title: Bioequivalence and pharmacokinetics of chlorpheneramine in healthy human volunteers.
abstract: This study was carried out to evaluate the bioavailability of a new regular release tablet formulation of chlorphenamine (CPA) (Histop) relative to a reference formula (Piriton) using 13 human healthy volunteers. Each one received the two formulations as two 4 mg tablets in a two-way double-blind, crossover study. The concentration of CPA was measured with a sensitive high performance liquid chromatography (HPLC). The geometric mean for the area under the curve up to the last concentration (AUC0-t), to infinity (AUC0-oo) and the maximum concentration (Cp max) were 316.5, 315 + 439.8, 431.2 (ngh/ml) and 22, 20.5 (ug/ml) for the test (T) and reference (R) formulations, respectively. The parametric 90% confidence intervals of T/R ratio of the above parameters were within the bioequivalence acceptable range of 80-125%. The mean time to the maximum concentration Tmax (h) were 2.5 and 2.08 for the two formulations respectively and the parametric 90% confidence intervals of the Tmax difference (T-R) were in the range of -0.26-1.14 h, with point estimate of 0.44 h. The two formulations were found to be bioequivalent by the Schuirmann two one-sided t-test. Based on the pharmacokinetic results obtained frequent (ie, Q 4-6 h) CPA daily dosing may not be required particularly for the adults because of its long elimination half-life.
authors.affiliation: Department of Clinical Pharmacy, King Saud University, Saudi Arabia.
authors.forename: T A
authors.initials: TA
authors.lastname: Najjar
authors.forename: O A
authors.initials: OA
authors.lastname: Al-Alsheikh
authors.forename: A A
authors.initials: AA
authors.lastname: Al-Dhawailie
authors.forename: A
authors.initials: A
authors.lastname: Shereif
mesh_terms: D000328:Adult; D018926:Anti-Allergic Agents / Q000097:blood / Q000493:pharmacokinetics*; D002744:Chlorpheniramine / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013810:Therapeutic Equivalency
chemical_list: D018926:Anti-Allergic Agents; D002744:Chlorpheniramine