ABSTRACT
OBJECTIVE： To prepare Melatonin solid lipid nanoparticles （MT-SLNs）， and to investigate in vitro transcutaneous absorption characteristics of them in isolated skin of mice. METHODS： Using melatonin （MT） as model drug， glycerin sorbate as oil phase， poloxamer 188 （F188） as emulsifier， MT-SLNs was prepared by melt-emulsion method. The morphology of MT-SLNs was observed by TEM； the particle size distribution of MT-SLNs was measured by laser particle size analyzer， and the infrared spectrum characteristics were measured by infrared spectroscopy. The entrapped efficiency and drug loading amount were determined by HPLC and ultrafiltration centrifugation method. The transcutaneous absorption characteristics in vitro of MT-SLNs and MT raw material were compared using Franz diffusion cells method. RESULTS： The formulation of MT-SLNs included 2.5 mg/mL MT raw material， 25 mg/mL glycerin sorbate and 1％F188. The obtained MT-SLNs were spherical， and no aggregation was observed. Average particle size was （67.88±0.17）nm， and polydispersity index was 0.188±0.001. The characteristic absorption peaks of N—H stretching and bending vibration were not found in infrared spectra， and the characteristic absorption peaks of C—H stretching vibration of benzene ring shifted red to 1 750 cm－1. The entrapped efficiency and drug loading amount of MT-SLNs were （87.54±5.31）％ and （8.42±0.78）％. The transcutaneous absorption behavior of MT-SLNs and MT raw material conformed to zero-order kinetics release rule. The steady-state transmission rate of MT-SLNs [（31.71+2.78） μg/（h·cm2）] was significantly higher than that of its raw material [（10.32±3.24） μg/（h·cm2）]， and its lag time [（0.17±0.01） h] was significantly shorter than that of its raw material [（1.57±0.37） h] （P＜0.01）. CONCLUSIONS： Prepared MT-SLNs have small particle size and distributed evenly， and can promote in vitro transcutaneous absorption.
ABSTRACT
Context: Topical corticosteroids are the treatment of choice for oral lichen planus (OLP) due to its potential anti‑inflammatory effect. However, chronic nature of OLP often requires long‑term and frequent applications, exposing patients to local and systemic side effects. Aim: To detect the systemic absorption of 0.1% triamcinolone acetonide (TAC) through the oral mucosa of patients with OLP. Subjects and Methods: This was a pilot pharmacokinetic study carried out in the Department of Oral Medicine and Radiology in collaboration with the Department of Toxicology, over 10 months. A total of twenty patients with OLP were included and advised to apply 0.1% TAC 3 times/day for 2 weeks and 2 times/day for next 2 weeks. Blood samples were obtained on the first and second visits and analyzed for triamcinolone using High pressure liquid chromatography (HPLC). Statistical Analysis Used: Paired t‑test was done to compare visual analog scale (VAS) score for burning sensation at the first and second visits, statistically significant if P < 0.05. The baseline demographic data were analyzed using descriptive statistics. Results: Paired t‑test was done to compare VAS score for burning sensation at the first and second visits, which turned to being statistically significant (P = 0.001). Although HPLC is an established method for the detection of TAC, none of the study populations showed evidence of steroid (TAC) in the blood sample during 4 weeks of treatment duration. Conclusions: 0.1% triamcinolone is a relatively safe drug to be used with no systemic absorption in the standard dose regimen for oral lichen palnus.