Clarithromycin-Loaded Ocular Chitosan Nanoparticle: Formulation, Optimization, Characterization, Ocular Irritation, and Antimicrobial Activity

Development of chitosan lipid nanoparticles to alleviate the pharmacological activity of piperine in the management of cognitive deficit in diabetic rats

The aim of the present study was to prepare and evaluate Piperine (PP) loaded chitosan lipid nanoparticles (PP-CLNPs) to evaluate its biological activity alone or in combination with the antidiabetic drug Metformin (MET) in the management of cognitive deficit in diabetic rats. Piperine was successfully loaded on CLNPs prepared using chitosan, stearic acid, Tween 80 and Tripolyphosphate (TPP) at different concentrations. The developed CLNPs exhibited high entrapment efficiency that ranged from 85.12 to 97.41%, a particle size in the range of 59.56-414 nm and a negatively charged zeta potential values (- 20.1 to - 43.9 mV). In vitro release study revealed enhanced PP release from CLNPs compared to that from free PP suspensions for up to 24 h. In vivo studies revealed that treatment with the optimized PP-CLNPs formulation (F2) exerted a cognitive enhancing effect and ameliorated the oxidative stress associated with diabetes. PP-CLNPs acted as an effective bio-enhancer which increased the potency of metformin in protecting brain tissue from diabetes-induced neuroinflammation and memory deterioration. These results suggested that CLNPs could be a promising drug delivery system for encapsulating PP and thus can be used as an adjuvant therapy in the management of high-risk diabetic cognitive impairment conditions.

Enhanced oral delivery of hesperidin-loaded sulfobutylether-β-cyclodextrin/chitosan nanoparticles for augmenting its hypoglycemic activity: in vitro-in vivo assessment study

Hesperidin (Hsd), a bioactive phytomedicine, experienced an antidiabetic activity versus both Type 1 and Type 2 Diabetes mellitus. However, its intrinsic poor solubility and bioavailability is a key challenging obstacle reflecting its oral delivery. From such perspective, the purpose of the current study was to prepare and evaluate Hsd-loaded sulfobutylether-β-cyclodextrin/chitosan nanoparticles (Hsd/CD/CS NPs) for improving the hypoglycemic activity of the orally administered Hsd. Hsd was first complexed with sulfobutylether-β-cyclodextrin (SBE-β-CD) and the complex (CX) was found to be formed with percent complexation efficiency and percent process efficiency of 50.53 ± 1.46 and 84.52 ± 3.16%, respectively. Also, solid state characterization of the complex ensured the inclusion of Hsd inside the cavity of SBE-β-CD. Then, Hsd/CD/CS NPs were prepared using the ionic gelation technique. The prepared NPs were fully characterized to select the most promising one (F1) with a homogenous particle size of 455.7 ± 9.04 nm, a positive zeta potential of + 32.28 ± 1.12 mV, and an entrapment efficiency of 77.46 ± 0.39%. The optimal formula (F1) was subjected to further investigation of in vitro release, ex vivo intestinal permeation, stability, cytotoxicity, and in vivo hypoglycemic activity. The results of the release and permeation studies of F1 manifested a modulated pattern between Hsd and CX. The preferential stability of F1 was observed at 4 ± 1 °C. Also, the biocompatibility of F1 with oral epithelial cell line (OEC) was retained up to a concentration of 100 µg/mL. After oral administration of F1, a noteworthy synergistic hypoglycemic effect was recorded with decreased blood glucose level until the end of the experiment. In conclusion, Hsd/CD/CS NPs could be regarded as a hopeful oral delivery system of Hsd with enhanced antidiabetic activity.

Chitosan nanoparticles improve the effectivity of miltefosine against Acanthamoeba

BACKGROUND

Acanthamoeba keratitis (AK) is a corneal sight-threatening infection caused by the free-living amoebae of the genus Acanthamoeba. Early and appropriate treatment significantly impacts visual outcomes. Mucoadhesive polymers such as chitosan are a potential strategy to prolong the residence time and bioavailability of the encapsulated drugs in the cornea. Regarding the recent administration of miltefosine (MF) for treating resistant AK, in the present study, we synthesized miltefosine-loaded chitosan nanoparticles (MF-CS-NPs) and evaluated them against Acanthamoeba.

METHODOLOGY/PRINCIPAL FINDINGS

Chitosan nanoparticles (CNPs) were prepared using the ionic gelation method with negatively charged tripolyphosphate (TPP). The zeta-potential (ZP) and the particle size of MF-CS-NPs were 21.8±3.2 mV and 46.61±18.16 nm, respectively. The release profile of MF-CS-NPs indicated linearity with sustained drug release. The cytotoxicity of MF-CS-NPs on the Vero cell line was 2.67 and 1.64 times lower than free MF at 24 and 48 hours. This formulation exhibited no hemolytic activity in vitro and ocular irritation in rabbit eyes. The IC50 of MF-CS-NPs showed a significant reduction by 2.06 and 1.69-fold in trophozoites at 24 and 48 hours compared to free MF. Also, the MF-CS-NPs IC50 in the cysts form was slightly decreased by 1.26 and 1.21-fold at 24 and 48 hours compared to free MF.

CONCLUSIONS

The MF-CS-NPs were more effective against the trophozoites and cysts than free MF. The nano-chitosan formulation was more effective on trophozoites than the cysts form. MF-CS-NPs reduced toxicity and improved the amoebicidal effect of MF. Nano-chitosan could be an ideal carrier that decreases the cytotoxicity of miltefosine. Further analysis in animal settings is needed to evaluate this nano-formulation for clinical ocular drug delivery.

Exploring the Ocular Absorption Pathway of Fasudil Hydrochloride towards Developing a Nanoparticulate Formulation with Improved Performance

Rho-kinase (ROCK) inhibitors represent a new category of anti-glaucoma medications. Among them, Fasudil hydrochloride, a selective ROCK inhibitor, has demonstrated promising outcomes in glaucoma treatment. It works by inhibiting the ROCK pathway, which plays a crucial role in regulating the trabecular meshwork and canal of Schlemm's aqueous humor outflow. This study aims to investigate the ocular absorption pathway of Fasudil hydrochloride and, subsequently, develop a nanoparticle-based delivery system for enhanced corneal absorption. Employing the ionic gelation method and statistical experimental design, the factors influencing chitosan nanoparticle (Cs NP) characteristics and performance were explored. Fasudil in vitro release and ex vivo permeation studies were performed, and Cs NP ocular tolerability and cytotoxicity on human lens epithelial cells were evaluated. Permeation studies on excised bovine eyes revealed significantly higher Fasudil permeation through the sclera compared to the cornea (370.0 μg/cm2 vs. 96.8 μg/cm2, respectively). The nanoparticle size (144.0 ± 15.6 nm to 835.9 ± 23.4 nm) and entrapment efficiency range achieved (17.2% to 41.4%) were predominantly influenced by chitosan quantity. Cs NPs showed a substantial improvement in the permeation of Fasudil via the cornea, along with slower release compared to the Fasudil aqueous solution. The results from the Hen's Egg Test Chorioallantoic Membrane (HET-CAM) and Bovine Corneal Opacity and Permeability (BCOP) tests indicated good conjunctival and corneal biocompatibility of the formulated chitosan nanoparticles, respectively. Lens epithelial cells displayed excellent tolerance to low concentrations of these nanoparticles (>94% cell viability). To the best of our knowledge, this is the first report on the ocular absorption pathway of topically applied Fasudil hydrochloride where the cornea has been identified as a potential barrier that could be overcome using Cs NPs.

