RESUMEN
BACKGROUND: Methimazole, an oral antithyroid drug, has recently gained attention for its skin-brightening effects when applied topically to treat melasma. This study aims to develop, optimize, and characterize a methimazole microemulsion as a novel, safe approach for local melasma treatment. MATERIALS AND METHODS: We prepared microemulsion formulations containing 3% methimazole by combining appropriate amounts of surfactants (Tween 80 and Span 20), propylene glycol cosurfactant, and an oil phase (oleic acid-transcutol p at a 1:10 ratio). We then assessed droplet size, stability, viscosity, and skin permeation using rat skin models. RESULTS: The microemulsions' droplet sizes ranged from 7.06 to 28.13 nm, with viscosities between 120 and 254 centipoises. Our analysis identified droplet size, viscosity, and membrane release as significant independent variables. We determined the permeability parameters of the optimal formulation through rat skin, including steady-state permeability rate (Jss), permeability coefficient (p), lag time (Tlag), and apparent diffusion coefficient (Dapp). CONCLUSION: We found that the microemulsions' characteristics, physicochemical properties, and in vitro release depended on the surfactant-to-cosurfactant ratio, water content, and oil content. We developed an optimal formulation with a high surfactant-to-cosurfactant ratio and low water and oil percentages. This formulation shows potential for commercialization and manufacturing of final products.
RESUMEN
BACKGROUND: Parkinson's disease (PD), the second most prevalent neurological disorder in the elderly, manifests with distinctive movement disorders, including bradykinesia, resting tremor, and stiffness. With a progressive course, current treatment strategies primarily target symptomatic relief. Crocin is a chemical compound isolated from the dry stigma of Crocus sativus, and has demonstrated neuroprotective properties. OBJECTIVES: This study explores the impact of crocin on movement disorders and neuronal oxidative DNA damage in PD patients. METHOD: Conducted as a randomized, blinded, and controlled trial, this research focused on patients aged 30 to 80 with idiopathic PD. Using the second and third parts of the movement disorder society-unified PD rating scale (MDS-UPDRS), aspects of daily life activity and movement disorders were assessed before and after an 8-week intervention. Patients in the crocin groups received capsules containing 30 mg of crocin twice daily. Additionally, the 8-hydroxy-2-deoxydiguanosine (8-OHdG) to urinary creatinine ratio (8-OHdG/uCr) was measured to evaluate neuronal oxidative DNA damage. RESULTS: Out of the initially evaluated 164 patients, 30 were randomly assigned to each group, with 53 subjects completing the study. Within-group analysis revealed a significant improvement in the second and third parts of MDS-UPDRS after 8 weeks of crocin intervention (P < 0.05). However, the 8-OHdG/uCr did not show significant changes. The well-tolerated daily dose of 60 mg of crocin demonstrated minimal side effects. CONCLUSION: This study establishes the efficacy of crocin in enhancing daily life activities and mitigating movement disorders, suggesting its potential as a supplementary intervention alongside conventional PD medications.
