Formulation and Physical Stability Test of Anti-Mosquito Lotion Preparations Combining Lemongrass (Cymbopogon citratus) and Cosmos caudatus Kunth. Extracts

Background: Dengue hemorrhagic fever (DHF) cases in Indonesia have shown significant increases, with 210,644 confirmed cases and 1,239 deaths reported by week 43 of 2024. Commercial mosquito repellents containing DEET pose various health risks, including skin irritation, nervous system effects, and environmental concerns, necessitating the development of safer natural alternatives. Objective: This study aimed to formulate and evaluate a mosquito repellent lotion containing a combination of extracts of lemongrass (Cymbopogon citratus) and kenikir (Cosmos caudatus Kunth.) obtained through the maceration method, and to test its physical stability and effectiveness as a natural repellent. Methods: This study employed a quantitative approach with a true experimental design using a full factorial design with six formulation variations (F0-F5). Plant materials were extracted using 96% ethanol maceration for 5 days. Population and Sample: The population comprised all possible lotion formulations with lemongrass and kenikir extract combinations at various concentrations, with samples consisting of six formulations selected using purposive sampling and 20 Aedes aegypti mosquitoes per test cage. Instruments and Data Analysis: Evaluation instruments included standard pharmaceutical equipment for organoleptic, homogeneity, pH, spreadability, adhesiveness tests, and a climatic chamber for accelerated stability testing, with data analyzed using SPSS through descriptive analysis and ANOVA with significance level α = 0.05. Results: All formulations met physical quality standards with acceptable organoleptic characteristics, good homogeneity, skin-compatible pH (5.40-5.70), optimal spreadability (6.5-7.0 cm), and adequate adhesiveness (>4 seconds), with F3 formulation (5% lemongrass + 5% kenikir extracts) demonstrating highest mosquito repellent effectiveness of 88%, equivalent to commercial positive control, and accelerated stability testing showed no significant changes in physical characteristics after three storage cycles. Conclusion: The combination of lemongrass and kenikir extracts successfully formulated into mosquito repellent lotion meeting pharmaceutical standards, with F3 as optimal formulation providing synergistic effects and excellent physical stability, representing a promising natural alternative to synthetic DEET-based repellents for national DHF vector control programs