Study of the Effect of Formulation Parameters/Variables to Control the Nanoencapsulation of Hydrophilic Drug via Double Emulsion Technique
ABSTRACT Preparation of biodegradable nanoparticles containing active molecule is now taking much attention of researchers. The aim of the present work is to achieve the nanosize particles for the first time by double emulsion (W1/O/W2,) evaporation method to encapsulate hydrophilic substance using high performance stirring apparatus. A fluorescent stable hydrophilic agent (Stilbene derivative) was used as a model drug to be encapsulated. For this purpose, PCL (polycaprolactone) was chosen as polymer in this study. Several kinds of stabilizers [triton-405, tween 80, poloxamer, PVP (polyvinylpyrrolidone), PEG (poly ethylene glycol) & PVA (poly vinyl alcohol)] were investigated and the results indicate that the PVA (0.5% concentration) leads to the most stable double emulsion with the particle size in nano range. Different parameters affecting the size of particles have been studied such as stirring time (for 1st and 2nd emulsion), stirring speed (for 1st and 2nd emulsion), polymer and stabilizer concentrations etc. After duration of one month, the encapsulation efficiency of obtained particles was estimated using U.V. analysis. Transmission Electron Microscopy (TEM) showed that the prepared particles were spherical in shape. The size and size distribution were found to be submicron and ranging from 150 to 400 nm.
SourceAvailable from: Rebeca Hernandez[Show abstract] [Hide abstract]
ABSTRACT: The preparation of poly (lactic-co-glycolic acid) spheres functionalized with tri-(nitrilotriacetic acid) (NTA) employing a double-emulsion and evaporation method is described. First, polyacrylic acid (PAA) employed as emulsion stabilizer was chemically modified with NTA to yield modified PAA (PAA-NTA). PAA-NTA was characterized by 1H-NMR, ATR-FTIR spectroscopy and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was employed to characterize the morphology and particle size distribution of PLGA spheres obtained with both type of surfactants, PAA and PAA-NTA. Finally, we proved that PLGA particles obtained with modified PAA are able to chelate nickel ions, key for the development of future biomedical applications for these materials.Colloids and Surfaces A Physicochemical and Engineering Aspects 03/2015; 468:122-128. DOI:10.1016/j.colsurfa.2014.12.008 · 2.35 Impact Factor
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ABSTRACT: We use hydrophobic poly(lactic-co-glycolic) acid (PLGA) to encapsulate hydrophilic ofloxacin to form drug loading microspheres. Hyaluronic acid (HA) and polylysine (Pls) were used as internal phase additives to see their influences on the drug loading and releasing. Double emulsion (water-in-oil-in-water) solvent extraction/evaporation method was used for the purpose. Particle size analysis display that the polyelectrolytes have low impact on the microsphere average size and distribution. Scanning electron microscope (SEM) pictures show the wrinkled surface resulted by the internal microcavity of the microspheres. Microspheres with HA inside have higher drug loading amounts than microspheres with Pls inside. The loading drug amounts of the microspheres increase with the HA amounts inside, while decreasing with the Pls amounts inside. All the polyelectrolytes adding groups have burst release observed in experiments. The microspheres with Pls internal phase have faster release rate than the HA groups. Among the same polyelectrolyte internal phase groups, the release rate increases with the amounts increasing when Pls is inside, while it decreases with the amounts increasing when HA is inside.02/2014; 2014:297808. DOI:10.1155/2014/297808
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ABSTRACT: A microcapsule prepared from triblock copolymer poly(lactic acid)-poly(ethylene glycol)-poly(lactic acid) (PLA-PEG-PLA, PELA) was investigated as a controlled release carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2). The rhBMP-2/PELA microspheres were prepared using the water-in-oil-in-water (W/O/W) solvent evaporation method. This work was conducted to optimize the entrapping conditions of the rhBMP-2 loaded PELA copolymer. The effects on encapsulation efficiency (EE) of different molecular weights (MW) of PEG in the copolymer, the amount of PELA, the amount of rhBMP-2, the span-20 concentration, the polyvinyl alcohol (PVA) concentration and stirring time were tested. On the basis of single-factor experiments, the optimum parameters were achieved using response surface methodology (RSM). The results showed that the highest EE of BMP-2 was achieved with a span-20 concentration of 0.5%, PEG MW 4000 Da, a stirring time of 30 min at 800 rpm min−1, 282.3 mg of PELA, 1 μg of rhBMP-2 and PVA concentration 0.79%. Under these optimal conditions, it was predicted that the highest EE to be achieved would be 76.5%; the actual EE achieved was 75%.Biomedical Materials 02/2015; 10(1). DOI:10.1088/1748-6041/10/1/015002 · 2.92 Impact Factor