Oral Delivery of Photopolymerizable Nanogels Loaded with Gemcitabine for Pancreatic Cancer Therapy: Formulation Design, and in vitro and in vivo Evaluations.

Background: Gemcitabine (GEM) faces challenges of poor oral bioavailability and extensive first-pass metabolism. Currently, only injectable formulations are available for clinical use. Hence, there is an urgent demand for the development of advanced, efficacious, and user-friendly dosage forms to maintain its status as the primary treatment for pancreatic ductal adenocarcinoma (PDAC). Nanogels (NGs) offer a novel oral drug delivery system, ideal for hydrophilic compounds like GEM. This study aims to develop NGs tailored for GEM delivery, with the goal of enhancing cellular uptake and gastrointestinal permeability for improved administration in PDAC patients. Methods: We developed cross-linked NGs via photopolymerization of methacryloyl for drug delivery of GEM. We reveal characterization, cytotoxicity, and cellular uptake studies in Caco-2 and MIA PaCa-2 cells. In addition, studies of in vitro permeability and pharmacokinetics were carried out to evaluate the bioavailability of the drug. Results: Our results show NGs, formed via photopolymerization of methacryloyl, had a spherical shape with a size of 233.91±7.75 nm. Gemcitabine-loaded NGs (NGs-GEM) with 5% GelMA exhibited efficient drug loading (particle size: 244.07±19.52 nm). In vitro drug release from NGs-GEM was slower at pH 1.2 than pH 6.8. Cellular uptake studies indicated significantly enhanced uptake in both MIA PaCa-2 and Caco-2 cells. While there was no significant difference in GEM's AUC and Cmax between NGs-GEM and free-GEM groups, NGs-GEM showed markedly lower dFdU content (10.07 hr∙µg/mL) compared to oral free-GEM (19.04 hr∙µg/mL) after oral administration (p<0.01), highlighting NGs' efficacy in impeding rapid drug metabolism and enhancing retention. Conclusion: In summary, NGs enhance cellular uptake, inhibit rapid metabolic degradation of GEM, and prolong retention after oral administration. These findings suggest NGs-GEM as a promising candidate for clinical use in oral pancreatic cancer therapy.

Differential cellular responses to FDA-approved nanomedicines: an exploration of albumin-based nanocarriers and liposomes in protein corona formation.

Albumin nanoparticles (NPs) and PEGylated liposomes have garnered tremendous interest as therapeutic drug carriers due to their unique physicochemical properties. These unique properties also have significant effects on the composition and structure of the protein corona formed around these NPs in a biological environment. Herein, protein corona formation on albumin NPs and liposomes was simultaneously evaluated through in vitro and simulation studies. The sizes of both types of NPs increased with more negatively charged interfaces upon being introduced into fetal bovine serum. Gel electrophoresis and label-free quantitative proteomics were performed to identify proteins recruited to the hard corona, and fewer proteins were found in albumin NPs than in liposomes, which is in accordance with isothermal titration calorimetry. The cellular uptake efficiency of the two NPs significantly differed in different serum concentrations, which was further scrutinized by loading an anticancer compound into albumin NPs. The presence of the hard protein corona increased the cellular uptake of albumin NPs in comparison with liposomes. In our simulation study, a specific receptor present in the membrane was greatly attracted to the albumin-apolipoprotein E complex. Overall, this study not only evaluated protein corona formation on albumin NPs, but also made promising advancements toward albumin- and liposome-based therapeutic systems.

A physiologically-based pharmacokinetic model for predicting doxorubicin disposition in multiple tissue levels and quantitative toxicity assessment.

Doxorubicin is a widely-used chemotherapeutic drug, however its high toxicity poses a significant challenge for its clinical use. To address this issue, a physiologically-based pharmacokinetic (PBPK) model was implemented to quantitatively assess doxorubicin toxicity at cellular scale. Due to its unique pharmacokinetic behavior (e.g. high volume of distribution and affinity to extra-plasma tissue compartments), we proposed a modified PBPK model structure and developed the model with multispecies extrapolation to compensate for the limitation of obtaining clinical tissue data. Our model predicted the disposition of doxorubicin in multiple tissues including clinical tissue data with an overall absolute average fold error (AAFE) of 2.12. The model's performance was further validated with 8 clinical datasets in combined with intracellular doxorubicin concentration with an average AAFE of 1.98. To assess the potential cellular toxicity, toxicity levels and area under curve (AUC) were defined for different dosing regimens in toxic and non-toxic scenarios. The cellular concentrations of doxorubicin in multiple organ sites associated with commonly observed adverse effects (AEs) were simulated and calculated the AUC for quantitative assessments. Our findings supported the clinical dosing regimen of 75 mg/m2 with a 21-day interval and suggest that slow infusion and separated single high doses may lower the risk of developing AEs from a cellular level, providing valuable insights for the risk assessment of doxorubicin chemotherapy. In conclusion, our work highlights the potential of PBPK modelling to provide quantitative assessments of cellular toxicity and supports the use of clinical dosing regimens to mitigate the risk of adverse effects.

One-pot fabrication of sacchachitin for production of TEMPO-oxidized sacchachitin nanofibers (TOSCNFs) utilized as scaffolds to enhance bone regeneration.