Recent advances in nanotechnology for the treatment of fungal keratitis

Fungal keratitis (FK) is a serious pathogenic disease usually associated with serious ocular complications. The current mainstay of treatment for FK is topical eye drops; however, poor corneal penetration, low bioavailability of the drug and the need to administer high and frequent doses due to the presence of an effective clearance mechanism in the eye result in poor patient compliance. Nanocarriers can extend the duration of drug action through sustained and controlled release of the drug, protect the drug from ocular enzymes and help overcome ocular barriers. In this review, we discussed the mechanisms of action of antifungal drugs, the theoretical basis for the treatment of FK, and recent advances in the clinical treatment of FK. We have summarized the results of research into the most promising nanocarriers for ocular drug delivery and highlight their efficacy and safety in the therapy.

Development of kojic acid loaded collagen-chitosan nanoparticle as skin lightener product: in vitro and in vivo assessment

In the present study, an ionic gelation and ultrasonic approach was performed to produce kojic acid (KA) loaded chitosan(CS)/collagen(CN) nanoparticle(NP) (CSCN-NP) which aimed to increase the dermal delivery and anti-pigmentation effect. To optimize the CSCN-NP the effect of the amount of CN was investigated. The results showed that increasing CN from 0 to 500 mg increased the mean particle size and entrapment efficiency of KA-CSCN-NP from 266.07 ± 9.30 nm to 404.23 ± 9.44 nm and 17.37 ± 2.06% to 82.34 ± 2.16%, respectively. Differential scanning calorimetry confirmed the amorphous form of KA in CSCN-NP, while scanning electron microscopy revealed that the nanoparticles were spherical. There was no chemical interaction between KA and the other components base on attenuated total reflectance-Fourier transform infrared spectroscopy. The skin permeability test showed that KA-CSCN-NP gel delivered more KA to the dermal layers (29.16 ± 1.67% or 537.26 ± 537.26 μg/cm2) and receiver compartment (15.04 ± 1.47% or 277.15 ± 27.22 μg/cm2) compared to KA plain gel. In vitro cytotoxicity assay demonstrated that the improved KA-CSCN-NP was non-toxic. Dermal irritating test on Wistar rats showed that the KA gel was non-irritating. Furthermore, KA-CSCN-NP was found to inhibit melanin formation to a greater extent than free KA and significantly inhibited L-dopa auto-oxidation (94.80 ± 2.41%) compared to pure kojic acid solution (75.28 ± 3.22%). The observations of this study revealed that the produced KA-CSCN-NP might be used as a potential nano-vehicle for KA dermal administration, thereby opening up innovative options for the management of hyper-melanogenesis problems.

Immunomodulatory chitosan nanoparticles for Toxoplasma gondii infection: Novel application of chitosan in complex propranolol-hydrochloride as an adjuvant in vaccine delivery

The study aimed to investigate the immunomodulatory effects of propranolol hydrochloride (PRO) in combination with chitosan nanoparticles (CS NPs) as an adjuvant to develop an effective vaccine against T. gondii. A total of 105 BALB/c mice were randomly divided into seven equal groups including PBS alone, CS NPs, SAG1 (Surface antigen 1), CS-SAG1 NPs, CS-PRO NPs, SAG1-PRO, and CS-SAG1-PRO NPs. The immunostimulatory effect of each adjuvant used for vaccine delivery was evaluated in a mice immunization model. The results showed that the mice immunized with CS-SAG1-PRO NPs exhibited the highest lymphocyte proliferation rate, along with increased secretion of IFN-γ, TNF-α, IL-6, IL-12, IL-17, and IL-23, as well as elevated levels of protective cytokines such as TGF-β, IL-27, and IL-10. Although, the CS-SAG1-PRO NPs immunized mice showed the highest level of T. gondii specific IgG compared to the other groups, a significant production of IgG2a and IgG1 was observed in the sera of mice immunized with the CS-SAG1-PRO NPs compared to the other group (p <0.001). The higher IgG2a/IgG1 ratio observed in the CS-SAG1-PRO NPs group indicates a bias towards Th1 cell polarization, suggesting the promotion of Th1 cell-mediated immune responses. Considering the combination of the highest lymphocyte proliferation and survival rates, IgG2a/IgG1 ratio, and cytokine levels in the mice immunized with CS-SAG1-PRO NPs, this approach holds promise for immunostimulation and vaccine delivery against T. gondii infection.

Spanlastic-laden in situ gel as a promising approach for ocular delivery of Levofloxacin: In-vitro characterization, microbiological assessment, corneal permeability and in-vivo study

The objective of this study was to encapsulate the antibacterial drug levofloxacin hemihydrate (LF) into spanlastics (SLs) followed by incorporation into gelrite in situ gel to enhance its antibacterial activity and sustain ocular delivery. A combination of Span 60 as main vesicle component and Tweens as an edge activator (EA) was used to prepare SLs using the thin film hydration method. A 32 factorial design was applied to study the effect of formulation variables (ratio of Span 60: EA and type of EA) on SLs characteristics (encapsulation efficiency (EE%), particle size (PS), zeta potential (ZP) and percentage of drug released). In-vitro antimicrobial study was conducted to determine the antibacterial activity of the optimized formula. Finally confocal laser scanning microscopy (CLSM) was applied to monitor SLs corneal penetration. The optimum formulation (F5), contains 240 mg Span 60 and 60 mg Tween 60 as EA. F5 exhibited EE% = 59.7 ± 4.2%, PS = 177.6 ± 1.8 nm, PDI = 0.27 ± 0.022 and ZP = -40.6 ± 0.68 mV. Furthermore, only 39.37 ± 0.72% of LF amount was released after 4 h compared to complete release from drug solution. The apparent permeation coefficient was (14.7 × 10-3 cm/h) compared to (9.7 × 10-3 cm/h) for LF solution. Moreover, F5 exhibited 200% and 100% increase in the antibacterial efficacy against Pseudomonas aeruginosa and Staphylococcus aureus respectively.

