Effect of hypotonic 0.18% sodium hyaluronate eyedrops on inflammation of the ocular surface in experimental dry eye

Tear film stability in patients with symptoms of dry eye after instillation of dual polymer hydroxypropyl guar/sodium hyaluronate vs single polymer sodium hyaluronate

PURPOSE

This study evaluated the tear film stability in patients with symptoms of dry eye after installation of dual polymer hydroxypropyl guar/sodium hyaluronate (DPHG/SH) vs single polymer SH.

METHODS

Patients with recently diagnosed mild to moderate dry eye disease (OSDI score 23-32 points) were included. For each patient, the right eye was randomized to receive DPHG/SH or 0.15% SH. Just after the administration of the drop to the right eye, the fellow eye received the other eye drop. The first non-invasive Keratograph first break-up time (NIKBUT), average NIKBUT and tear meniscus height (TMH) were measured before administration of the eye drops, at 1-min, 15 min, 30 min, 60 min, 90 min, and 120 min after instillation.

RESULTS

A total of 29 patients aged 22.8 ± 2.2 years participated in the study (21 women). No differences between the eye receiving DPHG/SH and single polymer SH were observed for the first NIKBUT (p = 0.45) and average NIKBUT (p = 0.24) variables at any time point. Both DPHG/SH and single polymer SH increased the TMH (p of time effect < 0.001), but with no difference between groups (p = 0.95).

CONCLUSION

Both DPHG/SH and single polymer SH solutions provide lubrication of the eye surface, however, with no difference in NIKBUT and TMH evaluations for up to two hours following administration.

Polysaccharides in contact lenses: From additives to bulk materials

As the number of applications has increased, so has the demand for contact lenses comfort. Adding polysaccharides to lenses is a popular way to enhance comfort for wearers. However, this may also compromise some lens properties. It is still unclear how to balance the variation of individual lens parameters in the design of contact lenses containing polysaccharides. This review provides a comprehensive overview of how polysaccharide addition impacts lens wear parameters, such as water content, oxygen permeability, surface wettability, protein deposition, and light transmittance. It also examines how various factors, such as polysaccharide type, molecular weight, amount, and mode of incorporation into lenses modulate these effects. Polysaccharide addition can improve some wear parameters while reducing others depending on the specific conditions. The optimal method, type, and amount of added polysaccharides depend on the trade-off between various lens parameters and wear requirements. Simultaneously, polysaccharide-based contact lenses may be a promising option for biodegradable contact lenses as concerns regarding environmental risks associated with contact lens degradation continue to increase. It is hoped that this review will shed light on the rational use of polysaccharides in contact lenses to make personalized lenses more accessible.

A Critical Appraisal of the Physicochemical Properties and Biological Effects of Artificial Tear Ingredients and Formulations

Dry eye disease is among the most prevalent diseases affecting the ocular surface. Artificial tears remain the cornerstone therapy for its management. There are currently a wide variety of marketed artificial tears available to choose from. These artificial tears differ significantly in their composition and formulation. This article reviews the physicochemical and biological properties of artificial tear components and how these characteristics determine their use and efficacy in the management of dry eye. Furthermore, this article also discusses the various formulations of artificial tears such as macro and nanoemulsion and the type of preservatives present in them.

Collecting and deactivating TGF-β1 hydrogel for anti-scarring therapy in post-glaucoma filtration surgery

Scar formation can lead to glaucoma filtration surgery (GFS) failure, wherein transforming growth factor (TGF)-β is the core regulator. To reducing scar formation, this paper presents our study on the design of hydrogels to deactivate TGF-β1. We hypothesized that excess TGF-β1 can be removed from aqueous humor through the addition of oxidized hyaluronic acid (O-HA) hydrogels that are seeded with decorin (O-HA ​+ ​D). Immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were performed to demonstrate the adsorption properties of O-HA ​+ ​D hydrogel, thus reducing the TGF-β1 concentration in aqueous humor. In the light that collagen contraction in human Tenon's capsule fibroblasts (HTFs) and the angiogenesis of human umbilical vein endothelial cells (HUVECs) can be activated by TGF-β1 and β2, we performed the quantitative analysis of polymerase chain reaction to determine the effect of O-HA ​+ ​D on the type I collagen, fibronectin, and angiogenesis. Our results illustrate that O-HA ​+ ​D can inhibit the increase of α-SMA expression in HTF induced by TGF-β1 and that O-HA ​+ ​D can inhibit the production of collagen I and fibronectin in HTF treated with TGF-β1. Furthermore, we performed in vivo studies by employing a rabbit model, where rabbits were treated with hydrogels post GFS. Our results demonstrate that, as compared with other groups, the rabbits treated with O-HA ​+ ​D had the greatest reduction in inflammatory cells with reduced level of collagen in wounds. Taken together, the present study paves the way toward the treatment of post-glaucoma fibrosis following surgery.

