Synthesis and characterization of a non-cytotoxic and biocompatible acrylamide grafted pullulan – Application in pH responsive controlled drug delivery

Construction of intelligent drug delivery system based on polysaccharide-derived polymer micelles: A review

Micelles are nanostructures developed via the spontaneous assembly of amphiphilic polymers in aqueous systems, which possess the advantages of high drug stability or active-ingredient solubilization, targeted transport, controlled release, high bioactivity, and stability. Polysaccharides have excellent water solubility, biocompatibility, and degradability, and can be modified to achieve a hydrophobic core to encapsulate hydrophobic drugs, improve drug biocompatibility, and achieve regulated delivery of the loaded drug. Micelles drug delivery systems based on polysaccharides and their derivatives show great potential in the biomedical field. This review discusses the principles of self-assembly of amphiphilic polymers and the formation of micelles; the preparation of amphiphilic polysaccharides is described in detail, and an overview of common polysaccharides and their modifications is provided. We focus on the review of strategies for encapsulating drugs in polysaccharide-derived polymer micelles (PDPMs) and building intelligent drug delivery systems. This review provides new research directions that will help promote future research and development of PDPMs in the field of drug carriers.

Pullulan in pharmaceutical and cosmeceutical formulations: A review

Pullulan, an α-glucan polysaccharide, is colorless, odorless, non-toxic, non-carcinogenic, highly biocompatible, edible and biodegradable in nature. The long chains of glucopyranose rings in pullulan structure are linked together by α-(1 → 4) and α-(1 → 6) glycosidic linkages. The occurrence of both glycosidic linkages in the pullulan structure contributes to its distinctive properties. The unique structure of pullulan makes it a potent candidate for both pharmaceutical and cosmeceutical applications. In pharmaceuticals, it can be used as a drug carrier and in various dosage formulations. It has been widely used in drug targeting, implants, ocular dosage forms, topical formulations, oral dosage forms, and oral liquid formulations, etc. Pullulan can be used as a potential carrier of active ingredients and their site-specific delivery to skin layers for cosmeceutical applications. It has been extensively used in cosmeceutical formulations like creams, shampoo, lotions, sunscreen, facial packs, etc. The current review highlights applications of pullulan in pharmaceutical and cosmeceutical applications.

Fabricating gum polysaccharides based nano-composites for drug delivery uses via sustainable green approach

Recent advancements in development of natural polymer nono-composites led to exploration of potential of gum acacia (GA) and tragacanth gum (TG) for design of silver nanoparticles (AgNPs) impregnated grafted copolymers via green approach for use in drug delivery (DD). The formation of copolymers was confirmed by UV-Vis spectroscopy, TEM, SEM, AFM, XPS, XRD, FTIR,TGA and DSC. UV-Vis spectra indicated the formation of AgNPs using GA as reducing agent. TEM, SEM, XPS and XRD revealed impregnation of AgNPs inside the copolymeric network hydrogels. TGA inferred thermal stability of polymer enhanced by grafting and incorporation of AgNPs. The non-Fickian diffusion of antibiotic drug meropenem was revealed from drug encapsulated GA-TG-(AgNPs)-cl-poly(AAm) network which were also pH responsive and release profile was fitted in Korsmeyer-Peppas kinetic model. Sustained release was due to polymer-drug interaction. The polymer-blood interaction demonstrated biocompatible characteristics of polymer. Mucoadhesive property exhibited by copolymers because of supra-molecular interactions. Antimicrobial characteristics were shown by copolymers against bacteria S. flexneri, P. auroginosa, and B. cereus.

Fabrication and characterization of octenyl succinic anhydride modified pullulan micelles for encapsulating curcumin

BACKGROUND

Curcumin has become increasingly popular in functional foods and beverages field as a result of its high biological activity. Nevertheless, the application of curcumin is usually limited by its poor water solubility, low absorption, rapid metabolism and instability. Accordingly, the development of an appropriate wall material is crucial for its effective use. In the present study, curcumin-octenyl succinic anhydride modified pullulan (Cur-OSAP) micelles were successfully prepared by an anti-solvent co-precipitation method.

RESULTS

Octenyl succinic anhydride modified pullulan (OSAP) micelles exhibited the highest encapsulation efficiency (57.31%) and loading capacity (5.73%) of curcumin when the mass ratio of OSAP to curcumin was 10:1 and the degree of substitution of OSAP was 0.0469, at which point Cur-OSAP micelles formed via hydrogen binding and hydrophobic interactions, as confirmed by Fourier transform infrared and fluorescence techniques. The transmission electron microscopy results showed that the Cur-OSAP micelles were roughly spherical in shape with diameters in the approximate range 30-60 nm.

