Preparation, characterisation, pharmacokinetics and distribution of esculin microspheres administered via intravitreal injection into rabbit brain.

This study explored the distribution of esculin microspheres in rabbit brain tissue following intravitreal injection and investigated the possibility of direct entry of the drug into the brain through the eye, to develop a formulation with enhanced therapeutic efficacy against Parkinson's disease.Chitosan microspheres of esculin were prepared via an emulsification cross-linking method and their characteristics were evaluated, including angle of repose, bulk density, and swelling ratio. Furthermore, the pharmacokinetic parameters and brain tissue distribution in rabbits were compared among groups administered esculin eye drops, intravitreal esculin solution, and intravitreal esculin microspheres, to determine whether esculin could enter the brain through an ocular route.The results showed that the prepared esculin microspheres were spherical and had good fluidity. Notably, intravitreal administration enhanced the area under the curve (AUC) of esculin in the thalamus. Delivery through microspheres prolonged the drug retention time in both rabbit plasma and brain tissues, as well as the brain-targeting efficiency of esculin.The collective findings indicated that there may be a direct eye-brain pathway facilitating enter of esculin microspheres into brain tissue after intravitreal injection, supporting the utility of intravitreal esculin microspheres as an effective therapeutic formulation for Parkinson's disease, a long-term chronic condition.

Development and Assessment of Acyclovir Gel Plaster Containing Sponge Spicules.

Acyclovir is an acyclic purine nucleoside analog that is highly effective in inhibiting the herpes simplex virus. However, topical acyclovir has poor efficacy because of its low skin permeability. This study aimed to develop an acyclovir gel plaster containing sponge spicules (AGP-SS) to achieve synergistic improvements in skin absorption and deposition of acyclovir. The process of preparing the gel plaster was optimized by orthogonal experiments, while the composition of the formulation was optimized using the Plackett-Burman and Box-Behnken experimental designs. The selected formula was tested for physical properties, in vitro release, stability, ex vivo permeation, skin irritation, and pharmacokinetics. The optimized formulation exhibited good physical characteristics. In vitro release and ex vivo permeation studies showed that acyclovir release from AGP-SS was dominated by diffusion with significantly higher skin permeation (20.00 ± 1.07 µg/cm2) than that of the controls (p < 0.05). Dermatopharmacokinetic analyses revealed that the maximum concentration (78.74 ± 11.12 µg/g), area under the curve (1091.81 ± 29.05 µg/g/h) and relative bioavailability (197.12) of AGP-SS were higher than those of the controls. Therefore, gel plaster containing sponge spicules show potential for development as transdermal delivery systems to achieve higher skin absorption and deposition of acyclovir, especially in deep skin layers.

Insight into the effect of nitrate on AGS granulation: Granular characteristics, microbial community and metabolomics response.

As a promising wastewater treatment technology, aerobic granular sludge (AGS) process is still hindered by slow granule formation and easy disintegration in the application. While nitrate, one of the target pollutants in wastewater, showed a potential effect on AGS granulation process. Herein, this study attempted to reveal the role of nitrate in AGS granulation. By adding exogenous nitrate (10 mg L-1), the AGS formation was markedly improved and accomplished at 63 d, while the control group achieved AGS formation at 87 d. However, a disintegration was observed under a long-term nitrate feeding. A positive correlation was observed among granule size, extracellular polymeric substances (EPS) and intracellular c-di-GMP level in both formation and disintegration phases. The subsequent static biofilm assays indicated that nitrate might upregulate c-di-GMP via denitrification-derived NO, and c-di-GMP further upregulated EPS, thereby promoting AGS formation. However, excessive NO probably caused disintegration by downregulating c-di-GMP and EPS. Microbial community showed that nitrate favored the enrichment of denitrifiers and EPS producing microbes, which were responsible for the regulation of NO, c-di-GMP and EPS. Metabolomics analysis showed that amino acid metabolism was the most affected metabolism by nitrate. Some amino acids, such as Arg, His and Asp, were upregulated in the granule formation phase and downregulated in the disintegration phase, indicating the potential contribution to EPS biosynthesis. This study provides metabolic insight into how nitrate promotes/inhibits granulation, which may contribute to unwrapping the mystery of granulation and overcoming the limitations of AGS application.

Study on the aerobic remediation of Ni(II) by Pseudomonas hibiscicola strain L1 interaction with nitrate.

