Mucoadhesive Potentials of a Natural Polymer Obtained from the Seeds of Dioclea reflexa in Aminophylline Tablet Formulations

Aim: The mucoadhesive potentials of a natural gummy polysaccharide obtained from the seeds of Dioclea reflexa Hook F., (Fam.: Papilionaceae) (DR) was evaluated under varying pH conditions using aminophylline tablet formulations.

Study Design: The work was designed to experimentally evaluate the mucoadhesive effects of DR in comparison with that of a synthetic polymer, hydroxypropyl methylcellulose (HPMC).

Place and Duration of Study: The study was carried out in the Department of PT & RMD of NIPRD, Idu, Abuja, Nigeria between May 2011 and June 2012.

Methodology: The tablets were prepared by the wet granulation method using 1% w/w of the polymers as binders and 2.5% w/w as coating solutions, respectively. Some basic tablet characteristics were evaluated following standard procedures. In vitro drug release was also assessed after tablet coating. The mucoadhesive potentials at various pH levels: 1.2, 4.0, 6.5, 7.4 and 9.2, corresponding to those of the different gastrointestinal tract compartments, were evaluated by the wash-off method. The results were analyzed by analysis of variance (ANOVA) and t-test at P = .05.

Results: The release profiles showed that coating caused prolongation up to 8 h for both DR- and HPMC-coated tablets with the latter having significantly (P < .05) higher rates from 0.25 to 6 h (86.23±0.50: 44.10±0.31% and 101.71±0.20: 94.15±0.33% in 1 and 6 h for HPMC and DR tablets, respectively). The mucoadhesive potentials of DR were generally less than that of HPMC over the range of pH tested, except at 6.5 where it performed significantly (P < .05) better.

Conclusion: DR is useful as a mucoadhesive pharmaceutical excipient in aminophylline tablet formulations. It had optimum and better mucoadhesive strength than HPMC at the pH of 6.5 but less at 1.2, 4.0, 7.4 and 9.2.