Tiwari D, Goldman D, Dixit S, Malick W A, Madan P L
College of Pharmacy & Allied Health Professions, St. John's University, New York 11439, USA.
Drug Dev Ind Pharm. 1998 Apr;24(4):345-52. doi: 10.3109/03639049809085629.
Compatibility of propellants, excipients, and solvents with the components of the valve greatly influences performance of metered-dose inhalers (MDIs). Ozone-friendly hydrofluoroalkane propellant 134a has potential for use as a chlorofluorocarbon (CFC) replacement. No suitable replacement for propellant 11 and 114 has yet been found and the problems arising from this may be overcome by use of ethanol as a solvent. In this study, compatibility of MDI valve elastomers Dowty Nitrile 0117, White Buna, and Type 674 (B) with P134a placebo formulations having different concentrations of ethanol was investigated. The results indicate that formulations containing no ethanol adversely affected the functioning of the valves. Higher concentrations of ethanol improved valve performance, but showed increased leakage. Physical characteristics of the valve elastomers evaluated by determining swelling caused after exposure to the P134a placebo formulations exhibited increased swelling with increasing concentrations of ethanol in the formulation.
推进剂、辅料和溶剂与阀门组件的兼容性对定量吸入器（MDIs）的性能有很大影响。对臭氧友好的氢氟烷烃推进剂134a有潜力用作氯氟烃（CFC）的替代品。尚未找到推进剂11和114的合适替代品，使用乙醇作为溶剂可能会克服由此产生的问题。在本研究中，研究了MDI阀门弹性体陶氏丁腈0117、白色丁腈橡胶和674（B）型与具有不同乙醇浓度的P134a安慰剂制剂的兼容性。结果表明，不含乙醇的制剂对阀门功能有不利影响。较高浓度的乙醇改善了阀门性能，但泄漏增加。通过测定暴露于P134a安慰剂制剂后引起的溶胀来评估阀门弹性体的物理特性，结果显示随着制剂中乙醇浓度的增加，溶胀也增加。
