Lipid-polymer hybrid nanoparticles: Development & statistical optimization of norfloxacin for topical drug delivery system

Considerations and Caveats in Combating ESKAPE Pathogens against Nosocomial Infections

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are among the most common opportunistic pathogens in nosocomial infections. ESKAPE pathogens distinguish themselves from normal ones by developing a high level of antibiotic resistance that involves multiple mechanisms. Contemporary therapeutic strategies which are potential options in combating ESKAPE bacteria need further investigation. Herein, a broad overview of the antimicrobial research on ESKAPE pathogens over the past five years is provided with prospective clinical applications.

Therapeutic lipid-coated hybrid nanoparticles against bacterial infections

One of the most important health concerns in society is the development of pathogen-causing nosocomial infections. Since the first discovery of antibiotics, bacterial infections have been highly treatable. However, with evolution and the nondiscretionary usage of antibiotics, pathogens have also found new ways to survive the onslaught of antibiotics by surviving intracellularly or through the formation of obstinate biofilms, and through these, the outcomes of regular antibiotic treatments may now be unsatisfactory. Lipid-coated hybrid nanoparticles (LCHNPs) are the next-generation core–shell structured nanodelivery system, where an inorganic or organic core, loaded with antimicrobials, is enveloped by lipid layers. This core–shell structure, with multifarious decorations, not only improves the loading capabilities of therapeutics but also has the potential to improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections. Although there has been significant interest in the development of LCHNPs, they have yet to be widely exploited for bacterial infections. In this review, we will provide an overview on the latest development of LCHNPs and the various approaches in synthesizing this nano-delivery system. In addition, a discussion on future perspectives of LCHNPs, in combination with other novel anti-bacterial technologies, will be provided towards the end of this review.

Lipid-coated hybrid nanoparticles are next-generation core–shell structured nanodelivery systems, which improve the loading capabilities of therapeutics and can improve therapeutic delivery, especially for targeting biofilm-based and intracellular bacterial infections.

Bioinspired Polymeric-based Core-shell Smart Nano-systems

Smart nanosystems (SNs) have the potential to revolutionize drug delivery. Conventional drug delivery systems have poor drug-loading, early burst release, limited therapeutic effects, etc. Thus, to overcome these problems, researchers have taken advantage of the host-guest interactions as bioinspired nanosystems which can deliver nanocarriers more efficiently with the maximum drug loading capacity and improved therapeutic efficacy as well as bioavailability. SNs employ nanomaterials to form cage molecules by entrapping new nanocarriers called smart nanosystems in their cargo and design. The activities of SNs are based on responsive materials that interact with the stimuli either by changing their properties or conformational structures. The aptitude of living systems to respond to stimuli and process information has encouraged researchers to build up integrated nanosystems exhibiting similar function and therapeutic response. Various smart materials, including polymers, have been exhaustively employed in fabricating different stimuli-responsive nanosystems which can deliver bioactive molecules to a specific site for a certain period with minimal side effects. SNs have been widely explored to deliver diverse kinds of therapeutic agents ranging from bioactive compounds, genes, and biopharmaceuticals like proteins and peptides, to diagnostic imaging agents for biomedical applications. Nanotechnology-based different nanosystems are promising for health care issues. The advancement of SNs with physical science and engineering technology in synthesizing nanostructures and their physicochemical characterization should be exploited in medicine and healthcare for reducing mortality rate, morbidity, disease prevalence and general societal burden.

