Optimized Preparation of Levofloxacin Loaded Polymeric Nanoparticles

Synergistic antifungal activity against Candida albicans between voriconazole and cyclosporine a loaded in polymeric nanoparticles

The goal of this work is to investigate if the synergistic antifungal activity between cyclosporine A, CsA, and voriconazole, VRZ, increases when both drugs are encapsulated in a nanocarrier as compared when they are free. The preparation and characterization of blank and VRZ and CsA loaded polymeric based PLGA nanoparticles (PLGA, PLGA-PEG, and PLGA+PEG) was a necessary previous step. Using the more suitable NPs, those of PLGA, the antifungal susceptibility tests performed with VRZ-loaded PLGA NPs, show no significant increase of the antifungal activity in comparison to that of free VRZ. However, the synergistic behavior found for the (VRZ+CsA)-loaded PLGA NPs was fourfold stronger than that observed for the two free drugs together. On the other hand, the investigation into the suppression of C. albicans biofilm formation showed that blank PLGA NPs inhibit the biofilm formation at high NPs concentrations. However, a minor effect or even a slight biofilm increase formation was observed at low and moderate NPs concentrations. Therefore, the enhancement of the biofilm inhibition found for the three tested treatments (CsA alone, VRZ alone, and VRZ+CsA) when comparing free and encapsulated drugs, within the therapeutic window, can be attributed to the drug encapsulation approach. Indeed, polymeric PLGA NPs loaded with CsA, VRZ, or VRZ+CsA are more effective at inhibiting the C. albicans biofilm growth than their free counterparts.

Levofloxacin loaded chitosan and poly-lactic-co-glycolic acid nano-particles against resistant bacteria: Synthesis, characterization and antibacterial activity

BACKGROUND

With the global increase in antibacterial resistance, the challenge faced by developing countries is to utilize the available antibiotics, alone or in combination, against resistant bacterial strains. We aimed to encapsulate the levofloxacin (LVX) into polymeric nanoparticles using biodegradable polymers i.e. Chitosan and PLGA, estimating their physicochemical characteristics followed by functional assessment as nanocarriers of levofloxacin against the different resistant strains of bacteria isolated from biological samples collected from tertiary care hospital in Lahore, Pakistan.

METHODS

LVX-NPs were synthesized using ion gelation and double emulsion solvent-evaporation method employing chitosan (CS) and poly-lactic-co-glycolic acid (PLGA), characterized via FTIR, XRD, SEM, and invitro drug release studies, while antibacterial activity was assessed using Kirby-Bauer disc-diffusion method.

RESULTS

Data revealed that the levofloxacin-loaded chitosan nanoparticles showed entrapment efficiency of 57.14% ± 0.03 (CS-I), 77.30% ± 0.08(CS-II) and 87.47% ± 0.08 (CS-III). The drug content, particle size, and polydispersity index of CS-I were 52.22% ± 0.2, 559 nm ± 31 nm, and 0.030, respectively, whereas it was 66.86% ± 0.17, 595 nm ± 52.3 nm and 0.057, respectively for CS-II and 82.65% ± 0.36, 758 nm ± 24 nm and 0.1, respectively for CS-III. The PLGA-levofloxacin nanoparticles showed an entrapment efficiency of 42.80% ± 0.4 (PLGA I) and 23.80% ± 0.4 (PLGA II). The drug content, particle size and polydispersity index of PLGA-I were 86% ± 0.21, 92 nm ± 10 nm, and 0.058, respectively, whereas it was 52.41% ± 0.45, 313 nm ± 32 nm and 0.076, respectively for PLGA-II. The XRD patterns of both polymeric nanoparticles showed an amorphous nature. SEM analysis reflects the circular-shaped agglomerated nanoparticles with PLGA polymer and dense spherical nanoparticles with chitosan polymer. The in-vitro release profile of PLGA-I nanoparticles showed a sustained release of 82% in 120 h and it was 58.40% for CS-III. Both types of polymeric nanoparticles were found to be stable for up to 6 months without losing any major drug content. Among the selected formulations, CS-III and PLGA-I, CS-III had better antibacterial potency against gram+ve and gram-ve bacteria, except for K. pneumonia, yet, PLGA-I demonstrated efficacy against K. pneumonia as per CSLI guidelines. All formulations did not exhibit any signs of hemotoxicity, nonetheless, the CS-NPs tend to bind on the surface of RBCs.

