Folate-decorated maleilated pullulan-doxorubicin conjugate for active tumor-targeted drug delivery

Potential of Pullulan-Based Polymeric Nanoparticles for Improving Drug Physicochemical Properties and Effectiveness

Pullulan, a natural polysaccharide with unique biocompatibility and biodegradability, has gained prominence in nanomedicine. Its application in nanoparticle drug delivery systems showcases its potential for precision medicine.

AIM OF STUDY

This scientific review aims to comprehensively discuss and summarize recent advancements in pullulan-based polymeric nanoparticles, focusing on their formulation, characterization, evaluation, and efficacy.

METHODOLOGY

A search on Scopus, PubMed, and Google Scholar, using "Pullulan and Nanoparticle" as keywords, identified relevant articles in recent years.

RESULTS

The literature search highlighted a diverse range of studies on the pullulan-based polymeric nanoparticles, including the success of high-selectivity hybrid pullulan-based nanoparticles for efficient boron delivery in colon cancer as the active targeting nanoparticle, the specific and high-efficiency release profile of the development of hyalgan-coated pullulan-based nanoparticles, and the design of multifunctional microneedle patches that incorporated pullulan-collagen-based nanoparticle-loaded antimicrobials to accelerate wound healing. These studies collectively underscore the versatility and transformative potential of pullulan-based polymeric nanoparticles in addressing biomedical challenges.

CONCLUSION

Pullulan-based polymeric nanoparticles are promising candidates for innovative drug delivery systems, with the potential to overcome the limitations associated with traditional delivery methods.

Use of Aureobasidium in a sustainable economy

Aureobasidium is omnipresent and can be isolated from air, water bodies, soil, wood, and other plant materials, as well as inorganic materials such as rocks and marble. A total of 32 species of this fungal genus have been identified at the level of DNA, of which Aureobasidium pullulans is best known. Aureobasidium is of interest for a sustainable economy because it can be used to produce a wide variety of compounds, including enzymes, polysaccharides, and biosurfactants. Moreover, it can be used to promote plant growth and protect wood and crops. To this end, Aureobasidium cells adhere to wood or plants by producing extracellular polysaccharides, thereby forming a biofilm. This biofilm provides a sustainable alternative to petrol-based coatings and toxic chemicals. This and the fact that Aureobasidium biofilms have the potential of self-repair make them a potential engineered living material avant la lettre. KEY POINTS: •Aureobasidium produces products of interest to the industry •Aureobasidium can stimulate plant growth and protect crops •Biofinish of A. pullulans is a sustainable alternative to petrol-based coatings •Aureobasidium biofilms have the potential to function as engineered living materials.

Targeted drug conjugate systems for ovarian cancer chemotherapy

Ovarian cancer is a highly lethal disease that affects women. Early diagnosis and treatment of women with early-stage disease improve the probability of survival. Unfortunately, the majority of women with ovarian cancer are diagnosed at advanced stages 3 and 4 which makes treatment challenging. While the majority of the patients respond to first-line treatment, i.e. cytoreductive surgery integrated with platinum-based chemotherapy, the rate of disease recurrence is very high and the available treatment options for recurrent disease are not curative. Thus, there is a need for more effective treatment options for ovarian cancer. Targeted drug conjugate systems have emerged as a promising therapeutic strategy for the treatment of ovarian cancer. These systems provide the opportunity to selectively deliver highly potent chemotherapeutic drugs to ovarian cancer, sparing healthy normal cells. Thus, the effectiveness of the drugs is improved and systemic toxicity is greatly reduced. In this review, different targeted drug conjugate systems that have been or are being developed for the treatment of ovarian cancer will be discussed.

