Hydrogel-based hybrid membrane enhances in vitro ophthalmic drug evaluation in the OphthalMimic device.

Envisaging to improve the evaluation of ophthalmic drug products while minimizing the need for animal testing, our group developed the OphthalMimic device, a 3D-printed device that incorporates an artificial lacrimal flow, a cul-de-sac area, a moving eyelid, and a surface that interacts effectively with ophthalmic formulations, thereby providing a close representation of human ocular conditions. An important application of such a device would be its use as a platform for dissolution/release tests that closely mimic in vivo conditions. However, the surface that artificially simulates the cornea should have a higher resistance (10 min) than the previously described polymeric films (5 min). For this key assay upgrade, we describe the process of obtaining and thoroughly characterizing a hydrogel-based hybrid membrane to be used as a platform base to simulate the cornea artificially. Also, the OphthalMimic device suffered design improvements to fit the new membrane and incorporate the moving eyelid. The results confirmed the successful synthesis of the hydrogel components. The membrane's water content (86.25 ± 0.35 %) closely mirrored the human cornea (72 to 85 %). Furthermore, morphological analysis supported the membrane's comparability to the natural cornea. Finally, the performance of different formulations was analysed, demonstrating that the device could differentiate their drainage profile through the viscosity of PLX 14 (79 ± 5 %), PLX 16 (72 ± 4 %), and PLX 20 (57 ± 14 %), and mucoadhesion of PLXCS0.5 (69 ± 1 %), PLX16CS1.0 (65 ± 3 %), PLX16CS1.25 (67 ± 3 %), and the solution (97 ± 8 %). In conclusion, using the hydrogel-based hybrid membrane in the OphthalMimic device represents a significant advancement in the field of ophthalmic drug evaluation, providing a valuable platform for dissolution/release tests. Such a platform aligns with the ethical mandate to reduce animal testing and promises to accelerate the development of safer and more effective ophthalmic drugs.

OphthalMimic: A new alternative apparatus without animal tissue for the evaluation of topical ophthalmic drug products.

The necessity of animal-free performance tests for novel ophthalmic formulation screening is challenging. For this, we developed and validated a new device to simulate the dynamics and physical-chemical barriers of the eye for in vitro performance tests of topic ophthalmic formulations. The OphthalMimic is a 3D-printed device with an artificial lacrimal flow, a cul-de-sac area, a support base, and a simulated cornea comprised of a polymeric membrane containing poly-vinyl alcohol 10 % (w/v), gelatin 2.5 % (w/v), and different proportions of mucin and poloxamer, i.e., 1:1 (M1), 1:2 (M2), and 2:1 (M3) w/v, respectively. The support base is designed to move between 0° and 50° to replicate the movement of an eyelid. We challenged the model by testing the residence performance of poloxamer®407 16 % and poloxamer®407 16 % + chitosan 1 % (PLX16CS10) gels containing fluconazole. The test was conducted with a simulated tear flow of 1.0 mL.min-1 for 5 min. The OphthalMimic successfully distinguished PLX16 and PLX16C10 formulations based on their fluconazole drainage (M1: 65 ± 14 % and 27 ± 10 %; M2: 58 ± 6 % and 38 ± 9 %; M3: 56 ± 5 % and 38 ± 18 %). In conclusion, the OphthalMimic is a promising tool for comparing the animal-free performance of ophthalmic formulations.

A SU6668 pure nanoparticle-based eyedrops: toward its high drug Accumulation and Long-time treatment for corneal neovascularization.

Corneal neovascularization (CNV) is one of the common blinding factors worldwide, leading to reduced vision or even blindness. However, current treatments such as surgical intervention and anti-VEGF agent therapy still have some shortcomings or evoke some adverse effects. Recently, SU6668, an inhibitor targeting angiogenic tyrosine kinases, has demonstrated growth inhibition of neovascularization. But the hydrophobicity and low ocular bioavailability limit its application in cornea. Hereby, we proposed the preparation of SU6668 pure nanoparticles (NanoSU6668; size ~135 nm) using a super-stable pure-nanomedicine formulation technology (SPFT), which possessed uniform particle size and excellent aqueous dispersion at 1 mg/mL. Furthermore, mesenchymal stem cell membrane vesicle (MSCm) was coated on the surface of NanoSU6668, and then conjugated with TAT cell penetrating peptide, preparing multifunctional TAT-MSCm@NanoSU6668 (T-MNS). The T-MNS at a concentration of 200 µg/mL was treated for CNV via eye drops, and accumulated in blood vessels with a high targeting performance, resulting in elimination of blood vessels and recovery of cornea transparency after 4 days of treatment. Meanwhile, drug safety test confirmed that T-MNS did not cause any damage to cornea, retina and other eye tissues. In conclusion, the T-MNS eye drop had the potential to treat CNV effectively and safely in a low dosing frequency, which broke new ground for CNV theranostics.

