Drug Delivery Research Articles

Abstract A027: Enhancing pancreatic cancer chemotherapy through photochemical internalisation

Abstract Introduction Pancreatic cancer is the deadliest common cancer. Its poor prognosis is associated with its complex biology and lack of early detection strategies. Although much progress has been made in finding more effective therapeutic strategies, pancreatic tumours remain difficult to treat. A major reason why chemotherapy is relatively ineffective against this type of cancer is inefficient delivery of drugs to their target sites combined with multidrug resistance. Our aim is to use the technique called Photochemical Internalisation (PCI), a light-triggered intracellular drug delivery method which combines low dose Photodynamic Therapy (PDT) with chemotherapy, to induce efficient cytosolic delivery of therapeutic compounds to their specific subcellular targets. Methodology Treatment outcomes using saporin (a type I ribosome-inactivating protein) and gemcitabine as monotherapies, or in combination with a light-activated photosensitizer (the porphyrin TPPS2a), were thoroughly analysed in both established pancreatic cancer cell lines and patient-derived xenograft (PDX) models. The efficacy of these treatments was assessed in both 2D and 3D tumour models through various cell viability assays, including MTT, crystal violet staining, and neutral red staining. Additionally, molecular techniques such as western blotting, protein arrays, and flow cytometry were employed to determine the effects on cell viability and to elucidate changes in signalling pathways leading to the therapeutic response. Results In this study, we observed minimal cytotoxicity induced by saporin, gemcitabine or TPPS2a + light monotherapies. However, PCI synergistically enhanced saporin and gemcitabine cytotoxicity (p<0.001) using very low concentrations in all tumour models. Moreover, we determined the mechanism of cell death triggered by these protocols. PCI induced endosomal disruption following light excitation and apoptosis leading to caspases 3/7 activation, in a time dependent manner. Conclusions Overall, our findings demonstrate the potential of PCI to enhance the efficacy of cancer chemotherapy for pancreatic cancer using lower doses than in monotherapy and open a new window for future translational studies. By using low doses of light therapy, we have found a promising avenue for future studies that could eventually lead to better treatments for this challenging disease. Citation Format: Maria Rosado, Ismahan Mahamed, Andres Garcia-Sampedro, Sandy MacRoberts, Pål Selbo, Stephen Pereira, Pilar Acedo. Enhancing pancreatic cancer chemotherapy through photochemical internalisation [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A027.

Leveraging the Physicochemical Attributes of Biomimetic Hydrogel Nanocomposites in Stem Cell Differentiation.

The field of tissue engineering has witnessed significant advancements with the advent of hydrogel nanocomposites (HNC), emerging as a highly promising platform for regenerative medicine. HNCs provide a versatile platform that significantly enhances the differentiation of stem cells into specific cell lineages, making them highly suitable for tissue engineering applications. By incorporating nanoparticles, the mechanical properties of hydrogels, such as elasticity, porosity, and stiffness, are improved, addressing common challenges such as short-term stability, cytotoxicity, and scalability. These nanocomposites also exhibit enhanced biocompatibility and bioavailability, which are crucial to their effectiveness in clinical applications. Furthermore, HNCs are responsive to various triggers, allowing for precise control over their chemical properties, which is beneficial in creating 3D microenvironments, promoting wound healing, and enabling controlled drug delivery systems. This review provides a comprehensive overview of the production methods of HNCs and the factors influencing their physicochemical and biological properties, particularly in relation to stem cell differentiation and tissue repair. Additionally, it discusses the challenges in developing HNCs and highlights their potential to transform the field of regenerative medicine through improved mechanotransduction and controlled release systems.

Formulation and Evaluation of Acyclovir Loaded Transferosomal Gel for Transdermal Drug Delivery