Assessment of the hepatoprotective effect of developed lipid-polymer hybrid nanoparticles (LPHNPs) encapsulating naturally extracted β-Sitosterol against CCl4 induced hepatotoxicity in rats

The hepatoprotective effect of β-Sitosterol (BSS), a natural phytosterol, after being formulated into a suitable pharmaceutical drug delivery system has not been widely explored. BSS was isolated from Centaurea pumilio L., identified and formulated as lipid-polymer hybrid nanoparticles (LPHNPs) using the poly(D,L-lactide-co-glycolide) polymer and DSPE-PEG-2000 lipid in different ratios. The selected formulation, prepared with a lipid: polymer: drug ratio of 2:2:2, had an entrapment efficiency (EE%) of 94.42 ± 3.8, particle size of 181.5 ± 11.3 nm, poly dispersity index (PDI) of 0.223 ± 0.06, zeta potential of −37.34 ± 3.21 and the highest drug release after 24 h. The hepatoprotective effect of the formulation at two different doses against CCl₄ induced hepatotoxicity was evaluated in rats. The results showed that the BSS-LPHNPs (400 mg/kg) have the ability to restore the liver enzymes (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)), liver lipid peroxidation markers (malondialdehyde (MDA) and catalase (CAT)), total bilirubin and albumin to their normal levels without inhibitory effect on the CYP2E1 activity. Also, the formulation could maintain the normal histological structure of liver tissue and decrease the cleaved caspase-3 expression. LPHNPs formulation encapsulating natural BSS is a promising hepatoprotective drug delivery system.

Meglumine-based supra-amphiphile self-assembled in water as a skin drug delivery system: Influence of unfrozen bound water in the system bioadhesiveness

Hexagonal liquid crystals and supramolecular polymers from meglumine-based supra-amphiphiles were developed as drug delivery systems to be applied on the skin. The influence of fatty acid unsaturation on the structure and mechanical properties was evaluated. Moreover, we have investigated the system biocompatibility and how the type of water could influence its bioadhesive properties. Meglumine-oleic acid (MEG-OA) was arranged as hexagonal liquid crystals at 30-70 wt% water content, probably due to its curvature and increased water solubility. Meglumine-stearic acid (MEG-SA) at 10-80 wt% water content self-assembled as a lamellar polymeric network, which can be explained by the low mobility of MEG-SA in water due to hydrophobic interactions between fatty acid chains and H-bonds between meglumine and water molecules. Both systems have shown suitable mechanical parameters and biocompatibility, making them potential candidates to encapsulate therapeutic molecules for skin delivery. Moreover, a strong positive correlation between the amount of unfrozen bound water in meglumine-based systems and the bioadhesion properties was observed. This work shows that a better understanding of the physicochemical properties of a drug delivery system is extremely important for the correlation with the desired biological response and, thus, improve the product performance for biomedical applications.

Improved oral delivery of tilianin through lipid-polymer hybrid nanoparticles to enhance bioavailability

Tilianin (TIL) may prevent and treat myocardial ischemia reperfusion injuries. However, its oral administration is hampered by its low bioavailability. The present study aimed to formulate lipid-polymer hybrid nanoparticles (LPHNs) as carriers for the sustained release and oral bioavailability enhancement of TIL in vitro and in vivo. A nanodrug delivery system of TIL-loaded LPHNs (TIL-LPHNs) was constructed. TIL-LPHNs were prepared via a self-assembly method, and their particle size, polymer dispersity index (PDI), zeta potential, encapsulation efficiency (EE) and morphology were investigated. In addition, pharmacokinetic studies were performed in vivo. The TIL-LPHN formulation produced a spherical, homogeneous, smooth surface and multi-lamellar structured nanoparticles. The particle size and distribution profile of TIL-LPHNs had a mean particle diameter of 54.6 ± 5.3 nm and PDI of 0.112 ± 0.017. The zeta potential was -33.4 ± 4.7 mV. The EE of TIL-LPHNs was 86.6 ± 3.6%, which was determined with the dialysis method. The TIL-LPHNs significantly enhanced the oral bioavailability of TIL with a 3.7-fold increase in the area under the concentration-time curve in comparison with the TIL solution. These findings support the potential use of LPHNs in improving the stability and bioavailability of TIL via oral administration.

