In-silico approach as a tool for selection of excipients for safer amphotericin B nanoformulations

Study on network cross-linked hydrogel with cationic Bletilla striata polysaccharide/carbopol as a drug delivery system

In this study, we developed a novel cationic Bletilla striata polysaccharide (CBSP)/Carbopol ETD 2020 (CP) composite hydrogel matrix (CBSP-CP) for local drug delivery of traditional Chinese medicine formulations and compounds. This approach addresses the shortcomings of the existing commercial gel matrices in delivering complex components. We used molecular dynamics simulations to confirm the feasibility of crosslinking and compounding the polymer components. The structure of the composite was characterized using various traditional methods, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The composite polyelectrolyte hydrogel prepared through electrostatic interactions between CBSP and CP exhibited favorable rheological properties, excellent ion resistance stability, and good skin adaptability. Furthermore, the safety of the gel matrix was validated using cytotoxicity and skin irritation tests. In summary, the CBSP-CP gel matrix not only enhanced ion resistance compared to current commercial gel matrices but also expanded its applicability for the local delivery of complex components, such as traditional Chinese medicine formulations and compounds.

Oral In-Situ Nanoplatform with Balanced Hydrophobic-Hydrophilic Property for Transport Across Gastrointestinal Mucosa

Transport of oral nanocarriers across the GI epithelium necessitates transport across hydrophilic mucus layer and the hydrophobic epithelium. Based on hydrophobic-hydrophilic balance, Curcumin-Lipomer (lipid-polymer hybrid nanoparticles) comprising hydrophobic stearic acid and hydrophilic Gantrez™ AN 119 (Gantrez) were developed, by a radical in-situ approach, to successfully traverse both barriers. A monophasic preconcentrate (Cur-Pre) comprising Cur (Curcumin), stearic acid, Gantrez and stabilizers, prepared by simple solution, was added to an aqueous phase to instantaneously generate Curcumin-Lipomer (Cur-Lipo) of nanosize and high entrapment efficiency (EE). Cur-Lipo size and EE was optimized by Box-Behnken Design. Cur-Lipomers of varying hydrophobic-hydrophilic property obtained by varying the stearic acid: Gantrez ratio exhibited size in the range 200-400 nm, EE > 95% and spherical morphology as seen in the TEM. A decrease in contact angle and in mucus interaction, evident with increase in Gantrez concentration, indicated an inverse corelation with hydrophilicity, while a linear corelation was observed for mucopenetration and hydrophilicity. Cur-SLN (solid lipid nanoparticles) which served as the hydrophobic reference revealed contact angle > 90°, maximum interaction with mucus and minimal mucopenetration. The ex-vivo permeation study through chicken ileum, revealed maximum permeation with Cur-Lipo1 and comparable and significantly lower permeation of Cur-Lipo1-D and Cur-SLN proposing the importance of balancing the hydrophobic-hydrophilic property of the nanoparticles. A 1.78-fold enhancement in flux of hydrophobic Cur-SLN, with no significant change in permeation of the hydrophilic Cur-Lipomers (p > 0.05) following stripping off the mucosal layer was observed. This reiterated the significance of hydrophobic-hydrophilic balance as a promising strategy to design nanoformulations with superior permeation across the GI barrier.

Polydispersity-mediated high efficacy of an in-situ aqueous nanosuspension of PPEF.3HCl in methicillin resistant Staphylococcus aureus sepsis model

Recently, World Health Organization declared antimicrobial resistance as the third greatest threat to human health. Absence of known cross-resistance, new class, new target, and a new mode of action are few major strategies being undertaken by researches to combat multidrug resistant pathogen. PPEF.3HCl, a bisbenzimidazole was developed as highly potent antibacterial agent against ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens, targeting topoisomerase IA. The present work encompasses a radical on-site generation of In-situ nanosuspension of PPEF.3HCl with enhanced efficacy against methicillin resistant S. aureus in septicemia model. We have generated instantaneously a PPEF.3HCl nanosuspension (IsPPEF.3HCl-NS) by mixing optimized monophasic PPEF.3HCl preconcentrate in propylene glycol into an aqueous medium comprising tween 80 as stabilizer. The IsPPEF.3HCl-NS showed precipitation efficiency of > 90 %, average particle size < 500 nm, retained upto 5 h, a negative zeta potential and bi/trimodal particle size distribution. Differential scanning calorimetry, X-ray diffraction confirmed partial amorphization and transmission electron microscopy revealed spherical particles. IsPPEF.3HCl-NS was non-hemolytic and exhibited good stability in serum. More significantly, it exhibited a ∼ 1.6-fold increase in macrophage uptake compared to free PPEF.3HCl in the RAW 264.7 macrophage cell line. Confocal microscopy revealed accumulation of IsPPEF.3HCl-NS within the lysosomal compartment and cell cytosol, proposing high efficacy. In terms of antimicrobial efficacy, IsPPEF.3HCl-NS outperforms free PPEF.3HCl against clinical methicillin sensitive and resistant S. aureus strains. In a pivotal experiment, IsPPEF.3HCl-NS exhibited over 83 % survival at 8 mg/kg.bw and an impressive reduction of ∼ 4-5 log-fold in bacterial load, primarily in the kidney, liver and spleen of septicemia mice. IsPPEF.3HCl-NS prepared by the In-situ approach, coupled with enhanced intramacrophage delivery and superior efficacy, positions IsPPEF.3HCl-NS as a pioneering and highly promising formulation in the battle against antimicrobial resistance.

