Effects of molecular weight on permeability and microstructure of mixed ethyl-hydroxypropyl-cellulose films
Artikel i vetenskaplig tidskrift, 2013

Films of ethyl cellulose (EC) and water-soluble hydroxypropyl cellulose (HPC) can be used for extended release coatings in oral formulations. The permeability and microstructure of free EC/HPC films with 30% w/w HPC were studied to investigate effects of EC molecular weight. Phase separation during film spraying and subsequent HPC leaching after immersion in aqueous media cause pore formation in such films. It was found that sprayed films were porous throughout the bulk of the films after water immersion. The molecular weight affected HPC leaching, pore morphology and film permeability; increasing the molecular weight resulted in decreasing permeability. A model to distinguish the major factors contributing to diffusion retardation in porous films showed that the trend in permeability was determined predominantly by factors associated with the geometry and arrangement of pores, independent of the diffusing species. The film with the highest molecular weight did, however, show an additional contribution from pore wall/permeant interactions. In addition, rapid drying and increasing molecular weight resulted in smaller pores, which suggest that phase separation kinetics affects the final microstructure of EC/HPC films. Thus, the molecular weight influences the microstructural features of pores, which are crucial for mass transport in EC/HPC films.

pore geometry

permeability

ethyl cellulose

molecular weight

hydroxypropyl cellulose

Författare

Helene Andersson

Chalmers, Material- och tillverkningsteknik, Polymera material och kompositer

SuMo Biomaterials

Johan Hjärtstam

AstraZeneca Sweden

Mats Stading

Chalmers, Material- och tillverkningsteknik, Polymera material och kompositer

Christian von Corswant

AstraZeneca Sweden

Anette Larsson

Chalmers, Kemi- och bioteknik, Farmaceutisk teknologi

SuMo Biomaterials

European Journal of Pharmaceutical Sciences

0928-0987 (ISSN)

Vol. 48 240-248

Ämneskategorier

Farmaceutisk vetenskap

Medicinteknik

Biomaterial

Kemiteknik

Polymerteknologi

Annan materialteknik

Medicinska material och protesteknik

Styrkeområden

Materialvetenskap

DOI

10.1016/j.ejps.2012.11.003