Dual-ROS-scavenging and dual-lingering nanozyme-based eye drops alleviate dry eye disease.

Efficiently removing excess reactive oxygen species (ROS) generated by various factors on the ocular surface is a promising strategy for preventing the development of dry eye disease (DED). The currently available eye drops for DED treatment are palliative, short-lived and frequently administered due to the short precorneal residence time. Here, we developed nanozyme-based eye drops for DED by exploiting borate-mediated dynamic covalent complexation between n-FeZIF-8 nanozymes (n-Z(Fe)) and poly(vinyl alcohol) (PVA) to overcome these problems. The resultant formulation (PBnZ), which has dual-ROS scavenging abilities and prolonged corneal retention can effectively reduce oxidative stress, thereby providing an excellent preventive effect to alleviate DED. In vitro and in vivo experiments revealed that PBnZ could eliminate excess ROS through both its multienzyme-like activity and the ROS-scavenging activity of borate bonds. The positively charged nanozyme-based eye drops displayed a longer precorneal residence time due to physical adhesion and the dynamic borate bonds between phenyboronic acid and PVA or o-diol with mucin. The in vivo results showed that eye drops could effectively alleviate DED. These dual-function PBnZ nanozyme-based eye drops can provide insights into the development of novel treatment strategies for DED and other ROS-mediated inflammatory diseases and a rationale for the application of nanomaterials in clinical settings.

Preparation and in vivo and ex vivo studies of sirolimus nano-in-situ gel ophthalmic formulation.

Sirolimus (SR) is a macrolide with antifungal and antitumor immunosuppressant properties, classified as a selective inhibitor of mammalian target of rapamycin (mTOR). In this study, an ionic in situ gel of SR (SR-SUS-ISG) was formulated using gellan gum, exhibiting stability regardless of temperature and pH variations, causing minimal irritation. Harnessing the physiological conditions of the eye, SR-SUS-ISG underwent gelation upon contact with ions, increasing drug viscosity and prolonging retention on the ocular surface. Concurrently, SR-SUS-ISG displayed favorable shear dilution properties, reducing viscosity at ambient temperature, enhancing fluidity, and facilitating convenient packaging and transport. Biocompatibility assessments on both human corneal epithelial cells and rabbit eyes demonstrated that SR-SUS-ISG could well be tolerated. Pharmacokinetic investigations in rabbit ocular aqueous humor revealed sustained release, improved corneal penetration, and enhanced bioavailability. Additionally, in a rat corneal alkali burn model, SR-SUS-ISG exhibited inhibitory effects on corneal neovascularization, associated with decreased levels of the inflammatory factors VEGF and MMPs. These findings suggested that SR-SUS-ISG held promise as an effective ocular drug delivery system.

Green method by National Environmental Methods Index and Eco-Scale Assessment for evaluation of gatifloxacin-based product by HPLC.

The literature reveals gaps in the availability of green analytical methods for assessing products containing gatifloxacin (GFX), a fluoroquinolone. Presently, method development is supported by tools such as the National Environmental Methods Index (NEMI) and Eco-Scale Assessment (ESA), which offer objective insights into the environmental friendliness of analytical procedures. The objective of this work was to develop and validate a green method by the NEMI and ESA to quantify GFX in eye drops using HPLC. The method utilized a C8 column (4.6 × 150 mm, 5 µm), with a mobile phase of purified water containing 2% acetic acid and ethanol (70:30, v/v). The injection volume was 10 µL and the flow rate was 0.7 mL/min in isocratic mode at 25°C, with detection performed at 292 nm. The method demonstrated linearity in the range of 2-20 µg/mL, and precision at intra-day (relative standard deviation [RSD] 1.44%), inter-day (RSD 3.45%), and inter-analyst (RSD 2.04%) levels. It was selective regarding the adjuvants of the final product (eye drops) and under forced degradation conditions. The method was accurate (recovery 101.07%) and robust. The retention time for GFX was approximately 3.5 min. The greenness of the method, as evaluated by the NEMI, showed four green quadrants, and by ESA, it achieved a score of 88.

