In Vitro Performance of Ibuprofen Thermosensitive-gels for Topical Oral Application

Objectives: Ibuprofen (IBU) is a non-steroidal anti-inflammatory agent. Its topical use can increase availability in the site of action and avoid adverse effects of systemic use. Poloxamer 407 (PL407), a thermosensitive gel, has attracted interest as a drug delivery system, however it has a poor mucoadhesiveness. In this context, the objective of the present study was to evaluate the influence of different polymers (xanthan gum and carbopol) in the permeation, mechanical, mucoadhesion properties and of poloxamer gels containing IBU aiming at topical application on the oral mucosa.
Methods: IBU gels (0.02%) were composed of 20% PL407 alone or mixed with 0.15% xanthan gum (XG) or with 1% Carbopol (C). Mechanical (hardness, compressibility, elasticity and adhesiveness) and mucoadhesive (detachment force and mucoadhesion work) properties were evaluated in a texture analyzer (n=5). Permeation of IBU was carried out in Franz-type vertical diffusion cells, during 5 h. Mucoadhesive properties and permeation studies were performed in fresh porcine buccal mucosa. Data was analyzed by ANOVA and Tukey-Kramer Test.
Results: PL407 and PL407+XG presented lower values of hardness and compressibility (p<0.05), but the formulations were not different in the parameters elasticity and adhesiveness (p>0.05). In relation to mucoadhesion, the formulations were not different considering detachment force (p>0.05), but PL407+XG and PL407+C presented higher mucoadhesion work when compared with PL407 (p<0.05). In the permeation test, PL407 and PL407+XG presented the highest flux across the mucosa.
Conclusions: The addition of xanthan gum, but not carbopol, was able to improve mechanical properties and mucoadhesion of poloxamer, and maintained its ability to penetrate the tissue. PL407+XG formulation is a good candidate for future studies focusing on transbuccal delivery of ibuprofen for the treatment of inflammatory conditions that affects oral cavity.