CONCLUSION

These data suggested that available antibiotics can effectively be utilized as nano-antibiotics against resistant bacterial strains, causing severe infections, for improved antibiotic sensitivity without compromising patient safety.

Poly(ethylene glycol) Methyl Ether Acrylate-Grafted Chitosan-Based Micro- and Nanoparticles as a Drug Delivery System for Antibiotics

Nanotechnology is the science of creating materials at the nanoscale by using various devices, structures, and systems that are often inspired by nature. Micro- and nanoparticles (MPs, NPs) are examples of such materials that have unique properties and can be used as carriers for delivering drugs for different biomedical applications. Chitosan (CS) is a natural polysaccharide that has been widely studied, but it has a problem with low water solubility at neutral or basic pH, which limits its processability. The goal of this work was to use a chemically modified CS with poly(ethylene glycol) methyl ether acrylate (PEGA) to prepare CS micronic and submicronic particles (MPs/NPs) that can deliver different types of antibiotics, respectively, levofloxacin (LEV) and Ciprofloxacin (CIP). The particle preparation procedure employed a double crosslinking method, ionic followed by a covalent, in a water/oil emulsion. The studied process parameters were the precursor concentration, stirring speeds, and amount of ionic crosslinking agent. MPs/NPs were characterized by FT-IR, SEM, light scattering granulometry, and Zeta potential. MPs/NPs were also tested for their water uptake capacity in acidic and neutral pH conditions, and the results showed that they had a pH-dependent behavior. The MPs/NPs were then used to encapsulate two separate drugs, LEV and CIP, and they showed excellent drug loading and release capacity. The MPs/NPs were also found to be safe for cells and blood, which demonstrated their potential as suitable drug delivery systems for biomedical applications.

Mucosal Adhesive Chitosan Nanogel Formulations of Antibiotics and Adjuvants (Terpenoids, Flavonoids, etc.) and Their Potential for the Treatment of Infectious Diseases of the Gastrointestinal Tract

Bacterial infections are usually found in the stomach and the first part of the small intestine in association with various pathologies, including ulcers, inflammatory diseases, and sometimes cancer. Treatment options may include combinations of antibiotics with proton pump inhibitors and anti-inflammatory drugs. However, all of them have high systemic exposure and, hence, unfavorable side effects, whereas their exposure in stomach mucus, the predominant location of the bacteria, is limited. Chitosan and nanogels based on chitosan presumably are not absorbed from the gastrointestinal tract and are known to adhere to the mucus. Therefore, they can serve as a basis for the local delivery of antibacterial drugs, increasing their exposure at the predominant location of therapeutic targets, thus improving the risk/benefit ratio. We have used E. coli ATCC 25922 (as a screening model of pathogenic bacteria) and Lactobacilli (as a model of a normal microbiome) to study the antibacterial activity of antibacterial drugs entrapped in a chitosan nanogel. Classical antibiotics were studied in a monotherapeutic regimen as well as in combination with individual terpenoids and flavonoids as adjuvants. It has been shown that levofloxacin (LF) in combination with zephirol demonstrate synergistic effects against E. coli (cell viability decreased by about 50%) and, surprisingly, a much weaker effect against Lactobacilli. A number of other combinations of antibiotic + adjuvant were also shown to be effective. Using FTIR and UV spectroscopy, it has been confirmed that chitosan nanogels with the drug are well adsorbed on the mucosal model, providing prolonged release at the target location. Using an ABTS assay, the antioxidant properties of flavonoids and other drugs are shown, which are potentially necessary to minimize the harmful effects of toxins and radicals produced by pathogens. In vivo experiments (on sturgeon fish) showed the effective action of antibacterial formulations developed based on LF in chitosan nanogels for up to 11 days. Thus, chitosan nanogels loaded with a combination of drugs and adjuvants can be considered as a new strategy for the treatment of infectious diseases of the gastrointestinal tract.