Chitosan nanoparticle toxicity: A comprehensive literature review of in vivo and in vitro assessments for medical applications

Topic definition

This literature review aims to update the current knowledge on toxicity of chitosan nanoparticles, compare the recent findings and identify the gaps with knowledge that is present for the chitosan nanoparticles.

Methods

The publications between 2010 and 2020 were searched in Science Direct, Pubmed.gov, Google Scholar, Research Gate, and ClinicalTrials.gov, according to the inclusion and exclusion criteria. 30 primary research studies were obtained from the literature review to compare the in vitro in vivo toxicity profiles among the chitosan nanoparticles.

Major highlights

Chitosan nanoparticles and other types of nanoparticles show cytotoxic effects on cancer cells while having minimal toxicity on normal cells. This apparent effect poses some considerations for use in incorporating cancer therapeutics into chitosan nanoparticles as an administration form. The concentration, duration of exposure, and pH of the solution can influence nanoparticle cytotoxicity, particularly in zebrafish. Different cell lines exhibit varying degrees of toxicity when exposed to nanoparticles, and of note are liver cells that show toxicity under exposure as indicated by increased alanine transaminase (ALT) levels. Aside from ALT, platelet aggregation can be considered a toxicity induced by chitosan nanoparticles. In addition, zebrafish cells experience the most toxicity, including organ damage, neurobehavioral impairment, and developmental abnormalities, when exposed to nanoparticles. However, nanoparticles may exhibit different toxicity profiles in different organisms, with brain toxicity and liver toxicity being present in zebrafish but not rats. Different organs exhibit varying degrees of toxicity, with the eye and mouth apparently having the lowest toxicity, while the brain, intestine, muscles and lung showing mixed results. Cardiotoxicity induced by chitosan nanoparticles was not observed in zebrafish embryos, and nanoparticles may reduce cardiotoxicity when delivering drug. Toxicity found in an organ may not necessarily mean that it is toxic towards all the cells found in that organ, as muscle toxicity was present when tested in zebrafish but not in C2C12 myoblast cells. Some of the studies conducted may have limitations that need to be reconsidered to account for differing results, with some examples being two experiments done on HeLa cells where one study concluded chitosan nanoparticles were toxic to the cells while the other seems to have no toxicity present. With regards to LD50, one study has stated the concentration of 64.21 mg/ml was found. Finally, smaller nanoparticles generally exhibit higher toxicity in cells compared to larger nanoparticles.

Scope for future work

This literature review did not uncover any published clinical trials with available results. Subsequent research endeavors should prioritize conducting clinical trials involving human volunteers to directly assess toxicity, rather than relying on cell or animal models.

Nanomedicine for the Detection and Treatment of Ocular Bacterial Infections

Ocular bacterial infection is a prevalent cause of blindness worldwide, with substantial consequences for normal human life. Traditional treatments for ocular bacterial infections areless effective, necessitating the development of novel techniques to enable accurate diagnosis, precise drug delivery, and effective treatment alternatives. With the rapid advancement of nanoscience and biomedicine, increasing emphasis has been placed on multifunctional nanosystems to overcome the challenges posed by ocular bacterial infections. Given the advantages of nanotechnology in the biomedical industry, it can be utilized to diagnose ocular bacterial infections, administer medications, and treat them. In this review, the recent advancements in nanosystems for the detection and treatment of ocular bacterial infections are discussed; this includes the latest application scenarios of nanomaterials for ocular bacterial infections, in addition to the impact of their essential characteristics on bioavailability, tissue permeability, and inflammatory microenvironment. Through an in-depth investigation into the effect of sophisticated ocular barriers, antibacterial drug formulations, and ocular metabolism on drug delivery systems, this review highlights the challenges faced by ophthalmic medicine and encourages basic research and future clinical transformation based on ophthalmic antibacterial nanomedicine.

Augmentation of anti-proliferative efficacy of quercetin encapsulated chitosan nanoparticles by induction of cell death via mitochondrial membrane permeabilization in oral cancer

Quercetin (QCT), an antioxidant plant flavonoid, is known to impart prominent anti-cancer properties. However, its clinical application as a potential drug is hindered owing to its hydrophobicity, extensive metabolism, low absorption, and rapid elimination. The drawbacks of these phytochemical-based therapies can be addressed using nanotechnology-based drug delivery systems. In this study, we sought to develop chitosan nanoparticles (CSNPs) as the drug vehicle for encasing quercetin (QCT-CSNPs) and further investigate its anti-tumor potential against human oral cancer cell line Cal33. Our findings indicate that the average particle diameter of the formulated chitosan nanoparticles was around 100 nm, and they had a spherical structure, as per the TEM and FESEM images. The efficient entrapment of quercetin inside the CSNPs matrix is confirmed by XRD, UV-Vis spectrophotometry, FTIR, and DSC analysis. The in vitro cell cytotoxicity study against Cal33 oral cancer cells revealed that QCT-CSNPs exhibited superior toxicity compared to free QCT post-24-hour treatment. The improved anti-cancer efficacy of QCT-CSNPs was further confirmed by enhanced cellular apoptosis, colony formation inhibition, migration inhibition, and chromatin condensation. Moreover, the mitochondrial dysfunction and enhanced ROS (Reactive oxygen species) production indicated mitochondrial-mediated cell death in QCT-CSNPs treated Cal33 cells. In conclusion, our data suggest that quercetin-encapsulated chitosan nanoparticles may serve as a potential drug candidate against oral cancer.

How Combined Macrolide Nanomaterials are Effective Against Resistant Pathogens? A Comprehensive Review of the Literature

Macrolide drugs are among the broad-spectrum antibiotics that are considered as "miracle drugs" against infectious diseases that lead to higher morbidity and mortality rates. Nevertheless, their effectiveness is currently at risk owing to the presence of devastating, antimicrobial-resistant microbes. In view of this challenge, nanotechnology-driven innovations are currently being anticipated for promising approaches to overcome antimicrobial resistance. Nowadays, various nanostructures are being developed for the delivery of antimicrobials to counter drug-resistant microbial strains through different mechanisms. Metallic nanoparticle-based delivery of macrolides, particularly using silver and gold nanoparticles (AgNPs & AuNPs), demonstrated a promising outcome with worthy stability, oxidation resistance, and biocompatibility. Similarly, macrolide-conjugated magnetic NPs resulted in an augmented antimicrobial activity and reduced bacterial cell viability against resistant microbes. Liposomal delivery of macrolides also showed favorable synergistic antimicrobial activities in vitro against resistant strains. Loading macrolide drugs into various polymeric nanomaterials resulted in an enhanced zone of inhibition. Intercalated nanomaterials also conveyed an outstanding macrolide delivery characteristic with efficient targeting and controlled drug release against infectious microbes. This review abridges several nano-based delivery approaches for macrolide drugs along with their recent achievements, challenges, and future perspectives.

