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This study was performed to achieve two primary goals: First, a microemulsion containing betamethasone dipropionate was optimized using the quality by design approach. Second, a hydrogel-containing microemulsion was developed using cellulose derivatives, and its anti-inflammatory and skin irritation effects were evaluated. Face-centered central composite design was used to investigate the impacts of two independent variables (oleic acid and ratio of surfactant to cosolvent, S/CoS) on three dependent variables (skin deposition, flux of BMD, and microemulsion droplet size). The microemulsion including oleic acid at a low level (coded with -1) and S/CoS at a high level (coded with +1) was considered optimal since it was the most effective in terms of skin deposition and flux of BMD. Different cellulose derivatives (HPMC E6, HEC, NaCMC, and CMC) were screened to prepare a hydrogel-containing microemulsion based on four properties: flux and skin deposition of BMD, hydration of stratum corneum, and rheological properties of hydrogel-containing microemulsion (ME-hydrogel). The anti-inflammatory effect and flux of BMD from optimal ME-hydrogel with carboxymethyl cellulose as the hydrogel-forming agent were then compared to those of the hydrogel-containing solid lipid nanoparticles (SLN-hydrogel) and nanostructure lipid carriers (NLC-hydrogel). The percentage of edema inhibition declined proportionally with flux of BMD in the following order: ME-hydrogel (44.56 ± 8.08%) > NLC-hydrogel (35.93 ± 7.22%) > SLN-hydrogel (25.68 ± 9.05%)., (Copyright © 2019 Elsevier B.V. All rights reserved.)

We designed a temperature-responsive and biodegradable novel drug-delivery carrier. A block copolymer, poly (N-isopropylacrylamide-dl-lactide) (PNIPAAm-PLA), was synthesized by the ring-opening polymerization of dl-lactide, and used as a carrier for a drug-delivery system. In this study, temperature-responsive nanoparticles (NPs) encapsulating betamethasone disodium 21-phosphate (BP) were prepared from a blend of PLA homopolymer and block copolymers by an oil-in-water solvent-diffusion method in the presence of zinc ion (PLA/PNIPAAm-PLA (NPs)). The resulting NP size was around 140 nm. The drug release from temperature-responsive NP could be controllable by changing the temperature. Moreover, a murine macrophage-like cell line, RAW 264.7 cells, was used to measure and image the cell uptake of fluorescent PLA/PNIPAAm-PLA NPs at 30 °C and 37 °C on the boundary of LCST (34 °C). Below the LCST, cellular uptake was not observed, but contrary to cellular uptake it was clearly observed above the LCST. Moreover, we found this effect to be useful for controlling the stealthiness by changing the temperature. Present temperature-responsive NPs have successfully exhibited thermo-responsive drug release and intracellular uptake while possessing a biodegradable character., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A sensitive voltammetric method has been described for the determination of betamethasone sodium phosphate (BSP) using edge plane pyrolytic graphite electrode (EPPGE) modified with single walled carbon nanotubes-cetyltrimethyl ammonium bromide nanocomposite film. The reduction of BSP occurred in a well-defined peak having E(p) -1062 mV in phosphate buffer solution (PBS) of pH 7.2. The voltammetric response of betamethasone sodium phosphate enhanced effectively using cationic surfactant cetyltrimethyl ammonium bromide (CTAB) as electrode surface modifier. The nanotubes-surfactant modified edge plane pyrolytic graphite electrode shows great improvement in peak current and shift of the reduction potential towards less negative potential. The role of cetyltrimethylammonium bromide on electrocatalytic property is discussed. The limit of detection (3sigma/slope) was found to be 0.25 x 10(-9)M and limit of quantification was 0.86 x 10(-9)M. The analytical utility of the proposed method is demonstrated by the direct assay of betamethasone in urine samples of pregnant women., (Copyright 2010 Elsevier B.V. All rights reserved.)