Design, synthesis, spectroscopic characterization, in-vitro antibacterial evaluation and in-silico analysis of polycaprolactone containing chitosan-quercetin microspheres

Aim of present study was to synthesize a novel chitosan-quercetin (CTS-QT) complex by making a carbodiimide linkage using maleic anhydride as cross-linker and to investigate its enhanced antibacterial and antioxidant activities as compare to pure CTS and QT. Equimolar concentration of QT and maleic anhydride were used to react with 100 mg CTS to form CTS-QT complex. For this purpose, three bacterial strains namely E. Coli, S. Aureus and P. Aeruginosa were used for in-vitro antibacterial analysis (ZOI, MIC, MBC, checker board and time kill assay). Later molecular docking studies were performed on protein structure of E. Coli to assess binding affinity of pure QT and CTS-QT complex. MD simulations with accelerated settings were used to explore the protein-ligand complex's binding interactions and stability. Antioxidant profile was determined by performing DPPH• radical scavenging assay, total antioxidant capacity (TAC) and total reducing power (TRP) assays. Delivery mechanism to CTS-QT complex was improved by synthesizing polycaprolactone containing microspheres (CTS-QT-PCL-Levo-Ms) using Levofloxacin as model drug to enhance their antibacterial profile. Resulted microspheres were evaluated by particle size, charge, surface morphology, in-vitro drug release and hemolytic profile and are all were found within limits. Antibacterial assay revealed that CTS-QT-PCL-Levo-Ms showed more than two folds increased bactericidal activity against E. Coli and P. Aeruginosa, while 1.5 folds against S. Aureus. Green colored formation of phosphate molybdate complexes with highest 85 ± 1.32% TAC confirmed its antioxidant properties. Furthermore, molecular docking and dynamics studies revealed that CTS-QT was embedded nicely within the active pocket of UPPS with binding energy greater than QT with RSMD value of below 1.5. Conclusively, use of maleic acid, in-vitro and in-silico antimicrobial studies confirm the emergence of CTS-QT complex containing microspheres as novel treatment strategy for all types of bacterial infections.Communicated by Ramaswamy H. Sarma.

Using Targeted Nano-Antibiotics to Improve Antibiotic Efficacy against Staphylococcus aureus Infections

The poor bioavailability of antibiotics at infection sites is one of the leading causes of treatment failure and increased bacterial resistance. Therefore, developing novel, non-conventional antibiotic delivery strategies to deal with bacterial pathogens is essential. Here, we investigated the encapsulation of two fluoroquinolones, ciprofloxacin and levofloxacin, into polymer-based nano-carriers (nano-antibiotics), with the goal of increasing their local bioavailability at bacterial infection sites. The formulations were optimized to achieve maximal drug loading. The surfaces of nano-antibiotics were modified with anti-staphylococcal antibodies as ligand molecules to target S. aureus pathogens. The interaction of nano-antibiotics with the bacterial cells was investigated via fluorescent confocal microscopy. Conventional tests (MIC and MBC) were used to examine the antibacterial properties of nano-antibiotic formulations. Simultaneously, a bioluminescence assay model was employed, revealing the rapid and efficient assessment of the antibacterial potency of colloidal systems. In comparison to the free-form antibiotic, the targeted nano-antibiotic exhibited enhanced antimicrobial activity against both the planktonic and biofilm forms of S. aureus. Furthermore, our data suggested that the efficacy of a targeted nano-antibiotic treatment can be influenced by its antibiotic release profile.

