Page 131 - 69_01

VOL. 69 (1), MICROCÁPSULAS ORALES DE LIBERACIÓN CONTROLADA DE NAPROXENO

wall materials. In fact, acrylate polymers and their derivates, collectively
known as Eudragit polymers, origin films with excellent strength and
good flexibility and aesthetics (6-9).

The two acrylic resins evaluated in this study included Eudragit
RLPO and RSPM. The RL and RS acrylic resins are copolymers synthe-
sised from acrylic and methacrylic acid esters with a low content of
quaternary ammonium groups as chloride salts. The swelling capacity and
the permeability to water and dissolved drugs were defined, which is pH
independent. The RL resin is freely permeable whereas the RS resin is
slightly permeable to water.

The three different types of Cutina, used as plasticizers, evaluated
in this study included Cutina HR (Castor oil, hardened), KD 16 (self-
emulsifying mixture of mono- and diglycerides of higher saturated fatty
acids and potassium stearate) and MD (mixture of mono- and diglycerides
of palmitic and stearic acid).

The aim of this work was to prepare microcapsules containing
naproxen that could be used in the preparation of oral controlled release
forms. The work consisted on the preparation of microcapsules by the
solvent evaporation process. Different batches were prepared using two
polymers or mixtures of polymers and adding three types of Cutina. The
film-forming properties of polymers were examined and the physico-
chemical factors that influence drug release from the films were studied.

EXPERIMENTAL

Materials
Naproxen was kindly supplied by Janssen Cilag and Eudragit RS
PM and RL PO by Rohm Pharma GmbH. The different types of Cutina
were purchased from Henkel. All other materials and solvents were of
analytical reagent grade.

137