Inulin-g-poly-D,L-lactide, a sustainable amphiphilic copolymer for nano-therapeutics

Emerging strategies against accelerated blood clearance phenomenon of nanocarrier drug delivery systems

Nanocarrier drug delivery systems (NDDS) have gained momentum in the field of anticancer or nucleic acid drug delivery due to their capacity to aggrandize the targeting efficacy and therapeutic outcomes of encapsulated drugs. A disadvantage of NDDS is that repeated administrations often encounter an obstacle known as the "accelerated blood clearance (ABC) phenomenon". This phenomenon results in the rapid clearance of the secondary dose from the bloodstream and markedly augmented liver accumulation, which substantially undermines the accurate delivery of drugs and the therapeutic effect of NDDS. Nevertheless, the underlying mechanism of this phenomenon has not been elucidated and there is currently no effective method for its eradication. In light of the above, the aim of this review is to provide a comprehensive summary of the underlying mechanism and potential countermeasures of the ABC phenomenon, with a view to rejuvenating both the slow-release property and expectation of NDDS in the clinic. In this paper, we innovatively introduce the pharmacokinetic mechanism of ABC phenomenon to further elucidate its occurrence mechanism after discussing its immunological mechanism, which provides a new direction for expanding the mechanistic study of ABC phenomenon. Whereafter, we conducted a critical conclusion of potential strategies for the suppression or prevention of the ABC phenomenon in terms of the physical and structural properties, PEG-lipid derivatives, dosage regimen and encapsulated substances of nanoformulations, particularly covering some novel high-performance nanomaterials and mixed modification methods. Alternatively, we innovatively propose a promising strategy of applying the characteristics of ABC phenomenon, as the significantly elevated hepatic accumulation and activated CYP3A1 profile associated with the ABC phenomenon are proved to be conducive to enhancing the efficacy of NDDS in the treatment of hepatocellular carcinoma. Collectively, this review is instructive for surmounting or wielding the ABC phenomenon and advancing the clinical applications and translations of NDDS.

Engineered inulin-based hybrid biomaterials for augmented immunomodulatory responses

Modified biopolymers that are based on prebiotics have been found to significantly contribute to immunomodulatory events. In recent years, there has been a growing use of modified biomaterials and polymer-functionalized nanomaterials in the treatment of various tumors by activating immune cells. However, the effectiveness of immune cells against tumors is hindered by several biological barriers, which highlights the importance of harnessing prebiotic-based biopolymers to enhance host defenses against cancer, thus advancing cancer prevention strategies. Inulin, in particular, plays a crucial role in activating immune cells and promoting the secretion of cytokines. Therefore, this mini-review aims to emphasize the importance of inulin in immunomodulatory responses, the development of inulin-based hybrid biopolymers, and the role of inulin in enhancing immunity and modifying cell surfaces. Furthermore, we discuss the various approaches of chemical modification for inulin and their potential use in cancer treatment, particularly in the field of cancer immunotherapy.

Inulin Amphiphilic Copolymer-Based Drug Delivery: Unraveling the Structural Features of Graft Constructs

In this study, the structural attributes of nanoparticles obtained by a renewable and non-immunogenic "inulinated" analog of the "pegylated" PLA (PEG-PLA) were examined, together with the potential of these novel nanocarriers in delivering poorly water-soluble drugs. Characterization of INU-PLA assemblies, encompassing critical aggregation concentration (CAC), NMR, DLS, LDE, and SEM analyses, was conducted to elucidate the core/shell architecture of the carriers and in vitro cyto- and hemo-compatibility were assayed. The entrapment and in vitro delivery of sorafenib tosylate (ST) were also studied. INU-PLA copolymers exhibit distinctive features: (1) Crew-cut aggregates are formed with coronas of 2-4 nm; (2) a threshold surface density of 1 INU/nm2 triggers a configuration change; (3) INU surface density influences PLA core dynamics, with hydrophilic segment stretching affecting PLA distribution towards the interface. INU-PLA2NPs demonstrated an outstanding loading of ST and excellent biological profile, with effective internalization and ST delivery to HepG2 cells, yielding a comparable IC50.