Chitosan-Based Particulate Carriers: Structure, Production and Corresponding Controlled Release

The state of the art in the use of chitosan (CS) for preparing particulate carriers for drug delivery applications is reviewed. After evidencing the scientific and commercial potentials of CS, the links between targeted controlled activity, the preparation process and the kinetics of release are detailed, focusing on two types of particulate carriers: matrix particles and capsules. More precisely, the relationship between the size/structure of CS-based particles as multifunctional delivery systems and drug release kinetics (models) is emphasized. The preparation method and conditions greatly influence particle structure and size, which affect release properties. Various techniques available for characterizing particle structural properties and size distribution are reviewed. CS particulate carriers with different structures can achieve various release patterns, including zero-order, multi-pulsed, and pulse-triggered. Mathematical models have an unavoidable role in understanding release mechanisms and their interrelationships. Moreover, models help identify the key structural characteristics, thus saving experimental time. Furthermore, by investigating the close relation between preparation process parameters and particulate structural characteristics as well as their effect on release properties, a novel "on-demand" strategy for the design of drug delivery devices may be developed. This reverse strategy involves designing the production process and the related particles' structure based on the targeted release pattern.

Clarithromycin-Loaded Submicron-Sized Carriers: Pharmacokinetics and Pharmacodynamic Evaluation

The current study aims to improve clarithromycin bioavailability and effectiveness in complicated intra-abdominal infection management. Therefore, clarithromycin-loaded submicron dual lipid carriers (CLA-DLCs) were developed via hot high shear homogenization technique and evaluated for colloidal parameters, release behavior, stability study, and in-vitro antibiofilm activity. Bioavailability and therapeutic efficacy of optimized formulation on hampering cytokines storm induction was determined in E. coli-induced peritonitis. The developed CLA-DLCs (particle size 326.19 ± 24.14 nm, zeta potential -31.34 ± 2.81 mV, and entrapment efficiency 85.78 ± 4.01%) exhibited smooth spherical shapes and sustained in vitro release profiles. Long-term stability study of optimized CLA-DLCs ensured maintenance of colloidal parameters for 1 year at room temperature. In vitro antimicrobial studies revealed 3.43-fold higher anti-biofilm activity of CLA-DLCs compared with clarithromycin. In addition, the relative bioavailability of CLA-DLCs was enhanced 5.89-fold compared to pure drug in rats. The remarkable decrease in microbial burden in blood as well as tissues, along with oxidative stress markers (lipid peroxidation, myeloperoxidase activity, and carbonylated protein level) and immunological markers (total leukocyte count, neutrophil migration, NO, TNF-, and IL-6) on treatment with CLA-DLCs enhanced the survival in a rat model of peritonitis compared with the pure drug and untreated groups. In conclusion, CLA-DLCs hold promising potential in management of intra-abdominal infections and prevention of associated complications.

Engineering of clarithromycin loaded stimulus responsive dissolving microneedle patches for the treatment of biofilms

This study aimed to fabricate clarithromycin laden Eudragit S-100-based microfibers (MF), microfibers coated film (MB), clarithromycin loaded polyvinyl pyrollidone, hyaluronic acid and sorbitol-based dissolving microneedle patches (CP) and microfibers coated microneedle patches (MP). Morphological and phase analysis of formulations were carried out by scanning electron microscopy and differential scanning calorimetry, X-ray diffraction, respectively. Substrate liquefaction test, in vitro drug release, antimicrobial assay and in vivo antibiofilm studies were performed. MF exhibited a uniform surface and interconnected network. Morphological analysis of CP revealed sharp-tipped and uniform-surfaced microstructures. Clarithromycin was incorporated within MF and CP as amorphous solid. Liquefaction test indicated hyaluronate lyase enzyme responsiveness of hyaluronic acid. Fibers-based formulations (MF, MB and MP) provided an alkaline pH (7.4) responsive drug release; ∼79 %, ∼78 % and ∼81 %, respectively within 2 hours. CP showed a drug release of ∼82 % within 2 hours. MP showed ∼13 % larger inhibitory zone against Staphylococcus aureus (S. aureus) as compared to MB and CP. A relatively rapid eradication of S. aureus in infected wounds and subsequent skin regeneration was observed following MP application as compared to MB and CP indicating its usefulness for the management of microbial biofilms.

Nano-based eye drop: Topical and noninvasive therapy for ocular diseases

Eye drops are the most accessible therapy for ocular diseases, while inevitably suffering from their lower bioavailability which highly restricts the treatment efficacy. The introduction of nanotechnology has attracted considerable interest as it has advantages over conventional ones such as prolonged ocular surface retention time and enhanced ocular barrier penetrating properties, and achieving higher bioavailability and improved treatment efficacy. This review describes various ocular diseases treated with eye drops as well as the physiological and anatomical ocular barriers faced with through drug administration. It also summarizes the recent advances regarding the utilization of nanotechnology in developing eye drops, and how to optimize the nanocarrier-based ocular drug delivery systems. The prospective future research directions for nano-based eye drops are also discussed here.

Topical ocular delivery of nanoparticles with epoetin beta in Wistar Hannover rats

Topical instillation of drugs targeting the posterior ocular segment is an expanding area of research. Chitosan and hyaluronic acid have remarkable mucoadhesive properties and potentially enhance pre-corneal retention time after topical instillation. Bearing this in mind, we explored the possibility of delivering epoetin beta (EPOβ) to the posterior segment of the eye in a chitosan-hyaluronic acid (CS/HA-EPOβ) nanoparticulate system using the topical route of administration. Complete ophthalmological examinations, electroretinography and microhematocrit evaluations were performed in Wistar Hannover (WH) rats, before and after topical administration of nanoparticles. The right eye received CS/HA-EPOβ and the left eye received only empty nanocarriers (control). Animals were split into 6 groups and at designated timepoints, all animals from each group (n = 3) were euthanized and both eyes enucleated. Retinal morphology and EPOβ ocular distribution were assessed, respectively, through hematoxylin and eosin (HE) and immunofluorescence staining. After topical administration, no adverse ocular signs were noted and no significant changes either in microhematocrits nor in electroretinographies were detected. During the study, intraocular pressure (IOP) was always kept within physiological range bilaterally. No histological changes were detected in any of the ocular globes. Immunofluorescence enabled the identification of EPOβ in the retina 12 h after the administration, its presence still being detectable at day 21. In conclusion, CS/HA nanoparticles could efficiently deliver EPOβ to the retina of WH rats after topical instillation, being considered biologically safe. Topical administration of this nanoformulation could be a valuable tool for retinal neuroprotection, decreasing risks associated with more invasive routes of administration, being cost effective and also increasing long-term patients' compliance.

