title: Dispersing the Mists: An Experimental History of Medicine Study into the Quality of Volatile Inhalations.
abstract: BACKGROUND
  Dr. Nelson's Improved Inhaler was first marketed with an advertisement in The Lancet in 1865. Revolutionary at the time for its ease of use and patient-friendliness, the inhaler is still in use for self-treatment by many all over the world. On the occasion of its 150th anniversary, this study reports an experimental historical medicine approach to identify evidence for the quality of vapor inhalers.
  
  
  METHODS
  Through accessing reviews of the device's use by the contemporary medical establishment, it was established that Dr. Nelson's Inhaler enjoyed a reputation of quality and efficacy among reputable physicians generating empirical evidence of clinical performance. There was a general absence of product performance tests during this period. Therefore, modern inhalation performance testing was applied to test the aerosol delivery performance for Friars' Balsam, and its key chemical constituent, benzoic acid (BA).
  
  
  RESULTS
  A respirable dose of 59.9 ± 9.0 μg of BA was aerosolized in a 10 minutes period from a dose of 3.3 mL Friars' Balsam (equivalent to 35.1 ± 0.2 mg of BA) in 375 mL of steaming water using the glass twin stage impinger at a flow rate of 60 L·min-1. The respirable dose from a standardized aqueous BA inhalation formulation increased from 115.9 ± 10.6 to 200.2 ± 19.9 μg by increasing the simulated inhalation period from 5 to 10 minutes. When tested with a simulated inhalation maneuver (500 mL tidal volume, 13 minutes-1respiration rate, 1:2 inspiratory:expiratory ratio) a respirable dose of 112.8 ± 40.3 μg was produced.
  
  
  CONCLUSIONS
  This work has highlighted the potential for aerosol drug delivery using steam inhalers that are popular with patients. Physicians should therefore be aware of the potential for lung dosing with irritants when patients self-medicate using the Nelson Inhaler with vaporizing formulations such as Friars' Balsam.
authors.affiliation: 1 Faculty of Medieval and Modern Languages, University of Oxford , Oxford, United Kingdom .
authors.forename: Barry
authors.initials: B
authors.lastname: Murnane
authors.affiliation: 2 Department of Pharmacy, Pharmacology and Postgraduate Medicine, University of Hertfordshire , Hatfield, United Kingdom .
authors.forename: Cathal T
authors.initials: CT
authors.lastname: Gallagher
authors.affiliation: 3 Research Department, British Lung Foundation , London, United Kingdom .|5 Current address: National Heart & Lung Institute, Imperial College, London, United Kingdom .
authors.forename: Noel
authors.initials: N
authors.lastname: Snell
authors.affiliation: 4 Clement Clarke International Ltd. , Harlow, United Kingdom .
authors.forename: Mark
authors.initials: M
authors.lastname: Sanders
authors.affiliation: 2 Department of Pharmacy, Pharmacology and Postgraduate Medicine, University of Hertfordshire , Hatfield, United Kingdom .
authors.forename: Ramin
authors.initials: R
authors.lastname: Moshksar
authors.affiliation: 2 Department of Pharmacy, Pharmacology and Postgraduate Medicine, University of Hertfordshire , Hatfield, United Kingdom .
authors.forename: Darragh
authors.initials: D
authors.lastname: Murnane
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000266:history; D019817:Benzoic Acid / Q000008:administration & dosage*; D016503:Drug Delivery Systems; D004867:Equipment Design / Q000266:history; D049672:History, 19th Century; D006801:Humans; D009330:Nebulizers and Vaporizers / Q000266:history; D013678:Technology, Pharmaceutical / Q000379:methods*; D013997:Time Factors
chemical_list: D000336:Aerosols; D019817:Benzoic Acid
keywords: Dr. Nelson's Inhaler; experimental history of medicine; inhalation performance testing; volatile inhalations