title: The evolution of spacers and valved holding chambers.
abstract: Spacers and valved holding chambers (VHCs) are pressurized metered dose inhaler (pMDI) accessory devices, designed to overcome problems that patients commonly experience when administering aerosol via a pMDI. Spacers were developed in direct response to patient-related issues with pMDI technique, particularly, poor coordination between actuation and inhalation, and local side-effects arising from oropharyngeal deposition. Current clinical guidelines indicate the need for widespread prescription and use of spacers, but, despite their apparent ubiquity, the devices themselves are, unfortunately, all too commonly "disused" by patients. An understanding of the background from which spacers developed, and the key factors influencing the optimization of the spacer and the later VHC, is crucial to developing an appreciation of the potential of these devices, both contemporary and future, for improving the delivery of pressurized aerosols to patients. This review, informed by a full patent search and an extensive scientific literature review, takes into account the clinical and laboratory evidence, commercial developments, and the sometimes serendipitous details of scientific anecdotes to form a comprehensive perspective on the evolution of spacers, from their origins, in the early days of the pMDI, up to the present day.
authors: 1 InDevCo AB, Nyköping, Sweden .
authors: Kurt
authors: K
authors: Nikander
authors: Clare
authors: C
authors: Nicholls
authors: John
authors: J
authors: Denyer
authors: John
authors: J
authors: Pritchard
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000367:Age Factors; D002626:Chemistry, Pharmaceutical; D002648:Child; D002675:Child, Preschool; D016503:Drug Delivery Systems / Q000266:history / Q000295:instrumentation* / Q000639:trends; D004867:Equipment Design; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D007223:Infant; D008397:Masks / Q000266:history / Q000639:trends; D036501:Metered Dose Inhalers / Q000266:history / Q000639:trends; D010316:Particle Size; D010349:Patient Compliance; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry; D011312:Pressure
chemical_list: D000336:Aerosols; D004364:Pharmaceutical Preparations
keywords: adherence; electrostatic; inhalation delay; pMDI accessory device; patent; spacer; valved holding chamber