Myocardial Cell Preservation from Potential Cardiotoxic Drugs: The Role of Nanotechnologies

Cardiotoxic therapies, whether chemotherapeutic or antibiotic, represent a burden for patients who may need to interrupt life-saving treatment because of serious complications. Cardiotoxicity is a broad term, spanning from forms of heart failure induction, particularly left ventricular systolic dysfunction, to induction of arrhythmias. Nanotechnologies emerged decades ago. They offer the possibility to modify the profiles of potentially toxic drugs and to abolish off-target side effects thanks to more favorable pharmacokinetics and dynamics. This relatively modern science encompasses nanocarriers (e.g., liposomes, niosomes, and dendrimers) and other delivery systems applicable to real-life clinical settings. We here review selected applications of nanotechnology to the fields of pharmacology and cardio-oncology. Heart tissue-sparing co-administration of nanocarriers bound to chemotherapeutics (such as anthracyclines and platinum agents) are discussed based on recent studies. Nanotechnology applications supporting the administration of potentially cardiotoxic oncological target therapies, antibiotics (especially macrolides and fluoroquinolones), or neuroactive agents are also summarized. The future of nanotechnologies includes studies to improve therapeutic safety and to encompass a broader range of pharmacological agents. The field merits investments and research, as testified by its exponential growth.

Nanoparticle-Based Inhalation Therapy for Pulmonary Diseases

The lung is exposed to various pollutants and is the primary site for the onset of various diseases, including infections, allergies, and cancers. One possible treatment approach for such pulmonary diseases involves direct administration of therapeutics to the lung so as to maintain the topical concentration of the drug. Particles with nanoscale diameters tend to reach the pulmonary region. Nanoparticles (NPs) have garnered significant interest for applications in biomedical and pharmaceutical industries because of their unique physicochemical properties and biological activities. In this article, we describe the biological and pharmacological activities of NPs as well as summarize their potential in the formulation of drugs employed to treat pulmonary diseases. Recent advances in the use of NPs in inhalation chemotherapy for the treatment of lung diseases have also been highlighted.

Antibiotic-Loaded Amphiphilic Chitosan Nanoparticles Target Macrophages and Kill an Intracellular Pathogen

In this work, levofloxacin (LVX), a third-generation fluoroquinolone antibiotic, is encapsulated within amphiphilic polymeric nanoparticles of a chitosan-g-poly(methyl methacrylate) produced by self-assembly and physically stabilized by ionotropic crosslinking with sodium tripolyphosphate. Non-crosslinked nanoparticles display a size of 29 nm and a zeta-potential of +36 mV, while the crosslinked counterparts display 45 nm and +24 mV, respectively. The cell compatibility, uptake, and intracellular trafficking are characterized in the murine alveolar macrophage cell line MH-S and the human bronchial epithelial cell line BEAS-2B in vitro. Internalization events are detected after 10 min and the uptake is inhibited by several endocytosis inhibitors, indicating the involvement of complex endocytic pathways. In addition, the nanoparticles are detected in the lysosomal compartment. Then, the antibacterial efficacy of LVX-loaded nanoformulations (50% w/w drug content) is assessed in MH-S and BEAS-2B cells infected with Staphylococcus aureus and the bacterial burden is decreased by 49% and 46%, respectively. In contrast, free LVX leads to a decrease of 8% and 5%, respectively, in the same infected cell lines. Finally, intravenous injection to a zebrafish larval model shows that the nanoparticles accumulate in macrophages and endothelium and demonstrate the promise of these amphiphilic nanoparticles to target intracellular infections.

Spectroscopy Approach for Highly-Efficient Screening of Lectin-Ligand Interactions in Application for Mannose Receptor and Molecular Containers for Antibacterial Drugs

