title: In vitro and in vivo testing methods for respiratory drug delivery.
abstract: BACKGROUND
  Successful respiratory drug delivery for local and systemic purposes is predicated on the availability of in vitro and in vivo methods for determining drug delivery and disposition following respiratory administration.
  
  
  METHODS
  In this review, the relevance of new in vitro and in vivo methods for screening respiratory drug delivery is discussed. Specific topics covered include in vitro particle size characterization, in vitro dissolution test methods for respiratory formulations and in vitro respiratory absorption and disposition screening methods. Furthermore, in vivo respiratory dosing methods, in vivo respiratory aerosol deposition and drug absorption screening methods, and correlation between in vitro and in vivo methods are reviewed.
  
  
  RESULTS
  After reading this article, the reader will have an enriched knowledge regarding the various in vitro and in vivo testing methods for respiratory drug delivery. Most importantly, this paper will make it possible for readers to appreciate the strengths and weaknesses of each test method, which in turn will assist them in selecting specific methods that suit their scientific needs.
  
  
  CONCLUSIONS
  New in vitro and in vivo methods for screening respiratory drug delivery are indispensible, especially from the respiratory drug development and quality control perspective. Each method has unique advantages and disadvantages that influence method selection and data interpretation. Although in vitro methods are used during drug development, they augment rather than substitute in vivo methods.
authors.affiliation: Dalhousie University, College of Pharmacy, Faculty of Health Professions, Biopharmaceutics and Drug Delivery Laboratory, Halifax, NS, Canada. Remigius.agu@dal.ca
authors.forename: Remigius U
authors.initials: RU
authors.lastname: Agu
authors.forename: Michael I
authors.initials: MI
authors.lastname: Ugwoke
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D016503:Drug Delivery Systems; D015195:Drug Design; D006801:Humans; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D012140:Respiratory Tract Diseases / Q000503:physiopathology; D012995:Solubility
chemical_list: D000336:Aerosols; D004364:Pharmaceutical Preparations