Gantrez® AN-139, a copolymer

of methylvinylether and male

Gantrez® AN-139, a copolymer

of methylvinylether and maleic anhydride (PMVE/MA), was a gift provided by Ashland (Waterfield Tadworth Apoptosis inhibitor Surrey, KT20 5HQ, UK). Shandon M-1 embedding OCT (optimal cutting temperature) matrix was purchased from Thermo Electron Corporation (Beenham, Reading, UK). NPs were prepared using a modified emulsion–diffusion–evaporation method used in an earlier study where reproducibility of dye content, size, and surface charge of Rh B-loaded PLGA NPs has been demonstrated using triplicate experiments [10]. In brief, 50 mg of polymer was dissolved in 2.5 mL ethyl acetate for 2 h at ambient temperature using a magnetic stirrer (Cimarec i Poly 15 Multipoint stirrer, Thermo Electron Corporation, Beenham, Reading, UK). For the

preparation of Rh B-loaded NPs, a 200 μL aliquot of an aqueous Rh B solution of specified concentration was emulsified Selleck Cobimetinib in the organic phase for 5 min using a high speed homogenizer (Polytron PT4000, Littau, Switzerland) to produce a w/o emulsion. An aqueous DMAB solution (5 mL) of specified concentration was added to the resulting emulsion under stirring to produce a w/o/w emulsion. This was followed by homogenization for 5 min. The resulting emulsion was diluted with 25 mL of water with constant stirring. For FITC-loaded NPs, specified weights of the dye were dissolved in the polymer solution prior to the addition of either PVA or DMAB solution of specified concentration, followed by a single homogenization step to yield an o/w emulsion. This was diluted with water (25 mL) and stirred to allow solvent evaporation. Selected formulation variables and the emulsion homogenization

speed were modulated to generate dye-loaded PLGA NPs with different physicochemical characteristics (NPs size, hydrophilicity, surface charge, dye type, and dye initial loading). NPs size was modified by controlling the emulsion homogenization speed (5000, 10,000 and 15,000 rpm), while NPs hydrophilicity was modulated using PLGA copolymer with different lactic to glycolic acid ratios (50:50, 75:25, 100:0). The type of NPs surface charge was determined Farnesyltransferase by the emulsion stabilizer used. DMAB resulted in positively charged NPs, while PVA produced negatively charged NPs. The dye loading of NPs dispersions with Rh B and FITC was increased by adjusting the initial loading (5%, 10%, and 20% w/w) during emulsification. Unless otherwise mentioned, all experiments were conducted by varying one parameter while keeping other parameters set at selected conditions. Table 1 shows the test dye-loaded NP formulations obtained by modulating formulation variables and homogenization speed. The morphology of NPs was examined by transmission electron microscopy (TEM) (LEO 912 AB Omega, Zeiss, Oberkochen, Germany). A 50 μL volume of diluted NP dispersion (1:10) was placed onto the surface of a formvar/carbon coated 300 mesh grid and allowed to settle for 30 s.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>