Recent advances in pH/enzyme-responsive polysaccharide-small-molecule drug conjugates as nanotherapeutics

Now-a-days, the polysaccharides are extensively employed for the delivery of small-molecule drugs ascribed to their excellent biocompatibility, biodegradability and modifiability. An array of drug molecules is often chemically conjugated with different polysaccharides to augment their bio-performances. As compared to their therapeutic precursors, these conjugates could typically demonstrate an improved intrinsic solubility, stability, bioavailability and pharmacokinetic profiles of the drugs. In current years, various stimuli-responsive particularly pH and enzyme-sensitive linkers or pendants are also exploited to integrate the drug molecules into the polysaccharide backbone. The resulting conjugates could experience a rapid molecular conformational change upon exposure to the microenvironmental pH and enzyme changes of the diseased states, triggering the release of the bioactive cargos at the targeted sites and eventually minimize the systemic side effects. Herein, the recent advances in pH and enzyme -responsive polysaccharide-drug conjugates and their therapeutic benefits are systematically reviewed, following a brief description on the conjugation chemistry of the polysaccharides and drug molecules. The challenges and future perspectives of these conjugates are also precisely discussed.

Hybrid Micelles of Carbon Quantum Dot-Doxorubicin Conjugates as Nanotheranostics for Tumor Therapy and Turn-On Fluorescence Imaging: Impact of Conjugated Structures and On-Off-On Mechanism

Carbon quantum dots (CDs) have attracted more and more attention in the field of biological imaging, while their applications are restricted due to their nonspecific fluorescence and small particle size. Herein, two pH-responsive carbon quantum dot-doxorubicin (DOX) conjugates were designed with maleic acid (MA, cis-butenedioic acid) and fumaric acid (FA, trans-butenedioic acid) as linker, respectively, which could self-assemble into unique hybrid micelles as tumor-specific carrier-free nanotheranostics. Owing to the acid-labile covalent modification with conjugated groups and the interaction with the surrounding DOX molecules, the fluorescence of CDs was completely quenched, while it could be recovered in the tumor intracellular microenvironment by acid-triggered cleavage of the fluorophore-drug conjugates, showing excellent turn-on fluorescence for effective cellular imaging. Especially, the trans conjugate with FA as linker possessed higher drug content, better drug release behavior and stronger inhibition of tumor cells than the cis one with MA as linker, demonstrating its promising potential as carrier-free nanotheranostics for future tumor treatment.

Biopolymeric Prodrug Systems as Potential Antineoplastic Therapy

Nowadays, cancer represents a major public health issue, a substantial economic issue, and a burden for society. Limited by numerous disadvantages, conventional chemotherapy is being replaced by new strategies targeting tumor cells. In this context, therapies based on biopolymer prodrug systems represent a promising alternative for improving the pharmacokinetic and pharmacologic properties of drugs and reducing their toxicity. The polymer-directed enzyme prodrug therapy is based on tumor cell targeting and release of the drug using polymer–drug and polymer–enzyme conjugates. In addition, current trends are oriented towards natural sources. They are biocompatible, biodegradable, and represent a valuable and renewable source. Therefore, numerous antitumor molecules have been conjugated with natural polymers. The present manuscript highlights the latest research focused on polymer–drug conjugates containing natural polymers such as chitosan, hyaluronic acid, dextran, pullulan, silk fibroin, heparin, and polysaccharides from Auricularia auricula.

Role of Polysaccharides Mimetic Components in Targeted Cancer Treatment

Organic or inorganic compounds are synthesized or formulated in a manner that they completely show their therapeutic actions like as a natural polysaccharide in the body. Polysaccharides, the major type of natural polymers, are efficiently biologically active, non-toxic, hydrophilic, and biodegradable and show various properties. In this manuscript, the main focus is on delivering anticancer drugs with the help of mimetic components of polysaccharides. All data collected for this manuscript was from PubMed, Elsevier, Taylor, and Francis Bentham science journals. Most chemotherapeutics are therapeutically toxin to the human body, have a narrow therapeutic index, sluggish pharmaceutical delivery mechanisms, and are poorly soluble in water. The use of mimetic components of polysaccharides leads to the enhancement of the solubility of drugs in the biological environment. The manuscript summarizes the use of mimetic components of polysaccharides along with anticancer agents which are capable to inhibit the growth of cancerous cells in the body which shows lesser adverse effects in the biological system compared to other therapies.