Cutting-edge HPLC and MCR techniques for synchronically quantifying anticholinergic drugs in the presence of C12 and C14 homologs: Robust application to green and white chemistry.

Green and white chemistry are vital to revolutionizing the chemical industry through their unparalleled potential to enhance sustainability and efficiency. In this study, nine sustainability tools of both green and white metrics, including green analytical procedure index (GAPI), ComplexGAPI, analytical greenness, analytical greenness metric for sample preparation, Analytical Eco-Scale (ESA), analytical method greenness score, high-performance liquid chromatography- environmental assessment tool (HPLC-EAT), analytical method volume intensity, and blue applicability grade index (BAGI), have been developed for appraising environmental friendliness for both innovative and straightforward mean centering of ratio spectra (MCR) and reversed-phase high-performance liquid chromatography (RP-HPLC) strategies utilized for concurrent analysis and separation of cyclopentolate (CYC) and C12 and C14 homologs of benzalkonium chloride (BNZ) in pure and ophthalmic solution. The mobile phase, formed of buffer phosphate and acetonitrile (35:65, v/v), was adjusted to pH 6.3, and 215-nm UV detection was used. The experimental flow rate was 2.0 mL min-1, and the analytical column was L11 Inertsil Ph-3 (150 mm × 4.6 mm, 5 µm). All sequences were run at 25°C in the column oven. The MCR approach effectively resolved the drug's spectral overlapping. CYC and BNZ employed this approach at 227.5 and 220.4 nm, respectively. As part of the HPLC analysis, an isocratic method was employed with phosphate buffer and acetonitrile in the mobile phase at 35:65. A correlation coefficient greater than 0.999 was observed between the calibration curves for the HPLC and MCR methods in the ranges of 20-320 µg mL-1 and 5-30 µg mL-1 for all drugs. The technique yields excellent primary recovery rates, ranging from 97.2% to 100.5%. The recommended approach has been validated according to International Council for Harmonization guidelines.

Clinical Effectiveness, Safety, and Compliance of Two Compounded Formulations of Tacrolimus Eye Drops: An Open-Label, Sequential Prospective Study.

Ophthalmic tacrolimus compounded formulations are usually made from the commercial intravenous presentation, which contains ethanol as a solubilizer due to the low solubility of tacrolimus. The use of cyclodextrins is presented as an alternative to ethanol, an ocular irritant excipient, to avoid its long-term irritant effects. Open-label, sequential, prospective study to compare effectiveness, safety, and adherence of a new formulation of 0.015% tacrolimus with cyclodextrins (TCD) versus 0.03% tacrolimus with ethanol (TE). The ocular evaluation was assessed by ocular signs, corneal staining, subjective questionnaires as Visual Function Questionnaire (VFQ-25) and Visual Analogue Scale (VAS) of symptoms, lacrimal stability, ocular redness, and intraocular pressure. Compliance was assessed by VAS of adherence and empirically (difference between theoretical and actual consumption). Clinical ocular signs and corneal staining score remained stable for most patients 3 months after switching formulations. The TCD formulation did not modify the tear stability and intraocular pressure of the treated patients compared to the TE formulation. TCD eye drops significantly decreased the subjective pain values on VFQ-25 scale and burning sensation on the VAS symptom scale in comparison to TE formulation after 3 months after the change to TCD formulation. The novel tacrolimus in cyclodextrins formulation is a promising alternative for treating inflammatory ocular pathologies refractory to first-line treatments.

Formulation and Development of Nanofiber-Based Ophthalmic Insert for the Treatment of Bacterial Conjunctivitis.