Synthesis, characterization, and application of honey stabilized inulin nanoparticles as colon targeting drug delivery carrier

Inulin (INU) is a versatile natural polysaccharide primarily derived from chicory roots. INU possesses the unique quality of evading digestion or fermentation in the early stages of the human digestive tract, instead reaching the lower colon directly. Exploiting on this distinctive attribute, INU finds application in the creation of targeted carrier systems for delivering drugs tailored to colon-related diseases. This study presents a novel method for synthesizing highly stable and non-aggregatory inulin nanoparticles (INU NPs) by ionotropic gelation method, using calcium chloride as crosslinker and natural honey as a stabilizing agent. Different formulation and process parameters were optimized for the synthesis of monodispersed INU NPs. These INU NPs efficiently encapsulated a hydrophilic drug irinotecan hydrochloride trihydrate (IHT) and drug loaded formulation (IINPs) demonstrated excellent colloidal and storage stabilities. Notably, these IINPs exhibited pH-dependent drug release, suggesting potential for colon-specific drug delivery. Anticancer activity of the NPs was found significantly higher in comparison to IHT through cytotoxicity and apoptosis studies against human colorectal carcinoma cells. Overall, this study revealed that the INU NPs synthesized by ionotropic gelation will be an efficient nanocarrier system for colon-targeted drug delivery due to their exceptional biocompatibility and stability in stomach and upper intestinal conditions.

Dual stimuli-responsive and sustained drug delivery NanoSensoGel formulation for prevention of cisplatin-induced ototoxicity

Cisplatin (CisPt)-induced ototoxicity (CIO) is delineated as a consequence of CisPt-induced intracellular generation of reactive oxygen species (ROS) which can be circumvented by Bucillamine (BUC; an antioxidant drug with sulfhydryl groups) and Diltiazem (DLT, L-type calcium channel blocker). However, its effective accumulation in the Organ of Corti and cell cytoplasm is desired. Therefore, a biocompatible BUC- and DLT-nanoparticles (NPs)-impregnated dual stimuli-responsive formulation (NanoSensoGel) presented here with ROS- and thermo-responsive properties for the sustained and receptive delivery of drugs. The ROS-responsive polypropylene sulfide- methyl polyethylene glycol-2000 (PPS-mPEG2000) polymer was rationally designed, synthesized, and characterized to fabricate BUC- and DLT-loaded PPS-mPEG2000-NPs (BUC- and DLT-NPs). The fabricated BUC- and DLT-NPs showed efficient cellular uptake, intracellular delivery, ROS responsiveness, and cytoprotective effect which was characterized using cellular internalization, intracellular ROS, mitochondrial superoxide, and Caspase 3/7 assays on the House Ear Institute-Organ of Corti-1 (HEI-OC1) cells. The composite NanoSensoGel (i.e., ROS-responsive BUC- and DLT-NPs suspended in the thermo-responsive hydrogel) present in a sol state at room temperature and turned to gel above 33°C, which could be essential for retaining the formulation at the target site for long-term release. The NanoSensoGel showed sustained release of BUC and DLT following Fickian release diffusion kinetics. Overall, a novel NanoSensoGel formulation developed in this study has demonstrated its great potential in delivering therapeutics in the inner ear for prophylactic treatment of CIO, and associated hearing loss.

3D printed macroporous scaffolds of PCL and inulin-g-P(D,L)LA for bone tissue engineering applications

Bone repair and tissue-engineering (BTE) approaches require novel biomaterials to produce scaffolds with required structural and biological characteristics and enhanced performances with respect to those currently available. In this study, PCL/INU-PLA hybrid biomaterial was prepared by blending of the aliphatic polyester poly(ε-caprolactone) (PCL) with the amphiphilic graft copolymer Inulin-g-poly(D,L)lactide (INU-PLA) synthetized from biodegradable inulin (INU) and poly(lactic acid) (PLA). The hybrid material was suitable to be processed using fused filament fabrication 3D printing (FFF-3DP) technique rendering macroporous scaffolds. PCL and INU-PLA were firstly blended as thin films through solvent-casting method, and then extruded by hot melt extrusion (HME) in form of filaments processable by FFF-3DP. The physicochemical characterization of the hybrid new material showed high homogeneity, improved surface wettability/hydrophilicity as compared to PCL alone, and right thermal properties for FFF process. The 3D printed scaffolds exhibited dimensional and structural parameters very close to those of the digital model, and mechanical performances compatible with the human trabecular bone. In addition, in comparison to PCL, hybrid scaffolds showed an enhancement of surface properties, swelling ability, and in vitro biodegradation rate. In vitro biocompatibility screening through hemolysis assay, LDH cytotoxicity test on human fibroblasts, CCK-8 cell viability, and osteogenic activity (ALP evaluation) assays on human mesenchymal stem cells showed favorable results.

