Mucoadhesive chitosan-coated nanostructured lipid carriers for oral delivery of amphotericin B

Chitosan-coated nanoparticles in innovative cancer bio-medicine

In the recent decade, nanoparticles (NPs) have had enormous implications in cancer biomedicine, including research, diagnosis, and therapy. However, their broad application still faces obstacles due to some practical limitations and requires further development. Recently, there has been more interest in the coated class of nanoparticles to address those challenges. Chitosan-coated NPs are simple to produce, biodegradable, biocompatible, exhibit antibacterial activity, and have less cytotoxicity. This study provides an updated and comprehensive overview of the application of chitosan-coated NPs as a promising class of NPs in cancer biomedicine. Additionally, we discussed chitosan-coated lipid, metal, and polymer-based nanoparticles in biomedical applications. Furthermore, different coating methods and production/characterization procedures were reviewed. Moreover, the biological and physicochemical advantages of chitosan-coated NPs, including facilitated controlled release, greater physicochemical stability, improved cell/tissue interaction, and enhanced bioavailability of medications, were highlighted. Finally, the prospects of chitosan-coated NPs in cancer biomedicine were discussed.

Advances in nanotechnology for improving the targeted delivery and activity of amphotericin B (2011-2023): a systematic review

Amphotericin B (AmB) is a broad-spectrum therapeutic and effective drug, but it has serious side effects of toxicity and solubility. Therefore, reducing its toxicity should be considered in therapeutic applications. Nanotechnology has paved the way to improve drug delivery systems and reduce toxicity. The present study, for the first time, comprehensively reviews the studies from 2011 to 2023 on reducing the in vitro toxicity of AmB. The findings showed that loading AmB with micellar structures, nanostructured lipid carriers, liposomes, emulsions, poly lactide-co-glycolide acid, chitosan, dendrimers, and other polymeric nanoparticles increases the biocompatibility and efficacy of the drug and significantly reduces toxicity. In addition, modified carbon nanoparticles (including graphene, carbon nanotubes, and carbon dots) with positively charged amine groups, PEI, and other components showed favorable drug delivery properties. Uncoated and coated magnetic nanoparticles and silver NPs-AmB composites had less cytotoxicity and more antifungal activity than free AmB. Citrate-reduced GNPs and lipoic acid-functionalized GNPs were also effective nanocarriers to reduce AmB cytotoxicity and improve anti-leishmania efficacy. In addition, zinc oxide-NPs and PEGylated zinc oxide-NPs showed favorable antifungal activity and negligible toxicity. According to a review study, carbon-based nanoparticles, metal nanoparticles, and especially polymer nanoparticles caused some reduction in the toxicity and improved solubility of AmB in water. Overall, considering the discussed nanocarriers, further research on the application of nanotechnology as a cost-effective candidate to improve the efficiency and reduce the cytotoxicity of AmB is recommended.

A Window for Enhanced Oral Delivery of Therapeutics via Lipid Nanoparticles

Oral administration of dosage forms is convenient and beneficial in several respects. Lipid nanoparticulate dosage forms have emerged as a useful carrier system in deploying low solubility drugs systemically, particularly class II, III, and IV drugs of the Biopharmaceutics Classification System. Like other nanoparticulate delivery systems, their low size-to-volume ratio facilitates uptake by phagocytosis. Lipid nanoparticles also provide scope for high drug loading and extended-release capability, ensuring diminished systemic side effects and improved pharmacokinetics. However, rapid gastrointestinal (GI) clearance of particulate delivery systems impedes efficient uptake across the mucosa. Mucoadhesion of dosage forms to the GI mucosa results in longer transit times due to interactions between the former and mucus. Delayed transit times facilitate transfer of the dosage form across the mucosa. In this regard, a balance between mucoadhesion and mucopenetration guarantees optimal systemic transfer. Furthermore, the interplay between GI anatomy and physiology is key to ensuring efficient systemic uptake. This review captures salient anatomical and physiological features of the GI tract and how these can be exploited for maximal systemic delivery of lipid nanoparticles. Materials used to impart mucoadhesion and examples of successful mucoadhesive lipid nanoformulations are highlighted in this review.

Folic acid-chitosan functionalized polymeric nanocarriers to treat colon cancer

In the present study, polymeric nanoparticles loaded with IRI and quercetin, a p-gp inhibitor, were developed to target folate receptors expressed by colon cancer cells for oral targeted delivery. This work reports the development of PNPs with an entrapment efficiency of 41.26 ± 0.56 % for IRI and 55.83 ± 4.51 for QT. PNPs were further surface modified using chitosan-folic acid conjugates for better targetability to obtain folic acid-chitosan coated nanoparticles. DLS and FeSEM revealed particles in the nanometric size range with spherical morphology, while FTIR and DSC provided details on their structure and encapsulation. In vitro drug release studies confirmed a sustained release pattern of IRI and QT, while cell line studies confirmed the superiority of C-FA-PNPs when tested on Caco2 cells. Pharmacodynamic studies in colon cancer induced rats showed similar efficacy for PNPs and C-FA-PNPs. Further examination from a bio-distribution study in healthy rats, revealed the failure of C-FA-PNPs to deliver the drugs to the colon adequately, while the PNPs improved the available concentration of IRI at the colon by almost 1.8 folds when compared to the available marketed product. Hence, the developed PNP formulation sticks out as a plausible substitute for the intravenous dosage forms of IRI which have been conventionally prevailing.

