The samples were stored into a desiccator under vacuum at room temperature. All formulations were www.selleckchem.com/products/mek162.html obtained in triplicate. Unloaded microparticles were also prepared as negative controls.Table 1Composition of resveratrol-loaded PHBV/PCL microparticles.2.3. Residual MoistureThe water content of resveratrol, PHBV, PCL, and microparticles was performed using an infrared moisture analyzer (Top 160 Ray, Bel engineering, Monza, Italy). For each sample, an amount of 1.000g was placed on an aluminum plate and dried at 105��C until constant weight. The percentage corresponding to mass loss was obtained as moisture content. The tests were carried out in triplicate.2.4. Characterization2.4.1. Drug Loading and Encapsulation Efficiency An amount of microparticles, equivalent to 20mg of resveratrol, was weighed and magnetic stirred (1,000rev?min?1) with 7mL ethanol for 12h.

The volume was completed to 10mL and filtered through a poly(vinylidene fluoride) membrane filter (Durapore membrane, 0.22��m pore size, Millipore, Bedford, MA, USA). After suitable dilution in ethanol, the concentration of resveratrol was determined through HPLC system (Waters Alliance 2695 HPLC System, Milford, MA, USA) using a Waters XTerra C18 analytical column (250 �� 4.6mm, 5��m) with UV detection at 306nm, in triplicate. The mobile phase consisted of 0.2% (v/v) acetic acid in water, acetonitrile, and methanol (2.3:22.5:75v/v). The validation of this HPLC method was previously performed through the following parameters: linearity, limit of detection, limit of quantitation, accuracy, robustness, precision, and specificity [24].

The concentration range varied from 10.0 to 50.0��g?mL?1. Linearity was 0.99981, and the detection limit was 172.18ng?mL?1. The encapsulation efficiency (EE) was obtained using(1)EE=(mass??of??resveratrol??in??microparticlestheoretical??mass??of??resveratrol)��100.(1)2.4.2. Scanning Electron Microscopy (SEM) The samples were mounted on aluminum stubs, sputtered with gold (IC-50 Ion Coater, Shimadzu, Kyoto, Japan), and analyzed using a scanning electron microscope (SSX-550 Superscan, Shimadzu, Kyoto, Japan) at an accelerating voltage of 10 or 15kV with different magnifications.2.4.3. Particle Size and Size Dispersion The particle size and size dispersion of PHBV/PCL microparticles were measured by laser diffraction spectrometry (LDS) in a Cilas 920L apparatus (Marseille, France). The dried powder samples were suspended in filtered water and sonicated into the ultrasonic bath coupled to the equipment for 1min before measurements. Then, the mean diameters �� standard deviations and GSK-3 the size distributions were determined.