Abstract
Functionalized PVA microspheres are commonly used as drug carriers in the fields of pharmacy and medicine. With this aim, we obtained and test novel PVA-PVAc-AMPS sulfonated microspheres by free radical suspension polymerization of vinyl acetate (VAc) and 2-acrylamido-2-methyl-1-propanesulfonic sodium salt acid (AMPS), followed by saponification. The microspheres exhibited a porous core-shell structure with excellent sphericity, a mean size of 171 µm, and elasticity modulus comparable with commercial particles currently used in medical applications. Methylene blue (MB) which has shown similar adherence properties as the cytostatic drug doxorubicin was used as a model drug to study the drug loading/release characteristics of the sulfonated microspheres prepared in this work. 20.7 mg g-1 MB per gram of microspheres was the maximum adsorption capacity in two hours using UV-Vis absorption spectroscopy. The experimental data on adsorption were well described by the pseudo-second order kinetic model. The in vitro release profile of loaded MB microspheres showed rapid desorption in the first hour followed by slower MB release, reaching 8.6% elution at four hours. The diffusion process was found to be dominant in the MB desorption from the PVA-PVAc-AMPS microspheres.
Highlights
Ion exchange microspheres (IEM) are commonly used in fields related to pharmacy and medicine, in the controlled administration of medications, diagnosis and administration of anticancer drugs [1,2,3,4,5]
In this work we present novel "PVAc-PVA-acrylamido-2 methylpropanesulfonate sodium salt (AMPS)" sulphonated PVA microspheres with a view to its application in controlled drug release
The peaks at 4.7, 1.75, 1.4 and 1.92 ppm were those of the methine (c), methylene (a, a’) and methyl (d) groups of PVA-PVAc chain, respectivamente [11,30], and the peaks at 2.1 and 1.40 ppm could be assigned to the methine (e) and methyl (g) groups of AMPS [31,32]
Summary
Ion exchange microspheres (IEM) are commonly used in fields related to pharmacy and medicine, in the controlled administration of medications, diagnosis and administration of anticancer drugs [1,2,3,4,5] These particles consist of a polymer solid phase containing integrated ionic moieties with high affinity for oppositely charged ions. Embolic microspheres of PVA modified with sulfonate groups or sodium acrylate have been developed, and are known as DC Beads and Hepasphere, respectively [1,14,15] These functional groups give the microspheres a negative charge and the ability to capture and release positively charged drugs such as Doxorubicin and Irinotecan through ionic interaction. Its synthesis method consists of the preparation of a macromer based on PVA and N-acryloyl-aminoacetaldehyde (NAAADA) which is subsequently copolymerized with 2-acrylamido-2 methylpropanesulfonate sodium salt (AMPS), the monomer that confers the sulfonate groups, and the negative charge to the microspheres [8,19,20]
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