In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion

Abstract

Objective: To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures. Materials and methods: A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity. Results:The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed. Conclusion:The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity associated with the administration of microemulsion on mouse skin fibroblasts.

Mucoadhesive Emulsion Microgels for Intravesical Drug Delivery: Preparation, Retention at Urothelium, and Biodistribution Study

“…This behavior may be associated not with the negative impact of the examined emulsion microgels but with the procedure for replacing pure media in which cells were cultivated with media containing emulsion microgels. Calcein AM staining was performed once before the addition of emulsion microgels, and therefore the intensity of fluorescence in this channel was lowered during 24 h. The absence of a significant effect on cell morphology after adding emulsion microgel composition to the NIH/3T3 line cells (mouse fibroblasts) was also shown by Zhang et al 50 The results of cytotoxicity tests (Figure 5B) showed that the emulsion microgels had extremely low cytotoxicity over a wide range of particle amounts added per cell. Only a (5%, 1:1) sample had a pronounced cytotoxicity when 300 particles per cell were added.…”

Current Advances of Nanocarrier Technology-Based Active Cosmetic Ingredients for Beauty Applications

“…25 In additional, there are also small amounts of free drug uptake via intracellular route. 26 The surfactants, cosurfactants and oil phases used in the preparation of microemulsions and nanoemulsions usually have a certain permeability promoting effect, which can reverse and temporarily destroy the double layer structure of the lipid in the stratum corneum, increase the fluidity of the lipid in the stratum corneum, and thus fortify the transdermal permeability of drugs. Meanwhile, surfactants, cosurfactants and oil phases, as permeability enhancers, can perform a "diffuse-distribution-dissolution" effect in the skin, thereby elevating the percutaneous absorption of drugs.…”