title: The Bioavailability of Salbutamol in Urine via Volumatic and Nonvolumatic Valved Holding Chambers.
abstract: OBJECTIVE
  Pressurized metered dose inhalers are commonly used in patients with asthma. However, the need to coordinate inhalation with inhaler actuation means that they are not suitable for use per se. Valved holding chamber devices were developed to overcome some of the problems of pressurized metered dose inhalers. Several types of holding chambers of different sizes are available in Iran. This study was designed to compare the effects of 2 commonly used valved holding chambers (Asthm Yar and Dam Yar) in Iran on bioavailability of salbutamol spray and also spirometric parameters in asthmatic patients.
  
  
  METHODS
  This was a comparative experimental crossover study. Patients with mild to moderate asthma were entered in this study. Lung function was assessed using a portable spirometer (Spirolab, Progetti, Italy). Spirometric parameters of forced expiratory flow (FEF)(50%), FEF(25-75%), peak expiratory flow (PEF), forced expiratory volume in the first second of expiration (FEV(1)), forced vital capacity (FVC), and FEV(1)/FVC were measured. Urinary concentration of salbutamol as an index of pulmonary bioavailability was assayed with high-performance liquid chromatography.
  
  
  RESULTS
  Forty patients (25 women and 15 men) with the mean age of 43.10 ± 12.99 years were studied. Mean ± SD changes of spirometric parameters before and after using Asthm Yar were not significantly different from those of Dam Yar. The relative bioavailability after inhalation with Asthm Yar was significantly higher than after inhalation with Dam Yar (P = 0.002).
  
  
  CONCLUSIONS
  Although the results indicate that relative bioavailability to the lung after inhalation with Asthm Yar was significantly higher than after inhalation with Dam Yar, its clinical importance should be tested.
authors.affiliation: Department of Clinical Pharmacy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Pharmaceutical Care, Chronic Respiratory Disease Research Center, TB and Lung Disease Research Center, NRITLD, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Fanak
authors.initials: F
authors.lastname: Fahimi
authors.forename: Farzad
authors.initials: F
authors.lastname: Kobarfard
authors.forename: Jamshid
authors.initials: J
authors.lastname: Salamzadeh
authors.forename: Atefeh
authors.initials: A
authors.lastname: Fakharian
authors.forename: Pegah
authors.initials: P
authors.lastname: Abdolahi
authors.forename: Azita Hajhossein
authors.initials: AH
authors.lastname: Talasaz
authors.forename: Hamid Mahboobi
authors.initials: HM
authors.lastname: Pour
authors.forename: Shadi
authors.initials: S
authors.lastname: Baniasadi
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Masjedi