Background: A carrying structure for targeted transdermal drug delivery is a transferosome. These unique liposomes are made of an edge activator and phosphatidylcholine. The most common antiviral drug is acyclovir, a synthetic nucleotide nucleoside analog derived from guanine. It works well to cure the varicella-zoster virus and the virus that causes herpes simplex (HSV), primarily HSV-1 and HSV-2. But its skin permeability is minimal. Therefore, this work aimed to use transferosomes to prepare acyclovir so that it could pass through the skin's barrier function. Objective: This study uses a 32-factorial factorial design to develop a transferosomal gel containing acyclovir through thin-film hydration method for painless acyclovir delivery services for skin disease treatment. Material and Methods: The independent variables are the amount of phospholipid (X1) and tween 80 (X2), while the dependent variables are particle size (Y1) and percentage entrapment efficiency (Y2). To create an ideal formulation, the produced transferosomes were assessed for particle size, in vitro drug release amount, and entrapment efficiency (EE%). A Carbopol 934 gel basis was prepared using the optimized acyclovir transferosome formulation, and its drug concentration, pH, spreadability, viscosity, and stability were assessed. Results: With small particles ranging from 176.6 to 324.4 nm, the produced acyclovir transferosomes had a high EE% range from 66.34 to 76.42 %. According to the in vitro release study, there is a negative correlation between in vitro release and EE%. The formulation TF5, including 1%w/w of carbopol 940, provides a superior profile of drug absorption in vitro. Consequently, acyclovir can enter the skin as transferosomes and cross the stratum corneum barrier. Conclusion: Acyclovir can be transformed into a transfersomal gel, which will improve antiviral efficacy, get over the skin's protective layer, prevent adverse oral reactions, and eventually improve patient adherence. Keywords: Transferosome, Transdermal drug delivery system, Acyclovir, 32 Fractional factorial design, Carbopol 934

Investigation of effect of complexing agent and processing method on solubility of Efonidipine

Nanosponges are versatile carriers due to their exceptional capability to improve the solubility of poorly water-soluble drugs, taste masking and enhancement of stability. This study investigates potential of nanosponges, prepared by crosslinking β-cyclodextrin with diphenyl carbonate in 1:4 ratio for enhancing solubility of Efonidipine. Nanosponges were characterized in terms of particle size. Phase solubility studies and solution state interaction studies were employed to understand the nature and strength of drug: nanosponge complexation. Complexes were prepared by kneading method and spray drying. Saturation solubility, in vitro dissolution studies and molecular modeling studies were performed. Complexes were characterized by differential scanning calorimetry (DSC), infrared spectroscopy, X ray powder diffraction (XRPD) and scanning electron microscopy. Phase solubility studies revealed 1:2 complexation between drug and carriers. Saturation solubility studies showed significant solubility increase with both beta CD and nanosponges. The increase was higher in case of spray dried complexes in all media. An 18 fold increase was observed in case of spray dried complexes in distilled water. DSC and PXRD confirmed amorphization of drug in the complexes. Thus solubility enhancement of EFD could be attributed to complexation and amorphization. Molecular modeling studies revealed the mode of entrapment of efonidipine in the carriers. In conclusion the versatility of nanosponges in encapsulating both hydrophilic and hydrophobic drug molecules holds immense promise for personalized medicine and targeted therapy, ultimately leading to improved patient outcomes. Moreover, the study introduces the efficacy of spray drying as a scalable and practical approach to maximize the solubility-enhancing benefits of nanosponges. This research highlights the potential of nanosponges to overcome a fundamental challenge in pharmaceuticals, opening new avenues for drug delivery and therapeutic advancement. Keywords: Nanosponges, β -cyclodextrin, inclusion complexes, solubility enhancement, molecular modelling

Abstract B059: Modulating the immunosuppressive pancreas tumor microenvironment through intratumoral delivery of cytokine-encoding mRNAs

