D-optimal mixture design: Formulation development, mechanical characterization, and optimization of curcumin chewing...

Curcumin (CUR) chewing gums have potential therapeutic benefits to head and neck cancer patients. The objective of this work was to develop medicated chewing gums (MCGs) with high CUR loading and desirable mastication properties. This was accomplished by evaluating the effect of five gum ingredients: (X₁) polyisobutene, (X₂) polyvinyl acetate, (X₃) wood rosin, (X₄) wax, and (X₅) CUR on the mechanical properties of the MCGs using a 25-run, five-factor, two-level D-Optimal mixture design. CUR MCGs were prepared by the conventional fusion method for making chewing gums. They were characterized by a two-bites texture and uniaxial tension tests to generate force-displacement curves from which the cohesiveness (Y₁), springiness (Y₂), chewiness (Y₃), compressibility (Y₄), resistance to extension (Y₅), and extensibility (Y₆) were measured. Observed responses were used to generate polynomial models correlating the independent with the dependent variables. Elasticity and stiffness of the gums were found to be readily impacted by PIB and CUR levels. Fitted models were then used to predict a gum composition that has comparable mechanical properties to commercially procured chewing gums. The optimized MCG was loaded with 50% of either CUR or CUR/SBE-β-CD inclusion complex and tested in vitro for drug release. Although no differences in mechanical properties were observed, substituting CUR with the inclusion complex was found to significantly enhance drug release. This study highlighted the impact of each gum ingredient on the quality of the MCGs and demonstrated the feasibility of preparing chewing gums with up to 50% drug loading.