A Novel Approach for the Availability and Ocular Delivery of Tenoxicam Potassium: Synthesis, Characterization, and In Vivo Application

Tenoxicam (TX) is a non-steroidal anti-inflammatory agent that can be used to control pain in various ophthalmic lesions like cataracts, refractive surgery, and corneal abrasion. TX has a very slightly aqueous solubility of 0.072 mg/mL resulting in difficulty to be formulated in ophthalmic solutions. This study aims to improve TX solubility by converting it into its potassium salt to achieve a target of 10 mg/mL (1%w/v) concentration of TX in the desired aqueous medium for the formulation of aqueous ophthalmic solutions. The synthesized TX salt was characterized by different evaluation parameters such as solubility studies, ¹H NMR, IR, and elemental analyses. Different TX potassium solutions were formulated at concentrations of 0.5% and 1% w/v using different viscosity-imparting agents. The prepared solutions were characterized for their physicochemical properties including visual inspection, pH, rheological, in vitro release, and kinetic behavior. Also, the formulations were biologically evaluated in vivo using male albino rabbits. The obtained results showed the successful synthesis of TX salt, as indicated by IR and NMR, and elemental analysis. The solubility study showed that the solubility of TX was improved hugely to 18 mg/mL (250-fold). In addition, the results showed that the prepared formulations showed acceptable physicochemical properties. The highest release rate was obtained with formula F1, which contains no viscosity-imparting agents. While as, the lowest release rate was obtained in the case of formula F9, composed of Pluronic F127 (12% w/v). The in vivo results showed that TX optimized ophthalmic solutions F8 and F9 inhibited the redness and edema in an extended or sustained manner.

Design, Characterization, and Biological Activities of Erythromycin-Loaded Nanodroplets to Counteract Infected Chronic Wounds Due to Streptococcus pyogenes

Streptococcus pyogenes causes a wide spectrum of diseases varying from mild to life threatening, despite antibiotic treatment. Nanoparticle application could facilitate the foreign pathogen fight by increasing the antimicrobial effectiveness and reducing their adverse effects. Here, we designed and produced erythromycin-loaded chitosan nanodroplets (Ery-NDs), both oxygen-free and oxygen-loaded. All ND formulations were characterized for physico-chemical parameters, drug release kinetics, and tested for biocompatibility with human keratinocytes and for their antibacterial properties or interactions with S. pyogenes. All tested NDs possessed spherical shape, small average diameter, and positive Z potential. A prolonged Ery release kinetic from Ery-NDs was demonstrated, as well as a favorable biocompatibility on human keratinocytes. Confocal microscopy images showed ND uptake and internalization by S. pyogenes starting from 3 h of incubation up to 24 h. According to cell counts, NDs displayed long-term antimicrobial efficacy against streptococci significantly counteracting their proliferation up to 24 h, thanks to the known chitosan antimicrobial properties. Intriguingly, Ery-NDs were generally more effective (10⁴-10³ log₁₀ CFU/mL), than free-erythromycin (10⁵ log₁₀ CFU/mL), in the direct killing of streptococci, probably due to Ery-NDs adsorption by bacteria and prolonged release kinetics of erythromycin inside S. pyogenes cells. Based on these findings, NDs and proper Ery-NDs appear to be the most promising and skin-friendly approaches for the topical treatment of streptococcal skin infections allowing wound healing during hypoxia.

Chitosan modified 5-fluorouracil nanostructured lipid carriers for treatment of diabetic retinopathy in rats: A new dimension to an anticancer drug

Diabetic retinopathy (DR) is one of the chronic complications of diabetes. It includes retinal blood vessels' damage. If untreated, it leads to loss of vision. The existing treatment strategies for DR are expensive, invasive, and need expertise during administration. Hence, there is a need to develop a non-invasive topical formulation that can penetrate deep to the posterior segment of retina and treat the damaged retinal vessels. In addition, it should also provide sustained release. In recent years, novel drug delivery systems (NDDS) have been explored for treating DR and found successful. In this study, chitosan (CS) modified 5-Fluorouracil Nanostructured Lipid Carriers (CS-5-FU-NLCs) were prepared by modified melt emulsification-ultrasonication method and optimized by Box-Behnken Design. The size, polydispersity index, zeta potential and entrapment efficiency of CS-5-FU-NLCs were 163.2 ± 2.3 nm, 0.28 ± 1.52, 21.4 ± 0.5 mV and 85.0 ± 0.2 %, respectively. The in vitro drug release and ex vivo permeation study confirmed higher and sustained drug release in CS-5-FU-NLCs as compared to 5-FU solution. HET-CAM Model ensured the non-irritant nature of CS-5-FU-NLCs. In vivo ocular studies of CS-5-FU-NLCs confirmed antiangiogenic effect of 5-FU by CAM model and diabetic retinopathy induced rat model, indicating successful delivery of 5-FU to the retina.

Preparation and Evaluation of Modified Chitosan Nanoparticles Using Anionic Sodium Alginate Polymer for Treatment of Ocular Disease

Mucoadhesive nanoparticles offer prolonged drug residence time at the corneal epithelium by adhering to the mucous layer of the eye. Here, in this research investigation, voriconazole-loaded chitosan mucoadhesive nanoparticles (VCZ-MA-NPs) were modified to mucous-penetrating nanoparticles (VCZ-MP-NPs) by coating them with anionic polymer sodium alginate. The ionic gelation method was utilized to prepare mucoadhesive chitosan nanoparticles, which were further coated with sodium alginate to obtain the surface properties essential for mucous penetration. The developed VCZ-MA-NPs and VCZ-MP-NPs were evaluated extensively for physicochemical delineation, as well as in vitro and ex vivo studies. The particle size, polydispersity index, and ζ potential of the VCZ-MA-NPs were discovered to be 116 ± 2 nm, 0.23 ± 0.004, and +16.3 ± 0.9 mV, while the equivalent values for VCZ-MP-NPs were 185 ± 1 nm, 0.20 ± 0.01, and -24 ± 0.9 mV, respectively. The entrapment efficiency and drug loading were obtained as 88.06%±1.29% and 7.27% ± 0.95% for VCZ-MA-NPs and 91.31% ± 1.05% and 10.38% ± 0.87% for VCZ-MP-NPs, respectively. The formulations were found to be stable under different conditions (4 °C, 25 °C, and 40 °C). Chitosan nanoparticles and modified nanoparticles showed a spherical and smooth morphology under electron microscopic imaging. An excised caprine cornea was used for the ex vivo permeation study, exhibiting 58.98% ± 0.54% and 70.02% ± 0.61% drug permeation for VCZ-MA-NPs and VCZ-MP-NPs, respectively. The findings revealed that the mucous-penetrating nanoparticles could effectively pass through the corneal epithelium, thus overcoming the mucous barrier and fungal layer of the eye, which highlights their potential in the treatment of fungal keratitis.

