Surasswadee Pooponpun. The mechanical and adhesion properties of film coats of Cellulose derivatives containing some selected solid additives . Master's Degree(Pharmaceutics). Mahidol University. : Mahidol University, 2005.
The mechanical and adhesion properties of film coats of Cellulose derivatives containing some selected solid additives
Abstract:
The main goal of this study was to investigate the effect of solid additives on mechanical
properties (tensile strength, modulus of elasticity and elongation at break) and adhesion properties
(adhesive force and adhesive toughness) of film-coats of cellulose derivatives. The free films and film
coated tablets of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC), alone and mixed
with two types of solid additives, corn starch and magnesium stearate, in concentrations of 10% and
20% by weight of the polymer, were prepared by cast and spray methods. The mechanical properties
of the free films and adhesion properties of the film-coated tablets were determined by a texture
analyser testing machine. The characterization of interaction between polymeric film and solid
additive was also determined by FTIR technique.
The obtained results revealed that the mechanical properties both of HPMC and EC free films
decreased as the concentration of solid additives was increased because of the lower stiffening effect
being brought about either by hydrodynamic or reinforcing effect. However adhesion properties of
HPMC film-coated tablets were found to increased whereas those of EC film-coated tablets decreased
with the increasing concentration of solid additives. Such contradictory results between these two
polymers may be attributed to whether the interference of film-tablet interfacial bonds or the reduction
of mechanical properties were dominant . The former seemed to be preferential in the case of EC
films, and the latter for HPMC films. Such conclusions were supported by the FTIR results, in which
the polymer-additive interaction was found for EC.