Aerobic denitrifying bacteria have the potential to remove the co-pollutants Ni(II) and nitrate in industrial wastewater. In this study, aerobic denitrifying bacteria with significant Ni(II) removal efficiency was isolated from the biological reaction tank and named as Pseudomonas hibiscicola L1 strain after 16 S rRNA identification analysis. The removal of ever-increasing Ni(II) and NO3--N wastewater under aerobic conditions by strain L1 was discussed. The experimental results showed that strain L1 removed 84% of Ni(II) and 81% of COD, with the use of 34.8 mg L-1 of nitrogen source and without nitrite accumulation yet. Strain L1 had remarkable activity (OD600 = 0.51-0.56 (p < 0.05)) at 20 mg L-1 of Ni(II) and 100 mg L-1 of NO3--N. It was found that high Ni(II) gradients (2-10 mg L-1) had little effect on nitrate removal ratio (35-34% (p > 0.05), and the removal ratios of Ni(II) was enhanced (from 42% to 83% (p < 0.05)) by increasing nitrate (25-100 mg L-1). Also, the results indicated that strain L1 could reduce Ni(II) and nitrate under different pH (6-9); electron donor-glucose, sodium acetate, sodium succinate and trisodium citrate; C/N (5-20) and coexisting ions (Cu(II) and Zn(II)). Notably, the nitrogen balance analysis showed 32.4% of TN was lost nitrogen and 19.7% of TN was assimilated for cell growth, which indicated aerobic denitrification process of strain L1. Meanwhile, characterization technology (SEM, FTIR, and XRD) showed Ni(II) was bioadsorbed in the form of Ni(NH2)2, NiCO3, and Ni(OH)2·2H2O through surface functional groups. This research provides new microbial method for the simultaneous removal of nitrate and Ni(II) in wastewater.

Fabs-in-tandem immunoglobulin is a novel and versatile bispecific design for engaging multiple therapeutic targets.

In recent years, the development of bispecific antibody (bsAb) has become a major trend in the biopharmaceutical industry. By simultaneously engaging 2 molcular targets, bsAbs show unique mechanisms of action that could lead to clinical benefits unattainable by conventional monoclonal antibodies. Various bsAb generation formats have been described, and several are being investigated in clinical development. However, some bsAb constructs have proven to be problematic due to their unfavorable physicochemical and pharmacokinetic properties, as well as poor manufacturing efficiencies. We describe here a new bispecific design, Fabs-in-tandem immunoglobulin (FIT-Ig), in which 2 antigen-binding fragments are fused directly in a crisscross orientation without any mutations or use of peptide linkers. This unique design provides a symmetric IgG-like bispecific molecule with correct association of 2 sets of VH/VL pairs. We show that FIT-Ig molecules exhibit favorable drug-like properties, in vitro and in vivo functions, as well as manufacturing efficiency for commercial development.

[Determination of mandelic acid and phenylglyoxylic acid in urine by reagent-free ion chromatography].

OBJECTIVE: To develop a method for determination of mandelic acid (MA) and phenylglyoxylic acid (PGA) in urine by reagent-free ion chromatography. METHODS: Ion chromatography was performed on an AS19 column with a gradient elution solution containing 10-35 mmoL/L KOH at a flow rate of 1.00 ml/min, and MA and PGA were detected at ultraviolet wavelengths of 225 nm and 254 nm, respectively. The samples were diluted 10 times with purified water, then purified on a silver column to remove high concentrations of chloride ion, and injected after being filtered through a 0.2-µm m filter membrane. RESULTS: The recoveries of standard addition of MA and PGA were 96.5% and 99.3%, respectively, with both relative standard deviations less than 5.0%. Good linear relationships were noted in the range of 1.0-100.0 mg/L for both MA and PGA (r >0.9995). The detection limits of MA and PGA were 0.02 mg/L and 0.05 mg/L, respectively; the minimum detectable concentrations of MA and PGA were 0.2 mg/L and 0.5 mg/L (when the sampling amount was 5.0 ml and diluted to 50.0 ml with water, and the injection volume was 300 µL). CONCLUSIONS: This method is fast, convenient, and highly sensitive and selective. It can be used for the analysis of MA and PGA in the urine of styrene-exposed workers.

Direct self-assembly of hepatocytes spheroids within hollow fibers in presence of collagen.

Opposite to the established view that collagen is an extracellular substratum for only dispersed hepatocyte culture, hepatocyte spheroids were directly formed within hollow fibers by addition of moderate concentrations of soluble collagen. Morphologically, these spheroids indicated a close relationship with their in vivo structure of liver. The albumin and urea synthetic profiles confirmed that those spheroids maintained liver-specific functions for at least 8 days. Spheroid formation by addition of collagen not only presents a potential methodology for clinical use of spheroids in bioartificial liver device but also indicates a likely function of collagen for self-assembly of primary cells in tissue engineering.

Evaluation of diffusion in gel entrapment cell culture within hollow fibers.

AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers. METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type I collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell. RESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 mum than that in hollow fibers with MWCO of 100 ku. CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.

Hepatocyte culture in bioartificial livers with different membrane characteristics.

Rat hepatocytes were cultured in three polysulfone, hollow-fiber cartridges, characterized by two membrane variables: pore size and inner diameter (ID). Hepatocytes entrapped in a micro-filtration (MF) cartridge with the membrane pore size 0.1 microm had twice the production of urea and 4-fold the amount of albumin in comparison to the control cartridge, a ultra-filtration (UF) cartridge with a molecular weight cut-off (MWCO) of 100 kDa. Hepatocytes entrapped in a UF cartridge with ID of 0.5 mm secreted twice the amount of urea and 10-fold the amount of albumin compared with the control UF cartridge.