Biomaterials with antifungal strategies to fight oral infections

Oral fungal infections pose a threat to human health and increase the economic burden of oral diseases by prolonging and complicating treatment. A cost-effective strategy is to try to prevent these infections from happening in the first place. With this purpose, biomaterials with antifungal properties are a crucial element to overcome fungal infections in the oral cavity. In this review, we go through different kinds of biomaterials and coatings that can be used to functionalize them. We also review their potential as a therapeutic approach in addition to prophylaxis, by going through traditional and alternative antifungal compounds, e.g., essential oils, that could be incorporated in them, to enhance their efficacy against fungal pathogens. We aim to highlight the potential of these technologies and propose questions that need to be addressed in prospective research. Finally, we intend to concatenate the key aspects and technologies on the use of biomaterials in oral health, to create an easy to find summary of the current state-of-the-art for researchers in the field.

Optimization of Chitosan-Decorated Solid Lipid Nanoparticles for Improved Flurbiprofen Transdermal Delivery

Transdermal delivery is a potential alternative route to oral administration for drugs associated with stomach discomfort, such as flurbiprofen, a widely nonsteroidal anti-inflammatory drug (NSAID). This study aimed to design solid lipid nanoparticle (SLN) transdermal formulations of flurbiprofen. Chitosan-coated SLNs were prepared by the solvent emulsification method, and their properties and permeation profiles across the excised rat skin were characterized. The particle size of uncoated SLNs was at 695 ± 4.65 nm, which increased to 714 ± 6.13, 847 ± 5.38, and 900 ± 8.65 nm upon coating with 0.05, 0.10, and 0.20% of chitosan, respectively. The drug association efficiency was improved when a higher concentration of chitosan was employed over SLN droplets that endowed a higher affinity of flurbiprofen with chitosan. The drug release was significantly retarded as compared to the uncoated entities and followed non-Fickian anomalous diffusion that was depicted by "n" values of >0.5 and <1. Also, the total permeation of chitosan-coated SLNs (F7-F9) was significantly higher than that of the noncoated formulation (F5). Overall, this study has successfully designed a suitable carrier system of chitosan-coated SLNs that provide insight into the current conventional therapeutic approaches and suggest new directions for the advancements in transdermal drug delivery systems for improved permeation of flurbiprofen.

Folic acid-Chitosan Coated Stylosin Nanostructured Lipid Carriers: Fabrication, In Vitro-In Vivo Assessment in Breast Malignant Cells

Synthesis of targeted nanostructure lipid carriers for stylosin (STY-CFN-NPs) delivery to MCF-7 cells. STY-CFN-NPs were formulated via the homogenization and ultra-sonication technique. After evaluating the amount of drug encapsulation and FA binding, the toxicity effect of the STY and STY-CFN-NPs on MCF-7 cells was measured by the MTT method. Cell cycle analysis, AO/PI staining and qPCR to assess the inducing of apoptosis as well as Tubo cancer cell inoculated mouse model for antitumor properties of STY-CFN-NPs were used. Significant increases in nanoparticle size and changes in zeta potential were observed after FA-CS coating on nanoparticles. Slow release of the STY within 144 h as well as the acceptable rate for STY encapsulation efficiency (92.4% and FA binding (52.5%) to the STY-CFN-NPs (PS: 66.26 ± 3.02 nm, ZP: 29.54 ± 1.01 mV and PDI: 0.32 ± 0.01) was reported. STY-CFN-NPs exhibited higher toxicity compared to STY suspension and treatment with STY-CFN-NPs was lead to increased apoptotic cells, stopped cells in the SubG1 phase, and also increased caspase and BAX expression and decreased BCL-2 and BCL-XL expression in in vitro and decreased the size of murine tumors (54.57% in 16 days) in in vivo. The results showed STY-CFN-NPs have good potential for breast cancer management.

Review of Novel Oral Amphotericin B Formulations for the Treatment of Parasitic Infections

Amphotericin B (AmpB) is a polyene macrolide antibiotic used in the treatment of blood-borne parasitic and fungal infections. However, its use, particularly in the developing world, has been limited by dose-dependent kidney toxicity, other systemic-related toxicity issues following injection, the inconvenience of parenteral administration, and accessibility. Oral formulation approaches have focused on the dual problem of solubility and permeability of AmpB, which is poorly water soluble, amphoteric and has extremely low oral bioavailability. Therefore, to enhance oral absorption, researchers have employed micellar formulations, polymeric nanoparticles, cochleates, pro-drugs, and self-emulsifying drug delivery systems (SEDDS). This paper will highlight current uses of AmpB against parasitic infections such as leishmaniasis, preclinical and clinical formulation strategies, applications in veterinary medicine and the importance of developing a cost-effective and safe oral AmpB formulation.

Mucus interaction to improve gastrointestinal retention and pharmacokinetics of orally administered nano-drug delivery systems

Oral delivery of therapeutics is the preferred route of administration due to ease of administration which is associated with greater patient medication adherence. One major barrier to oral delivery and intestinal absorption is rapid clearance of the drug and the drug delivery system from the gastrointestinal (GI) tract. To address this issue, researchers have investigated using GI mucus to help maximize the pharmacokinetics of the therapeutic; while mucus can act as a barrier to effective oral delivery, it can also be used as an anchoring mechanism to improve intestinal residence. Nano-drug delivery systems that use materials which can interact with the mucus layers in the GI tract can enable longer residence time, improving the efficacy of oral drug delivery. This review examines the properties and function of mucus in the GI tract, as well as diseases that alter mucus. Three broad classes of mucus-interacting systems are discussed: mucoadhesive, mucus-penetrating, and mucolytic drug delivery systems. For each class of system, the basis for mucus interaction is presented, and examples of materials that inform the development of these systems are discussed and reviewed. Finally, a list of FDA-approved mucoadhesive, mucus-penetrating, and mucolytic drug delivery systems is reviewed. In summary, this review highlights the progress made in developing mucus-interacting systems, both at a research-scale and commercial-scale level, and describes the theoretical basis for each type of system.

