Optimisation of lozenge formulation from Citronella (Cymbopogon nardus (L.) Rendle) extract with various binding materials using a simplex lattice design method

Abstract

Background: Antibacterial and antifungal activities of citronella grass extract are widely used, but there is no pleasant dosage form for patients who are unable to swallow. Citronella grass (Cymbopogon nardus (L.) Rendle) extract lozenges were prepared with wet granulation method containing natural or synthetic polymer (PGA/PVP/gelatin) binders. Objective: This study aimed to determine the most optimal lozenge formula using the simplex lattice design method with Design Expert software 13.0.0. Methods: The extract was made using maceration method with 70% ethanol as solvent. Furthermore, the preparation of tablets and physical, chemical and stability tests were performed. Results: The results of the physical test showed that Formula IV with a ratio of PGA:PVP:Gelatin of 0.5:0.5:0 was optimal with a hardness value of 48.85 ± 0.46 kg/cm2, dissolving time of 684 ± 7 seconds, and friability value of 0.31 ± 0.136%. Chemical testing by the total phenolic content of the extract using the Folin-Ciocalteu method at a wavelength of 750 nm obtained a 78.262 mgGAE/gram extract. Moreover, the optimal tablet obtained a 0.063 ± 0.027 mgGAE/gram extract, and stability testing at room temperature for 28 days found that the obtained lozenges were stable. Conclusion: It can be concluded that the combination of PGA (natural polymer) and PVP (synthetic polymer) binders with a ratio of 1:1 can produce optimal and stable citronella grass extract lozenges.