Synthesis and Design of Norfloxacin drug delivery system based on PLA/TiO2 nanocomposites: Antibacterial and antitumor activities

Biodegradable, biocompatible and non-toxic polymer-based nanoparticles are the novel nanotherapeutic tool which is used for adsorption and encapsulation drugs. Extended release formulation of Norfloxacin antibiotic, chemotherapeutic agent model, drug in the form of encapsulated and loaded poly (lactic acid) nanocomposites-based Titanium dioxide (PLA/TiO₂) was developed. Nanocomposites were prepared using different contents (1, 3, 5 wt %) and morphologies of TiO₂ (spheres (S), rods (R). The dispersion of TiO₂ was aided by ultrasonic technique followed by solution casting method. The morphology, particle size, crystallite size and composition of the nanocomposites were examined by SEM, TEM, XRD and FTIR. The crystallinity and thermal behavior of the nanocomposites were characterized by DSC and TGA. NOR was loaded onto TiO₂ nanospheres (NOR@TiO₂ (S)) and the optimum conditions for loading was investigated. Pseudo-second order model was the more adequate to represent the kinetic data. The equilibrium data followed Freundlich adsorption isotherm and the adsorption process was exothermic. NOR@TiO₂ (S) was encapsulated into PLA and in vitro release behavior of drug was compared with NOR adsorbed into PLA (NOR@PLA) and nanocomposites (NOR@PLA/TiO₂) using different pH (6.7, 7.4) media. To study the mechanism of NOR release, first order, Higuchi, Hixon Crowell and Korsmeyer-Peppas models were applied on the experimental results. The cytotoxicity of the loaded nanocomposites using MTT assay was studied against HepG 2, MCF-7, HCT 116, PC-3, Hela, WI-38 and WISH cells. The encapsulated (NOR@ 5S/En PLA) showed the highest cytotoxic efficacy with moderate effect on normal cells. Moreover, the nanocomposites have great potential against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella and Klebsiella pneumonia. NOR@ PLA/TiO₂ nanocomposites showed better antibacterial efficacy than NOR encapsulated nanocomposites. The nanocomposites could be effective vehicles for the sustained delivery of toxic anticancer drug.

PEGylated Lipova E120 liposomes loaded with celecoxib: in-vitro characterization and enhanced in-vivo anti-inflammatory effects in rat models

The goal of the current investigation was to prepare PEGylated Lipova E120 liposomes loaded with celecoxib for the effective treatment of rheumatoid arthritis (RA). PEGylated liposomes were prepared and were characterized using techniques such as particle size distribution, polydispersity index (PDI), zeta potential, encapsulation efficiency and in-vitro release, in-vivo and stability studies. The morphological study was characterized by scanning electron microscopy and transmission electron microscopy. To determine the interaction between drug and polymer Fourier transform infrared, Raman, thermogravimetric analysis and differential scanning calorimetry studies were performed. Results show that formulation F6 was optimized with a particle size of 92.12 +/- 1.7 nm, a PDI of 0.278 +/- 0.22, a zeta potential of - 40.8 +/- 1.7 mV with a maximum encapsulation of 96.6 +/- 0.05% of drug in the PEGylated liposomes. The optimized formulation shows a maximum release of drug i.e. 94.45 +/- 1.13% in 72 h. Tail immersion assay shows that the optimized formulation F6 significantly increases the reaction time and carrageenan-induced assay shows that the optimized formulation inhibits the increase in paw edema thus providing a pain relief treatment in RA. These results suggest that the PEGylated liposomes provide a sustained release of celecoxib and helps in effective treatment of RA.

Phospholipid-polymer hybrid nanoparticle-mediated transfollicular delivery of quercetin: prospective implement for the treatment of androgenic alopecia

