Abstract
Background:
The aim of this study was to determine the bioequivalence of generic (test) and branded
(reference) formulations of betamethasone injectable suspension in healthy Iranian
subjects for the purpose of meeting regulatory requirements for bioequivalence of
the generic formulation in Iran.
Methods:
24 healthy Iranian male volunteers were participated for this single-dose, randomized,
open label, 2 period crossover study separated by a 2-week washout period. For the
assessment of betamethasone, blood samples were obtained before and at 0.5, 1, 1.5,
2, 3, 4, 6, 8, 10, 12 and 24 h after drug administration. Plasma concentration of
betamethasone was analyzed with a simple, rapid and validated high performance liquid
chromatography method with ultraviolet detection. Pharmacokinetic parameters, representing
the rate (Cmax, Tmax), and the extent (AUC0–t and AUC0–∞) of betamethasone absorption were calculated and analyzed for 2 formulations. The
2 formulations were to be considered bioequivalent if the 90% confidence intervals
(CI)s for the logarithm-transformed values of Cmax, AUC0–t and AUC0–∞ fell within the predetermined range of 80–125%.
Results:
The 90% CIs of Cmax, AUC0–t and AUC0–∞ were 85.4–104.4%, 96.2–112.1% and 98.3–115.8%, respectively.
Conclusion:
Based on the 90% CIs of Cmax, AUC0–t and AUC0–∞ in these healthy Iranian male subjects, the test and reference formulations of betamethasone
injectable suspension met the regulatory requirements for bioequivalence.
Key words
bioequivalence - betamethasone injectable suspension - pharmacokinetics - HPLC
