Author: novelconjugates

Drug delivery platforms for neonatal brain injury

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Hypoxic-ischemic encephalopathy (HIE), initiated by the interruption of oxygenated blood supply to the brain, is a leading cause of death and lifelong disability in newborns. The pathogenesis of HIE involves a complex interplay of excitotoxicity, inflammation, and oxidative stress that results in acute to long term brain damage and functional impairments. Therapeutic hypothermia is the only approved treatment for HIE but has limited effectiveness for moderate to severe brain damage; thus, pharmacological intervention is explored as an adjunct therapy to hypothermia to further promote recovery. However, the limited bioavailability and the side-effects of systemic administration are factors that hinder the use of the candidate pharmacological agents. To overcome these barriers, therapeutic molecules may be packaged into nanoscale constructs to enable their delivery. Yet, the application of nanotechnology in infants is not well examined, and the neonatal brain presents unique challenges. Novel drug delivery platforms have the potential to magnify therapeutic effects in the damaged brain, mitigate side-effects associated with high systemic doses, and evade mechanisms that remove the drugs from circulation. Encouraging pre-clinical data demonstrates an attenuation of brain damage and increased structural and functional recovery. This review surveys the current progress in drug delivery for treating neonatal brain injury. (Journal of Controlled Release., Volume 330, 10 February 2021, Pages 765-787.)

Targeting the Brain Lesions Using Peptides: A Review Focused on the Possibility of Targeted Drug Delivery to Multiple Sclerosis Lesions

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As described by Jean Martin Charcot in 1868, multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease of the central nervous system (CNS) which leads to permanent disability in patients. Following CNS insults, astrocytes and microglial cells undergo changes, which lead to scar formation in the site of injury. Owning to the pathophysiology of MS lesions, changes in both cellular and extracellular matrix (ECM) components occur over the progression of disease. In spite of advances in therapeutic approaches, drug delivery to MS lesions appears of great interest with big challenges and limitations. Targeting with peptides is a novel promising approach in the field of drug delivery. Recently peptides have been used for active targeting of different pathological disorders in which specific peptides make targeted accumulation of cargos to enhance local drug concentration at the pathological area, lead to increased therapeutic efficacy and decreased side effects. However, specific approaches for targeting the lesion in MS are still lacking. In this review, we discuss the changes of the ECM components as well as the cellular characteristics of demyelinated lesions and emphasis on opportunities for peptide based targeted drug delivery to highlight the possibility of such approaches for neurodegenerative disease with specific focus on MS.

Lactoferrin coated or conjugated nanomaterials as an active targeting approach in nanomedicine

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A successful drug delivery to a specific site relies on two essential factors including; efficient entrapment of the drug within the carrier and successful delivery of drug- loaded nanocarrier to the target site without opsonisation or drug release in the circulation before reaching the organ of interest. Lactoferrin (LF) is a glycoprotein belonging to the transferrin (TF) family which can bind to TF receptors (TFRs) and LF membrane internalization receptors (LFRs) highly expressed on the cell surface of both highly proliferating cancer cells and blood brain barrier (BBB), which in turn can facilitate its accessibility to the cell nucleus. This merit could be exploited to develop actively targeted drug delivery systems that can easily cross the BBB or internalize into tumor cells. In this review, the most recent advances of utilizing LF as an active targeting ligand for different types of nanocarriers including: inorganic nanoparticles, dendrimers, synthetic biodegradable polymers, lipid nanocarriers, natural polymers, and nanoemulstions will be highlighted. Collectively, LF seems to be a promising targeting ligand in the field of nanomedicine. (International Journal of Biological Macromolecules., Volume 167, 15 January 2021, Pages 1527-1543.)

First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics

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A decline in energy is common in aging, and the restoration of mitochondrial bioenergetics may offer a common approach for the treatment of numerous age-associated diseases. Cardiolipin is a unique phospholipid that is exclusively expressed on the inner mitochondrial membrane where it plays an important structural role in cristae formation and the organization of the respiratory complexes into supercomplexes for optimal oxidative phosphorylation. The interaction between cardiolipin and cytochrome c determines whether cytochrome c acts as an electron carrier or peroxidase. Cardiolipin peroxidation and depletion have been reported in a variety of pathological conditions associated with energy deficiency, and cardiolipin has been identified as a target for drug development. This review focuses on the discovery and development of the first cardiolipin-protective compound as a therapeutic agent. SS-31 is a member of the Szeto-Schiller (SS) peptides known to selectively target the inner mitochondrial membrane. SS-31 binds selectively to cardiolipin via electrostatic and hydrophobic interactions. By interacting with cardiolipin, SS-31 prevents cardiolipin from converting cytochrome c into a peroxidase while protecting its electron carrying function. As a result, SS-31 protects the structure of mitochondrial cristae and promotes oxidative phosphorylation. SS-31 represents a new class of compounds that can recharge the cellular powerhouse and restore bioenergetics. Extensive animal studies have shown that targeting such a fundamental mechanism can benefit highly complex diseases that share a common pathogenesis of bioenergetics failure. This review summarizes the mechanisms of action and therapeutic potential of SS-31 and provides an update of its clinical development programme. (Br J Pharmacol. 2014 Apr;171(8):2029-50.)

