Preparation of semi-solid dosage forms containing Psidium guava leaves extract as antimicrobial preservative
Mohammad Daud Abdallah Atieh
محمد داود عبدالله عطية
As it is known, guava leaves extract has several medicinal characteristics, such as antimicrobial, antioxidant, anti-cancer and anti-inflammatory. Several studies have been proposed to use guava leaves extract in several preparations. However, applying guava leaves extract as a preservative in a pharmaceutical product has not been studied in previously. In the present work, we try to use a natural preservative instead of chemical (methyl and propyl paraben) since many studies were warning from their effect and that it must be used at limited concentration. Guava leaves were extracted with ethanol 95.5 % as extraction solvent. The percentage yield was 20% which was acceptable. This extract was tested by HPLC; several phenolic compounds were detected. To determine the ability to use this extraction powder as a preservative, antimicrobial effectiveness test (preservative efficacy test) was conducted for extracted powder in purified water at different concentrations (0.5, 2.5, 5, 7.5, 9.5, 10) % w/w, against three bacteria, one gram-positive (S. aureus), two gram-negative (P. aeruginosa, E. coli) and two fungi: one yeast (Candida albicans) and one mold (Aspergillus (Niger) brasiliensis). The results showed that the only concentration that passed the test was 10%; this concentration was used in semi-solid pharmaceutical products. For this purpose, six different preparations (Ketoconazole shampoo, Clotrimazole Cream, Permethrin Cream, Gentamycin Cream, Ibuprofen gel, Indomethacin emulgel) were used. Chemical preservative was replaced by natural one (guava leaves extract powder) to serve as a preservative. Only three out of all six preparations (Ketoconazole shampoo, Clotrimazole Cream, Ibuprofen gel,) passed preservative efficacy test. This passed preparations were fully checked-up by chemical (drug content,) physical (odor, physical appearance) and biological test (Direct transfer test, Total count test) for three months at accelerated condition. The results confirmed that pharmaceutical preparations were stable and effective.