Delivering macrolide antibiotics to heal a broken heart - And other inflammatory conditions

Drug carriers to deliver macrolide antibiotics, such as azithromycin, show promise as antibacterial agents. Macrolide drug carriers have largely focused on improving the drug stability and pharmacokinetics, while reducing adverse reactions and improving antibacterial activity. Recently, macrolides have shown promise in treating inflammatory conditions by promoting a reparative effect and limiting detrimental pro-inflammatory responses, which shifts the immunologic setpoint from suppression to balance. While macrolide drug carriers have only recently been investigated for their ability to modulate immune responses, the previous strategies that deliver macrolides for antibacterial therapy provide a roadmap for repurposing the macrolide drug carriers for therapeutic interventions targeting inflammatory conditions. This review describes the antibacterial and immunomodulatory activity of macrolides, while assessing the past in vivo evaluation of drug carriers used to deliver macrolides with the intention of presenting a case for increased effort to translate macrolide drug carriers into the clinic.

Development and Evaluation of Chitosan Nanoparticles for Ocular Delivery of Tedizolid Phosphate

This study investigates the development of topically applied non-invasive chitosan-nanoparticles (CSNPs) for ocular delivery of tedizolid phosphate (TZP) for the treatment of MRSA-related ocular and orbital infections. An ionic-gelation method was used to prepare TZP-encapsulated CSNPs using tripolyphosphate-sodium (TPP) as cross-linker. Particle characterization was performed by the DLS technique (Zeta-Sizer), structural morphology was observed by SEM. The drug encapsulation and loading were determined by the indirect method. In-vitro release was conducted through dialysis bags in simulated tear fluid (pH 7) with 0.25% Tween-80. Physicochemical characterizations were performed for ocular suitability of CSNPS. An antimicrobial assay was conducted on different strains of Gram-positive bacteria. Eye-irritation from CSNPs was checked in rabbits. Transcorneal flux and apparent permeability of TZP from CSNPs was estimated through excised rabbit cornea. Ionic interaction between the anionic and cationic functional groups of TPP and CS, respectively, resulted in the formation of CSNPs at varying weight ratios of CS/TPP with magnetic stirring (700 rpm) for 4 h. The CS/TPP weight ratio of 3.11:1 with 10 mg of TZP resulted in optimal-sized CSNPs (129.13 nm) with high encapsulation (82%) and better drug loading (7%). Release profiles indicated 82% of the drug was released from the TZP aqueous suspension (TZP-AqS) within 1 h, while it took 12 h from F2 to release 78% of the drug. Sustained release of TZP from F2 was confirmed by applying different release kinetics models. Linearity in the profile (suggested by Higuchi’s model) indicated the sustained release property CSNPs. F2 has shown significantly increased (p < 0.05) antibacterial activity against some Gram-positive strains including one MRSA strain (SA-6538). F2 exhibited a 2.4-fold increased transcorneal flux and apparent permeation of TZP as compared to TZP-AqS, indicating the better corneal retention. No sign or symptoms of discomfort in the rabbits’ eyes were noted during the irritation test with F2 and blank CSNPs, indicating the non-irritant property of the TZP-CSNPs. Thus, the TZP-loaded CSNPs have strong potential for topical use in the treatment of ocular MRSA infections and related inflammatory conditions.

Formulation of Chitosan-Coated Apigenin Bilosomes: In Vitro Characterization, Antimicrobial and Cytotoxicity Assessment

We prepared apigenin (APG)-loaded bilosomes (BLs) and evaluated them for vesicle size, zeta-potential and encapsulation efficiency. The formulations were prepared with cholesterol (CHL), sodium deoxy cholate (SDC), Tween 80 (T80) and phosphatidylcholine (PC) using solvent evaporation method. The prepared formulations showed the optimum result was coated with much mucoadhesive polymer chitosan (CH, 0.25 and 0.5% w/v). The chitosan-coated bilosomes (CH-BLs) were further evaluated for surface morphology, drug−polymer interaction, mucoadhesion, permeation, antimicrobial activity and cell viability. The prepared APG-BLs showed nano-metric size (211 ± 2.87 nm to 433 ± 1.98 nm), polydispersibility index <0.5, negative zeta potential (−15 to −29 mV) and enhanced encapsulation efficiency (69.5 ± 0.93 to 81.9 ± 1.3%). Based on these findings, selected formulation (F2) was further coated with chitosan and showed a marked increase in vesicle size (298 ± 3.56 nm), a positive zeta potential (+17 mV), superior encapsulation efficiency (88.1 ± 1.48%) and improved drug release (69.37 ± 1.34%). Formulation F2C1 showed significantly enhanced permeation and mucoadhesion (p < 0.05) compared to formulation F2 due to the presence of CH as a mucoadhesive polymer. The presence of CH on the surfaces of BLs helps to open the tight membrane junctions and leads to enhanced permeation. A TEM study revealed non-aggregated smooth surface vesicles. The antimicrobial and cell viability assessment revealed better effects in terms of zone of inhibition and cell line assessment against two different cancer cell line. From the study, it can be concluded that APG-CHBLs could be a superior alternative to conventional delivery systems.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

Sirolimus loaded chitosan functionalized poly (lactic-co-glycolic acid) (PLGA) nanoparticles for potential treatment of age-related macular degeneration

The usefulness of sirolimus (SIR) in the treatment of diseases that involve retinal degeneration like age-related macular degeneration (AMD) has been well documented. However, the problem still remains probably owing to the peculiar environment of the eye and/or unfavourable physiochemical profile of SIR. In the present work, we aimed to fabricate sirolimus loaded PLGA nanoparticles (SIR-PLGA-NP) and chitosan decorated PLGA nanoparticles (SIR-CH-PLGA-NP) to be administered via non-invasive subconjunctival route. Both the nanoparticles were characterized in terms of size, zeta potential, DSC, FTIR and XRD analysis. Quality by Design (QbD) approach was employed during the preparation of nanoparticles and the presence of chitosan coating was confirmed through thermogravimetric analysis and contact angle studies. Cationic polymer modification showed sustained in-vitro SIR release and enhanced ex-vivo scleral permeation and penetration. Further, SIR-CH-PLGA-NP revealed enhanced cellular uptake and thus, reduced lipopolysaccharide (LPS)-induced free-radicals generation by RAW 264.7 cells. The prepared nanoparticles were devoid of residual solvent and were found to be safe in HET-CAM analysis, RBCs damage analysis and histopathology studies. Moreover, high anti-angiogenic potential was observed in SIR-CH-PLGA-NP compared with SIR-PLGA-NP in chorioallantoic membrane (CAM) test. Overall, the current work opens up an avenue for further investigation of CH-PLGA-NP as SIR nanocarrier in the treatment of AMD.