Chemical and physical approaches for improved biopharmaceutical activity of amphotericin B: Current and future prospective

Over the last 50 years, the number of patients with mycotic infections has been increasing gradually. Amphotericin-B is a gold standard drug used in serious systemic fungal infections. However, limited solubility and permeability are challenging issues associated with Amphotericin-B. Chemical modification is one of the ways to get its broader applicability along with improved physicochemical properties. The review article provides a comprehensive overview of the chemical modification approach for investigation of the mechanism of action, biological activity, bioavailability, toxicity of Amphotericin B. Further, several drug delivery approaches have also been utilized to provide better therapeutic outcomes. This gives an overview of chemical approaches for the exploration of various factors associated with Amphotericin B and information on its drug delivery approaches for improved biopharmaceutical outcomes.

Surface Modification of Lipid-Based Nanoparticles

There is a growing interest in the development of lipid-based nanocarriers for multiple purposes, including the recent increase of these nanocarriers as vaccine components during the COVID-19 pandemic. The number of studies that involve the surface modification of nanocarriers to improve their performance (increase the delivery of a therapeutic to its target site with less off-site accumulation) is enormous. The present review aims to provide an overview of various methods associated with lipid nanoparticle grafting, including techniques used to separate grafted nanoparticles from unbound ligands or to characterize grafted nanoparticles. We also provide a critical perspective on the usefulness and true impact of these modifications on overcoming different biological barriers, with our prediction on what to expect in the near future in this field.

Orally delivered solid lipid nanoparticles of irinotecan coupled with chitosan surface modification to treat colon cancer: Preparation, in-vitro and in-vivo evaluations

Irinotecan-loaded solid lipid nanoparticles (IRI-SLNs) was formulated and tested for its potential activity against colon cancer. IRI-SLNs were prepared by applying the principles of DoE. Nanoparticles were further surface modified using chitosan. Characterizations such as size, poly-dispersity, surface charge, morphology, entrapment, drug release pattern, cytotoxicity were conducted. In-vivo studies in male Wistar rats were carried to ascertain distribution pattern of SLNs and their acute toxicity on various vital organs. Lastly, stability of the SLNs were evaluated. Particles had a size, polydispersity and zeta potential of 430.77 ± 8.69 nm, 0.36 ± 0.02 and -40.06 ± 0.61 mV, respectively. Entrapment of IRI was 62.24 ± 2.90% in IRI-SLNs. Sustained drug release was achieved at a colonic pH and long-term stability of NPs was seen. Cytotoxicity assay results showed that SLNs exhibited toxicity on HCT-116 cells. Biodistribution studies confirmed higher concentration of drug in the colon after surface modification. An acute toxicity study conducted for 7 days showed no severe toxic effects on major organs. Thus, we picture that the developed SLNs may benefit in delivering IRI to the tumour cells, therefore decreasing the dose and dose-associated toxicities.

Ion exchange column technique as a novel method for evaluating the release of docetaxel from different lipid nanoparticles

Lipid nanoparticles with their unique characters showed many advantages as carriers for anticancer drugs. To compare between these nanoparticles as carriers for anticancer drugs, it was important to evaluate and characterize their drug retention and release properties. In this study, ion exchange column is used as a new evaluation technique. Solid lipid nanoparticles (SLN), nanostructured lipid carrier (NLC), and cubic nanoparticles were prepared using the homogenization technique. Characterization of these nanoparticles was carried out by measuring particle size, zeta potential, and entrapment efficiency. The ion exchange column was used to evaluate docetaxel release from the different nanoparticles as donors to acceptor liposomes that mimic the cell membranes. Both populations were mixed and at different time points, separated using the columns. The amounts of docetaxel in the eluted nanoparticles and retained liposomes were calculated. The particle size of all donors was in the nanometer range with almost neutral zeta potential. The particle size of the acceptor liposomes was 135 nm with a high negative zeta potential -55 mV. Ion exchange columns showed excellent retention of the negative acceptor liposomes while less than 1% of the different donors were retained on the columns. Cubic nanoparticles showed the highest entrapment efficiency (95%) and the slowest drug transfer in comparison with SLN and NLC. In conclusion, the ion exchange column technique can be applied successfully to evaluate the release of docetaxel from the different lipid nanoparticles to acceptor liposomes. Cubic nanoparticles showed advantageous docetaxel incorporation and transfer over SLN and NLC.

Improved Bioavailability of Poorly Soluble Drugs through Gastrointestinal Muco-Adhesion of Lipid Nanoparticles

Gastrointestinal absorption remains indispensable in the systemic delivery of most drugs, even though it presents several challenges that, paradoxically, may also provide opportunities that can be exploited to achieve maximal bioavailability. Drug delivery systems made from nanoparticle carriers and especially, lipid carriers, have the potential to traverse gastrointestinal barriers and deploy in the lymphatic pathway, which aptly, is free from first pass via the liver. Several poorly soluble drugs have presented improved systemic bioavailability when couriered in lipid nanoparticle carriers. In this review, we propose an additional frontier to enhancing the bioavailability of poorly soluble drugs when encapsulated in lipid nano-carriers by imparting muco-adhesion to the particles through application of appropriate polymeric coating to the lipid carrier. The combined effect of gastrointestinal muco-adhesion followed by lymphatic absorption is a promising approach to improving systemic bioavailability of poorly soluble drugs following oral administration. Evidence to the potential of this approach is backed-up by recent studies within the review.

