Eudragit polymeric films were investigated as a potential drug delivery system for
controlling the release of tetracaine HCl. The effect of modification in polymeric ratio of both
Eudragit RS100 and RL100, drug loading and nature of plasticizer on the in vitro release of the
drug from each film into a receiving medium of citrate buffer (pH=5) was measured. The
obtained results indicated that the film containing Eudragit polymer and plasticizer affected the
drug release rate and that the release followed Higuchi-diffusion model. The release rate was
found to be enhanced with increasing Eudragit RL100 ratio. The release rate was also found to
be directly proportional to drug concentration. Tetracaine HCl was slowly released from
Eudragit RS100 / dimethylphthalate films and Eudragit RS100 / diethyl-phthalate films.
Eduragit films plasticized with GTA, PEG400 and PG produced a fast drug release. This study
demonstrated that tetracaine HCl was compatible with Eudragit RS100 as indicated by the
clear and transparent formed films. Also, the characterizations of Eudragit films were
conducted by IR-spectroscopy, X-ray diffraction pattern and differential thermal analysis to
explore the possibility of the drug polymer interaction occurring between tetracaine HCl and
either Eudragit RS100 or Eudragit RL100. The therapeutic potential of tetracaine HCl Eudragit
polymeric films was evaluated using "Tail-Flick" method on a Techano analyiseometer model.
Results indicated that tetracaine HCL polymeric film composed of Eudragit RS100: Eudragit
RL100 ratio (8:2) and plasticized with 20% w/w diethylphthalate gave a long duration of
analgesic response.