Advances in Molecularly Imprinted Polymers as Drug Delivery Systems

Despite the tremendous efforts made in the past decades, severe side/toxic effects and poor bioavailability still represent the main challenges that hinder the clinical translation of drug molecules. This has turned the attention of investigators towards drug delivery vehicles that provide a localized and controlled drug delivery. Molecularly imprinted polymers (MIPs) as novel and versatile drug delivery vehicles have been widely studied in recent years due to the advantages of selective recognition, enhanced drug loading, sustained release, and robustness in harsh conditions. This review highlights the design and development of strategies undertaken for MIPs used as drug delivery vehicles involving different drug delivery mechanisms, such as rate-programmed, stimuli-responsive and active targeting, published during the course of the past five years.

Folic Acid-Doxorubicin-Double-Functionalized-Lipid-Core Nanocapsules: Synthesis, Chemical Structure Elucidation, and Cytotoxicity Evaluation on Ovarian (OVCAR-3) and Bladder (T24) Cancer Cell Lines

PURPOSE

Folic acid-doxorubicin-double-functionalized-lipid-core nanocapsules (LNC-CS-^L-Zn⁺²-DOX-FA) were prepared, characterized, and evaluated in vitro against ovarian and bladder cancer cell lines (OVCAR-3 and T24).

METHODS

LNC-CS-^L-Zn⁺²-DOX-FA was prepared by self-assembly and interfacial reactions, and characterized using liquid chromatography, particle sizing, transmission electron microscopy, and infrared spectroscopy. Cell viability and cellular uptake were studied using MTT assay and confocal microscopy.

RESULTS

The presence of lecithin allows the formation of nanocapsules with a lower tendency of agglomeration, narrower size distributions, and smaller diameters due to an increase in hydrogen bonds at the surface. LNC-^L-CS-Zn⁺²-DOX-FA, containing 98.00 ± 2.34 μg mL^-1 of DOX and 105.00 ± 2.05 μg mL^-1 of FA, had a mean diameter of 123 ± 4 nm and zeta potential of +12.0 ± 1.3 mV. After treatment with LNC-^L-CS-Zn⁺²-DOX-FA (15 μmol L^-1 of DOX), T24 cells had inhibition rates above 80% (24 h) and 90% (48 h), whereas OVCAR-3 cells showed inhibition rates of 68% (24 h) and 93% (48 h), showing higher cytotoxicity than DOX.HCl. The fluorescent-labeled formulation showed a higher capacity of internalization in OVCAR-3 compared to T24 cancer cells.

CONCLUSION

Lecithin favored the increase of hydrogen bonds at the surface, leading to a lower tendency of agglomeration for nanocapsules. LNC-CS-^L-Zn⁺²-DOX-FA is a promising therapeutic agent against tumor-overexpressing folate receptors.

Pullulan in biomedical research and development - A review

Pullulan is an imperative microbial exo-polymer commercially produced by yeast like fungus Aureobasidium pullulans. Its structure contains maltosyl repeating units which comprises two α-(1 → 4) linked glucopyranose rings attached to one glucopyranose ring through α-(1 → 6) glycosidic bond. The co-existence of α-(1 → 6) and α-(1 → 4) glycosidic linkages endows distinctive physico-chemical properties to pullulan. It is highly biocompatible, non-toxic and non-carcinogenic in nature. It is extremely resistant to any mutagenicity or immunogenicity. The unique properties of pullulan make it a potent candidate for biomedical applications viz. drug delivery, gene delivery, tissue engineering, molecular chaperon, plasma expander, vaccination, etc. This review highlights the potential of pullulan in biomedical research and development.

