Development and evaluation of a medicated chewing gum containing Sceletium tortuosum

Abstract

Sceletium tortuosum is one of the most promising medicinal plant species endemic to South Africa. It belongs to the Mesembryanthemaceae family and is traditionally used for treatment of anxiety and depression. Recent studies have shown that it is safe to use and that minimal to no side effects present in most patients. Four major alkaloids (mesembrenone, mesembrine, mesembranol and mesembrenol) have been identified in this species and are responsible for the pharmacological action. Medicated chewing gum (MCG) is used globally not only for its confectionary role, but also as a delivery system. MCG is defined by the European Pharmacopoeia (EP) as a "solid dose preparation with a base consisting mainly of gum that is intended to be chewed but not to be swallowed, providing a slow steady state release of the medicine contained". MCG is well described in scientific literature although no information could be found on MCG containing S. tortuosum. The purpose of this study is to develop and evaluate a medicated chewing gum containing S. tortuosum crude extract. Various MCG formulations were prepared containing the active ingredient (i.e. S. tortuosum crude extract containing mesembrine alkaloids), Cafosa®'s Health In Gum (HIG) base powders (i.e. HIG 01, 03 or 04 base powder), sweetener, flavouring agent and a lubricant (0% or 0.5% magnesium stearate) using a full factorial design. The flow and compressibility properties of S. tortuosum extract powder, the HIG base powders and the different formulations were analysed utilising the SeDeM Expert Diagram System. Formulations were tableted by means of direct compression on a Korsch® single tablet press with a 12 mm diameter flat punch to form individual MCG units. Each of the different MCG units was formulated in such a way as to contain a theoretical value of 6.38 mg of S. tortuosum crude extract that is equivalent to 50 mg raw S. tortuosum plant material, which represents the estimated quantity to be chewed as a single dose by indigenous people. The optimal MCG formulation achieved successful Parameter Index (PI), Parameter Profile Index (PPI) and Good Compressibility Index (GCI) values of 0.75, 7.16 and 6.81, respectively, indicating that the S0.5HIG01 is the most appropriate for direct compression according to the SeDeM Expert Diagram System. Additionally, index values indicated that overall S. tortuosum extract MCG formulations comprising magnesium stearate are deemed more appropriate for direct compression. The SeDeM Expert Diagram System could be successfully applied to directly compressible MCG formulations. The MCG formulations produced from the factorial design were evaluated in terms of physico-chemical properties and dissolution studies in order to obtain optimised MCG formulations. Prepared MCG units of the different formulations were evaluated in terms of morphology, mass variation, crushing strength, diameter, thickness, tensile strength, friability and pharmaceutical availability. Scanning electron microscopy (SEM) was used to evaluate the morphology of the S. tortuosum crude extract, the HIG base powders as well as the different MCG units. The physico-chemical properties as well as the dissolution studies of the formulations containing magnesium stearate indicated improved values when compared to formulations that contained no magnesium stearate. Therefore, in this study, different MCG units containing S. tortuosum crude extract with different base powders in their formulations were developed with the potential to be manufactured and implemented in the pharmaceutical industry.