BUCCOADHESIVE SLOW-RELEASE TABLETS OF ACITRETIN - DESIGN AND IN-VIVO EVALUATION

Acitretin is an aromatic retinoid used in the treatment of buccal kera tinization disorders. The local therapy has recently shown promising r esults. The aims of this study were to develop buccoadhesive tablets w ith different 'in vitro' release profiles of acitretin in order to sel ect the types of tablets to be tested 'in vive', to determine the sali va acitretin concentration and to verify the therapeutical efficacy. O n the basis of preliminary in vivo studies the dose of 10 mg of acitre tin was used. Ten different formulations of two-layer buccoadhesive ta blets were considered. The inferior layer (10 mg of Carbopol(R) 934P:M ethocel(R) K4M, 1:2) provided bioadhesive properties to all the tablet s. The upper layer of all tablets was the slow-release matrix containi ng the acitretin. The release-controlling component was an hydroxyprop ylmethylcellulose (HPMC); lactose was used as soluble filler. Aiming t o achieve a wide range of release rates, three types of HPMC with diff erent viscosity grades were used. A good relation was found between th e in vitro dissolution profile and the in vivo permanence of acitretin in the oral cavity, that was longer for the formulation containing 85 % of Methocel(R) E5 than the formulation containing 45% of Methocel(R) E5. Both formulations permitted to obtain good clinical results. (C) 1998 Elsevier Science B.V. All rights reserved.