Acid-labile anhydride-linked doxorubicin-doxorubicin dimer nanoparticles as drug self-delivery system with minimized premature drug leakage and enhanced anti-tumor efficacy

Acid-labile anhydride-linked doxorubicin-doxorubicin dimers (D-DOX) were designed as doxorubicin-doxorubicin conjugate-based drug self-delivery systems (DSDSs) with high drug content for tumor intracellular pH-triggered release, by conjugating doxorubicin (DOX) with various anhydrides, such as maleic anhydride (MAH), succinic anhydride (suc), and 2,3-dimethylmaleic anhydride (DMMAH). With the similar diameter of about 200 nm, the D-DOXMAH showed better pH-triggered DOX release and was thus selected for the further investigation. The D-DOX-5 nanoparticles with desirable average hydrodynamic diameter (Dh) of 162 nm and high drug content of 51.20% were obtained via self-assembly by a facile dialysis technique, with the PEGylated dimer (D-DOXMAH-S-PEG) as surfactant. The cumulative DOX release from the proposed D-DOX nanoparticles reached 40.6% within 36 h in the simulated tumor intracellular acidic micro-environment, while the premature drug leakage was only 4.5% in the simulated normal physiological medium. The MTT results indicated the proposed DSDS possessed an enhanced anti-tumor efficacy for the HepG2 cancer cell than the free DOX.

Poly(ε-caprolactone) (PCL) Hollow Nanoparticles with Surface Sealability and On-Demand Pore Generability for Easy Loading and NIR Light-Triggered Release of Drug

A new system for the easy loading and NIR light-triggered release of drugs is introduced. It consists of poly(ε-caprolactone) (PCL) hollow nanoparticles with surface openings containing a biodegradable fatty acid with phase-change ability and a biocompatible photothermal agent. These openings, which can enhance the connectivity between the interior and the exterior, enable the easy loading of drug molecules into the interior voids, and their successive sealing ensures a stable encapsulation of the drug. Upon exposure to an external NIR light irradiation, the photothermal agent generates heat that raises the local temperature of the hollow particles above the melting point of the fatty acid, leading to the formation of nanopores on their shells, and consequently, the instant release of the encapsulated drug molecules through the pores. The synergistic activity of the hyperthermia effect from the photothermal agent and the NIR-triggered release of the drug molecules results in noticeable anticancer efficacy.

Evaluation of cytotoxic activity of docetaxel loaded gold nanoparticles for lung cancer drug delivery

The effective use of the gold nanoparticle (AuNPs) conjugated drugs for targeted drug delivery applications is one of the most promising research areas in the field of cancer. Herein, we aimed to establish a nano drug conjugated with docetaxel as a possible therapy option. Gold nanoparticles were synthesized by chemical reduction method. This is followed by the conjugation with an anticancer drug, docetaxel (Dtx) by a non-covalent method and folic acid (FA) was conjugated by a covalent method. The physicochemical characteristics of the synthesized AuNPs, Dtx and FA were studied by various analytical techniques such as UV-vis spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM) high-resolution transmission electron microscope (HR-TEM) and energy dispersive X-ray spectroscopy (EDS). The surface morphology and microstructure of the synthesized AuNPs and gold conjugates (AuNPs-Dtx-FA) were examined by FESEM and HR-TEM. The average size of the spherical shaped AuNPs was observed in the range of 5-18 nm. XPS and EDS spectra were examined the oxidation state and chemical composition of the synthesized nanoparticles. The cytotoxicity of the synthesized AuNPs nano-conjugates was evaluated by in-vitro studies against lung cancer cell line (H520). The chemical reduction method followed here in the development of AuNPs is a simple and one-step process, which exhibits the excellent binding specificity, biocompatibility and feasible for the large scale up process of the AuNPs.

Derivatization approaches and applications of pullulan

Pullulan (PUL), a linear exo-polysaccharide, is useful in industries as diverse as food, cosmetics and pharmaceuticals. PUL presents many favorable characteristics, such as renewable origin, biocompatibility, stability, hydrophilic nature, and availability of reactive sites for chemical modification. With an inherent affinity to asialoglycoprotein receptors, PUL can be used for targeted drug delivery to the liver. Besides, these primary properties have been combined with modern synthetic approaches for developing multifunctional biomaterials. This is evident from numerous studies on approaches, such as hydrophobic modification, cross-linking, grafting and transformation as a polyelectrolyte. In this review, we have discussed up-to-date advances on chemical modifications and emerging applications of PUL in targeted theranostics and tissue engineering. Besides, we offer an overview of its applications in food, cosmetics and environment remediation.