Olive Leaves (Olea europaea L) Extract Loaded Lipid Nanoparticles: Optimization of Processing Parameters by Box-Behnken Statistical Design, in-vitro Characterization, and Evaluation of Anti-oxidant and Anti-microbial Activity

The present study was aimed to prepare and evaluated solid lipid nanoparticles (SLNs) of olive leaves extract powder (OLP) which contained many anti-oxidant and antimicrobial agents like oleuropein, a natural polyphenol. The major issue concern OLP was the instability due to environmental conditions and hence compromised bioactivity. To overcome this problem, SLNs were designed by hot homogenous followed by sonication technique to protect the drug and improve its antioxidant and antimicrobial activity. Lipids like compritol 888ATO and surfactant like tween 80 were used for the development and stabilization of SLNS and optimization was done by Box-Behnken statistical design (3x3). The optimized batch (F9) showed particle size, entrapment efficiency, PDI, and zeta potential 277.46 nm, 80.48%, 0.275, and －23.18 mV respectively. Optimized formulation (F9) exhibited a sustained release pattern up to 24 h with first-order release kinetic (R² = 0.9984) and the mechanism of drug release was found to be Fickian diffusion type (n = 0.441). Upon the stability study, it could be found that SLNs formulation was stable. Anti-oxidation and anti-microbial studies were conducted on optimized formulation and findings suggested that SLNs showed an improved radical scavenging activity and anti-microbial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria. Finally, it was concluded that developed SLNs were able to protect and suitable for the delivery of OLP.

Formulation of Chitosan-Coated Piperine NLCs: Optimization, In Vitro Characterization, and In Vivo Preclinical Assessment

In the present research work, surface-modified nanostructured lipid carriers (NLCs) with chitosan (CH) were prepared to improve the therapeutic efficacy of piperine (PP). NLCs were developed and optimized (CH-PP-NLCs-opt) by design expert software and the selected NLCs surface was coated with chitosan (0.2% w/v). CH-PP-NLCs-opt have shown a particle size of 149.34 ± 4.54 nm and entrapment efficiency of 80.65 ± 1.23%. The results of the solid-state characterization study exhibited that PP enclosed in lipids and present amorphous form. It might be due to the nanoparticle size of NLCs. The drug release study revealed PP-NLCs-opt and CH-PP-NLCs-opt exhibited significant (P < 0.05) difference in PP release (88.87 ± 5.23% and 76.34 ± 4.54%) as compared to pure PP (19.02 ± 2.87%). CH-PP-NLCs-opt exhibited strong bioadhesion than PP-NLCs-opt which has a positive influence the drug permeation and absorption. CH-PP-NLCs-opt showed higher permeation (1083.34 ± 34.15 μg/ cm2) than pure PP (106.65 ± 15.44 μg/cm²) and PP-NLCs-opt (732.45 ± 28.56 μg/ cm²). The significantly enhanced bioavailability of PP was observed from CH-PP-NLCs-opt (3.76- and 1.21-fold) than PP-dispersion and PP-NLCs-opt. The diabetes was induced in rats by a single intraperitoneal administration of streptozotocin (STZ, 40 mg/kg, citrate buffer pH 4.5), and results revealed that PP-NLCs-opt and CH-PP-NLCs-opt reduce the blood glucose level (28.26% and 36.52% respectively) as compared to PP-dispersion (10.87%). It also helps to maintain the altered biochemical parameters. In conclusion, CH-PP-NLC can be a novel oral nanocarrier for the management of diabetes.

Design and Optimization of New Enteric Nanoparticles of Ceftriaxone for Oral Delivery: In vitro and in vivo Assessments

PURPOSE

Development of new strategies for oral delivery of existing antibiotics administered exclusively through intravenous route is one of the global priorities of pharmaceutical research. The encapsulation of these active pharmaceutical agents within nanosized natural products offers several traits due to their tunable surface properties. Ceftriaxone (CTX) is an injectable, third-generation cephalosporin that suffers poor oral bioavailability.

METHODS

In the present study, ionic gelation of two biopolymers, namely chitosan (CH) and shellac (SH), was implemented to consolidate CTX, within elegant nanoparticles (NPs) for oral administration that would increase its bioavailability and sustainability. Quality by design approach (23 full factorial design) was adopted to optimize CTX-loaded nanoparticles. The optimized formula (F2) was characterized through transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC). In vitro release behavior and stability study were also evaluated. Pharmacokinetic studies of enteric-coated hard gelatin capsules (HGCs) loaded with F2-NPs were finally assessed.

RESULTS

The optimized spherical F2-NPs had a mean particle size of 258 nm, zeta potential of about +30.1 and appreciable drug entrapment efficiency of 83%. The in vitro drug release profile of F2-NPs in pH 7.4 experienced biphasic configuration with an initial burst release for an hour, followed by a sustained release over 15 h with Higuchi model and non-Fickian diffusion mechanism (R2=0.9852). High stability upon storage at refrigerated and room temperature for 3 months and good flow properties (θ= 32.2 and HR= 1.13) of the optimized formula were also conferred. In vivo pharmacokinetic assessment in rabbits fruitfully displayed 92% absolute bioavailability of CTX.

CONCLUSION

The obtained results provide evidence for the potential combination of CH and SH in NPs preparation to enhance the oral bioavailability of CTX.

Formulation of carteolol chitosomes for ocular delivery: formulation optimization, ex-vivo permeation, and ocular toxicity examination

Background:Conventional delivery systems like solution and suspension are commonly used for the treatment of ocular diseases but have low corneal residence time and hence the duration of effect is limited. These drawbacks of conventional systems can be reduced by preparing bioadhesive chitosan (CH) coated noisome.Methods: Niosomes (NIM) of carteolol (CT) were developed by the thin-film hydration method and optimised by the Box-Behnken statistical design. Further, the optimised CT-NIM was coated with CH to enhance the ocular residence time . The optimised formulation was evaluated for vesicle size, entrapment efficiency, and in-vitro drug release and transcorneal permeation, histopathology, etc.Results: CT-NIM-opt showed the vesicle size and entrapment efficiency of 235 ± 3.54 nm, and 70.45 ± 0.87%, respectively. DSC spectra exhibited that CT was completely encapsulated into the CH-CT-NIM matrix. Drug release from CH-CT-NIM-opt was more sustained (68.28 ± 4.2%) than CT-NIM (75.69 ± 4.5% in 12 h) and CT solution (99.89 ± 2.8% in 4 h). The CH-CT-NIM-opt represented a strong bio-adhesion (89.76 ± 3.6%) than CT-NIM-opt (15.65 ± 3.4%). The permeation flux exhibited 1.13-fold higher permeation than CT-NIM and 3.23 fold than CT solution. The corneal hydration was found to be within the limit value. The histopathology study exhibited no structural damage to the cornea . HET-CAM results showed zero scores indicating no bleeding or haemorrhage. CH-CT-NIM-opt was found to be isotonic and exhibited good stability when stored at 4 °C for the stated duration of time.Conclusion: The above findings suggested that NIM can be a potential carrier for the delivery of CT with better ocular residence time.

