The purpose of this research was to study the compression force influence on
polymers,
tablet behavior and drug release rate. Several
tablet batches were produced by varying the compression force and by using hydroxyethyl
cellulose (HEC) and
Carbopol 940 in the 1:1 ratio as matrix forming
polymers. All batches were characterized by DSC and X-ray analyses and in terms of swelling, ex vivo and in vivo mucoadhesive time, ex vivo mucoadhesion force, and in vitro and in vivo release. No significant
excipient-
excipient or
excipient-drug interactions were observed in any of the batches. All the
tablets hydrated quickly and their high hydration percentage showed that the compression forces used did not remarkably affect the water penetration and the polymeric chain stretching. Mucoadhesion performances and drug release were mainly influenced by compression force; its increase produced higher ex vivo and in vivo mucoadhesion and the in vitro and in vivo
drug releases were seen to decrease with the increase of the compression force. However
tablets fabricated by using the lowest compression force showed the best in vivo mucoadhesive time and hydrated faster when compared to the others.
Tablets 4 and 5, prepared with the highest forces, caused
pain during in vivo application and gave rise to irritation needing to be detached by the volunteers while
tablet 1, prepared with the lowest force, gave the best results because it was able to produce the highest
drug salivary concentration and no
pain. All
tablets exhibited an anomalous release mechanism.