Enzyme-functionalized hydrogel film for extracorporeal uric acid reduction.

Enzyme replacement therapy for hyperuricemia treatment has been proven effective for critical state hyperuricemia patients. Still, direct administration of recombinant uricase can induce several fatal side effects. To circumvent this drawback, hydrogel protein carriers can be used in platforms for extracorporeal treatment such as microscale-based devices. In this work, calcium alginate and poly-(vinyl alcohol) hydrogel films were studied for their urate oxidase immobilization and uric acid reduction, which could be implemented in microscale-based extracorporeal devices. A mathematical model was developed in conjunction with uric acid reduction experiments to evaluate the influence of mass transfer and reaction parameters in the Michaelis-Menten kinetic expression. Alginate hydrogels prepared with crosslinker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-(hydroxysuccinimide) offered superior diffusivity of uric acid in the gel matrix at the maximum value of D g , UA ≈ $$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$ 1.98 × 10-11 m2 /s compared with alginate prepared solely from ionic crosslinking with D g , UA ≈ $$ {D}_{\mathrm{g},\mathrm{UA}}\approx $$ 5.31 × 10-12 m2 /s at the same alginate concentration. The maximum value of νmax was experimentally determined at 7.78 × 10-5 mol/(m3 s). A 3% sodium alginate hydrogel with crosslinkers yielded the highest reduction of uric acid at 92.70%. The mathematical model demonstrated an excellent prediction of uric acid conversion suggesting potential use of the model for formulation and maximizing the therapeutic performance of functionalized hydrogels.

Effect of Oil Content on Physiochemical Characteristics of γ-Oryzanol-Loaded Nanostructured Lipid Carriers.

Nanostructured lipid carriers (NLCs) are used as alternative carriers for many different drug delivery administration routes. They are composed of both solid lipid and liquid lipid (oil content) with both influencing their structural properties. Amounts of liquid lipid in NLCs play a role in drug release. Effect of liquid lipid (oil content) on physiochemical characteristics of NLCs related to drug-release requires detailed investigation. Here, many techniques were performed to analyze the physiochemical characteristics of NLCs, especially inside the particles. γ-Oryzanol (GO)-loaded NLCs were prepared at varying solid lipid to liquid lipid ratios. Their physicochemical properties, drug release profiles, and stability studies of prepared NLCs were investigated. Oil contents in NLCs were found to play a significant role in physiochemical characteristics related to drug release and stability, and also influence the efficiency of analytical techniques such as transmission electron microscopy (TEM) and dynamic force microscopy (DFM). Moreover, x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) gave information regarding crystallinity inside the NLCs. FTIR showed broad peaks in the range from 1184 cm-1 to 1475 cm-1 while XRD presented a broad curve indicated amorphous forms in NLCs. Orthorhombic lattices (ß' polymorph) were also elucidated by XRD and differential scanning calorimetry (DSC).

Development of γ-Oryzanol Rich Extract from Leum Pua Glutinous Rice Bran Loaded Nanostructured Lipid Carriers for Topical Delivery.

Leum Pua is native Thai glutinous rice that contains antioxidants higher than white rice and other colored rice. One of the major antioxidants in rice brans is γ-oryzanol (GO). In this study, Leum Pua glutinous rice bran was extracted by different solvents. Oleic acid (~40 g/100 g extract), linoleic acid (~30 g/100 g extract), and palmitic acid (~20 g/100 g extract) were found to be major lipid components in the extracts. Methanol extract showed less variety of lipid components compared to the others. However, hexane extract showed the highest percent of γ-oryzanol compared to other solvents. Therefore, the hexane extract was selected to prepare nanostructured lipid carriers (NLC). The prepared NLC had small particles in the size range of 142.9 ± 0.4 nm for extract-loaded NLC and 137.1 ± 0.5 nm for GO-loaded NLC with narrow size distribution (PI < 0.1) in both formulations. The release profile of extract-loaded NLC formulation was slightly higher than GO-loaded NLC formulation. However, they did not follow the Higuchi model because of small amounts of γ-oryzanol loaded in NLC particles.