A novel ophthalmic delivery system utilizing levofloxacin-loaded, preservative-free, nanofiber-based inserts was investigated. Polyvinyl alcohol (PVA) and Poloxamer 407 (Polox)were employed as matrix materials, while hydroxypropyl-beta-cyclodextrin (HP-ß-CD) was a solubilizer. The formulations were prepared via electrospinning and characterized for fiber morphology, drug dissolution, cytotoxicity, and antimicrobial activity. Scanning electron microscopy confirmed uniform fibrous structures. Fourier Transform Infrared spectroscopy and X-ray diffraction analyses demonstrated the amorphous state of levofloxacin within the fibers. In vitro dissolution studies revealed a rapid (within 2 min) and complete drug release, with higher HP-ß-CD levels slightly delaying the release. Cytotoxicity tests showed increased HP-ß-CD concentrations induced irritation, that was mitigated by sodium hyaluronate. The antimicrobial efficacy of the nanofibers was comparable to conventional eye drops, with lower minimum inhibitory concentrations for most tested strains. The nanofibrous formulation prepared from a PVA-Polox-based viscous solution of the drug:CD 1:1 mol ratio, containing 0.4% (w/w) sodium hyaluronate) was identified as a particularly promising alternative formulation due to its rapid and complete dissolution, good biocompatibility, and effective antimicrobial properties. Its gelling properties indicate that the residence time on the eye surface can be increased, potentially reducing discomfort and enhancing therapeutic outcomes. The nanofibrous formulations enhanced antimicrobial efficacy, providing a preservative-free alternative that minimizes the potential eye irritation that might occur because of the preservative agent and reduces the administrated dose frequency by extending the drug's retention time on the eye's surface. Subsequently, it improves patients' adherence, which would reflect positively on the bioavailability. The levofloxacin-HP-ß-CD nanofibers demonstrate promise as an alternative to traditional eye drops, offering advantages in solubility, stability, and patient compliance for ocular infection treatment.

Keratin Formed Bioadhesive Ophthalmic Gel for the Bacterial Conjunctivitis Treatment.

Keratin has the potential to function as the gel matrix in an ophthalmic formulation for the encapsulation of the macrolide antibiotic azithromycin. The quality of this formulation was thoroughly evaluated through various analyses, such as in vitro release assessment, rheological examination, intraocular retention studies in rabbits, assessment of bacteriostatic efficacy, and safety evaluations. It is worth mentioning that the gel demonstrated shear thinning properties and exhibited characteristics of an elastic solid, thereby confirming its structural stability. The gel demonstrated a notable affinity for mucosal surfaces in comparison to traditional azithromycin aqueous solutions. In vitro release testing revealed that drug release transpired via diffusion mechanisms, following a first-order kinetic release pattern. Additionally, the formulated gel exhibited remarkable antibacterial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa in bacteriostatic evaluations. Lastly, safety assessments confirmed that the gel eye drops induced minimal irritation and displayed no apparent cytotoxicity, indicating their good safety and biocompatibility for ocular application. Thus, these findings indicated that the prepared azithromycin gel eye drops complied with the requisite standards for ophthalmic preparations.

Aqueous eye drop formulations: Cyclodextrins as enabling excipients.

Cyclodextrins are enabling pharmaceutical excipients that solubilize and stabilize drugs in aqueous formulations. Cyclodextrins possess very favorable pharmacokinetic and toxicological profiles and are commonly used in marketed drug products for oral and parenteral administration. However, their use in ophthalmic products is still very limited. Cyclodextrins have a broad range of physical properties that are specifically appropriate for designing topical ophthalmic dosage forms. Additionally, both the regulatory and intellectual property environments have been cleared over the last years and should foster their use for designing new drugs for ophthalmic use.

A review on topical ophthalmic drug delivery system: Reference to viscosity enhancer.

The eye is the most accessible site for topical drug delivery. Drug's ocular bioavailability is quite low when administered topically as eye drops. Viscosity enhancers are used to increase ocular bioavailability by extending the precorneal residence time of the drug at the ocular site. Cellulose, polyalcohol and polyacrylic acid are examples of hydrophilic viscosity enhancers. The addition of viscosity modifiers increases the amount of time the drug is in contact with the ocular surface. Several polysaccharides have been studied as excipients and viscosity boosters for ocular formulations, including cellulose derivatives such as chitosan (CS), xyloglucan and arabinogalactan (methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose (HPMC), and sodium carboxymethylcellulose). Viscosity-increasing substances reduce the surface tension, extend the corneal contact time, slow the drainage, and improve the bioavailability. Chitosan is a viscosity enhancer that was originally thought to open tight junction barrier cells in the epithelium. Chitosan thickens the medication solution and allows it to penetrate deeper. Alginate is an anionic polymer with carboxyl end groups that has the highest mucoadhesive strength and is used to improve penetration. Carboxymethylcellulose (CMC), a polysaccharide with a high molecular weight, is one of the most common viscous polymers used in artificial tears to achieve their longer ocular surface residence period. Hyaluronic acid (HA) is biocompatible and biodegradable in nature, and it is available in ocular sustained-release dose forms. A polymer known as xanthan gum is used to increase viscosity. At 0.2% concentration, carbomer forms a highly viscous gel.