Abstract Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive cancer, with a mere 13% average 5-year survival rate. The hallmark desmoplastic stromal response in PDAC leads to poor vascularization, drug delivery challenges, and impaired cytotoxic immune cell infiltration, contributing to de novo therapy resistance. Our previous research has shown therapeutic induction of cellular senescence with RAS pathway targeting therapies can induce cytokine and chemokine production through the senescence-associated secretory phenotype (SASP) that can effectively activate anti-tumor T cell immunity and responses to anti-PD-1 immune checkpoint blockade. To build on these findings as well as overcome limitations associated with senescence-inducing therapy toxicity and induction of pro-tumorigenic SASP cytokines, here we leveraged mRNA technology to deliver specific SASP cytokines and chemokines we have found to stimulate immune responses directly into the suppressive PDAC TME as an immune oncology platform. We created an in vitro transcription pipeline for mRNA production and multiplexing, and demonstrate we can intratumorally deliver multiple mRNAs simultaneously into the TME of transplanted and autochthonous PDAC mouse models, stimulating the local production of cytokines normally absent in PDAC. We further characterized a novel combination of five cytokines and chemokines that can effectively recruit and activate both innate and adaptive immune responses against PDAC. Through repeated bi-weekly dosing, this mRNA combination also promotes tumor destruction and improves survival outcomes. Considering the recent success of off-the-shelf neoantigen mRNA vaccines in early human PDAC patient trials, we have now developed mRNAs that encode PDAC-specific antigens. By integrating our cytokine mRNA platform with antigen mRNAs, we observe a significant increase in intratumoral antigen-presenting dendritic cell populations and a substantially enhanced T-cell mediated anti- tumor immune response in orthotopic transplant models of PDAC. Overall, this study not only unveils pivotal insights into the cytokines absent in PDAC that are crucial for promoting anti- tumor immunity, but also pioneers an innovative immunotherapy approach. This platform has the potential to be integrated with existing immunotherapy modalities, addressing the longstanding challenge of therapy resistance in PDAC. Citation Format: Chaitanya Naimesh Parikh, Kelly De Marco, Katherine Murphy, Loretah Chibaya, Lin Zhou, Youwei Qiao, Griffin Kane, Li Li, Wen Xue, Marcus Ruscetti. Modulating the immunosuppressive pancreas tumor microenvironment through intratumoral delivery of cytokine-encoding mRNAs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B059.

Formulation and Evaluation of Gastroretentive Bilayer Tablets

Gastroretentive bilayer tablets were designed to prolong the gastric residence time after oral administration and to achieve immediate release of lansoprazole and controlled release floating layer of clarithromycin to treat gastric ulcers. Instant release layer has a combination of super disintegrating agents. A combination of effervescent mechanism is used. HPMC K5 was used as swelling polymer and citric acid, sodium bicarbonate as gas generating agent to reduce the floating lag time. Bilayer floating tablets were prepared with varying proportions of instant layer and sustained release floating approaches. The prepared formulations were evaluated for various tablet and floating parameters. Tablet properties were found to be within the limits according to procedures prescribed in USP. They had a floating lag time around 3-7 seconds and floating time more than 24 hours. The cumulative % drug release in simulated gastric fluids after 10 hours was 70% - 95%. The mechanism of drug release was analyzed by fitting the release data into various kinetic models. It was found that all the formulations best fit the Higuchi’s model. Keywords: Gastroretentive drug delivery system; Bilayer tables, Instant release layer, Floating layer, Lansoprazole, Clarithromycin.

Abstract A054: Collagen fiber architecture modulates PDAC cell and organoid phenotype

Abstract Introduction Collagen plays a significant role in the development of pancreatic ductal adenocarcinoma (PDAC). Disease progression is mediated by a dense collagenous stroma, which acts as a barrier to drug delivery and immune cell access. Current in vitro models do not well represent the collagenous stroma seen in PDAC. The aim of this study is to develop a fibrillar collagen-based hydrogel system which mimics the tumour microenvironment seen in PDAC and assess cell-mediated collagen remodeling. Methods Metastatic SUIT2-007 pancreatic cancer cells, non-metastatic BxPC3 pancreatic cancer cells, and human pancreatic stellate cells (hPSCs) were encapsulated in bovine type I collagen gels of various concentrations. KPC mouse derived tumour organoids were also encapsulated in bovine type I collagen gels of 2 mg/ml and 6 mg/ml concentrations, basement membrane extract (BME), and a combination of BME and collagen gel. Cell viability and proliferation was assessed using Live/Dead imaging and CellTitre-Glo 3D respectively. Cell mediated collagen remodeling was assessed via monitoring of gel contraction on the mm scale, and confocal reflectance microscopy on the cellular scale. Collagen contraction around cells was assessed by measuring the pixel intensity of collagen fibrils within the vicinity of the cell. Cell phenotype was assessed via immunofluorescent staining and qPCR. Results Collagen concentration alters the hydrogel structure and stiffness, with 3 mg/ml collagen resulting in straighter, shorter and thicker fibrils. Metastatic SUIT-007 cells contracted collagen gels more rapidly than non-metastatic BxPC3 cells, with both achieving similar contraction by day 7. SUIT2-007 cells remodel and align soft 1 mg/ml gels while 3 mg/ml gels proved to be sufficiently stiff to resist remodeling. Cellular collagen association was increased in more elongated SUIT-007 cells than in BxPC3 cells. Organoid proliferation varies with hydrogel collagen concentration. Conclusion Metastatic SUIT2-007 cells were able to remodel collagen more rapidly and to a greater extent than non-metastatic BxPC3 cells. Collagen supports an invasive organoid phenotype. Collagen gels combined with confocal reflectance microscopy provide a platform for the quantitative assessment of cell-matrix interactions in PDAC. Acknowledgements This project was funded by a Medical Traineeship from UCD School of Medicine, and summer student scholarships from Irish Cancer Society and Breakthrough Cancer Research. We acknowledge the Conway Imaging Core Facility for assistance with microscopy. Citation Format: Ciara L Doyle, Shanu Xavier, Jarren Y.S Lu, Leah Fallon, Anwesha Sarkar, Jan J Baguyo, Maela Gars, Stephen D Thorpe. Collagen fiber architecture modulates PDAC cell and organoid phenotype [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A054.

