title: Comparison of WHO and US FDA biowaiver dissolution test conditions using bioequivalent doxycycline hyclate drug products.
abstract: OBJECTIVE
  The dissolution characteristics of immediate-release doxycycline hyclate products with certified in-vivo bioequivalence to the innovator product were tested with a view to possible application of biowaiver-based approval.
  
  
  METHODS
  Five products were tested using US Pharmacopeia Apparatus 2: Antodox 100 mg hard gelatin capsules, Doxycyclin AL 100 T tablets, Doxycyclin-ratiopharm 100 soft gelatin capsules, Doxycyclin STADA 100 mg tablets and Doxy-Wolff 100 mg tablets. Three compendial buffers were used as dissolution media: simulated gastric fluid without pepsin, pH 1.2, acetate buffer, pH 4.5, and simulated intestinal fluid without pancreatin, pH 6.8. Results were obtained at two paddle speeds recommended for biowaiver applications: 75 rpm (World Health Organization; WHO) and 50 rpm (US Food and Drug Administration; US FDA).
  
  
  RESULTS
  The results for the tablets and hard gelatin capsules indicate that a paddle speed of 75 rpm is more representative than 50 rpm, since 75 rpm generates dissolution profiles corresponding more closely to the in-vivo profiles than those at 50 rpm. For evaluating soft gelatin capsule formulations with lipid fill, both US FDA and WHO methods were found to be over-discriminating.
  
  
  CONCLUSIONS
  Bioequivalence of immediate-release doxycycline hyclate tablets and hard gelatin capsules, but not soft gelatin capsules, can be evaluated in vitro using the biowaiver dissolution test conditions specified by the WHO.
authors.affiliation: Institute of Pharmaceutical Technology, Goethe University, Frankfurt am Main, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Strauch
authors.forename: Ekarat
authors.initials: E
authors.lastname: Jantratid
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Dressman
mesh_terms: D002214:Capsules; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004318:Doxycycline / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D017277:Drug Approval / Q000331:legislation & jurisprudence*; D005750:Gastric Juice / Q000378:metabolism; D005780:Gelatin / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007419:Intestinal Secretions / Q000378:metabolism; D012995:Solubility; D013607:Tablets; D013810:Therapeutic Equivalency; D014481:United States; D014486:United States Food and Drug Administration; D014944:World Health Organization
chemical_list: D002214:Capsules; D013607:Tablets; D005780:Gelatin; D004318:Doxycycline