New Candidate Preservative in Ophthalmic Solution Instead of Benzalkonium Chloride: 1,3-Didecyl-2-methyl Imidazolium Chloride.

Benzalkonium chloride (BAC) is a useful preservative for ophthalmic solutions but has some disadvantageous effects on corneal epithelium, especially keratinocytes. Therefore, patients requiring the chronic administration of ophthalmic solutions may suffer from damage due to BAC, and ophthalmic solutions with a new preservative instead of BAC are desired. To resolve the above situation, we focused on 1,3-didecyl-2-methyl imidazolium chloride (DiMI). As a preservative for ophthalmic solutions, we evaluated the physical and chemical properties (absorption to a sterile filter, solubility, heat stress stability, and light/UV stress stability), and also the anti-microbial activity. The results indicated that DiMI was soluble enough to prepare ophthalmic solutions, and was stable under severe heat and light/UV conditions. In addition, the anti-microbial effect of DiMI as a preservative was considered to be stronger than BAC. Moreover, our in vitro toxicity tests suggested that DiMI is safer to humans than BAC. Considering the test results, DiMI may be an excellent candidate for a new preservative to replace BAC. If we can overcome manufacturing process issues (soluble time and flushing volume) and the insufficiency of toxicological information, DiMI may be widely adopted as a safe preservative, and immediately contribute to the increased well-being of all patients.

Development of Fenofibrate/Randomly Methylated ß-Cyclodextrin-Loaded Eudragit® RL 100 Nanoparticles for Ocular Delivery.

Fenofibrate (FE) has been shown to markedly reduce the progression of diabetic retinopathy and age-related macular degeneration in clinical trials and animal models. Owing to the limited aqueous solubility of FE, it may hamper ocular bioavailability and result in low efficiency to treat such diseases. To enhance the solubility of FE, water-soluble FE/cyclodextrin (CD) complex formation was determined by a phase-solubility technique. Randomly methylated-ß-CD (RMßCD) exhibited the best solubility and the highest complexation efficiency (CE) for FE. Additionally, water-soluble polymers (i.e., hydroxypropyl methyl cellulose and polyvinyl alcohol [PVA]) enhanced the solubility of FE/RMßCD complexes. Solid- and solution-state characterizations were performed to elucidate and confirm the formation of inclusion FE/RMßCD complex. FE-loaded Eudragit® nanoparticle (EuNP) dispersions and suspensions were developed. The physicochemical properties (i.e., pH, osmolality, viscosity, particle size, size distribution, and zeta potential) were within acceptable ranges. Moreover, in vitro mucoadhesion, in vitro release, and in vitro permeation studies revealed that the FE-loaded EuNP eye drop suspensions had excellent mucoadhesive properties and sustained FE release. The hemolytic activity, hen's egg test on chorioallantoic membrane assay, and in vitro cytotoxicity test showed that the FE formulations had low hemolytic activity, were cytocompatible, and were moderately irritable to the eyes. In conclusion, PVA-stabilized FE/RMßCD-loaded EuNP eye drop suspensions were successfully developed, warranting further in vivo testing.

Construction and Evaluation of Hyaluronic Acid-Coated Flurbiprofen-Layered Double Hydroxide Ocular Drug Delivery System.

