Preparation and in vitro characteristics of insulin buccal adhesive tablets

The objective of this study is to optimize the formulation of insulin buccal adhesive tablets and study the effects of adhesive excipients on in vitro characteristics of insulin buccal adhesive tablets.Twelve formulation (designated as F1-F12，80-mg tablet weight，and 2-mg insulin per tablet) were prepared using chitosan (CS)，apple pectin (AP)，carbomer-934P (CP)，hydroxypropyl methyl cellulose (HPMC)，sodium carboxymethyl cellulose (CMC-Na) and sodium alginate (SA) as adhesive excipient.Double-layer insulin buccal adhesive tablets were prepared by lyopyilization.Evaluation was performed on each formulation in the aspects of the appearance characteristics，the weight，in vitro adhesive strength，swelling percent and in vitro release of the tablets.The tablets have sponge-like porous structures，which might promote the release of insulin.The impermeable layer ensured directional release of insulin and attenuated drug loss.F5，F7 and F12 of poor compaction were aborted.In addition，the adhesive strength of F6 and F8 tablets and the swelling velocity of F1 and F11 tablets were unsatisfactory.Ultimately，tablets F2，F9 and F10，whose adhesive strengths were (66.1±6.65) g/cm²，(75.62±4.53) g/cm² and (69.39±8.03) g/cm²，respectively，and swelling percents at 2 h lower than 4%，were acceptable.Therefore，tablets F2 using AP as primary adhesive excipient，and tablets F9 and F10 using CP have better overall pharmaceutical properties in vitro，which can be used for further studies.