Preparation and Release Behavior of Atorvastatin Calcuim - Encapsulated Polyoxalate Microspheres

Abstract

Atorvastatin calcium-loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/extraction method of oil-in-oil-in-water (O 1 /O 2 /W) for sustained release. We investigated the release behavior according to initial drug ratio, molecular weight (M w ) and concentration of POX and concentration of emulsifier. The microsphere was characterized on the surface, the cross-section morphology and the behavior of atorvastatin calcium release for 10 days by scanning electron microscopy (SEM) and high performance liquid chromatography (HPLC). The analysis of crystallization was analyzed to use X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). These results showed that the release behaviors can be controlled by preparation conditions.

Selective Release System for Antioxidative and Anti-Inflammatory Activities Using H2O2-Responsive Therapeutic Nanoparticles

“…The treatment of H 2 O 2 caused morphological changes of the particles with size increase of ∼1135.2 nm (Figure D) and generation of many holes (Figure C). The holes of the particles were generated by H 2 O 2 -induced degradation of oxalyl ester bond, which can be decomposed to CO 2 and incorporated compounds, leading to release drug rapidly . In addition, the size of the particles showed upper 10000 nm, which was generated by aggregation of destroyed particles (Figure D).…”

“…The holes of the particles were generated by H 2 O 2induced degradation of oxalyl ester bond, which can be decomposed to CO 2 and incorporated compounds, leading to release drug rapidly. 18 In addition, the size of the particles showed upper 10000 nm, which was generated by aggregation of destroyed particles (Figure 2D). These results suggest that H 2 O 2 -sensitive degradation of TPOX nanoparticles contributes to release rapidly incorporated tyrosol and entrapped drugs through breakdown of polyoxalates depending on the H 2 O 2 concentration.…”

“…This sensitive character contributes to targeting and drug release in oxidative damaged cells effectively. Polyoxalate nanoparticle (POX) was previously developed for biomedical usage and does not cause toxic and inflammatory reactions in vivo. , But this particles could release entrapped drug only. In addition, salicylic acid-derived poly­(anhydride-esters), composing polyoxalate, have a higher deliverable conjugated drug and responsive release effectively by the degradation of polymer …”

Synthesis of PVP Coated Superparamagnetic Iron Oxide Nanoparticles with a High Saturation Magnetization

“…The main drawbacks of conventional co-precipitation method are broad size distribution and agglomeration of iron oxide nanoparticles due to their high surface energy. To avoid the imitation of co-precipitation during washing process, surface of iron oxide nanoparticles was modified with formation of a polymeric layer such as dextran, chitosan, polyvinyl alcohol (PVA), polyethylene glycol (PEG), or polyvinylpyrrolidone (PVP) [10][11][12][13][14]. For example, Sousa et al found that citric acid coating improved the stability and biocompatibility of magnetite (Fe3O4) nanoparticles synthesized via co-precipitation with saturation magnetization of 26 emu/g.…”