CONCLUSION

The encapsulation of OSAP greatly improved photostability and sustained release properties of curcumin in Cur-OSAP micelles. These findings suggest that OSAP can be used as a carrier to encapsulate and protect hydrophobic food ingredients. © 2021 Society of Chemical Industry.

Hypoxia-responsive pullulan-based nanoparticles as erlotinib carriers

A hypoxia-responsive pullulan-based co-polymer was developed to assess its efficacy to deliver erlotinib (ERL) to the cervical cancer cells. Upon exposure to hypoxic condition, the synthesized and structurally characterized co-polymer i.e. succinyl pullulan-g-6-(2-nitroimidazole) hexylamine (Pull-SA-HA-NI) exhibited a hypochromic shift in the UV spectra and alteration in its self-assembled structures as compared to the control co-polymer, succinyl pullulan-g-hexylamine (Pull-SA-HA). Its corresponding ERL-loaded nanoparticles (NPs) displayed an attenuated crystallinity of pure ERL with excellent drug-trapping capacity (DEE, 94.23 ± 1.36%) and acceptable zeta potential (+39.21 ± 1.09 mV) and diameter (84.10 ± 2.10 nm) values. These also evidenced a faster drug release profile under hypoxic condition relative to the normoxic condition. The cellular internalization of the NPs was mediated through the energy-dependent endocytic process, which could utilize its multiple pathways (i.e., macropinocytosis, clathrin- and caveolae-mediated endocytosis). The ERL-loaded NPs suppressed HeLa cell proliferation and induced apoptosis more efficiently than the pristine drug.

Etherified pullulan-polyethylenimine based nanoscaffolds improved chemosensitivity of erlotinib on hypoxic cancer cells

The current research endeavor aimed to accomplish hypoxia-responsive polyethyleneimine-conjugated carboxymethyl pullulan-based co-polymer (CMP-HA-NI-PEI-NBA) bearing nitroaromatic subunits to efficiently deliver erlotinib (ERL) to reverse its hypoxia-induced resistance in cancer cells. As compared to a control co-polymer (CMP-HA-MI-PEI-BA) devoid of hypoxia-sensitive moieties, this scaffold demonstrated a hypochromic shift in the UV spectra and rapid dismantling of its self-assembled architecture upon exposure to simulated hypoxic condition. The hypoxia-responsive co-polymer encapsulated ERL with desirable loading capacity (DEE, 63.05 ± 2.59%), causing attenuated drug crystallinity. The drug release rate of the scaffold under reducing condition was faster relative to that of non-reducing environment. Their cellular uptake occurred through an energy-dependent endocytic process, which could exploit its caveolae/lipid raft-mediated internalization pathway. The ERL-loaded scaffolds more efficiently induced apoptosis and suppressed the proliferation of drug-resistant hypoxic HeLa cells than the pristine ERL. Hence, this study presented a promising drug delivery nanoplatform to overcome hypoxia-evoked ERL resistance.

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.

Synthesis and quantitative analyses of acrylamide-grafted poly(lactide-co-glycidyl methacrylate) amphiphilic copolymers for environmental and biomedical applications

Bio-degradable/bio-compatible poly(lactide-co-glycidyl methacrylate), P(LA-co-GMA), a copolymer has been synthesized. The material contains curable CC groups, which enable its self-curing and grafting reactions with other vinyl monomers. The copolymer was grafted with a pH-responsive polyacrylamide (PAAm), by UV-assisted reactions using acrylamide (AAm) and N,N'-methylene bisacrylamide monomers, and various photoinitiator systems. The original copolymer and its partially-cured counterpart were employed in the grafting reaction. Chemical structures and properties of the resulting materials were characterized. Standard quantitative analysis techniques for measurement of the grafted AAm content and the degree of CC conversion have been developed by ¹H NMR and FTIR spectroscopy. FTIR offers more advantages, in terms of non-destructive analysis, ease of operation, and lower cost of analysis. The results show that the grafted products from pre-cured P(LA-co-GMA) copolymers contain higher grafted AAm contents than their uncured counterparts. The highest grafted AAm content was obtained by using benzophenone (BP) as an initiator, while camphorquinone (CQ) led to the lowest content. In contrast, the degree of CC conversion of the copolymer from the two initiator systems shows a reverse trend. These amphiphilic and pH-responsive grafted copolymers with tunable AAm contents have a high potential for use in various applications, especially in biomedical and environmental fields.