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The Role of Synthetic Pharmaceutical Polymer Excipients in Oral Dosage Forms – Poly(ethylene oxide)‐ graft ‐poly(vinyl alcohol) Copolymers in Tablet Coatings
Author(s) -
Gutzler Rainer,
Smulders Maarten,
Lange Ronald F.M.
Publication year - 2005
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200550707
Subject(s) - materials science , copolymer , ethylene oxide , vinyl alcohol , polymer chemistry , ethylene glycol , chemical engineering , grafting , polymer , composite material , engineering
A number of tablet coatings are available to provide a controlled release of pharmaceutically active compounds in the stomach or intestine using both instant or sustained released systems. The preferred properties of these tablet coatings are a low solution viscosity (preferable in water) combined with a phase separated morphology, showing good mechanical properties. PEO‐ g ‐PVAl copolymers have been developed as an instant‐release tablet coating, and were obtained via a conventional radical polymerisation of VAc in the presence of PEO. No free PEO was observed in the PEO‐ g ‐PVAl copolymers 1f and 1i using 2D LCCC‐SEC and MALDI‐TOF analysis. Next to the requirement of being PEO free, the PEO‐ g ‐PVAl copolymers show a good combination of film forming properties, a fast dissolution and a low solution viscosity in water. The phase separated morphology, as demonstrated by TEM, DSC, DMTA, and WAXS experiments, should provide the PEO‐ g ‐PVAl copolymers with relatively constant mechanical properties. A model reaction, using 2‐methoxyethyl‐ether and 1,4,7,10‐tetraoxacyclododecane, has been developed to imitate the grafting reaction of VAc on PEO. Using this model reaction and using the same reaction conditions (temperature, initiator, concentration, VAc:“PEO” ratio, etc.) as applied in the PEO‐ g ‐PVAl polymerisation procedure, a degree of grafting for PEO of 13±3% was found. Comparing this figure with the results of LCCC‐SEC and MALDI‐TOF measurements, this figure seems a few percent too high, pointing to a slightly increased reactivity of the two model compounds compared to the PEO used.