Lipopolysaccharide Nanosystems for the Enhancement of Oral Bioavailability

Nanosystems that incorporate both polymers and lipids have garnered attention as emerging nanotechnology approach for oral drug delivery. These hybrid systems leverage on the combined properties of polymeric and lipid-based nanocarriers while eliminating their inherent limitations. In view of the safety-related benefits of naturally occurring polymers, we have focused on systems incorporating polysaccharides and derivatives into the hybrid structure. The aim of this review is to evaluate existing biopolymers with specific focus on lipopolysaccharide hybrid systems and their advancement toward enhancing oral drug delivery. Furthermore, we shall identify future research areas that require further exploration toward achieving an optimized hybrid system for easy translation into clinical use. In this review, we have appraised formulations that combined polysaccharides/derivatives with lipids in a single nanocarrier system. These formulations were grouped into lipid-core-polysaccharide-shell systems, polysaccharide-core-lipid-shell systems, self-emulsifying lipopolysaccharide hybrid systems, and hybrid lipopolysaccharide matrix systems. In these systems, we highlighted how the polysaccharide phase enhances the oral absorption of encapsulated bioactives with regard to their function and mechanism. The various lipopolysaccharide designs presented in this review demonstrated significant improvement in pharmacokinetics of bioactives. A multitude of studies found lipopolysaccharide hybrid systems as nascent nanoplatforms for the oral delivery of challenging bioactives due to features that favor gastrointestinal absorption and bioavailability improvement. With future research already geared toward product optimization and scaling up processes, as well as detailed pharmacological and toxicology pre-clinical testing, these versatile systems will have remarkable impact in clinical application.

Oral delivery of solid lipid nanoparticles: underlining the physicochemical characteristics and physiological condition affecting the lipolysis rate

INTRODUCTION

Lipid-based nano-drug delivery systems (LBNDDSs) have gained widespread attention in oral drug delivery due to their tunable and versatile properties such as biocompatibility and biodegradability, which makes them promising delivery systems for a variety of therapeutics. Currently, different types of LBNDDSs including liposomes, micelles, nanoemulsions, and solid lipid nanoparticles (SLNs) are developed for drug delivery applications. SLNs can be used as a controlled drug delivery system for oral delivery applications. However, its lipidic context makes that susceptible to lipolysis. The lipolysis rate of SLNs is affected by many factors that raise many questions for developing a more efficient delivery system.

AREAS COVERED

In the present work, we highlighted different factors affecting the digestion rate/level of SLNs in the gastrointestinal tract. This paper can be most useful for those researchers who are keen to develop a properly controlled drug delivery system based on SLNs for oral delivery applications.

EXPERT OPINION

SLNs can be used as a controlled drug delivery system for oral delivery applications. However, its lipidic context makes that susceptible to lipolysis. The lipolysis rate of SLNs is affected by many factors that raise many questions for developing a more efficient delivery system.

Cubosomal lipid nanoassemblies with pH-sensitive shells created by biopolymer complexes: A synchrotron SAXS study

We report a strategy for sustainable development of pH-responsive cubic liquid crystalline nanoparticles (cubosomes), in which the structure-defining lyotropic nonlamellar lipid and the eventually encapsulated guest molecules can be protected by pH-sensitive polyelectrolyte shells with mucoadhesive properties. Bulk non-lamellar phases as well as pH-responsive polyelectrolyte-modified nanocarriers were formed by spontaneous assembly of the nonlamellar lipid monoolein and two biopolymers tailored in nanocomplexes with pH-dependent net charge. The mesophase particles involved positively charged N-arginine-modified chitosan (CHarg) and negatively charged alginate (ALG) chains assembled at different biopolymer concentrations and charge ratios into a series of pH-responsive complexes. The roles of Pluronic F127 as a dispersing agent and a stabilizer of the nanoscale dispersions were examined. Synchrotron small-angle X-ray scattering (SAXS) investigations were performed at several N-arginine-modified chitosan/alginate ratios (CHarg/ALG with 10, 15 and 20 wt% ALG relative to CHarg) and varying pH values mimicking the pH conditions of the gastrointestinal route. The structural parameters characterizing the inner cubic liquid crystalline organizations of the nanocarriers were determined as well as the particle sizes and stability on storage. The surface charge variations, influencing the measured zeta-potentials, evidenced the inclusion of the CHarg/ALG biopolymer complexes into the lipid nanoassemblies. The polyelectrolyte shells rendered the hybrid cubosome nanocarriers pH-sensitive and influenced the swelling of their lipid-phase core as revealed by the acquired SAXS patterns. The pH-responsiveness and the mucoadhesive features of the cubosomal lipid/polyelectrolyte nanocomplexes may be of interest for in vivo drug delivery applications.

Assessment of Exenatide loaded Biotinylated Trimethylated Chitosan/HP-55 Nanoparticles

BACKGROUND

Exenatide (EXE) is an anti-hyperglycemic agent approved for treating type 2 diabetes by the Food and Drug Administration (FDA). However, twice-daily injection of exenatide inconveniences most patients.

OBJECTIVE

In this study, biotinylated trimethylated chitosan (Bio-TMC) based nanoparticles were proposed to promote oral absorption of exenatide. Realizing the oral administration of exenatide is very important to alleviate patient suffering and improve patient compliance.