In this study, flurbiprofen (FB) was selected as the model drug, and hyaluronic acid-coated flurbiprofen-layered double hydroxide ophthalmic drug delivery system (HA-FB-LDH) was designed and prepared. In this system, the model drug flurbiprofen was intercalated in layered double hydroxide and coated with hyaluronic acid (HA), so as to prolong the corneal residence time and increase the corneal permeability of the drug. Layered double hydroxide (LDH) was prepared by alcohol-water coprecipitation method. Through single factor investigation, the optimum preparation conditions were obtained as follows: The Mg/Al ratio was 2:1, the reaction pH was 11.0, the hydrothermal reaction time was 24 h, and the hydrothermal reaction temperature was 100°C. Under these conditions, the particle size of LDH was 116.4 ± 0.8 nm, the potential was 42.2 ± 1.2 mV, and a relatively regular crystal structure could be had. Then FB was intercalated into the LDH layer to prepare flurbiprofen-layered double hydroxide (FB-LDH). In the end, HA-FB-LDH was prepared by the stirring-ultrasonic method, in which through prescription screening, the molecular weight of HA was 200-400 kDa and the concentration of HA solution was 1.25 mg·mL -1, the final particle size of HA-FB-LDH was 185.8 ± 3.3 nm, and potential of - 31.4 ± 0.7 mV. The successful loading of FB and the coating of HA were verified by XRD, FTIR, TGA, TEM, and other characterization methods. The results of in vitro stability experiment indicated that the coating of HA could significantly enhance the stability of LDH in the presence of electrolytes. The in vitro release results suggested that the cumulative release amounts of FB-LDH and HA-FB-LDH within 12 h were 92.99 ± 0.37% and 74.82 ± 0.29% respectively, showing a certain sustained release effect. At the same time, the release mechanism of FB-LDH was preliminarily explored by in vitro release experiment, which proved that the release mechanism of FB-LDH was mainly ion exchange. The results of in vivo ocular irritation experiments demonstrated that the ophthalmic preparation studied in this paper was safe and non-irritating. The results of tear pharmacokinetics in rabbits showed that the area under the curve(AUC), the average residence time (MRT), and the highest concentration (Cmax) in tears in the HA-FB-LDH group were 4.43, 4.48, and 2.27 times higher than those in eye drops group separately. Furthermore, the AUC of the HA-FB-LDH group was 1.48 times higher than that of the FB-LDH group. The above results suggested that HA-FB-LDH could improve the precorneal residence time. The results of aqueous humor pharmacokinetics in rabbits indicated that the AUC, MRT, and maximum concentration (Cmax) in aqueous humor in the HA-FB-LDH group were 6.88, 2.15, and 4.08 times of those in the eye drop group respectively. Additionally, the AUC and MRT of the HA-FB-LDH group were 1.55 and 1.63 times those of the FB-LDH group separately. These mentioned findings verified that HA-FB-LDH could enhance the corneal permeability of the drug. The fluorescent substance-fluoresce isothiocyanate (FITC) was substituted for FB intercalation in LDH for in vitro tissue imaging study of rabbits, whose results stated clearly that FITC-LDH and HA-FITC-LDH could both prolong the precorneal residence time of drugs, and HA-FITC-LDH could increase the corneal permeability of the drug to a certain extent. To sum up, HA-FB-LDH, which can overcome the shortcomings of low bioavailability of traditional eye drops to a certain degree, is a safe and effective ophthalmic drug delivery system.

Graphene Family Nanomaterials in Ocular Applications: Physicochemical Properties and Toxicity.

Graphene family nanomaterials (GFNs) are rapidly emerging for ocular applications due to their outstanding physicochemical properties. Since the eyes are very sensitive organs and the contact between the eyes and GFNs in eye drops, contact lenses, intraocular drug delivery systems and biosensors and even the workers handling these nanomaterials is inevitable, it is necessary to investigate their ocular toxicities and physiological interactions with cells as well as their toxicity mechanisms. The toxicity of GFNs can be extremely affected by their physicochemical properties, including composition, size, surface chemistry, and oxidation level as well as dose and the time of exposure. Up to now, there are several studies on the in vitro and in vivo toxicity of GFNs; however, a comprehensive review on ocular toxicity and applications of GFNs is missing, and a knowledge about the health risks of eye exposure to the GFNs is predominantly unspecified. This review highlights the ocular applications of GFNs and systematically covers the most recent advances of GFNs' physicochemical properties, in vitro and in vivo ocular toxicity, and the possible toxicity mechanisms as well as provides some perspectives on the potential risks of GFNs in material development and biomedical applications.

Generation of Ophthalmic Nanosuspension of Prednisolone Acetate Using a Novel Technology.