Objectives: The aim of the study was to deliver effective doses of quercetin (Que) to the lower region of hair follicles (HFs) using the transfollicular route through dipalmotylphosphatidylcholine (DPPC)-reinforced poly lactide-co- glycolide nanoparticles (DPPC-PLGA hybrid NPs) for the treatment of alopecia. Method: PLGA and DPPC-PLGA hybrid NPs were prepared by double-emulsification solvent evaporation method. NPs were characterized for size, shape, zeta potential entrapment and drug release. Drug-polymer interactions were determined by infrared spectroscopy (Fourier transform infrared spectroscopy, FTIR) and differential scanning calorimetry (DSC). Follicular uptake of fluorescent marker tagged NPs was assessed on isolated rat skin by fluorescent microscopy. Potential of hybrid NPs to induce hair regrowth was tested on testosterone-induced alopecia in rat models by visual inspection, hair follicular density measurement (no./mm), and histological skin tissue section studies. Key findings: Hybrid NPs had mean vesicles size 339 ± 1.6, zeta potential -32.6 ± 0.51, and entrapment efficiency 78 ± 5.5. Cumulative drug release after 12 h was found to be 47.27 ± 0.79%. FTIR and DSC confirmed that drug was independently dispersed in the amorphous form in the polymer. Data from fluorescence microscopy suggested that NPs were actively taken up by HFs. In-vivo studies on alopecia-induced rat models showed that hybrid NPs improved hair regrowth potential of Que and accumulation of NPs at HFs end region inhibit HFs cells apoptosis. Conclusion: This study concludes that phospholipid-polymer hybrid NPs could be the promising transfollicular delivery system for Que in the treatment of androgenic alopecia management.

PEG-PLGA- hybrid nanoparticles loaded with etoricoxib - phospholipid complex for effective treatment of inflammation in rat model

The aim of the present study was to increase the bioavailability of the etoricoxib by making PEG-PLGA-Hybrid nanoparticles using emulsion solvent evaporation method. Then the prepared nanoparticles were further characterised using TEM, particle size, PDI, zeta potential, encapsulation efficiency and drug release study. Lipid (Phospholipon 90-G) and drug thermal behaviour were studied using DSC, TGA. The results of optimised formulation of Particle size, PDI and zeta potential was found 216.6 ± 4.0 nm, 0.24 ± 0.19 and +36.3 ± 1.9 mV. Encapsulation efficiency was found in the range of 77.15% w/v to 93.88% w/v. In-vivo study shows that the optimised formulation at a particular dose decreases the swelling index and number of writhes. Stability study indicated that the nanoparticles can be stored at a temperature of 4 ± 2 °C/60 ± 5% RH in well-closed container, away from heat and damp places. The prepared formulation has significantly increased the bioavailability of etoricoxib via oral administration.

Self-Assembled Benznidazole-Loaded Cationic Nanoparticles Containing Cholesterol/Sialic Acid: Physicochemical Properties, In Vitro Drug Release and In Vitro Anticancer Efficacy

Cationic polymeric nanoparticles (NPs) have the ability to overcome biological membranes, leading to improved efficacy of anticancer drugs. The modulation of the particle-cell interaction is desired to control this effect and avoid toxicity to normal cells. In this study, we explored the surface functionalization of cationic polymethylmethacrylate (PMMA) NPs with two natural compounds, sialic acid (SA) and cholesterol (Chol). The performance of benznidazole (BNZ) was assessed in vitro in the normal renal cell line (HEK-293) and three human cancer cell lines, as follows: human colorectal cancer (HT-29), human cervical carcinoma (HeLa), and human hepatocyte carcinoma (HepG2). The structural properties and feasibility of NPs were evaluated and the changes induced by SA and Chol were determined by using multiple analytical approaches. Small (<200 nm) spherical NPs, with a narrow size distribution and high drug-loading efficiency were prepared by using a simple and reproducible emulsification solvent evaporation method. The drug interactions in the different self-assembled NPs were assessed by using Fourier transform-infrared spectroscopy. All formulations exhibited a slow drug-release profile and physical stability for more than 6 weeks. Both SA and Chol changed the kinetic properties of NPs and the anticancer efficacy. The feasibility and potential of SA/Chol-functionalized NPs has been demonstrated in vitro in the HEK-293, HepG2, HeLa, and HT-29 cell lines as a promising system for the delivery of BNZ.

pH-sensitive doxorubicin-loaded polymeric nanocomplex based on β-cyclodextrin for liver cancer-targeted therapy

BACKGROUND

Doxorubicin (DOX) is one of the most effective treatments for hepatocellular carcinoma (HCC), but is restricted by its poor pharmacokinetics. Herein, we exploited efficient targeted drug delivery systems and they have been found to be a worthy strategy for liver cancer therapy.