Green composite synthesis based on aluminum fumarate metal-organic framework (MOF) for doxorubicin delivery: An in vitro study

The development of an eco-friendly and cost-effective drug delivery system (DDS) remains a challenge in cancer treatment. This study suggests a novel, eco-friendly, and cost-effective method to synthesize aluminum fumarate (A520) MOF using tangerine peel extract (TPE) as a pH-sensitive coating agent on a reduced graphene oxide (rGO) substrate. The system also incorporates the 2,2′-bipyridine dimethyltin diisothiocyanate complex, (Sn(bpy), as an organotin complex) to enhance therapeutic efficacy while minimizing off-target effects. In vitro cellular and molecular cytotoxicity examinations were conducted using HEK-293 and MCF-7 cell lines to evaluate cytotoxicity after 24 and 72 h. The findings of the MTT assay indicated that the final nanocarriers, without and with doxorubicin (DOX), exhibited relative cell viability of 95 % and 55 %, respectively, highlighting the system's potential for efficient and safe drug delivery. The TPE coating created a pH-sensitive DDS with high drug loading efficiency (DLE) (59.1 %) and low cytotoxicity. Drug release was studied over 200 h at pH 5.5 and 7.2. The augmented drug release profile (47 %) demonstrated a targeted release and successful inhibition of premature release in acidic environments due to pH-sensitive TPE molecules. The efficacy of targeted drug delivery to the MCF-7 cell was evaluated using 2D fluorescence microscopy, which demonstrated successful delivery of drugs to the cells. This innovative approach addresses the limitations of existing studies while promoting biocompatibility, stability, and functionality in DDSs.

Supramolecular Chemistry of Polymer-Based Molecular Tweezers: A Minireview

Polymer-based molecular tweezers have emerged as a prominent research area due to their enhanced ability to form host–guest complexes, driven by advancements in their design and synthesis. The impact of the spacer structure on the tweezers is predominant. They can be rigid, flexible, and stimuli-responsive. Herein, a new generation of molecular tweezers is introduced as polymer-based molecular tweezers. The integration of molecular tweezers onto biopolymers has significantly expanded their potential applications, making them promising candidates, especially in drug delivery, owing to their biocompatibility, adaptive structural features, and versatile interaction capabilities. The unique structure of polymer-based molecular tweezers, particularly when integrated with biopolymers, creates a unique nano-environment that enhances their interaction with guest molecules. This minireview focuses on the synthesis and applications of polymer-based molecular tweezers and examines how the incorporation of various spacers affects their binding affinity and specificity. These features highlight the advancement of these polymer-based systems, emphasizing their potential applications, particularly in drug delivery, water treatment technology, and future research opportunities.

Synthesis and properties of oligopropylamines with photosensitive o-nitrobenzyl ester core

The o-nitrobenzyl ester group is known for more than 50 years as a convenient protecting group and fragment for the design of photosensitive systems, including drug delivery agents. Polymeric amines with these groups are promising systems for medical applications, but the lack of basic knowledge about the possible degradation of these compounds under physiological conditions restrains the development of real preparations. We synthesized five new polyamines with the insertion of the o-nitrobenzyl ester group into the chain, including an oligomeric mixture with a weight average number of amine groups equal to 21. The ester group in the polyamine chain was found to be sensitive to hydrolysis at neutral and alkaline pH values. The presence of an amine group near the ester group facilitates hydrolysis through coordination with a hydroxyl ion or water molecule. The catalytic action of the amine moieties is prevented by protonation of the amine at low pH values or by interaction with polymeric acid. The study of photodegradation of new polyamines by HPLC-MS showed the formation of a number of products, most of which were not considered in previous works with o-nitrobenzyl ester derivatives. The o-nitrobenzyl ester group is used in the design of gene delivery systems and other biomedical preparations as a fragment that can be degraded by light. Our results indicate that photodegradation of o-nitrobenzyl esters can produce a number of compounds whose structure and safety for living organisms must be evaluated before use. On the other hand, the discovered hydrolyzability of o-nitrobenzyl esters catalyzed by a neighboring amine group may find application in the development of drug delivery systems. We have shown that the lifetime of o-nitrobenzyl ester containing polyamines is sufficient for gene delivery. Self-degradation of the delivery agent after penetration into a living cell is a desirable case for the release of the delivered agent.