METHODS

Bio-TMC was synthesized, and the chemical structure was characterized by Fourier transform infrared (FT-IR) spectroscopy and 1H NMR spectroscopy. Nanoparticles were prepared through polyelectrolyte interaction in the presence of sodium tripolyphosphate (TPP) and Hydroxypropyl methylcellulose phthalate (HP-55). The formulations were physically and chemically characterized. In vitro release was investigated in different pH media. In vivo antidiabetic activities of biotin modified and non-biotin modified chitosan were evaluated in db/db mice.

RESULTS

EXE-loaded Bio-TMC/HP-55 nanoparticles were spherical in shape with a mean diameter of 156.2 nm and zeta potential of +11.3 mV. The drug loading efficiency and loading contents were 52.38% and 2.08%, respectively. In vitro release revealed that EXE-loaded Bio-TMC/HP-55 nanoparticles were released faster in pH 1.2 than pH 6.8 (63.71% vs. 50.12%), indicating that nanoparticles had enteric characteristics. Antidiabetic activity study revealed that after oral administration to diabetic mice, the relative pharmacological bioavailability (FPharm%) of the biotin modified nanoparticles was found to be 1.27-fold higher compared with the unmodified ones and the hypoglycemic effect was also better.

CONCLUSION

Bio-TMC/HP-55 nanoparticles are feasible as oral drug carriers of exenatide and have the potential to be extended to other drugs that are not readily oral, such as monoclonal antibodies, vaccines, genes, etc., thus, this would be beneficial for pharmaceutical industries. Further research will focus on the biodistribution of Bio-TMC/HP-55 nanoparticles after oral administration.

Subcutaneously Injectable Hyaluronic Acid Hydrogel for Sustained Release of Donepezil with Reduced Initial Burst Release: Effect of Hybridization of Microstructured Lipid Carriers and Albumin

The daily oral administration of acetylcholinesterase (AChE) inhibitors for Alzheimer’s disease features low patient compliance and can lead to low efficacy or high toxicity owing to irregular intake. Herein, we developed a subcutaneously injectable hyaluronic acid hydrogel (MLC/HSA hydrogel) hybridized with microstructured lipid carriers (MLCs) and human serum albumin (HSA) for the sustained release of donepezil (DNP) with reduced initial burst release. The lipid carrier was designed to have a microsized mean diameter (32.6 ± 12.8 µm) to be well-localized in the hydrogel. The hybridization of MLCs and HSA enhanced the structural integrity of the HA hydrogel, as demonstrated by the measurements of storage modulus (G′), loss modulus (G″), and viscosity. In the pharmacokinetic study, subcutaneous administration of MLC/HSA hydrogel in rats prolonged the release of DNP for up to seven days and reduced the initial plasma concentration, where the C_max value was 0.3-fold lower than that of the control hydrogel without a significant change in the AUC_last value. Histological analyses of the hydrogels supported their biocompatibility for subcutaneous injection. These results suggest that a new hybrid MLC/HSA hydrogel could be promising as a subcutaneously injectable controlled drug delivery system for the treatment of Alzheimer’s disease.

Highly thermally conductive and eco-friendly OH-h-BN/chitosan nanocomposites by constructing a honeycomb thermal network

More than 110,000,000 tons of mismanaged plastics were to be produced in 2020. Polymers are favored in the preparation of thermally conductive materials due to their excellent comprehensive properties. However, most polymers fabricated for thermally conductive materials are difficult to degrade in the natural environment. To alleviate the increasingly severe environmental problems, we reported a novel eco-friendly material with high thermal conductivity, which was composited of chitosan microspheres (CSM) and hydroxyl-functionalized hexagonal boron nitride (OH-h-BN) nanoplatelets. Utilizing their significant difference in scales, the OH-h-BN nanoplatelets were arranged between each CSM. Their overall structure was similar to the honeycomb: CSM were honeycomb cores, and OH-h-BN nanoplatelets were honeycomb network. The routine-structure OH-h-BN/CS nanocomposites were only 0.94 ± 0.02 W·m^-1·K^-1 at 50 wt% in thermal conductivity. However, the OH-h-BN/CSM nanocomposites with honeycomb structure can reach 5.66 ± 0.32 W·m^-1·K^-1 in the same loading, for enhancement of 502% and 1914% than OH-h-BN/CS nanocomposites and pure CS, respectively.

Nanotechnology approaches for delivery and targeting of Amphotericin B in fungal and parasitic diseases

Amphotericin B (AMB), with widespread antifungal and anti-parasitic activities and low cross-resistance with other drugs, has long been identified as a potent antimicrobial drug. However, its clinical toxicities, especially nephrotoxicity, have limited its use in clinical practice. Lately, nano-based systems have been the subject of serious research and becoming an effective strategy to improve toxicity and antimicrobial potency. Commercial AMB lipid formulations have been developed in order to improve the therapeutic index and nephrotoxicity, while limited use is mainly due to their high cost. The review aimed to highlight the updated information on nanotechnology-based approaches to the development of AMB delivery and targeting systems for treatment of fungal diseases and leishmaniasis, regarding therapeutic challenges and achievements of various delivery systems.

Diagnostic and therapeutic management of Cryptococcosis in a kitten with practical considerations to veterinary pediatric therapeutic approach

A 3-months-old male domestic kitten was referred for repeated seizures. Analysis revealed Cryptococcus neoformans. Levetiracetam and fluconazole were administered without significant clinical improvements and without negativization. Hypothesizing resistance, therapy was switched to amphotericin B. Seizure disappeared. Haematological controls highlighted transitory increasing of CK, BUN, ALP and cholesterol. PCR repeated two weeks after the treatment was negative for Cryptococcus neoformans. Nowadays the cat is 5 years old, and no seizures occurred since the age of 5 months.