Rational search of a ligand for a specific receptor is a cornerstone of a typical drug discovery process. However, to make it more “rational” one would appreciate having detailed information on the functional groups involved in ligand-receptor interaction. Typically, the 3D structure of a ligand-receptor complex can be built on the basis of time-consuming X-ray crystallography data. Here, a combination of FTIR and fluorescence methods, together with appropriate processing, yields valuable information about the functional groups of both the ligand and receptor involved in the interaction, with the simplicity of conventional spectrophotometry. We have synthesized the “molecular containers” based on cyclodextrins, polyethyleneimines (PEI) or spermine with mannose-rich side-chains of different molecular architecture (reticulated, star-shaped and branched) with variable parameters to facilitate delivery to alveolar macrophages. We have shown that synthetic mannose-rich conjugates are highly affine to the model mannose receptor ConA: K_d ≈ 10⁻⁵–10⁻⁷ M vs. natural ligand trimannoside (10⁻⁵ M). Further, it was shown that molecular containers effectively load levofloxacin (dissociation constants are 5·10⁻⁴–5·10⁻⁶ M) and the eugenol adjuvant (up to 15–80 drug molecules for each conjugate molecule) by including them in the cyclodextrins cavities, as well as by interacting with polymer chains. Promising formulations of levofloxacin and its enhancer (eugenol) in star-shaped and polymer conjugates of high capacity were obtained. UV spectroscopy demonstrated a doubling of the release time of levofloxacin into the external solution from the complexes with conjugates, and the effective action time (time of 80% release) was increased from 0.5 to 20–70 h. The synergy effect of antibacterial activity of levofloxacin and its adjuvants eugenol and apiol on Escherichia coli was demonstrated: the minimum effective concentration of the antibiotic was approximately halved.

Pharmaceutical nanotechnology: from the bench to the market

Background

Nanotechnology is considered a new and rapidly emerging area in the pharmaceutical and medicinal field. Nanoparticles, as drug delivery systems, impart several advantages concerning improved efficacy as well as reduced adverse drug reactions.

Main body

Different types of nanosystems have been fabricated including carbon nanotubes, paramagnetic nanoparticles, dendrimers, nanoemulsions, etc. Physicochemical properties of the starting materials and the selected method of preparation play a significant aspect in determining the shape and characteristics of the developed nanoparticles. Dispersion of preformed polymers, coacervation, polymerization, nano-spray drying and supercritical fluid technology are among the most extensively used techniques for the preparation of nanocarriers. Particle size, surface charge, surface hydrophobicity and drug release are the main factors affecting nanoparticles physical stability and biological performance of the incorporated drug. In clinical practice, many nanodrugs have been used for both diagnostic and therapeutic applications and are being investigated for various indications in clinical trials. Nanoparticles are used for the cure of kidney diseases, tuberculosis, skin conditions, Alzheimer’s disease, different types of cancer as well as preparation of COVID-19 vaccines.

Conclusion

In this review, we will confer the advantages, types, methods of preparation, characterization methods and some of the applications of nano-systems.

Formulation and Evaluation of Topical Biodegradable Films Loaded with Levofloxacin Lipid Nanocarriers

Skin ulcers have increased sharply due to rise in the incidence of obesity and diabetes. This study investigated lipid nanocarriers as a strategy to improve the efficacy of levofloxacin (LV) in penetrating skin. Two surfactant types and different lipid mixtures were used in preparation of lipid nanocarriers. Mean particle size, percentage entrapment efficiency (%EE), in vitro release, and antimicrobial activity were examined. The selected formula was incorporated into a chitosan (CS) film that was subjected to physic-chemical characterization and ex vivo permeation study. The selected formula showed particle size, PDI, and ZP: 80.3 nm, -0.21, and -26 mV, respectively, synchronized with 82.12 %EE. In vitro release study showed slow biphasic release of LV from lipid nanocarriers. The antimicrobial effect illustrated statistically significant effect of lipid nanocarriers on decreasing the minimum effective concentration (MIC) of LV, particularly against E. coli. The optimized nanocarriers' formula loaded into CS film was clear, colorless, translucent, and smooth in texture. Based on the release profiles, it could be speculated that the CS film loaded with LV nanocarriers can maintain the antibacterial activity for 4 consecutive days. Thus, the local delivery of the drug in a sustained release manner could be predicted to enhance the therapeutic effect. Further clinical studies are strongly recommended. Graphical Abstract.