Magnetic iron-based nanoparticles encapsulated in graphene/reduced graphene oxide: Synthesis, functionalization and cytotoxicity tests

Nanomaterials for suitable particle sizes, shapes, surface properties, biocompatibility, magnetic properties, and chemical stability are candidates for biomedical applications. Among these nanomaterials, iron-based ones are highly interested in their morphological and magnetic properties for potential utilizations in biomedicine. However, iron-based nanoparticles lose their chemical stability in body fluids because of their oxide formations and transformations. Their use in biomedical applications, especially in imaging, may be less effective if they are oxidized and have lower magnetization values. Thus, the idea of coating them with a protective layer has recently emerged to prevent magnetic nanoparticles from degrading in human fluids and losing their magnetic properties. However, the biological effects of these coated nanoparticles on human cells are poorly understood. In this paper, the synthesis of multilayer graphene (MLG) encapsulated iron-based nanoparticles was investigated by solvothermal and chemical vapor deposition (CVD) methods followed by purification. Subsequently, their surface modification was conducted with pyrene end-functional POEGMA obtained by atom transfer radical polymerization (ATRP). Cytotoxicities of synthesized nanoparticles were evaluated in MCF7 cell lines, which is a commonly used model for breast cancer research. We also compare the results with those obtained from bare iron oxide nanoparticles (IONPs) and iron oxides that were embedded in reduced graphene oxide (rGO) or partially coated with it. We aim to evaluate the safety and efficiency of these nanoparticles and increase their chemical stability as a multifunctional nano platform for cancer diagnosis and treatment. Characterization techniques such as XRD, XPS, SEM, TEM, DTA/TG, DLS, zeta potential, BET, NMR, FTIR, and VSM were performed on the nanoparticles. Cytotoxicity assessments on MCF-7 cell lines indicated the potential of these graphene-based magnetic nanoparticles for biomedical applications, particularly drug delivery, due to their small size, soft ferromagnetic properties, high chemical stability, and cytocompatibility at concentrations below 500 μg/mL over short incubation times.

Tetrahedral Framework Nucleic Acids Delivery of Pirfenidone for Anti-Inflammatory and Antioxidative Effects to Treat Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible lung disease, and developing an effective treatment remains a challenge. The limited therapeutic options are primarily delivered by the oral route, among which pirfenidone (PFD) improves pulmonary dysfunction and patient quality of life. However, its high dose and severe side effects (dyspepsia and systemic photosensitivity) limit its clinical value. Intratracheal aerosolization is an excellent alternative method for treating lung diseases because it increases the concentration of the drug needed to reach the focal site. Tetrahedral framework nucleic acid (tFNA) is a drug delivery system with exceptional delivery capabilities. Therefore, we synthesized a PFD-tFNA (Pt) complex using tFNA as the delivery vehicle and achieved quantitative nebulized drug delivery to the lungs via micronebulizer for lung fibrosis treatment. In vivo, Pt exhibited excellent immunomodulatory capacity and antioxidant effects. Furthermore, Pt reduced mortality, gradually restored body weight and improved lung tissue structure. Similarly, Pt also exhibited superior fibrosis inhibition in an in vitro fibrosis model, as shown by the suppression of excessive fibroblast activation and epithelial-mesenchymal transition (EMT) in epithelial cells exposed to TGF-β1. Conclusively, Pt, a complex with tFNA as a transport system, could enrich the therapeutic regimen for IPF via intratracheal aerosolization inhalation.

Biocompatible Glycopolymer-PLA Amphiphilic Hybrid Block Copolymers with Unique Self-Assembly, Uptake, and Degradation Properties.