Preparation and biological evaluation of a novel pH-sensitive poly (β-malic acid) conjugate for antitumor drug delivery

Poly (β‑malic acid), referred to as PMLA, has been synthesized and introduced as a polymeric drug carrier due to its desirable biological properties. In the present study, a novel pH‑sensitive polymer‑drug conjugate based on PMLA, PMLA‑Hz‑doxorubicin (DOX), was prepared, and another conjugate, PMLA‑ami‑DOX, was synthesized as a comparison. The structures, conjugation efficiency, and drug release properties of the prodrugs were determined. The cytotoxicity and cell uptake were assessed using the HT1080 human fibrosarcoma cell line as an in vitro cell model. The release of DOX in the two conjugates were pH‑dependent in PBS buffer at a pH of 5.6, 6.0, 6.8 and 7.4. The quantity of drug released increased with the decrease in pH, and PMLA‑ami‑DOX released twice as much as PMLA‑Hz‑DOX (12 h). The cytotoxicity of PMLA‑Hz‑DOX at pH 7.4 was lower than that of free DOX and increased with the decrease in pH, indicating that the cytotoxicity of PMLA‑Hz‑DOX was pH‑sensitive. Flow cytometry and confocal experiments confirmed the efficiency of the PMLA‑Hz‑DOX conjugate. Therefore, bonding DOX to PMLA via an acid‑sensitive hydrazone bond may be used to reduce its toxic side effects on normal tissues while responding to tumor pH and releasing the drug.

Monolayer grafting of aminosilane on magnetic nanoparticles: An efficient approach for targeted drug delivery system

Magnetic nanoparticles (MNPs) with higher magnetization are highly desirable for targeted drug delivery (TDD) systems, as it helps accumulation of drug at the target site. However, functionalization of MNPs for drug binding reduces the magnetization which affects the efficacy of TDD. Herein we report direct functionalization of MNPs with (3-Aminopropyl)triethoxysilane (APTES) which preserves the magnetization. Grafting density estimated by TGA and BET analysis showed monolayer grafting of APTES on MNP surface. MNPs were comprehensively characterized by XRD, HR-TEM, SQUID-VSM and FTIR. Anti-cancerous drug telmisartan (TEL) was loaded on monolayer APTES grafted MNPs. In-vitro controlled drug release and cytotoxicity study on PC-3 human prostate cancer cell line of TEL conjugated MNPs are also discussed. This functionalization strategy can be extended to other biomedical applications where higher magnetization is desired.

Calcium carbonate end-capped, folate-mediated Fe3O4@mSiO2 core-shell nanocarriers as targeted controlled-release drug delivery system

Magnetic mesoporous silica nanospheres (MMSN) were prepared and the surface was modified with cancer cell-specific ligand folic acid. Calcium carbonate was then employed as acid-activated gatekeepers to cap the mesopores of the MMSN, namely, MMSN-FA-CaCO₃. The formation of the MMSN-FA-CaCO₃ was proved by several characterization techniques, viz. transmission electron microscopy, zeta potential measurement, Fourier transform infrared spectroscopy, BET surface area measurement, and UV-Vis spectroscopy. Daunomycin was successfully loaded in the MMSN-FA-CaCO₃ and the system exhibited sensitive pH stimuli-responsive release characteristics under blood or tumor microenvironment. Cellular uptake by folate receptor (FR)-overexpressing HeLa cells of the MMSN-FA-CaCO₃ was higher than that by non-folated-conjugated ones. Intracellular-uptake studies revealed preferential uptake of these nanoparticles into FR-positive [FR(+)] HeLa than FR-negative [FR(-)]A549 cell lines. DAPI stain experiment showed high apoptotic rate of MMSN-FA-DNM-CaCO₃ to HeLa cells. The present data suggest that the CaCO₃ coating and folic acid modification of MMSN are able to create a targeted, pH-sensitive template for drug delivery system with application in cancer therapy.