Conjugates of amphotericin B to resolve challenges associated with its delivery

INTRODUCTION

Amphotericin B (AmB), a promising antifungal and antileishmanial drug, acts on the membrane of microorganisms. The clinical use of AmB is limited due to issues associated with its delivery including poor solubility and bioavailability, instability in acidic media, poor intestinal permeability, dose and aggregation state dependent toxicity, parenteral administration, and requirement of cold chain for transport and storage, etc.

AREAS COVERED

Scientists have formulated and explored various covalent conjugates of AmB to reduce its toxicity with increase in solubility, oral bioavailability, and payload or loading of AmB by using various polymers, lipids, carbon-based nanocarriers, metallic nanoparticles, and vesicular carriers, etc. In this article, we have reviewed various conjugates of AmB with polymers and nanomaterials explored for its delivery to give a deep insight regarding further exploration in future.

EXPERT OPINION

Covalent conjugates of AmB have been investigated by scientists, and preliminary in vitro and animal investigations have given successful results, which are required to be validated further with systematic investigation on safety and therapeutic efficacy in animals followed by clinical trials.

Interdisciplinary advances reshape the delivery tools for effective NASH treatment

BACKGROUND

Nonalcoholic steatohepatitis (NASH), a severe systemic and inflammatory subtype of nonalcoholic fatty liver disease, eventually develops into cirrhosis and hepatocellular carcinoma with few options for effective treatment. Currently potent small molecules identified in preclinical studies are confronted with adverse effects and long-term ineffectiveness in clinical trials. Nevertheless, highly specific delivery tools designed from interdisciplinary concepts may address the significant challenges by either effectively increasing the concentrations of drugs in target cell types, or selectively manipulating the gene expression in liver to resolve NASH.

SCOPE OF REVIEW

We focus on dissecting the detailed principles of the latest interdisciplinary advances and concepts that direct the design of future delivery tools to enhance the efficacy. Recent advances have indicated that cell and organelle-specific vehicles, non-coding RNA research (e.g. saRNA, hybrid miRNA) improve the specificity, while small extracellular vesicles and coacervates increase the cellular uptake of therapeutics. Moreover, strategies based on interdisciplinary advances drastically elevate drug loading capacity and delivery efficiency and ameliorate NASH and other liver diseases.

MAJOR CONCLUSIONS

The latest concepts and advances in chemistry, biochemistry and machine learning technology provide the framework and strategies for the design of more effective tools to treat NASH, other pivotal liver diseases and metabolic disorders.

Engineering Telodendrimer Nanocarriers for Monomeric Amphotericin B Delivery

Systemic fungal infections are an increasingly prevalent health problem. Amphotericin B (AmB), a hydrophobic polyene antibiotic, remains the drug of choice for life-threatening invasive fungal infections. However, it has dose-limiting side effects, including nephrotoxicity. The efficacy and toxicity of AmB are directly related to its aggregation state. Here, we report the preparation of a series of telodendrimer (TD) nanocarriers with the freely engineered core structures for AmB encapsulation to fine-tune AmB aggregation status. The reduced aggregation status correlates well with the optimized antifungal activity, attenuated hemolytic properties, and reduced cytotoxicity to mammalian cells. The optimized TD nanocarrier for monomeric AmB encapsulation significantly increases the therapeutic index, reduces the in vivo toxicity, and enhances antifungal effects in mouse models with Candida albicans infection in comparison to two common clinical formulations, i.e., Fungizone and AmBisome.

Cholesterol improves stability of amphotericin B nanoemulsion: promising use in the treatment of cutaneous leishmaniasis

Aim: Amphotericin B (AmB) is an antileishmanial drug with high toxicity; however, this drawback might overcome by decreasing the AmB self-aggregation state. This work aimed at evaluating the influence of cholesterol on the aggregation state of AmB loaded in a nanoemulsion (NE-AmB) for the treatment of cutaneous leishmaniasis. NE-AmB (1, 4 and 8 mg/kg/day) was administered intravenously to animals infected by Leishmania major every 2 days for a total of five injections. Results: Ultraviolet-visible spectroscopy and circular dichroism studies demonstrated that cholesterol reduced AmB aggregation state in NE. NE-AmB was stable after 180 days, and its hemolytic toxicity was lower than that observed for the conventional AmB. NE-AmB administered intravenously into animals infected by Leishmania major at 8 mg/kg was capable of stabilizing the lesion size and reducing the parasitic load. Conclusion: These findings support the NE potential as a stable nanocarrier for AmB in the treatment of cutaneous leishmaniasis.