Development of Chitosan/Cyclodextrin Nanospheres for Levofloxacin Ocular Delivery

Levofloxacin (LVF) is an antibacterial drug approved for the treatment of ocular infections. However, due to the low ocular bioavailability, high doses are needed, causing bacterial resistance. Polymeric nanospheres (NPs) loading antibiotic drugs represent the most promising approach to eradicate ocular infections and to treat pathogen resistance. In this study, we have developed chitosan NPs based on sulfobutyl-ether-β-cyclodextrin (CH/SBE-β-CD NPs) for ocular delivery of LVF. CH/SBE-β-CD NPs loading LVF were characterized in terms of encapsulation parameters, morphology, and sizes, in comparison to NPs produced without the macrocycle. Nuclear magnetic resonance and UV–vis spectroscopy studies demonstrated that SBE-β-CD is able to complex LVF and to influence encapsulation parameters of NPs, producing high encapsulation efficiency and LVF loading. The NPs were homogenous in size, with a hydrodynamic radius between 80 and 170 nm and positive zeta potential (ζ) values. This surface property could promote the interaction of NPs with the negatively charged ocular tissue, increasing their residence time and, consequently, LVF efficacy. In vitro, antibacterial activity against Gram-positive and Gram-negative bacteria showed a double higher activity of CH/SBE-β-CD NPs loading LVF compared to the free drug, suggesting that chitosan NPs based on SBE-β-CD could be a useful system for the treatment of ocular infections.

An Overview of the Antimicrobial Activity of Polymeric Nanoparticles Against Enterobacteriaceae

Bacterial resistance is considered one of the most important public health problems of the century, due to the ability of bacteria to rapidly develop resistance mechanisms, which makes it difficult to treat infections, leading to a high rate of morbidity and mortality. Based on this, several options are being sought as an alternative to currently available treatments, with a particular focus on nanotechnology. Nanomaterials have important potential for use in medical interventions aimed at preventing, diagnosing and treating numerous diseases by directing the delivery of drugs. This review presents data on the use of polymeric nanoparticles having in vitro and in vivo activity against bacteria belonging to the Enterobacteriaceae family.

Green Formulation of Microbial Biopolyesteric Nanocarriers Toward In Vitro Drug Delivery and Its Characterization

In the present study, formulation and characterization of microbial biopolyesteric nanocarrier (MBPNc) was reported for in vitro controlled release of the drugs, viz., amoxicillin and levofloxacin. The synthesis of microbial biopolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanoparticle was done by a triple emulsion method and loaded with amoxicillin and levofloxacin to improve its curative bioavailability. The synthesized MBPNc was found to be spherical in shape with a size range of 50-100 nm which was confirmed through Transmission Electron Microscopy (TEM) analysis. The surface topology and physicochemical characteristics were analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and X-Ray Diffraction (XRD) spectroscopy. The cell viability % of MBPNc, amoxicillin-loaded MBPNc, and levofloxacin-loaded MBPNc on HEK293 cells at a concentration of 400 µg/ml were found to be 93.43 ± 0.66%, 92.29 ± 0.61%, and 91.53 ± 0.46%, respectively, which confirmed that MBPNc is biocompatible and can be used for biomedical applications without any cytotoxic effect. A significant decrease in the bacterial survival ratio (%) and increase in the zone of inhibition were observed on increasing the concentration of drug-loaded MBPNc against E. coli (ATCC®8739™) and S. aureus (ATCC®23,235™). The in vitro drug delivery study showed controlled release of amoxicillin (99.85 ± 0.15%) and levofloxacin (99.73 ± 0.24%) up to 22 h.

Mini-Tablets versus Nanoparticles for Controlling the Release of Amoxicillin: In vitro/In vivo Study

Introduction

Controlling the drug release from the dosage form at a definite rate is the main challenge for a successful oral controlled-release drug delivery system. In this study, mini-tablets (MTs) and lipid/polymer nanoparticles (LPNs) of lipid polymer and chitosan in different ratios were designed to encapsulate and control the release time of Amoxicillin (AMX).

Methods

Physical characteristics and in vitro release profiles of both MT and LPN formulations were studied. Antimicrobial activity and oral pharmacokinetics of the optimum MT and LPN formulations in comparison to market tablet were studied in rats.