PURPOSE: Prednisolone Acetate (PAC) is currently marketed as micronized ophthalmic suspension. The microsuspension has poor dose accuracy and efficacy due to aggregation, slow dissolution rate and limited corneal residence. The ophthalmic nanosuspension of PAC shall show enhanced solubility, dissolution rate and corneal adhesion due to small particle size and increased surface area. METHODS: In the current work, we prepared ophthalmic formulation of PAC using a novel, spray drying based technology. Firstly, PAC nanocrystalline solid dispersions (NCSD) were prepared using Mannitol (MAN) as the crystallization inducing excipient and two separate stabilizers, Polyvinyl Alcohol (PAC_MAN_PVA) and Vitamin E Tocopheryl Polyethylene Glycol Sulphosuccinate (PAC_MAN_TPGS). The NCSD was dispersed in an aqueous vehicle to obtain an ophthalmic nanosuspension. RESULTS: The composition, PAC_MAN_PVA (0.3:0.67:0.03%), was pursued due to absence of crystal growth on storage at 40°C/75%RH for 3 months. The resulting nanosuspension showed crystal size, osmolality and viscosity of 590 ± 165 nm, 297 ± 6 mOsm/L and 11 ± 8cP respectively. In 1%w/v SLS media, the nanosuspension showed rapid and complete dissolution of PAC in 120 s. Ex-vivo goat corneal permeation and adhesion study revealed that in comparison to microsuspension, a higher fraction (6.2 times) of nanosuspension adhered to the cornea. Safety studies performed using corneal histopathology and Hen Egg Test- Chorio Allantoic Membrane (HET-CAM) assay showed no physical change in cornea or capillary damage, respectively. CONCLUSIONS: The NCSD can be explored for generation of ophthalmically acceptable nanosuspensions of poorly soluble drugs.

Metabolomics comparison of cord and peripheral blood-derived serum eye drops for the treatment of dry eye disease.

Allogeneic peripheral blood-derived (PBS) serum eye drops have been largely used in the treatment of dry eye disease (DED). Recently, cord blood has emerged as an effective alternative serum source (cord blood serum, CBS), containing a higher amount of growth factors than PBS, it holds the promise of a better capability to stimulate corneal healing. However, the lack of a standardized method for preparation, dispensation, storage and a poor biochemical characterization still hamper the establishment of a clinical consensus. Here the metabolomes of the two different serum eye drop preparations were compared using proton nuclear magnetic resonance spectroscopy. We found that both PBS and CBS contained several organic compounds, the majority of them already detected in human tears and may be thereby considered lacrimal substitutes. Metabolites having in the multivariate statistical analysis Partial least squares discriminant analysis (PLS-DA) a VIP scores > 1.0 were considered to be significantly different. All the metabolites identified were found to have a p < 0.05 in the univariate analysis. CBS, in particular, showed the highest amount of choline, myo-inositol, glutamine, creatine and ß-hydroxybutyrate. These evidences constitute relevant advances towards serum eye drops characterization and confirm that cord blood is a valid alternative source of serum eye drops.

Olive Pomace Phenolic Compounds Stability and Safety Evaluation: From Raw Material to Future Ophthalmic Applications.

Nowadays, increasing interest in olive pomace (OP) valorization aims to improve olive's industry sustainability. Interestingly, several studies propose a high-value application for OP extracts containing its main phenolic compounds, hydroxytyrosol and oleuropein, as therapy for ocular surface diseases. In this work, the stability and accessibility of OP total phenolic and flavonoid content, main representative compounds, and antioxidant activity were assessed under different pretreatment conditions. Among them, lyophilization and supercritical CO2 extraction were found to increase significantly most responses measured in the produced extracts. Two selected extracts (CONV and OPT3) were obtained by different techniques (conventional and pressurized liquid extraction); Their aqueous solutions were characterized by HPLC-DAD-MS/MS. Additionally, their safety and stability were evaluated according to EMA requirements towards their approval as ophthalmic products: their genotoxic effect on ocular surface cells and their 6-months storage stability at 4 different temperature/moisture conditions (CPMP/ICH/2736/99), together with pure hydroxytyrosol and oleuropein solutions. The concentration of hydroxytyrosol and oleuropein in pure or extract solutions was tracked, and possible degradation products were putatively identified by HPLC-DAD-MS/MS. Hydroxytyrosol and oleuropein had different stability as standard or extract solutions, with oleuropein also showing different degradation profile. All compounds/extracts were safe for ophthalmic use at the concentrations tested.

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.