Chitosan Coated Luteolin Nanostructured Lipid Carriers: Optimization, In Vitro-Ex Vivo Assessments and Cytotoxicity Study in Breast Cancer Cells

In the present study, luteolin (LTN)-encapsulated chitosan (CS) coated nanostructured lipid carriers (NLCs) were formulated using the melt emulsification ultrasonication technique. NLCs were optimized by using the 33-QbD approach for improved in vitro efficacy against breast cancer cell lines. The optimized LTN-CS-NLCs were successfully characterized by different in vitro and ex vivo experiments as well as evaluated for cytotoxicity in MDA-MB-231 and MCF-7 cell lines. The prepared LTN-CS-NLCs showed particle size (PS), polydispersity index (PDI), and entrapment efficiency (%EE) in the range between 101.25 nm and 158.04 nm, 0.11 and 0.20, and 65.55% and 95.37%, respectively. Coating of NLCs with CS significantly increased the particle size, encapsulation efficiency, and zeta potential changes positively. Moreover, slow-release rate of LTN was achieved during 24 h of study for LTN-CS-NLCs. In addition, optimized LTN-CS-NLCs showed significantly higher mucoadhesion, gastrointestinal stability, and intestinal permeation compared to non-coated LTN-NLCs and LTN suspension. Furthermore, LTN-CS-NLCs showed statistically enhanced antioxidant potential as well as dose and time-dependent cytotoxicity against MDA-MB-231 and MCF-7 cells compared to uncoated LTN-NLCs and pure LTN. On the basis of the above findings, it may be stated that chitosan-coated LTN-NLCs represents a great potential for breast cancer management.

Chitosan based-nanoparticles and nanocapsules: Overview, physicochemical features, applications of a nanofibrous scaffold, and bioprinting

Recent advancements in the synthesis, properties, and applications of chitosan as the second after cellulose available biopolymer in nature were discussed in this review. A general overview of processing and production procedures from A to Z was highlighted. Chitosan exists in three polymorphic forms which differ in degree of crystallinity (α, β, and γ). Thus, the degree of deacetylation, crystallinity, surface area, and molecular mass significantly affect most applications. Otherwise, the synthesis of chitosan nanofibers is suffering from many drawbacks that were recently treated by co-electrospun with other polymers such as polyvinyl alcohol (PVA), polyethylene oxide (PEO), and polycaprolactone (PCL). Ultimately, this review focuses on the area of new trend utilization of chitosan nanoparticles as nanospheres and nanocapsules, in cartilage and bone regenerative medicine. Owing to its biocompatibility, bioavailability, biodegradability, and costless synthesis, chitosan is a promising biopolymeric structure for water remediation, drug delivery, antimicrobials, and tissue engineering.

Enhanced Pharmacokinetic Activity of Zotepine via Nanostructured Lipid Carrier System in Wistar Rats for Oral Application

BACKGROUND

Zotepine (ZT) is a substituted dibenzothiepine tricyclic molecule and second generation antipsychotic drug. It is available as the parenteral and oral solid dosage form, but, orally administered ZT has a poor oral bioavailability (10%) that might be due to either poor water solubility, high lipophilicity (Log P 4) and also first-pass hepatic metabolism.

OBJECTIVE

The oral bioavailability of ZT was improved by loading into a nanostructured lipid carriers (NLCs) system.

METHODS

Hot homogenization with probe sonication method was used for the preparation of ZT-NLCs formulations and characterized for an optimal system based on physicochemical characteristics and in vitro release. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) studies were used to confirm the crystalline nature and shape of the optimized ZT-NLC formulation. The physical stability of the optimized ZT-NLC formulation was evaluated at the refrigerator and room temperature over two months. Furthermore, in vivo pharmacokinetic (PK) studies of optimized ZT-NLC and ZT coarse suspension (ZT-CS) as control formulation, were conducted in male Wistar rats.

RESULTS

The optimized formulation of ZT-NLC showed Z-avg, PDI, ZP of 145.8 ± 2.5 nm, 0.18 ± 0.05, -31.6 ± 1.8 mV, respectively. In vitro release studies indicated the sustained release of ZT. DSC and XRD studies revealed the conversion of ZT into an amorphous form. SEM studies showed the spherical shape of the ZT-NLC formulation. PK studies showed 1.8-folds improvement (p<0.05) in oral bioavailability when compared with ZTCS formulation.

CONCLUSION

Overall, the results established that NLCs could be used as a new alternative delivery vehicle for the oral delivery of ZT.

Development of an Oral Amphotericin B Formulation as an Alternative Approach to Parenteral Amphotericin B Administration in the Treatment of Blood-Borne Fungal Infections

In the Fall of 1999, we presented at medical "Grand Rounds" to a number of Infectious Diseases physicians at Vancouver General Hospital about the co-administration of several antifungal compounds in the treatment of blood-borne fungal infections to patients who were immunocompromised (i.e. cancer patients, patients waiting organ transplantation, HIV/AIDs patients, etc.). During the presentation, a physician from the back of the room called out "can you develop an oral formulation of amphotericin B which could be effective and not have the side-effects associated with the parenteral formulations of the drug". The physician stated that an oral formulation would be a big step forward, improving patient compliance, helping in pre-treatment without admitting patients to the hospital prior to organ transplantation and it would be cost-effective. Initially, I responded to the physician, that it would not be possible to develop an oral amphotericin B formulation that could be absorbed from the gastrointestinal (GI) tract in a high enough concentration to be effective in treating blood-borne fungal infections and yet remains non-toxic due to the physical chemical properties of the drug. However, as I travelled back to my lab from the meeting, it struck me that our understanding of how lipids had been processed and orally absorbed from the GI had advanced to the point the maybe incorporating amphotericin B into such lipids might work. Within several years, our laboratory was able to develop a novel oral amphotericin B formulation that was indeed effective in treating systemic fungal infections without the side-effects associated with the drug in a variety of fungal animal models.