Nanoaggregates of Biphilic Carboxyl-Containing Copolymers as Carriers for Ionically Bound Doxorubicin

Application of nanocarriers for drug delivery brings numerous advantages, allowing both minimization of side effects common in systemic drug delivery and improvement in targeting, which has made it the focal point of nanoscience for a number of years. While most of the studies are focused on encapsulation of hydrophobic drugs, delivery of hydrophilic compounds is typically performed via covalent attachment, which often requires chemical modification of the drug and limits the release kinetics. In this paper, we report synthesis of biphilic copolymers of various compositions capable of self-assembly in water with the formation of nanoparticles and suitable for ionic binding of the common anticancer drug doxorubicin. The copolymers are synthesized by radical copolymerization of N-vinyl-2-pyrrolidone and acrylic acid using n-octadecyl-mercaptan as a chain transfer agent. With an increase of the carboxyl group's share in the chain, the role of the electrostatic stabilization factor of the nanoparticles increased as well as the ability of doxorubicin as an ion binder. A mathematical description of the kinetics of doxorubicin binding and release is given and thermodynamic functions for the equilibrium ionic binding of doxorubicin are calculated.

The Use of Polymer Blends in the Treatment of Ocular Diseases

The eye is an organ with limited drug access due to its anatomical and physiological barriers, and the usual forms of ocular administration are limited in terms of drug penetration, residence time, and bioavailability, as well as low patient compliance. Hence, therapeutic innovations in new drug delivery systems (DDS) have been widely explored since they show numerous advantages over conventional methods, besides delivering the content to the eye without interfering with its normal functioning. Polymers are usually used in DDS and many of them are applicable to ophthalmic use, especially biodegradable ones. Even so, it can be a hard task to find a singular polymer with all the desirable properties to deliver the best performance, and combining two or more polymers in a blend has proven to be more convenient, efficient, and cost-effective. This review was carried out to assess the use of polymer blends as DDS. The search conducted in the databases of Pubmed and Scopus for specific terms revealed that although the physical combination of polymers is largely applied, the term polymer blend still has low compliance.

Beyond the Dilemmas: Design of PLA-PEG Assemblies Based on pH-Reversible Boronic Ester for the Synchronous PEG De-Shielding and Ligand Presentation to Hepatocytes

A new polymeric construct is proposed as a starting material for a liver-targeted delivery system in the present communication. The polymeric material has been designed to be sensitive to pH variations and potentially loaded with hydrophobic antitumoral agents. It is based on one of the most used copolymers in the field of nanomedicine: PEG-PLA. The latter, usually obtained by polymerization of lactic acid on the hydroxyl-terminated polyether, is assembled by the pH-reversible condensation between a phenylboronic acid-ended methoxy PEG 2000 (MeO-PEG2000-PBA) and a galactose-capped PLA of 1–10 kDa (PLA-Gal). Our approach is based on the strategic assumption that would allow a new ligand presentation strategy in which Gal is both a structural element for the stimulus-responsive PEG de-shielding and the targeting moiety. Indeed, Gal has a vicinal diol able to form a reversible boronate ester with a B(OH) 2 residue, which is cleavable at the acidic pH of the tumor microenvironment, and it is also recognized by the asialoglycoprotein receptor, which is hyper-expressed on the membrane of hepatocytes. The functionalization of the two blocks is presented here, and they are characterized using NMR, FTIR, and GPC. The analytical evaluation of the ability of the boronated PEG and Gal to condense in a pH sensible way completes the study.