Mucoadhesive buccal disks for novel nalbuphine prodrug controlled delivery: effect of formulation variables on drug release and mucoadhesive performance

The objective of this work was to assess the effects of drug solubility and loading percent, as well as Carbopol 934/hydroxypropylcellulose (CP/HPC) r atio, on drug release and mucoadhesive performance of the nalbuphine prodru g loaded buccal disks. Drug release rates for the disks were found to be a function of drug solubility, with higher drug release rates for disks loade d with more hydrophilic prodrugs and an increased amount of beta-cydodextri n. The drug release rates increased with loading percents for nalbuphine hy drochloride, whereas an opposite drug release trend was observed for disks loaded with nalbuphine enanthate, which can be explained by the diffusional drug release mechanism. The CP/HPC ratio affected release rates of nalbuph ine enanthate, whereas the ratio had no impact on the release of nalbuphine hydrochloride. Within the 2 days of experiment time, all formulations atta ched well to the porcine buccal tissues, indicating those formulation varia bles had no influence on the mucoadhesive performance of CP/HPC-based bucca l disks. (C) 1999 Elsevier Science B.V. All rights reserved.