Assessing the Safety, Tolerability, Pharmacokinetics, and Biodistribution of Novel Oral Formulations of Amphotericin B following Single- and Multiple-Dose Administration to Beagle Dogs

The purpose of this study was to assess the safety, tolerability, pharmacokinetics (PK), and biodistribution of novel oral amphotericin B (AmpB) formulations following single- and multiple-oral-dose administration to healthy beagle dogs. The liquid formulation of AmpB was administered to three male dogs, and the capsule formulations of AmpB were administered to each of two groups of six male dogs. Blood was collected for pharmacokinetic evaluation on days 1, 2, and 3 (up to 72 h postdosing). Dogs receiving the capsule formulations further received a single oral dose of 100 mg once daily for three more days, and on the 4th day, blood samples were taken at 24 h postdosing and the dogs were humanely sacrificed with the removal of organs, from which tissue samples were taken for analysis of the AmpB content. Multiple-dose studies were completed for 7 or 14 days with daily doses of up to 1,000 mg/day with the capsule formulations. All oral formulations of AmpB following both single- and multiple-dose administration were well tolerated in the dogs, and there were no relevant adverse signs observed, such as changes in hematologic, coagulation, or biochemistry parameters; loss of weight; changes in food or water intake; or signs of gastrointestinal distress. The oral absorption of AmpB from the liquid formulation and the capsule formulations were similar, with no significant differences. The tissue distributions of AmpB were similar following repeated doses of the two capsule formulations to dogs. Following 14 days of treatment with the iCo-010 liquid formulation and the iCo-019 and iCo-022 capsule formulations, the range of values of the maximum observed plasma concentration (C _max) was 53.2 to 62.3, 24.9 to 66.4, and 36.7 to 85.2 ng/ml, respectively; the range of values of the time to C _max was 4 to 12, 4 to 24, and 2 to 24 h, respectively; and the range of values of the area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration was 2,635 to 3,071, 1,053 to 2,517, and 1,443 to 3,713 ng · h/ml, respectively. We have developed a safe novel oral AmpB formulation suitable for future efficacy studies.

Safety, Tolerability, and Pharmacokinetics of a Novel Oral Amphotericin B Formulation (iCo-019) following Single-Dose Administration to Healthy Human Subjects: an Alternative Approach to Parenteral Amphotericin B Administration

This study evaluated the safety, tolerability, and pharmacokinetics of a novel oral amphotericin B (AmB) formulation (iCo-019) following single doses to healthy humans. The data from this study suggest that iCo-019 has a long circulation time and systemic exposure without the associated gastrointestinal, liver, and kidney toxicity associated with AmB. This novel oral AmB formulation can serve as a new treatment strategy to overcome the limitations of the use of parenterally administered AmB products.

Copolymeric Micelles Overcome the Oral Delivery Challenges of Amphotericin B

Classified as a Biopharmaceutical Classification System (BCS) class IV drug, amphotericin B (AmB) has low aqueous solubility and low permeability leading to low oral bioavailability. To improve these limitations, this study investigated the potential of AmB-loaded polymeric micelles (AmB-PM) to increase intestinal absorption. AmB-PM were prepared with polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol copolymer (Soluplus^®) as a polymeric carrier and used a modified solvent diffusion and microfluidics (NanoAssemblr^®) method. AmB-PM have a mean particle size of ~80 nm and are mono-disperse with a polydispersity index <0.2. The entrapment efficiency of AmB was up to 95% and achieved with a high drug loading up to ~20% (w/w) with a total amount of incorporated drug of 1.08 ± 0.01 mg/mL. Importantly, compared to free drug, AmB-PM protected AmB from degradation in an acidic (simulated gastric) environment. Viability studies in Caco-2 cells confirmed the safety/low toxicity of AmB-PM. In vitro cellular absorption studies confirmed that AmB-PM increased AmB uptake in Caco-2 cells 6-fold more than free AmB (i.e., 25% compared with 4% within 30 min). Furthermore, the permeability of AmB across Caco-2 monolayers was significantly faster (2-fold) and more pronounced for AmB-PM in comparison to free drug (3.5-fold increase). Thus, the developed AmB-PM show promise as a novel oral delivery system for AmB and justifies further investigation.

Amphotericin B loaded ethyl cellulose nanoparticles with magnified oral bioavailability for safe and effective treatment of fungal infection

Amphotericin B is a gold standard drug used in various fungal and parasitic infection treatment. Most of the marketed formulations are administered intravenously, but show dose-dependent adverse effects i.e., nephrotoxicity and hemolysis. Oral route eliminates the toxic concern but exhibits poor bioavailability. Therefore, ethylcellulose nanoparticles (EC-NPs) have been used for magnified oral delivery of AmB, where EC provides gastrointestinal stability. These nanoparticles were synthesized by high-pressure emulsification solvent evaporation (HPESE) method and evaluated for in vitro and in vivo studies. This method yields small, monodisperse AmB-EC-NPs along with smooth surface morphology and improved encapsulation efficiency. The developed formulation showed a sustained release pattern following Higuchi diffusion kinetics along with gastric and storage stability. Aggregation study revealed that AmB was present in its monomeric form inside the biocompatible EC matrix. The antifungal result demonstrated that the MIC of AmB-EC-NPs was reduced ∼1/3rd than AmB and Fungizone® at 24 h whereas it was observed ∼1/8th at 48 h. in vivo pharmacokinetic analysis demonstrated 1.3-fold higher AUC than Fungizone® even at a 4.5-time lesser dose via the oral route and a ∼15-fold rise in the bioavailability in contrast to the native AmB. The hemolytic study revealed that the developed formulation exhibited 8-fold lesser hemolysis than Fungizone®. Furthermore, the biosafety profile of AmB-EC-NPs was ensured by the significantly lesser level of blood urea nitrogen and plasma creatinine along with the normal pattern of renal tubules in comparison to AmB and Fungizone®. In conclusion, the results stipulated that the AmB-EC-NPs could be effective, viable and a better alternative to currently existing iv formulations, for magnified oral delivery of AmB in the treatment of fungal infection without associated adverse effects.

