Effects of storage conditions on the stability of spray dried, inhalable bacteriophage powders.
This study aimed to develop inhalable powders containing phages active against antibiotic-resistant Pseudomonas aeruginosa for pulmonary delivery. A Pseudomonas phage, PEV2, was spray dried into powder matrices comprising of trehalose (0-80%), mannitol (0-80%) and l-leucine (20%). The resulting powders were stored at various relative humidity (RH) conditions (0, 22 and 60% RH) at 4°C. The phage stability and in vitro aerosol performance of the phage powders were examined at the time of production and after 1, 3 and 12 months storage. After spray drying, a total of 1.3 log titer reduction in phage was observed in the formulations containing 40%, 60% and 80% trehalose, whereas 2.4 and 5.1 log reductions were noted in the formulations containing 20% and no trehalose, respectively. No further reduction in titer occurred for powders stored at 0 and 22% RH even after 12 months, except the formulation containing no trehalose. The 60% RH storage condition had a destructive effect such that no viable phages were detected after 3 and 12 months. When aerosolised, the total lung doses for formulations containing 40%, 60% and 80% trehalose were similar (in the order of 105pfu). The results demonstrated that spray drying is a suitable method to produce stable phage powders for pulmonary delivery. A powder matrix containing ≥40% trehalose provided good phage preservation and aerosol performances after storage at 0 and 22% RH at 4°C for 12 months.
Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia.
Sharon S Y
SSY
Leung
Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia.
Thaigarajan
T
Parumasivam
Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia.
Fiona G
FG
Gao
Vibrational Spectroscopy Core Facility, The School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia.
Elizabeth A
EA
Carter
Department of Mechanical Engineering, University of Alberta, Alberta, T6G 2G8, Canada.
Nicholas B
NB
Carrigy
Department of Mechanical Engineering, University of Alberta, Alberta, T6G 2G8, Canada.
Reinhard
R
Vehring
Department of Mechanical Engineering, University of Alberta, Alberta, T6G 2G8, Canada.
Warren H
WH
Finlay
AmpliPhi Biosciences AU, 7/27 Dale Street, Brookvale, Sydney, NSW, 2100, Australia.
Sandra
S
Morales
Tuberculosis Research Program, Centenary Institute and Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia.
Warwick J
WJ
Britton
The Evergreen State College, Olympia, WA, 98502, USA.
Elizabeth
E
Kutter
Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia. Electronic address: kim.chan@sydney.edu.au.
Hak-Kim
HK
Chan
D000280:Administration, Inhalation; D001435:Bacteriophages / Q000737:chemistry*; D003460:Crystallization; D003890:Desiccation / Q000379:methods; D004355:Drug Stability; D004356:Drug Storage / Q000379:methods; D006813:Humidity / Q000009:adverse effects; D010316:Particle Size; D011208:Powders; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000502:physiology; D014961:X-Ray Diffraction
D011208:Powders
MDR; Multi-drug resistance; PEV2; Phage; Pulmonary infection; Spray drying