Results

All designed formulations of AMX as MTs and LPNs showed accepted characteristics. MT-6 (Compritol/Chitosan 1:1) showed the greatest retardation among all prepared minitablet preparations, releasing about 79.5% of AMX over 8 h. In contrast, LPN-11 (AMX: Cr 1:3/Chitosan 1 mg/mL) had the slowest drug release, revealing the sustained release of 80.9% within 8 h. The MIC of both optimized tablet formula (MT-6) and LPNs formula (LPN-11) was around two-fold lower than the control against H. pylori. The C_max of MT-6 and LPN11 were non significantly different compared with the marketed AMX product. While the bioavailability experiment proved that the relative bioavailability of the AMX was 1.85 and 1.8 after the oral use of LPN11 and MT-6, respectively, compared to the market tablet.

Conclusion

The results verified that both controlled-release mini-tablets and lipid/polymer nanoparticles can be used for sustaining the release and hence improve the bioavailability of amoxicillin.

Synthesis and Antitumor Activity of Doxycycline Polymeric Nanoparticles: Effect on Tumor Apoptosis in Solid Ehrlich Carcinoma

Objectives: The aim of this study was to prepare doxycycline polymeric nanoparticles (DOXY-PNPs) with hope to enhance its chemotherapeutic potential against solid Ehrlich carcinoma (SEC). Methods: Three DOXY-PNPs were formulated by nanoprecipitation method using hydroxypropyl methyl cellulose (HPMC) as a polymer. The prepared DOXY-PNPs were evaluated for the encapsulation efficiency (EE%), the drug loading capacity, particle size, zeta potential (ZP) and the in-vitro release for selection of the best formulation. PNP number 3 was selected for further biological testing based on the best pharmaceutical characters. PNP3 (5 and 10 mg/kg) was evaluated for the antitumor potential against SEC grown in female mice by measuring the tumor mass as well as the expression and immunohistochemical staining for the apoptosis markers; caspase 3 and BAX. Results: The biological study documented the greatest reduction in tumor mass in mice treated with PNP3. Importantly, treatment with 5 mg/kg of DOXY-PNPs produced a similar chemotherapeutic effect to that produced by 10 mg/kg of free DOXY. Further, a significant elevation in mRNA expression and immunostaining for caspase 3 and BAX was detected in mice group treated with DOXY-PNPs. Conclusions: The DOXY-PNPs showed greater antitumor potential against SEC grown in mice and greater values for Spearman’s correlation coefficients were detected when correlation with tumor mass or apoptosis markers was examined; this is in comparison to free DOXY. Hence, DOXY-PNPs should be tested in other tumor types to further determine the utility of the current technique in preparing chemotherapeutic agents and enhancing their properties.

Chitosan and its Derivatives for Ocular Delivery Formulations: Recent Advances and Developments

Chitosan (CS) is a hemi-synthetic cationic linear polysaccharide produced by the deacetylation of chitin. CS is non-toxic, highly biocompatible, and biodegradable, and it has a low immunogenicity. Additionally, CS has inherent antibacterial properties and a mucoadhesive character and can disrupt epithelial tight junctions, thus acting as a permeability enhancer. As such, CS and its derivatives are well-suited for the challenging field of ocular drug delivery. In the present review article, we will discuss the properties of CS that contribute to its successful application in ocular delivery before reviewing the latest advances in the use of CS for the development of novel ophthalmic delivery systems. Colloidal nanocarriers (nanoparticles, micelles, liposomes) will be presented, followed by CS gels and lenses and ocular inserts. Finally, instances of CS coatings, aiming at conferring mucoadhesiveness to other matrixes, will be presented.

