Formulation of Lozenges Containing Menthol and <i>Citrus hystrix</i> DC. Essential Oil for Pharyngitis Support Treatment

Abstract

This study aimed to develop antibacterial lozenges using kaffir lime fruit peel oil (Citrus hystrix) and assess its efficacy  against bacteria responsible for sore throats. The essential components of the lozenges included Citrus hystrix DC  essential oil and menthol. The lozenges were fabricated through the direct compression method. Several parameters,  such as color, taste, odor, time for oral disintegration, and adherence to in-house specifications, were also assessed.  Additionally, the stability of the lozenges was examined following ICH guidelines under accelerated conditions for a  duration of six months (at 40°C and relative humidity of 70%). The antibacterial properties of menthol and Citrus hystrix  DC essential oil were evaluated against common bacterial strains, including Streptococcus pneumoniae ATCC 29212,  Haemophilus influenzae ATCC 33533, Staphylococcus aureus ATCC 29213, Streptococcus mutans ATCC 25175,  Streptococcus faecalis ATCC 29212, and Moraxella catarrhalis ATCC 25238. The development of lozenges incorporating  menthol and Citrus hystrix essential oil was successfully achieved. The preferred combination ratio was determined to  be 2:1 of calcium silicate to menthol and essential oils, as it effectively masked the bitter taste. These lozenges adhered  to the specifications outlined in the USP 38 monograph for menthol lozenges and exhibited notable antibacterial  efficacy. Based on accelerated stability testing, the estimated expiration date for these lozenges was approximately 26  months. The results suggested that the lozenge tablet containing menthol and Citrus hystrix DC essential oils may offer  an alternative functional supplement for the prevention of pharyngitis.