Polymeric nanocapsules via miniemulsion polymerization using redox initiation

Evaluation of the in vivo acute toxicity of poly(thioether-ester) and superparamagnetic poly(thioether-ester) nanoparticles obtained by thiol-ene miniemulsion polymerization

Poly(thioether-ester) (PTEe) nanoparticles obtained by thiol-ene polymerization have received attention of many researchers due to several advantages, including, biocompatibility and biodegradability. The search for new nanomaterials requires toxicity studies to assess potential toxic effects of their administration. Therefore, the aim of this study was to evaluate the in vivo acute toxicity of PTEe and poly(thioether-ester)-coated magnetic nanoparticles prepared by thiol-ene polymerization in miniemulsion. These nanoparticles presented a mean size of approximately 120 nm, spherical morphology, and negative surface charge. Doses of 40 mg/kg were administered intraperitoneally to Swiss mice and nociceptive, behavioral and biochemical parameters were investigated in five different organs. None of the nanoparticles led to any alterations in the nociceptive and behavioral responses. Biochemical alterations were observed in liver, decreasing the sulfhydryl and glutathione (GSH) levels, suggesting the dependence of the GSH metabolism in the elimination of the nanoparticles. In general, both nanoparticle types did not cause disturbances in biochemical parameters analyzed in others organs. These results suggest that both nanoparticle types did not induce acute toxicity to the different organs evaluated, reinforcing the biocompatibility of PTEe nanoparticles synthetized by thiol-ene polymerization.

Method Validation for Progesterone Determination in Poly(methyl methacrylate) Nanoparticles Synthesized via Miniemulsion Polymerization

Exogenous progesterone has several applications in human health and in veterinary medicine, especially in fixed-time artificial insemination protocol. Progesterone nanoencapsulation in biocompatible polymers, such as poly(methyl methacrylate) (PMMA), is an alternative to substitute silicone-based release device traditionally used for estrus control. Progesterone concentration inside the nanoparticles must be precisely known; for that reason, a validation methodology must be applied to ensure reliable results, suitable for nanoparticles application. In this work, an UV-Vis spectrophotometric method was validated for the determination of progesterone in PMMA nanoparticles synthesized by miniemulsion polymerization. Chloroform was used as solvent, showing selectivity to the encapsulated drug and the components of the polymeric matrix did not influence progesterone recovery. Detection and quantitation limits (DL and QL) obtained were 0.32 and 0.96 mg·L−1, respectively, and precision tests (between different analysts and equipment) indicated acceptable Relative Standard Deviations (RSD < 5%). Miniemulsion polymerization reactions were carried out producing two different morphologies: nanospheres (NS) and nanocapsules (NC), with average intensity diameters (Dz) of 150–200 nm and 240–300 nm, respectively. Polymerization gravimetric conversions obtained for both cases were higher than 95% and encapsulation efficiencies greater than 69% and 90% for the nanospheres and nanocapsules, respectively.