Chitosan coated nanostructured lipid carriers for enhanced in vivo efficacy of albendazole against Trichinella spiralis

The study investigated chitosan coated nanostructured lipid carriers (NLCs) for oral delivery of albendazole in treatment of trichinellosis. NLCs comprised precirol and oleic acid with Tween and Span 80. Dicetylphosphate was used as charging agent to allow chitosan coating. Trichinella spiralis infected mice were used and albendazole suspension, coated or uncoated NLCs were orally administered at different stages of infection. NLCs were spherical with size of 188 and 200 nm for coated and uncoated NLC, respectively. Treatment during intestinal phase reduced worm count with NLCs showing better rank. This was reflected further by reduced larvae count and improved histopathological features. Starting treatment in the migrating phase reduced larval count by 62.9, 99.6 and 89.5 % after administration of suspension, coated and uncoated NLCs, respectively. The same rank was recorded for the encysted phase. NLCs enhanced the efficacy of albendazole against Trichinella spiralis compared with suspension with chitosan coated NLCs being superior.

Lipid Systems for the Delivery of Amphotericin B in Antifungal Therapy

Amphotericin B (AmB), a broad-spectrum polyene antibiotic in the clinic for more than fifty years, remains the gold standard in the treatment of life-threatening invasive fungal infections and visceral leishmaniasis. Due to its poor water solubility and membrane permeability, AmB is conventionally formulated with deoxycholate as a micellar suspension for intravenous administration, but severe infusion-related side effects and nephrotoxicity hamper its therapeutic potential. Lipid-based formulations, such as liposomal AmB, have been developed which significantly reduce the toxic side effects of the drug. However, their high cost and the need for parenteral administration limit their widespread use. Therefore, delivery systems that can retain or even enhance antimicrobial efficacy while simultaneously reducing AmB adverse events are an active area of research. Among those, lipid systems have been extensively investigated due to the high affinity of AmB for binding lipids. The development of a safe and cost-effective oral formulation able to improve drug accessibility would be a major breakthrough, and several lipid systems for the oral delivery of AmB are currently under development. This review summarizes recent advances in lipid-based systems for targeted delivery of AmB focusing on non-parenteral nanoparticulate formulations mainly investigated over the last five years and highlighting those that are currently in clinical trials.

Antifungal and Mucoadhesive Properties of an Orally Administered Chitosan-Coated Amphotericin B Nanostructured Lipid Carrier (NLC)

Surface-modified nanostructured lipid carriers (NLC) represent a promising mode of drug delivery used to enhance retention of drugs at absorption site. Formulated chitosan-coated amphotericin-B-loaded NLC (ChiAmp NLC) had a size of 394.4 ± 6.4 nm, encapsulation and loading efficiencies of 86.0 ± 3% and 11.0 ± 0.1% respectively. Amphotericin-B release from NLCs was biphasic with no changes in physical properties upon exposure to simulated gastrointestinal conditions. Antifungal properties of Amphotericin-B and ChiAmpB NLC were comparable but ChiAmpB NLC was twice less toxic to red blood cells and ten times safer on HT-29 cell lines. In vitro mucoadhesion data were observed ex vivo, where ChiAmpB NLC resulted in higher retention within the small intestine compared to the uncoated formulation. The data strongly offers the possibility of orally administering a non-toxic, yet effective Amphotericin-B nanoformulation for the treatment of systemic fungal infections.

The Development of Oral Amphotericin B to Treat Systemic Fungal and Parasitic Infections: Has the Myth Been Finally Realized?

Parenteral amphotericin B has been considered as first-line therapy in the treatment of systemic fungal and parasitic infections, however its use has been associated with a number of limitations including affordability, accessibility, and an array of systemic toxicities. Until very recently, it has been very challenging to develop a bioavailable formulation of amphotericin B due to its physical chemical properties, limited water and lipid solubility, and poor absorption. This perspective reviews several novel oral Amphotericin B formulations under development that are attempting to overcome these limitations.

Therapy of Non-Dermatophytic Mycoses in Animals

This review focuses on aspects of antimycotic therapy specific to veterinary medicine. In the first part, drug availability, limited mostly by economic consideration but also by clinical applicability and specific adverse effects, is described for polyenes, 5 fluorocytosine, azoles, echinocandins and terbinafine. In the second part, current knowledge and experience in the treatment of selected fungal infections are overviewed. These mycoses include disseminated mold infections in small animals (dogs and cats) and avian species, upper respiratory tract infections of small animals (sino-nasal and sino-orbital aspergillosis) and horses (guttural pouch mycosis), eumycetoma, infections caused by dimorphic fungi, (blastomycosis, histoplasmosis, coccidioidomycosis, paracoccidioidomycosis and sporothrichosis) and by yeasts and yeast-like microorganism (Cryptococcus spp. and Malassezia pachydermatis).