixed dose combination.

METHOD

The trial was designed as a randomized, balanced, open-label, 2-period cross-over study. The drug was administered with 240 ml of water after a 10-h overnight fasting on two treatment days separated by a 21-day washout period. After dosing, serial blood samples were collected for a period of 96 h. Plasma harvested from blood was analyzed by simple rapid, selective and validated liquid chromatography-electrospray mass spectrometry (LC-ESI-MS/ MS) using diazepam (CAS 439-14-5) as an internal standard.

RESULTS

The calibration curves were found to be linear in the range of 1-25 ng/ml and 1-10 ng/ml for escitalopram oxalate and clonazepam, respectively, with a mean correlation coefficient of more than 0.99. No statistically significant differences were obtained between the two products with respect to the mean concentration-time profiles or in the pharmacokinetic parameters, including the area under the serum concentration-time curve from the present study.

CONCLUSION

Based on the statistical inferences, it was concluded that the test product is bioequivalent to the reference product. Both preparations were well tolerated with no adverse reactions throughout the study.

Evaluation of Bioequivalence of Two Formulations Containing 100 Milligrams of Aceclofenac

The bioequivalence of two oral formulations containing aceclofenac 100 mg was determined in 24 healthy Indian male volunteers. The study was designed as a single dose, fasting, two-period two-sequence crossover study with a washout period of 1 week. The content of aceclofenac in plasma was determined by a validated HPLC method with UV detection. The preparations were compared using the parameters area under the plasma concentration-time curve (AUC0-t), area under the plasma concentration-time curve from zero to infinity (AUC0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax). No statistically significant difference was observed between the logarithmic transformed AUC0-infinity and Cmax values of the two preparations. The 90% confidence interval for the ratio of the logarithmic transformed AUC0-t, AUC0-infinity, and Cmax were within the bioequivalence limit of 0.80-1.25.

Bioequivalence study of a sustained release fixed dose combination capsule containing esomeprazole and domperidone in healthy subjects

OBJECTIVE

The study was designed to determine the relative bioavailability of two sustained release fixed dose combination (FDC) products of two manufacturers containing esomeprazole (CAS 326602-80-6) 40 mg and domperidone (CAS 57808-66-9) 30 mg in 24 healthy male volunteers. The pharmacokinetics of esomeprazole and domperidone individually after oral administration of tablet formulation has been extensively evaluated in adult volunteers. However, no published data are available regarding the combined pharmacokinetics and bioavailability of this particular FDC.

METHOD

The study was designed as a randomized, balanced, open-label, 2-period cross-over study. Each subject was randomized at the beginning of the study to receive either a single dose of the Test FDC or Reference FDC during Period I. Following a 7-day wash-out period, all subjects received the alternate formulation during Period II.

RESULTS

No statistically significant differences were obtained between the two products with respect to the mean concentration-time profiles or in the pharmacokinetic parameters, including area under the serum concentration-time curve from the present study. The relative extent of absorption as assessed by the AUC ratio (Test/Reference) and C(max), the average value was found to be 1.00 +/- .09 with 90% confidence limits (C.L.) of 0.82-1.18.

CONCLUSION

These findings clearly indicate that the two products are bioequivalent in terms of rate and extent of drug absorption. Both preparations were well tolerated with no adverse reactions throughout the study.