MATERIALS AND METHODS

We investigated polymeric nanoparticles which were synthesized based on host-guest interaction between β-cyclodextrin and benzimidazole. The properties of nanoparticles with regard to size/shape, encapsulation efficiency, and drug release were investigated using conventional experiments. Cell proliferation assay in vitro, cell uptake assay, and cell apoptosis analysis were used to investigate cytotoxicity, uptake, and mechanism of targeted supramolecular prodrug complexes (TSPCs)-based self-assemblies and supramolecular prodrug complexes (SPCs)-based self-assemblies.

RESULTS

The pH-sensitive lactobionic acid (LA)-modified pH-sensitive self-assemblies were synthesized successfully. The results of in vitro released assay showed that the accelerated released of DOX from TSPCs-based self-assemblies with the decrease of pH value. When TSPCs-based self-assemblies were taken up by HepG2 cells, they demonstrated a faster release rate under acidic conditions and proved to have higher cytotoxicity than in the presence of LA. A mechanistic study revealed that TSPCs-based self-assemblies inhibited liver cell proliferation by inducing cell apoptosis.

CONCLUSION

The pH-sensitive nanocomplex, as liver-targeted nanoparticles, facilitated the efficacy of DOX in HepG2 cells, offering an appealing strategy for the treatment of HCC.

Bispecific antibodies (anti-mPEG/anti-HER2) for active tumor targeting of docetaxel (DTX)-loaded mPEGylated nanocarriers to enhance the chemotherapeutic efficacy of HER2-overexpressing tumors

Anti-mPEG/anti-human epidermal growth factor receptor 2 (HER2) bispecific antibodies (BsAbs) non-covalently bound to a docetaxel (DTX)-loaded mPEGylated lecithin-stabilized micellar drug delivery system (LsbMDDs) were endowed with active targetability to improve the chemotherapeutic efficacy of DTX. DTX-loaded mPEGylated LsbMDDs formulations were prepared using lecithin/DSPE-PEG(2K or 5K) nanosuspensions to hydrate the thin film, and then they were subjected to ultrasonication. Two BsAbs (anti-mPEG/anti-DNS or anti-HER2) were simply mixed with the LsbMDDs to form BsAbs-LsbMDDs formulations, respectively, referred as the DNS-LsbMDDs and HER2-LsbMDDs. Results demonstrated that the physical characteristics of the BsAbs-LsbMDDs were similar to those of the plain LsbMDDs but more slowly released DTX than that from the LsbMDDs. Results also showed that the HER2-LsbMDDs suppressed the growth of HER2-expressing MCF-7/HER2 tumors, increasing the amount taken up via an endocytosis pathway leading to high drug accumulation and longer retention in the tumor. In conclusion, the BsAbs-LsbMDDs preserved the physical properties of the LsbMDDs and actively targeted tumors with a drug cargo to enhance drug accumulation in tumors leading to greater antitumor activity against antigen-positive tumors.

Strategies to prevent the occurrence of resistance against antibiotics by using advanced materials

Drug resistance occurrence is a global healthcare concern responsible for the increased morbidity and mortality in hospitals, time of hospitalisation and huge financial loss. The failure of the most antibiotics to kill "superbugs" poses the urgent need to develop innovative strategies aimed at not only controlling bacterial infection but also the spread of resistance. The prevention of pathogen host invasion by inhibiting bacterial virulence and biofilm formation, and the utilisation of bactericidal agents with different mode of action than classic antibiotics are the two most promising new alternative strategies to overcome antibiotic resistance. Based on these novel approaches, researchers are developing different advanced materials (nanoparticles, hydrogels and surface coatings) with novel antimicrobial properties. In this review, we summarise the recent advances in terms of engineered materials to prevent bacteria-resistant infections according to the antimicrobial strategies underlying their design.