The self-assembly of Janus-type amphiphilic hybrid block copolymers composed of hydrophilic/hydrophobic layers has shown promise for drug encapsulation and delivery. Saccharides have previously been incorporated to improve the biocompatibility of self-assembled structures; however, glycopolymer block copolymers have been less explored, and their structure-property relationships are not well understood. In this study, novel glycopolymer-branched poly(lactic acid) (PLA) block copolymers were synthesized via thiol-ene coupling and their composition-dependent morphologies were elucidated. Stability as a function of pH, dye uptake capabilities, and cytotoxicity were evaluated. Systems with a hydrophilic weight ratio of 30% were found to produce bilayer nanoparticles, while systems with a hydrophilic weight ratio of 60% form micelles upon self-assembly in aqueous media. Regardless of composition and morphology, all systems exhibited uptake of both hydrophobic (curcumin, DL % from 4.25 to 11.55) and hydrophilic (methyl orange, DL % from 4.08 to 5.88) dye molecules with release profiles dependent on composition. Furthermore, all of the nanoparticles exhibited low cytotoxicity, confirming their potential for biomedical applications.

Chloro-aluminum phthalocyanine encapsulation into liquid crystalline nanodispersions enhance skin penetration and phototoxicity in skin cancer cells

Non-melanoma skin cancer is one of the most common tumors in the world. Photodynamic therapy (PDT) is currently a non-invasive therapeutic option for the treatment of skin cancer and actinic keratosis. Chloro-aluminum phthalocyanine (AlClPc) is a second-generation photosensitizer that has been studied for application in PDT. However, it has the disadvantage of self-aggregating in a biological environment, which impairs its therapeutic action, making it a candidate for nanocarrier delivery. Among the nanocarriers, liquid crystalline nanodispersions (LCN) are biocompatible and present unique organizational characteristics that make them suitable for skin delivery of drugs. Herein, a new LCN based on oleic acid (OA), Phosal 75SA® containing or not D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) was developed and characterized aiming its application for skin cancer. The selected LCN with AlClPc showed nanometric size (152.3 ± 1.93 nm), adequate PDI (0.231 ± 0.009) and encapsulation efficiency (70.26 ± 3.87 %) and stability for 30 days. Also, LCN were characterized by polarized light microscopy and small angle X-ray diffraction (SAXS) resulting in hexagonal liquid crystalline nanodispersions. In the in vitro skin penetration test, LCN-AlClPc showed better penetration into the deeper skin layers than the control. LCN-AlClPc showed greater phototoxicity in the A431 tumor cell line than the control in the same cell line and also greater phototoxicity in A431 when compared to L929 fibroblast cells. Thus, LCN developed could improve the phototoxicity and skin penetration in vitro and are potential drug delivery systems for the treatment of non-melanoma skin cancer.

A mucoadhesive-to-penetrating nanomotors-in-hydrogel system for urothelium-oriented intravesical drug delivery

Intravesical therapy (IT) is widely used to tackle various urological diseases. However, its clinical efficacy is decreased by the impermeability of various barriers presented on the bladder luminal surface, including the urinary mucus layer and the densely packed tissue barrier. In this study, we report a mucoadhesive-to-penetrating nanomotors-in-hydrogel system for urothelium-oriented intravesical drug delivery. Upon intravesical instillation, its poloxamer 407 (PLX) hydrogel gelated and adhered to the urothelium to prolong its intravesical retention. The urea afterwards diffused into the hydrogel, thus generating a concentration gradient. Urease-powered membrane nanomotors (UMN) without asymmetric surface engineering could catalyze the urea and migrate down this concentration gradient to deeply and unidirectionally penetrate the urothelial barrier. Moreover, the intravesical hybrid system-delivered gemcitabine could effectively inhibit the bladder tumor growth without inducing any side effect. Therefore, our mucoadhesive-to-penetrating nanomotors-in-hydrogel system could serve as an alternative to IT to meet the clinical need for more efficacious therapeutics for urological diseases.Graphical

PSIII-28 Evaluation of tissue and plasma meloxicam concentrations using a microneedle patch for drug delivery