Overviews on the cellular uptake mechanism of polysaccharide colloidal nanoparticles

Nanoparticulate drug/gene carriers have gained much attention in the past decades because of their versatile and tunable properties. However, efficacy of the therapeutic agents can be further enhanced using naturally occurring materials-based nanoparticles. Polysaccharides are an emerging class of biopolymers; therefore, they are generally considered to be safe, non-toxic, biocompatible and biodegradable. Considering that the target of nanoparticle-based therapeutic strategies is localization of biomedical agents in subcellular compartments, a detailed understanding of the cellular mechanism involved in the uptake of polysaccharide-based nanoparticles is essential for safe and efficient therapeutic applications. Uptake of the nanoparticles by the cellular systems occurs with a process known as endocytosis and is influenced by the physicochemical characteristics of nanoparticles such as size, shape and surface chemistry as well as the employed experimental conditions. In this study, we highlight the main endocytosis mechanisms responsible for the cellular uptake of polysaccharide nanoparticles containing drug/gene.

In vitro antioxidant and antibacterial activity of sulfated polysaccharides isolated from Spatoglossum asperum

Fucoidan was extracted productively from Spatoglossum asperum and its antioxidant and antibacterial potential against Aeromonos hydrophila was investigated. The isolated fucoidan was characterized by HPLC, FTIR, 1H and 13C NMR spectrum. The isolated fucoidan contained 60.9% fucose, 21.35±0.81% sulfate and 4.2±0.56% protein, respectively. The in vitro antioxidant activity was evaluated by DPPH radical scavenging, reducing power and total antioxidant activities. The extracted fucoidan showed antioxidant properties in a dose-dependent manner. The antibacterial activity of isolated fucoidan was tested against A. hydrophila using agar bioassay, agar well diffusion and confocal assays. In this study, the minimum inhibitory concentration was obtained at 100μg/ml and the maximum zone of inhibition (33mm) was observed at 150μg/ml of fucoidan concentration in agar bioassay and agar well diffusion assay. The experimental results proved that the extracted fucoidan from S. asperum possesses admirable antioxidant and antibacterial properties.

A Functional Iron Oxide Nanoparticles Modified with PLA-PEG-DG as Tumor-Targeted MRI Contrast Agent

PURPOSE

Tumor targeting could greatly promote the performance of magnetic nanomaterials as MRI (Magnetic Resonance Imaging) agent for tumor diagnosis. Herein, we reported a novel magnetic nanoparticle modified with PLA (poly lactic acid)-PEG (polyethylene glycol)-DG (D-glucosamine) as Tumor-targeted MRI Contrast Agent.

METHODS

In this work, we took use of the D-glucose passive targeting on tumor cells, combining it on PLA-PEG through amide reaction, and then wrapped the PLA-PEG-DG up to the Fe₃O₄@OA NPs. The stability and anti phagocytosis of Fe₃O₄@OA@PLA-PEG-DG was tested in vitro; the MRI efficiency and toxicity was also detected in vivo.

RESULTS

These functional magnetic nanoparticles demonstrated good biocompatibility and stability both in vitro and in vivo. Cell experiments showed that Fe₃O₄@OA@PLA-PEG-DG nanoparticles exist good anti phagocytosis and high targetability. In vivo MRI images showed that the contrast effect of Fe₃O₄@OA@PLA-PEG-DG nanoparticles prevailed over the commercial non tumor-targeting magnetic nanomaterials MRI agent at a relatively low dose.

CONCLUSIONS

The DG can validly enhance the tumor-targetting effect of Fe₃O₄@OA@PLA-PEG nanoparticle. Maybe MRI agents with DG can hold promise as tumor-targetting development in the future.

