A Rapid Reversed-Phase HPLC Method for Analysis of Trans-Resveratrol in PLGA Nanoparticulate Formulation

A rapid reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of trans-resveratrol (t-RVT) in PLGA nanoparticle formulation. A new formulation of t-RVT loaded PLGA nanoparticles (NPs) with potential stealth properties was prepared by nanoprecipitation method in our laboratory. The desired chromatographic separation was achieved on a Phenomenex C18 column under isocratic conditions using UV detection at 306？nm. The optimized mobile phase consisted of a mixture of methanol: 10？mM potassium dihydrogen phosphate buffer (pH 6.8): acetonitrile (63？:？30？:？7, v/v/v) at a flow rate of 1？mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range of 0.025–2.0？μg/ml, with determination coefficients, R2, exceeding 0.9997. The method was shown to be specific, precise at the intraday and interday levels, as reflected by the relative standard deviation (RSD) values, lower than 5.0%, and accurate with bias not exceeding 15% and percentage recovery was found to be in the range between 94.5 and 101.2. The limits of detection and quantification were 0.002 and 0.007？μg/ml, respectively. The method was successfully applied for the determination of t-RVT encapsulation efficiency. 1. Introduction Trans-resveratrol, trans-3,4′,5-trihydroxystilbene, (Figure 1) is a natural polyphenolic compound found in a variety of foods, nevertheless essentially in red grapes. It is a potent antioxidant and present mainly in the skin of grapes [1–3]. Small amount of t-RVT is also present in the seed and core of the grapes. t-RVT is also extracted from Polygonum cuspidatum, a plant found in China and Japan [4]. Resveratrol is existing as both cis- and trans-isomers, however; the trans-isomer is the most abundant and biologically active form. t-RVT has been suggested to possess cancer chemopreventive [5], antioxidative [6], antiplatelet, antifungal, cardioprotective [7], and HIV/AIDS properties [8]; however, the mechanism(s) of these proposed effects are not fully understood [9]. Figure 1: Chemical structures of trans-resveratrol. Results from pharmacokinetic studies indicate that the oral bioavailability of t-RVT is almost zero, which casts doubt on the physiological relevance of the high concentrations typically used for in vitro experiments [6]. However, its hydrosolubility of 3？mg/100？mL [10–12] makes it “practically insoluble” in water according to the European Pharmacopeia definition, and its log P is 3.1 [13]. Despite this poor water solubility, t-RVT exhibits high