Journal
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
Volume 119, Issue -, Pages 224-234Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.ejpb.2017.06.023
Keywords
Dry powder inhaler (DPI); Amino acids; Moisture protection; Spray drying; Surface coating
Categories
Funding
- Australian Research Council's [DP 150103953]
Ask authors/readers for more resources
Background: Inhalable particles containing amorphous form of drugs or excipients may absorb atmospheric moisture, causing powder aggregation and recrystallization, adversely affecting powder dispersion and lung deposition. The present study aims to explore hydrophobic amino acids for protection against moisture in spray-dried amorphous powders, using disodium cromoglycate (DSCG) as a model drug. Materials and methods: DSCG powders were produced by co-spray drying with isoleucine (Ile), valine (Val) and methionine (Met) in various concentrations (10, 20 and 40% w/w). Particle size distribution and morphology were measured by laser diffraction and scanning electron microscopy (SEM). Physiochemical properties of the powders were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic vapor sorption (DVS). Particle surface chemistry was analyzed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). In vitro aerosolization performance was evaluated by a next generation impactor (NGI) after the powders were stored at 60% or 75% relative humidity (RH) for one month and three months. Results and discussion: he, Val and Met significantly reduced the deleterious effect of moisture on aerosol performance, depending on the amount of amino acids in the formulation. Formulations containing 10% or 20% of Ile, Val and Met showed notable deterioration in aerosol performance, with fine particle fraction (FPF) reduced by 6-15% after one-month storage at both 60% and 75% RH. However, 40% Ile was able to maintain the aerosol performance of DSCG stored at 75% RH for one month, while the FPF dropped by 7.5% after three months of storage. In contrast, 40% Val or Met were able to maintain the aerosol performance at 60% RH storage but not at 75% RH. At 40% w/w ratio, these formulations had particle surface coverage of 94.5% (molar percent) of Ile, 87.1% of Val and 84.6% of Met, respectively, which may explain their moisture protection effects. Conclusion: Ile, Val and Met showed promising moisture protection effect on aerosol performance. The results broaden the understanding on the use of hydrophobic amino acids as an excipient for longterm storage of inhalation powders formulations that are hygroscopic. (C) 2017 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available