title: Bioequivalence study of two losartan formulations administered orally in healthy male volunteers.
abstract: The bioavailability of a new losartan preparation (2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt, CAS 114798-26-4) was compared with the reference preparation of the drug in 24 healthy male volunteers, aged between 19 and 32. The open, randomized, single-blind two-sequence, two-period crossover study design was performed. Under fasting conditions, each subject received a single oral dose of 100 mg losartan as a test or reference formulation. The plasma concentrations of losartan and its active metabolite were analyzed by a rapid and sensitive HPLC method with UV detection. The pharmacokinetic parameters included AUC0-36h, AUC0-infinity, Cmax, t1/2, and Ke. Values of AUC0-infinity demonstrate nearly identical bioavailability of losartan from the examined formulations. The AUC0-infinity of losartan was 2019.92+/-1002.90 and 2028.58+/-837.45 ng x h/ml for the test and reference formulation, respectively. The AUC0-infinity of the metabolite was 10851.52+/-4438.66 and 11041.18 +/-5015.81 ng x h/ml for test and reference formulation, respectively. The maximum plasma concentration (Cmax) of losartan was 745.94+/-419.75 ng/ml for the test and 745.74+/-329.99 ng/ml for the reference product and the Cmax of the metabolite was 1805.77+/-765.39 and 1606.22 +/-977.22 ng/ml for the test and reference product, respectively. No statistical differences were observed for Cmax and the area under the plasma concentration-time curve for both losartan and its active metabolite. 90 % confidence limits calculated for Cmax and AUC from zero to infinity (AUC0-infinity) of losartan and its metabolite were included in the bioequivalence range (0.8-1.25 for AUC). This study shows that the test formulation is bioequivalent to the reference formulation for losartan and its main active metabolite.
authors.affiliation: Department of Clinical Pharmacy and Biopharmacy, Faculty of Pharmacy, Karol Marcinkowski University of Medical Sciences, Poland. agnbienert@op.pl
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Bienert
authors.forename: Rafał
authors.initials: R
authors.lastname: Brzezińiski
authors.forename: Edyta
authors.initials: E
authors.lastname: Szałek
authors.forename: Vitali
authors.initials: V
authors.lastname: Dubai
authors.forename: Edmund
authors.initials: E
authors.lastname: Grześkowiak
authors.forename: Stanisław
authors.initials: S
authors.lastname: Dyderski
authors.forename: Leon
authors.initials: L
authors.lastname: Drobnik
authors.forename: Anna
authors.initials: A
authors.lastname: Wolc
authors.forename: Magdalena
authors.initials: M
authors.lastname: Olejniczak-Rabinek
mesh_terms: D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002138:Calibration; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid; D004311:Double-Blind Method; D004355:Drug Stability; D004356:Drug Storage; D006801:Humans; D019808:Losartan / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D008297:Male; D015203:Reproducibility of Results; D013810:Therapeutic Equivalency
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D019808:Losartan