Effective Ocular Delivery of Eplerenone Using Nanoengineered Lipid Carriers in Rabbit Model

Background

Eplerenone (Epl) is a selective mineralocorticoid-receptor antagonist used for chronic central serous chorioretinopathy treatment. Our goal was to enhance the corneal performance of Epl-loaded nanostructured lipid carriers (NLCs) through surface modification using different coating polymers.

Methods

Epl-loaded modified NLCs (Epl-loaded MNLCs) were prepared by coating the surface of Epl-loaded NLCs using different polymers, namely hyaluronic acid, chitosan oligosaccharide lactate, and hydrogenated collagen. A 3¹×4¹ full factorial design was used to evaluate the effect of the surface modification on the properties of the prepared systems. Selected optimal Epl-loaded MNLCs were further evaluated for in vitro drug release, morphology, pH, rheological properties, corneal mucoadhesion, irritation, and penetration.

Results

Epl-loaded MNLCs were successfully prepared with high drug-entrapment efficiency and nanosized particles with low size distribution. Transmission electron microscopy revealed nanosized spherical particles surrounded by a coating layer of the surface modifier. The pH, refractive index, and viscosity results of the Epl-loaded MNLCs confirmed the ocular compatibility of the systems with no blurring of vision. The safety and ocular tolerance of the optimal MNLCs were confirmed using the hen’s egg test on chorioallantoic membrane and by histopathological evaluation of rabbit eyes treated with the optimal systems. Confocal laser-scanning microscopy of corneal surfaces confirmed successful transcorneal permeation of the Epl-loaded MNLCs compared to the unmodified Epl-loaded NLCs, revealed by higher corneal fluorescence intensity at all time intervals.

Conclusion

Overall, the results confirmed the potential of Epl-loaded MNLCs as a direct approach for Epl ocular delivery.

Ocular microemulsion of brinzolamide: Formulation, physicochemical characterization, and in vitro irritation studies based on EpiOcular™ eye irritation assay

In recent years, the hydrophobic active substances have led researchers to develop new formulations to enhance bioavailability and dissolution rate; brinzolamide, a lipophilic drug belongs to carbonic anhydrase inhibitors, which cause reduction of intraocular pressure in patients suffering from glaucoma. Currently, the marketed product of brinzolamide is in the form of ocular drops; nonetheless, the conventional drops provide decreased therapeutic efficacy owing to their low bioavailability and pulsed drug release. Thus, the development of novel ocular formulations such as topical microemulsions is of high importance. In this work, the preparation of new microemulsions containing brinzolamide (0.2, 0.5 and 1% w/w) and comprised from isopropyl myristate, tween 80 and span 20 and Cremophor EL was performed. The obtained microemulsions were further characterized for their physicochemical properties. In addition, Fourier Transformed-Infrared spectroscopy was used touate the compatibility of active ingredients and components. In vitro release studies along with kinetic modeling were performed using the dialysis membrane method in simulated tear fluid. Bioadhesion studies were performed using Texture analysis. Finally, in vitro ocular irritation based on EpiOcular™ Eye Irritation Test and cytocompatibility studies was performed to examine any possible harm on ocular cells and predict in vivo safety profile.

Epithelium-Penetrable Nanoplatform with Enhanced Antibiotic Internalization for Management of Bacterial Keratitis

A standardized regimen for addressing the adverse effects of bacterial keratitis on vision remains an intractable challenge due to poor epithelial penetration and a short corneal retention time. In this study, a new strategy is proposed to implement the direct transport of antibiotics to bacteria-infected corneas via topical administration of an epithelium-penetrable biodriven nanoplatform, thereby enabling the efficacious treatment of bacterial keratitis. The nanoplatforms were composed of amphiphilic glycopolymers containing boron dipyrromethene and boronic acid moieties with stable fluorescence characteristics and the ability to potentiate epithelial penetration deep into the cornea. The boronic acid-derived nanoplatforms enabled efficient cellular internalization through the high affinity of boric acid groups for the diol-containing bacterial cell wall, resulting in enhanced drug penetration and retention inside the pathogenic bacteria. The bacterial cells formed agglomerations after incorporating the nanoplatforms along with a special mechanism to release the encapsulated cargo in response to in situ bacteria. Compared with the drug alone, this smart system achieved enhanced bacterial mortality and attenuated inflammation associated with Staphylococcus aureus-induced keratitis in rats, demonstrating a paradigm for targeted ocular drug delivery and an alternative strategy for managing bacterial keratitis or other bacterial infections by heightening corneal permeability and transcorneal bioavailability.

Cubogel as potential platform for glaucoma management

The aim of this work is to survey the potential of cubogel as an ocular dosage form to boost the corneal permeability of Dorzolamide Hydrochloride DZ; an antiglaucomal drug. DZ-loaded cubosomal dispersions were prepared according to Box-Behnken design, where the effect of independent variables; Monoolein MO concentration (2.5, 5 and 7.5%w/w), Pluronic^® F127 concentration (0.25, 0.5 and 0.75%w/w) and magnetic stirrer speed of (400, 800 and 1200 rpm) was studied on PS (nm), Zp (−mV) and Q 2 h (%) respectively. The prepared formulae were characterized via drug content DC (%), particle size PS (nm), polydispersity index PDI, zeta potential Zp (−mV), in-vitro drug release (Q 2 h%) and finally TEM. The optimized formulation composed of: 6.13% w/w of MO, 0.75% w/w of F127 and prepared at 1200 rpm stirring speed was chosen based on the criteria of minimum PS (nm), maximum Zp (−mV) and minimum Q 2 h (%). Results revealed that the optimum formula showed PS of 153.3 ± 8.4 n, Zp of 32 ± 3 −mV and 37.78 ± 1.3% released after 2 h. Carbopol 934 (1% w/v) as gelling agent was used to prepare the optimum cubogel, which was further evaluated by DSC, ex-vivo permeation and stability studies at 4 °C for three months. Moreover, in vivo studies of the optimized cubogel include; draize test, histological examination, confocal laser scanning microscopy (CLSM) and intraocular pressure (IOP) measurement. Results revealed that the optimized cubogel was considerably safe, stable and competent to corneal delivery as assured by draize and histological examination. CLSM showed a deeper penetration of more than 2.5-fold. A higher bioavailability (288.24 mg. h/ml) was attained from cubogel compared to the market product Trusopt^® eye drops (115.40 mg. h/ml) following IOP measurement. Therefore, DZ-loaded cubogel could be considered as promising delivery system to boost the transcorneal permeation hence corneal bioavailability of DZ as antiglaucomal drug.