Moisture sorption by cellulose powders of varying crystallinity.
Moisture in microcrystalline cellulose may cause stability problems for moisture sensitive drugs. The aim of this study was to investigate the influence of crystallinity and surface area on the uptake of moisture in cellulose powders. Powders of varying crystallinity were manufactured, and the uptake of moisture was investigated at different relative humidities. The structure of the cellulose powders was characterized by X-ray diffraction, BET surface area analysis, and scanning electron microscopy. Moisture uptake was directly related to the cellulose crystallinity and pore volume: Cellulose powders with higher crystallinity showed lower moisture uptake at relative humidities below 75%, while at higher humidities the moisture uptake could be associated with filling of the large pore volume of the cellulose powder of highest crystallinity. In conclusion, the structure of cellulose should be thoroughly considered when manufacturing low moisture grades of MCC.
Mihranyan
Albert
A
Department of Pharmacy, BMC, Uppsala University, Box 580, 75123 Uppsala, Sweden.
Llagostera
Assumpcio Piñas
AP
Karmhag
Richard
R
Strømme
Maria
M
Ek
Ragnar
R
D002482:Cellulose; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003461:Crystallography; D005079:Excipients; D011208:Powders; D014961:X-Ray Diffraction
D005079:Excipients; D011208:Powders; D002482:Cellulose; C109691:microcrystalline cellulose