title: Formulation and bioequivalence of two sildenafil 50 mg film-coated tablets after a single oral administration.
abstract: OBJECTIVE
  The aims of this study were to establish a bioanalytical method and to evaluate the bioequivalence of two drug products; a generic sildenafil 50 mg film-coated vs. the brand drug Viagra® 50 mg film-coated tablets.
  
  
  METHODS
  Bioequivalence of tablets was tested by comparisons against the reference brand product in accordance with the requirements of the Declaration of Helsinki, the current Good Clinical Practice (GCP) Guidelines and the International Conference Harmonization (ICH).
  
  
  RESULTS
  The relationship between concentration and peak area ratio was found to be linear within the range of 1.435 - 410.023 ng/mL for sildenafil. The correlation coefficient (r) was always greater than 0.99 during the course of the validation Statistical comparison of the main pharmacokinetic parameters showed no significant difference between test and reference. The 90% CIs of geometric mean ratios (test to reference ratios) were 99.656%, 99.806%, and 109.227% for AUC(0-last), AUC(0-∞), and C(max), respectively. These pharmacokinetic parameter values lie within the FDA and European Medicines Agency specified bioequivalence limit (80 - 125%). Both formulations were well tolerated by all subjects and they were discharged in good health.
  
  
  CONCLUSIONS
  The tested drug product was bioequivalent to the reference drug and had the same safety profile.
authors.forename: Abdel Naser
authors.initials: AN
authors.lastname: Zaid
authors.forename: Rowa' Al
authors.initials: RA
authors.lastname: Ramahi
authors.forename: Rana
authors.initials: R
authors.lastname: Bustami
authors.forename: Ayman
authors.initials: A
authors.lastname: Mousa
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D002626:Chemistry, Pharmaceutical; D002851:Chromatography, High Pressure Liquid / Q000592:standards; D018592:Cross-Over Studies; D016568:Drugs, Generic / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D016014:Linear Models; D008297:Male; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D058986:Phosphodiesterase 5 Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics*; D010879:Piperazines / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics*; D011687:Purines / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics; D012015:Reference Standards; D015203:Reproducibility of Results; D018570:Risk Assessment; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics*; D013607:Tablets; D013810:Therapeutic Equivalency; D055815:Young Adult
chemical_list: D016568:Drugs, Generic; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D013607:Tablets; D000068677:Sildenafil Citrate