A targeted drug delivery system based on folic acid-functionalized upconversion luminescent nanoparticles

In this paper, multifunctional upconversion luminescent NaYF₄:Yb,Er nanoparticles with excellent hollow mesoporous structure were first fabricated. The effects of various reaction conditions on the morphology and size of the as-prepared samples were investigated in detail and Ostwald ripening effect was adapted to explain the formation mechanism of the HMUCNPs. Then, folic acid, a well-known ligand for the selective targeting of drugs into tumor cells, was conjugated to the surface of the hollow mesoporous structured upconversion luminescent nanoparticles (HMUCNPs) via amide reaction for targeted delivery of anticancer drugs so as to enhance the therapeutic efficacy. The properties were extensively studied, which indicated the obtained samples showed a typical hollow mesoporous structure and excellent upconversion luminescence that were useful for cell imaging and drug delivery. Drug storage/release properties were demonstrated to be pH responsive, in which the drug release might be beneficial at the reduced pH in certain cancerous tissues for targeted release and controlled therapy at the pathological sites. Meanwhile, DOX-NaYF₄:Yb,Er-FA HMUCNPs exhibited greater cytotoxicity than free doxorubicin hydrochloride because folic acid-conjugated HMUCNPs can be specifically taken up by FR-positive KB cells via a receptor-mediated endocytosis. Therefore, the folic acid-functionalized nanoparticles combining upconversion luminescent property and hollow mesoporous structure have potential for simultaneous targeted anticancer drug delivery and cell imaging.

Ultrasound-guided intratumoral delivery of doxorubicin from in situ forming implants in a hepatocellular carcinoma model

BACKGROUND

Hepatocellular carcinomas are frequently nonresponsive to systemically delivered drugs. Local delivery provides an alternative to systemic administration, maximizing the dose delivered to the tumor, achieving sustained elevated concentrations of the drug, while minimizing systemic exposure.

RESULTS

Ultrasound-guided deposition of doxorubicin (Dox)-eluting in situ forming implants (ISFI) in an orthotopic tumor model significantly lowers systemic drug levels. As much as 60 µg Dox/g tumors were observed 21 days after ISFI injection. Tumors treated with Dox implants also showed a considerable reduction in progression at 21 days.

CONCLUSION

Dox-eluting ISFIs provide a promising platform for the treatment of hepatocellular carcinomas by which drug can be delivered directly into the lesion, bypassing distribution and elimination by the circulatory system.

Dual redox-triggered shell-sheddable micelles self-assembled from mPEGylated starch conjugates for rapid drug release

The new diselenide-linked mPEGylated starch amphiphilic micelles was developed, which could be disrupted in the presence of 0.1% (v/v) H₂O₂ or 1 mM GSH.

Polymer-Based Prodrugs: Improving Tumor Targeting and the Solubility of Small Molecule Drugs in Cancer Therapy

The majority of anticancer drugs have poor aqueous solubility, produce adverse effects in healthy tissue, and thus impose major limitations on both clinical efficacy and therapeutic safety of cancer chemotherapy. To help circumvent problems associated with solubility, most cancer drugs are now formulated with co-solubilizers. However, these agents often also introduce severe side effects, thereby restricting effective treatment and patient quality of life. A promising approach to addressing problems in anticancer drug solubility and selectivity is their conjugation with polymeric carriers to form polymer-based prodrugs. These polymer-based prodrugs are macromolecular carriers, designed to increase the aqueous solubility of antitumor drugs, can enhance bioavailability. Additionally, polymer-based prodrugs approach exploits unique features of tumor physiology to passively facilitate intratumoral accumulation, and so improve chemodrug pharmacokinetics and pharmacological properties. This review introduces basic concepts of polymer-based prodrugs, provides an overview of currently emerging synthetic, natural, and genetically engineered polymers that now deliver anticancer drugs in preclinical or clinical trials, and highlights their major anticipated applications in anticancer therapies.

Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs

In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.