One-pot fabrication of sacchachitin (SC) for mass-production was developed and optimized by selecting KOH as alkaline agent in depigmentation step and utilizing NaClO2 as bleaching agent in subsequent step in the same pot. Overall yield of one-pot-fabricated SC was up to 35 %w/w of initial weight with a fibrous texture soft enough for mechanical disintegration into SC nanofibers (SCNFs) and better dispersion for producing TEMPO-oxidized SCNFs (T033SC). Both SCNFs and T033SC could form a 3D gelatinous scaffold into which MC3T3-E1 cells were attracted. Higher calcium-trapping ability of T033SC resulting from a greater extent of carboxylate groups provided an excellent bone regeneration environment that resulted in better outcomes of bone regeneration in a femur defect rat model compared to those with SCNFs possessed fewer carboxylate groups. In conclusion, biomaterial scaffolds based on TEMPO-oxidized SCNFs produced from one-pot fabricated SC showed great potential for bone regeneration due to unique physical and chemical properties.

TEMPO-Oxidized Sacchachitin Nanofibers (TOSCNFs) Combined with Platelet-Rich Plasma (PRP) for Management of Dry Eye Syndrome.

INTRODUCTION: In this study, the combination of TEMPO-oxidized sacchachitin nanofibers (TOSCNFs) with chitosan-activated platelet-rich plasma (cPRP) was evaluated for remedying dry eye syndrome (DES). METHODS: TOSCNFs, designated T050SC, were generated. T050SC combined with chitosan-activated (cPRP) was formulated as eye drops for application for severe DES. To evaluate the effects of cPRP and TOSCNFs on the repair of corneal injury, in vitro studies were conducted using Statens Seruminstitut rabbit corneal (SIRC) epithelial cells for cell proliferation and cell migration assays, and a severe DES animal model using rabbits was established with benzalkonium chloride (BAC) treatment for the evaluation. RESULTS: Results showed that the optimal eye formulation contained PRP activated by 350 µg/mL of the low-molecular-weight chitosan group (L3) combined with 300 µg/mL TO50SC (L3+T050SC). In the WST-1 cell-proliferation assay, L3 and L3+TO50SC significantly increased Statens SIRC cell proliferation after 24 hrs of incubation. In the SIRC cell migration assay, the L3+TO50SC group showed a wound-healing efficiency of 89% after 24-hr treatment. After 5 days of treatment, Schirmer's test results did not simulate the dry eye animal model. Typical cornea appearance and eye fluorescein staining results showed that the L3 group had the best effect on improving cornea haze and epithelial damage. CONCLUSION: This study has determined that TOSCNFs effectively promoted the healing effect on severe cases of corneal damage, and also might enhance the clinical application and medical potential of PRP in ophthalmology.

Preparation and characterization of chemically TEMPO-oxidized and mechanically disintegrated sacchachitin nanofibers (SCNF) for enhanced diabetic wound healing.

TEMPO-oxidization and mechanical disintegration were utilized to develop sacchachitin nanofibers (SCNF) with a 3D gel structure for being an ideal scaffold. Mechanically disintegrated SCNF (MDSCNF) with NanoLyzer® at 20,000 psi for 5 cycles and TEMPO-oxidized SCNF (TOSCNF) produced with 5.0 and 10.0 mmole NaClO/g SC was designated as SCN5, T050SC, and T100SC, respectively. All 2% MDSCNF suspensions were demonstrated to be in gel form, while all except T100SC of 2% TOSCNF suspensions showed to be wet fiber-like hydrogel. In diabetic wound healing study, both SCN5 and T050SC incorporated in AMPS (2-acrylamide-2-methyl-propane sulfonate)-based wound dressing were showed to accelerate diabetic wound healing forming nearly the same as normal tissues. T050SC/H further provided the healed wound with growth of sweat glands and hair follicles indicating the wound had healed as functional tissue. Conclusively, TEMPO-oxidized SCNF-based hydrogel scaffolds showed greater potentials in tissue regeneration due to its unique physical and chemical properties.

Complex Hydrogels Composed of Chitosan with Ring-opened Polyvinyl Pyrrolidone as a Gastroretentive Drug Dosage Form to Enhance the Bioavailability of Bisphosphonates.

Complex hydrogels formed with chitosan (CS) and ring-opened polyvinyl pyrrolidone (roPVP) as a swellable mucoadhesive gastroretentive drug dosage form (smGRDDF) were prepared and characterized. CS/roPVP hydrogels were produced by blending CS with roPVP obtained by basic treatment of PVP. Effects of the heating time and NaOH concentration employed for preparing roPVP, and CS molecular weights (Mws), and roPVP/CS ratios on the swelling ability of the resultant hydrogels were characterized. Rheological characteristics were further examined. Results demonstrated that roPVP obtained in a 0.5 M NaOH solution heated to 50 °C for 4 h was suitable for producing complex hydrogels with CS. At a roPVP/CS ratio of 20:1, hydrogels composed of three different Mws of CS possessed optimal swelling and mucoadhesive abilities and rheological properties. In vitro dissolution revealed sustained drug release. A pharmacokinetic study exhibited that the plasma profile of alendronate followed a sustained manner with 3-fold enhancement of the oral bioavailability. In conclusion, the smGRDDF composed of CS/roPVP complex hydrogels was successfully developed and is potentially applicable to improve the clinical efficacy of bisphosphonates.