Abstract The objective of this study was to evaluate plasma and ear tissue meloxicam concentrations when the drug was delivered using two different formulations of a microneedle patch placed on the back of the ear. Nursing pigs [n = 10; body weight (BW) = 3.64 ± 0.32 kg) from 1 litter were assigned randomly to 1 of 2 treatment groups. Patches delivered 2.5 mg of meloxicam/kg BW to pigs regardless of formulation, with the differences in patches being based on type of polymer located on the microneedles and base of the patch. Treatment groups were: 1) pigs receiving a microneedle patch with collagen, polyvinyl alcohol (PVA), and meloxicam on the microneedles, with PVA and chitosan on the base (n = 6 pigs; Patch A); and 2) pigs receiving a microneedle patch with chitosan, PVA, and meloxicam on the microneedles, with collagen and PVA on the base (n = 4 pigs; Patch B). During the study, pigs remained in the crate with the sow and littermates. An Estrotect Breeding Indicator strip was used to adhere the microneedle patch on the ear of the pigs. Blood was collected at study initiation prior to patch administration (0 h) and 24 and 48 h for plasma meloxicam analysis. To evaluate tissue meloxicam concentrations, 3 pigs that received Patch A and 2 pigs that received Patch B were humanely euthanized after blood collection and patch removal at 24 and 48 h, with the entirety of the ear removed for analysis. Statistical analyses were performed using the MIXED procedure of SAS 9.4 (Cary, NC) to assess the effects of treatment, hour, and treatment × hour interaction. Statistical significance was determined at P ≤ 0.05, with tendencies at 0.05 < P ≤ 0.1. There were no differences (P = 0.83) between patch formulations for tissue meloxicam concentrations (Patch A = 6.55 ± 2.12 ng/mg; Patch B = 7.32 ± 2.60 ng/mg). Plasma concentrations were not detectable at any time point, but tissue concentrations of meloxicam were detectable for pigs that received either patch formulation at 24 (5.44 ± 2.37 ng/mg) and 48 h (8.42 ± 2.37 ng/mg). There were no differences (P = 0.41) between patch formulations for tissue meloxicam concentrations at either timepoint, nor was there an interaction of patch formulation and hour (P = 0.73). It is unknown why the meloxicam did not diffuse from the ear tissue into the plasma; however, further studies will focus on applying the microneedle patch at different areas on the animal to allow for optimal diffusion through the skin and into blood circulation for pain mitigation in livestock animals.

Interaction between reacetylated chitosan and albumin in alcalescent media

Interaction of chitosan and its derivatives with proteins of animal blood at blood pH relevant conditions is of a particular interest for construction of antimicrobial chitosan/protein-based drug delivery systems. In this work, the interaction of a series of N-reacetylated oligochitosans (RA-CHI) having Mw of 10–12 kDa and differing in the degree of acetylation (DA 19, 24, and 40 %) with bovine serum albumin (BSA) in alkalescent media is described in first. It is shown that RA-CHI forms soluble complexes with BSA in solutions with pH 7.4 and a low ionic strength. Light scattering study shows that soluble RA-CHI complexes have spherical form with the radius of about 100 nm. Circular dichroism, fluorescent spectroscopy, and micro-IR spectroscopy studies show that the secondary structure of BSA in soluble complexes remain intact. Isothermal titration calorimetry of RA-CHI with DA 24 % and BSA mixing in the buffers with different ionization heats reveals a significant contribution of electrostatic forces to the binding process and an additional ionization of chitosan due to the proton transfer from the buffer substance. An increase of ionic strength to the blood relevant value 0.15 M suppresses the binding. It is shown that application of RA-CHI with higher DA value leads to a decrease in the affinity of RA-CHI to BSA and an alteration of the interaction mechanism. The finding opens an opportunity to the application of N-reacetylated chitosan derivatives in the complex systems compatible with blood plasma proteins.

C-di-GMP@ZIF-8 nanocomposite injectable hydrogel based on modified chitosan and hyaluronic acid for infected wound healing by activating STING signaling