Development of Lipomer Nanoparticles for the Enhancement of Drug Release, Anti-microbial Activity and Bioavailability of Delafloxacin

Delafloxacin (DFL) is a novel potent and broad-spectrum fluoroquinolone group of antibiotics effective against both Gram-positive and negative aerobic and anaerobic bacteria. In this study, DFL-loaded stearic acid (lipid) chitosan (polymer) hybrid nanoparticles (L-P-NPs) have been developed by single-emulsion-solvent evaporation technique. The mean particle size and polydispersity index (PDI) of optimized DFL-loaded L-P-NPs (F1-F3) were measured in the range of 299–368 nm and 0.215–0.269, respectively. The drug encapsulation efficiency (EE%) and loading capacity (LC%) of DFL-loaded L-P-NPs (F1-F3) were measured in the range of 64.9–80.4% and 1.7–3.8%, respectively. A sustained release of DFL was observed from optimized DFL-loaded L-P-NPs (F3). Minimum inhibitory concentration (MIC) values of the DFL-loaded L-P-NPs (F3) appeared typically to be four-fold lower than those of delafloxacin in the case of Gram-positive strains and was 2-4-fold more potent than those of delafloxacin against Gram-negative strains. The pharmacokinetic study in rats confirmed that the bioavailability (both rate and extent of absorption) of DFL-loaded L-P-NPs was significantly higher (2.3-fold) than the delafloxacin normal suspension. These results concluded that the newly optimized DFL-loaded L-P-NPs were more potent against both Gram-positive and negative strains of bacteria and highly bioavailable in comparison to delafloxacin normal suspension.

Microfluidic Synthesis of Rifampicin Loaded PLGA Nanoparticles and the Effect of Formulation on their Physical and Antibacterial Properties

The encapsulation of drugs in nanoparticles serves as an effective way to modify pharmacokinetics and therapeutic efficacy. Nanoparticles comprised of poly(d,l-lactide-co-glycolide) (PLGA) are well suited for this purpose; they are accessible using multiple synthesis methods, are highly biocompatible and biodegradable, and possess desirable drug release properties. In the present study, we have explored the effects of various formulation parameters on the physical properties of PLGA nanoparticles synthesised using a microfluidic assisted nanoprecipitation method and loaded with a model drug. PLGA nanoparticles, with diameters ranging from 165–364nm, were produced using three alternate stabilisers; poly(vinyl alcohol) (PVA), d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), and didodecyldimethylammonium bromide (DMAB). Three additional formulations used PVA in addition to 20wt-% 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA), and oleic acid. Spectrophotometric analysis demonstrated that the use of PVA increased the loading efficiency over that of TPGS and DMAB formulations, while the inclusion of oleic acid in the PVA formulation resulted in a further 3-fold increase in loading efficiency. Invitro release studies demonstrate that the inclusion of lipid additives significantly alters release kinetics; release was most rapid and complete in the formulation containing oleic acid, while the addition of DOTAP and DOTMA significantly reduced release rates. Finally, the antimicrobial activity of each formulation was tested against Staphylococcus aureus and Bacillus cereus, with minimum inhibitory concentrations nearing or exceeding that of free rifampicin.

Chitosan-Based Hydrogels Embedded with Hyaluronic Acid Complex Nanoparticles for Controlled Delivery of Bone Morphogenetic Protein-2

Chitosan(CH)-poly(dioxanone) (CH-PDO) copolymers containing varied amounts of PDO and having free amino groups at their CH backbone were synthesized using a group protection method. The selected CH-PDO with soluble characteristics in aqueous media was used together with hyaluronic acid (HA) to prepare HA/CH-PDO polyelectrolyte complex nanoparticles (NPs) via an ionotropic gelation technique, and such a type of HA/CH-PDO NPs was employed as a carrier for delivering bone morphogenetic protein-2 (BMP-2). The optimal BMP-2-encapsulated HA/CH-PDO NPs with high encapsulation efficiency were embedded into CH/glycerophosphate composite solutions to form different hydrogels in order to achieve long-term BMP-2 release. The formulated gels were found to be injectable at room temperature and had its thermosensitive phase transition near physiological temperature and pH. They also showed abilities to administer the release of BMP-2 in approximately linear manners for a few weeks while effectively preserving the bioactivity of the encapsulated BMP-2. In view of their fully biocompatible and biodegradable components, the presently developed gel systems have promising potential for translation to the clinic use in bone repair and regeneration where the sustained and controlled stimuli from active signaling molecules and the stable biomechanical framework for housing the recruited cells are often concurrently needed.