Williams G
R&D Laboratory, Valois Pharm, Le Vaudreuil, France.
J Allergy Clin Immunol. 1999 Dec;104(6):S227-9. doi: 10.1016/s0091-6749(99)70035-7.
Moisture is known to affect the stability of some metered dose inhalers (MDIs). Hydrofluoroalkanes such as tetrafluoroethane (134a) and heptafluoropropane (227) are known to have higher affinity for moisture than the currently used chlorofluorocarbon propellents. An initial study was conducted to determine the water vapor transmission rates of various elastomers that may be used as gaskets in MDIs. A further study was conducted to measure the moisture ingress rates of various chlorofluorocarbon-free MDIs. The data indicate that moisture transport into chlorofluorocarbon-free MDIs is influenced by the elastomeric nature of the gaskets used and the type of hydrofluoroalkane formulation and storage conditions used.
众所周知，水分会影响一些定量吸入器（MDIs）的稳定性。诸如四氟乙烷（134a）和七氟丙烷（227）之类的氢氟烷烃对水分的亲和力高于目前使用的氯氟烃推进剂。开展了一项初步研究，以确定可用于MDIs垫圈的各种弹性体的水蒸气透过率。还开展了一项进一步的研究，以测量各种无氯氟烃MDIs的水分进入率。数据表明，水分进入无氯氟烃MDIs受所使用垫圈的弹性体性质、氢氟烷烃配方类型以及储存条件的影响。
