title: Moisture transfer into medicament chambers equipped with a double-barrier-desiccant system.
abstract: The present study illustrates and evaluates the capability of the double-barrier-desiccant system to regulate the humidity inside a medicament powder chamber. The model medicament chamber chosen was the reservoir-based dry powder inhaler Taifun. The study was focussed to screen the critical parameters affecting the function of the desiccant system. For this purpose a novel simulation method was developed and applied to predict the progress of the internal relative humidity of the powder chamber. The simulation method showed good correlation with the measurement results and, hence, it was concluded that it was valid for the system. According to the simulations, effective regulation of the humidity inside a closed powder chamber with the double-barrier-desiccant system is possible for a prolonged time. However, this can be achieved only if the critical parameters, such as the permeabilities of the desiccant container and the powder chamber, the amount of the desiccant and the initial moisture content of the desiccant, can be accurately specified and strictly controlled in the production of the components comprising the medicament chamber.
authors.affiliation: Department of Physics, University of Turku, FIN-20014 Turku, Finland. vlehto@utu.fi
authors.forename: Vesa-Pekka
authors.initials: VP
authors.lastname: Lehto
authors.forename: Tapio
authors.initials: T
authors.lastname: Lankinen
mesh_terms: D003890:Desiccation / Q000295:instrumentation* / Q000379:methods*; D004339:Drug Compounding; D004355:Drug Stability; D006813:Humidity; D009330:Nebulizers and Vaporizers; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011208:Powders; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D004364:Pharmaceutical Preparations; D011208:Powders; D014867:Water