The treatment of infected wounds relies on antibiotics; however, increasing drug resistance has made therapeutic processes more difficult. Activating self-innate immune abilities may provide a promising alternative to treat wounds with bacterial infections. In this work, we constructed an immunogenic injectable hydrogel crosslinked by the Schiff base reaction of carboxymethyl chitosan (NOCC) and aldehyde hyaluronic acid (AHA) and encapsulated with stimulator of interferon genes (STING) agonist c-di-GMP loaded ZIF-8 nanoparticles (c-di-GMP@ZIF-8). Nanocubic ZIF-8 was screened as the most efficient intracellular drug delivery vector from five differently-shaped morphologies. The NOCC/AHA hydrogel released c-di-GMP@ZIF-8 more quickly (43 %) in acidic environment (pH = 5.5) of infected wounds compared with 34 % in non-infected wound environment (pH = 7.4) at 96 h due to pH-responsive degradation performance. The released c-di-GMP@ZIF-8 was found to activate the STING signaling of macrophages and enhance the secretion of IFN-β, CCL2, and CXCL12 5.8–7.6 times compared with phosphate buffer saline control, which effectively inhibited S. aureus growth and promoted fibroblast migration. In rat models with infected wounds, the c-di-GMP@ZIF-8 nanocomposite hydrogels improved infected wound healing by promoting granulation tissue regeneration, alleviating S. aureus-induced inflammation, and improving angiogenesis. Altogether, this study demonstrated a feasible strategy using STING-targeted and pH-responsive hydrogels for infected wound management.

Enhanced diclofenac sodium delivery through advanced self-microemulsifying pectin-based transdermal patches

Diclofenac sodium (DCFNa) presents significant challenges in local pain relief due to its poor solubility and limited skin permeability. This study aimed to enhance the solubility and skin permeation of DCFNa by developing DCFNa-loaded self-microemulsifying drug delivery system (SMEDDS) embedded pressure-sensitive adhesive (PSA) patch. The solubility of DCFNa in various solvents was evaluated, and a ternary phase diagram was constructed to optimize the SMEDDS formulation. The transdermal patch, composed of pectin and polyacrylate, was optimized using a simplex lattice experimental design to achieve the desired adhesion strength and to select the most suitable patch for skin drug accumulation study. Clove oil, Tween® 80, and propylene glycol were identified as the appropriate oil, surfactant, and co-surfactant, respectively, for achieving highest DCFNa solubility. The SMEDDS was formed with a ratio of 5:35:60 (oil: Smix [1:1 surfactant: co-surfactant]: water), yielding nano-sized droplets (22.64 ± 0.74 nm) and significantly enhancing DCFNa solubility (329.62 ± 10.16 mg/mL) compared to phosphate buffer (5.03 ± 1.01 mg/mL). The DCFNa-loaded SMEDDS demonstrated a 9-fold increase in skin permeability compared to the DCFNa solution. The optimized PSA patch, containing 20 % pectin and 40 % polyacrylate, exhibited superior tacking and peel strength. Additionally, a 1 % DCFNa-loaded SMEDDS patch delivered twice greater drug accumulation in the skin and showed no skin irritation, maintaining better adhesion for up to 24 h compared to commercial patches.

Gastrointestinal-inert prebiotic micro-composites improve the growth and community diversity of mucosal-associated bacteria.

The process of microencapsulation and the development of microparticle-based drug formulations have gained increased pharmaceutical interest, particularly for drug delivery and bacterial-encapsulation purposes for probiotic delivery. Existing studies have examined microcomposite (MC) responses to gastrointestinal (GI) conditions with the aim of controlling disintegration, and thus release, across the small and large bowel. However, the delivery of MCs which remain intact, without degrading, could act as bacterial growth scaffolds or materials providing a prebiotic support, conferring potentially beneficial GI health properties. This present study employs prilling as a method to produce a portfolio of MCs using a variety of biopolymers (alginate, chitosan, pectin and gellan gum) with a range of MC diameters and density compositions. Fluorescent probes are co-encapsulated within each MC to enable flow-cytometry directed release profile assessments following exposure to chemical simulated gastric and intestinal digestion conditions. We observe that MC size, gel-strength, density, and biopolymer material all influence response to gastric and intestinal conditions. Gellan gum (GG) MCs demonstrated complete resistance to disintegration throughout GI-simulation in the stomach and small intestine. Considering these MCs could reach the colon intact, we then examined how such MCs, doped with prebiotic growth supporting Carboxymethyl cellulose (CMC) polymers, could impact microbial communities using a bioreactor model of the colonic microbiome. Following supplementation with GGCMC MCs, mucosal bacterial diversity (using 16 s rRNA sequencing and Shannon entropy and observed feature diversity metrics) and taxonomic composition changes were observed. Concentrations of short chain fatty acid (SCFA) metabolites were also found to be altered. This is the first study to comprehensibly examine how MC physicochemistry can be manipulated to tailor MCs to have the desired GI release performance and subsequently, how GI-resistant MCs could have influential microbial altering properties and could be adopted in novel prebiotic strategies.