Phthalocyanine–Peptide Conjugates: Receptor-Targeting Bifunctional Agents for Imaging and Photodynamic Therapy

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The synthesis of a series of new zinc phthalocyanine–peptide conjugates targeting the gastrin-releasing peptide (GRP) and integrin receptors is reported. Two alternative synthetic methods based on Sonogashira cross-coupling of an iodinated zinc phthalocyanine with acetylenic bombesin or arginine–glycine–aspartic acid (RGD) derivatives, either in solution or on solid phase, are presented. The water-soluble conjugates were screened for their photodynamic efficacy against several cancer cell lines expressing different levels of GRP and integrin receptors, and their intracellular localization was evaluated via confocal fluorescence microscopy. Variations in photocytotoxicity between the conjugates correlate to differences in hydrophobicity as well as receptor-mediated cell uptake. In the case of the phthalocyanine–bombesin conjugate, competition experiments confirm the involvement of the GRP receptor in both the phototherapeutic activity as well as intracellular localization. These findings warrant further in vivo studies to evaluate the potential of this conjugate as photosensitizer for photodynamic therapy (PDT) of cancers overexpressing the GRP receptor. (J. Med. Chem. 2013, 56, 4, 1520–1534.)

Synthesis and evaluation of novel dolastatin 10 derivatives for versatile conjugations

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Dolastatin 10 (1) is a highly potent cytotoxic microtubule inhibitor (cytotoxicity IC50 < 5.0 nM) and several of its analogs have recently been used as payloads in antibody drug conjugates. Herein, we describe the design and synthesis of a series of novel dolastatin 10 analogs useful as payloads for conjugated drugs. We explored analogs containing functional groups at the thiazole moiety at the C-terminal of dolastatin 10. The functional groups included amines, alcohols, and thiols, which are representative structures used in known conjugated drugs. These novel analogs showed excellent potency in a tumor cell proliferation assay, and thus this series of dolastatin 10 analogs is suitable as versatile payloads in conjugated drugs. Insights into the structure–activity relationships of the analogs are also discussed.(Bioorganic & Medicinal Chemistry. Volume 26, Issue 8, 1 May 2018, Pages 1643-1652.)

Potential protective effect of Trans-10-hydroxy-2-decenoic acid on the inflammation induced by Lipoteichoic acid

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Royal jelly (RJ) is known as a functional food for its diverse health-beneficial properties and complicated chemical compositions. Trans-10-hydroxy-2-decenoic acid (10-HDA) is the exclusive lipid component in RJ. In the present study, the in vitro anti-inflammatory effect of 10-HDA in LTA (Lipoteichoic acid from Staphylococcus aureus) induced RAW 264.7 macrophages are evaluated. The results showed that 10-HDA had potent, dose-dependent inhibitory effects on the release of major inflammatory mediators and NO. Several key inflammatory genes, including IL-1β, IL-6, MCP-1 and COX-2 have also been suppressed by 10-HDA. Furthermore, the effects of 10-HDA on LTA-induced pulmonary damage were also examined in mice. It was found that the administration of 10-HDA (100 mg/kg) can provide protective effects by attenuating lung histopathological changes and modulating the secretion of LTA-stimulated inflammatory cytokines in mice, such as IL-10, MCP-1 and TNF-α. Conclusively, the results reveal the potent anti-inflammatory properties of 10-HDA and provide biological information for the future application.(Journal of Functional Foods. Volume 45, June 2018, Pages 491-498.)

Properties of octenyl succinic anhydride (OSA) modified starches and their application in low fat mayonnaise

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Wheat starch (WS), corn starch (CS), waxy corn starch (WCS), potato starch (PS), sweet potato (SP), rice starch (RS) and kidney bean (KB) were modified using octenyl succinic anhydride (OSA) and evaluated for various properties. Degree of substitution (DS) showed significant increase with increase in amylose (AM) content. OSA modified starches showed higher paste viscosities compared to their native counterparts. OSA groups acted majorly on the surface and caused some superficial pores, but crystalline pattern was not significantly altered for all starches. OSA modified starches were used in preparing low fat mayonnaise by substituting 75% fat. OSA modified starches enhanced the emulsifying properties of mayonnaise. Mayonnaises prepared using OSA modified starches were evaluated for phase separation, brightness (L*), color index (dE), and rheological parameters (G′ and G″). Mayonnaises prepared using OSA modified starches showed higher G’ and exhibited gel like structure. Fat substituted (FS) mayonnaise was preferred over full fat (FF) mayonnaise by the consumers. No significant effect of fat substitution was observed on particle size and phase separation for all mayonnaise samples. (International Journal of Biological Macromolecules.,Volume 131, 15 June 2019, Pages 147-157.)