Iranian Journal of Pharmaceutical Research (2004): Supplement 2:
2nd International Congress on Traditional Medicine and Materia Medica
Evaluation of the efficacy of several phytopolymers in terms of their duration of mucoadhesion
Department of Pharmaceutics, School of Pharmacy, Shaheed Beheshti University of Medical Sciences and Health Services, Tehran, Iran
In recent years worldwide interest has grown towards the development of mucoadhesive drug delivery systems. These systems are capable of adhering to body's mucosal surfaces for an extended period of time, releasing their drug content in a retarded manner. The use of biopolymers, and in particular phytopolymers, could provide a natural basis for the development of such systems. The aim of this study was to evaluate the rank order of adhesion of several phytopolymers in terms of their invitro duration of mucoadhesion.
Several phytopolymers including carrageenan, sodium alginate, tragacanth, locust bean gum, pectin, acacia and guar gum were directly compressed into 100mg flat-faced solid discs with a diameter of 9mm. The duration of mucoadhesion (maximum time interval disc remained in contact with the mucosal surface) of prepared discs to rat intestinal mucosa (model biological membrane), present within a pH 6.8 phosphate buffer at 37 C and under a constant tensile force of 15g, was evaluated. Each study was performed six times and the mean±standard deviation was calculated.
Among the polymers investigated, carrageenan (4.6±0.8 h) and guar gum (4.1±0.5 h) containing discs resulted in the longest duration of mucoadhesion, which were significantly (P<0.05, ANOVA) greater than tragacanth (2.6±0.4 h), sodium alginate (1.8±0.3 h), acacia (0.9±0.3 h) and pectin. Locust bean gum remained mucoadhesive for a period of 3.9±0.7 h. The least duration of mucoadhesion was observed with pectin (0.3±0.1 h).
Among the phytopolymers investigated, carrageenan, guar gum and to a lesser extent locust bean gum, appear to be reasonable mucoadhesives. However, because of the relatively high hydrophilic nature of these polymers, it is predicted that their use alongside synthetic polymers (such as Carbopols) could provide a competent, compliant and desirable matrix for mucoadhesive drug delivery.