Effects of eye drops containing a mixture of 3% diquafosol sodium and tocopherol acetate (vitamin E) on the ocular surface of murine dry eye

PURPOSE

To investigate the efficacy of topical application of 3% diquafosol sodium (DQS) and tocopherol (TCP) acetate mixtures in a mouse model of experimental dry eye (EDE).

METHODS

After exposure to desiccating stress for 5 days, eye drops consisting of 3% DQS alone, 0.01% TCP alone, or 3% DQS and 0.005% or 0.01% TCP mixture were applied for the treatment of EDE. Tear volume, tear film break-up time (TBUT), corneal fluorescein staining scores (CFSS), and tear film lipid layer grades (TFLLG) were measured at 0, 5 and 10 days after treatment. The 2',7'-dichlorodihydrofluorescein diacetate assay (DCFDA) for reactive oxygen species (ROS) production, enzyme-linked immunosorbent assay (ELISA) for malondialdehyde (MDA), and flow cytometry for CD4 + interferon (IFN)-γ+ T cells were evaluated on the ocular surface at 10 days after treatment. In addition, levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and chemokine CC motif ligand 4 (CCL4) in the conjunctiva were measured using a multiplex immunobead assay, and conjunctival goblet cells were counted by periodic acid-Schiff staining at 10 days after treatment.

RESULTS

Both the TCP mixture groups indicated a significant improvement in TBUT, ROS production, and MDA concentrations compared to those in the DQS alone group. Furthermore, the 0.01% TCP mixture group also showed higher tear film lipid layer grades and conjunctival goblet cell density and lower corneal fluorescein staining scores, number of CD4 + IFN-γ+ T cells, and levels of TNF-α, IL-1β, and CCL4 than the DQS alone group (P < 0.05).

CONCLUSIONS

Application of eye drops containing the mixture of DQS and TCP could stabilize the tear film lipid layer, improve TBUT and corneal epithelial damages, decrease ROS production, inflammatory molecules, and T cells, and increase conjunctival goblet cell density on the ocular surface. Topical DQS and TCP mixtures may have a greater therapeutic effect on clinical signs, oxidative damage, and inflammation of dry eye than DQS eye drops.

Cross-linked hyaluronic acid viscoelastic scleral implant in trabeculectomy

Purpose:

Patients with glaucoma undergoing trabeculectomy develop bleb cicatrix causing poor postoperative intraocular pressure (IOP) control and low success rates. Several approaches have been explored over the years for better outcomes. This study assesses the safety, efficacy, and outcome of trabeculectomy with HealaFlow^® (Anteis S. A, Geneva, Switzerland), a high-molecular-weight cross-linked hyaluronic acid viscoelastic gel, and comparing it with the antimetabolite Mitomycin-C (MMC).

Methods:

A prospective, interventional, case-controlled study conducted at a tertiary care hospital in Southern India on 60 eyes of patients requiring trabeculectomy divided in two groups – HealaFlow scleral implant and adjuvant low-dose MMC (0.1 mg/mL). Postoperative IOP reduction along with bleb morphology was assessed over follow-up at 1 week, 1 month, 3 months, 6 months, and 12 months.

Results:

Preoperatively IOP in the two groups was statistically similar. Postoperative IOP on day 1 had statistically significant reduction in both groups with greater reduction in MMC group. However, by 12 months, the IOP reduction was statistically similar in both groups, i.e., 46.24% (to 11.04 ± 2.55 mmHg) and 54.47% (to 11.99 ± 3.37 mmHg) in HealaFlow^® group and MMC group, respectively (P > 0.05). The bleb morphologies were similar and complications were seen equally, which resolved by 4 weeks. A complete success rate of 89.29% and a qualified success rate of 10.71% were observed equally in both groups.

Conclusion:

Absorbable biosynthetic cross-linked hyaluronic acid and low-dose MMC are equally safe and efficacious in trabeculectomy with significant IOP reduction and good bleb morphology. Therefore, it is a novel substitute for MMC.

Biopharmaceutical Assessment of Dexamethasone Acetate-Based Hydrogels Combining Hydroxypropyl Cyclodextrins and Polysaccharides for Ocular Delivery

We previously developed two optimized formulations of dexamethasone acetate (DXMa) hydrogels by means of special cubic mixture designs for topical ocular administration. These gels were elaborated with hydroxypropyl-β-CD (HPβCD) and hydroxypropyl-γ-CD (HPγCD) and commercial hydrogels in order to enhance DXMa water solubility and finally DXMa's ocular bioavailability and transcorneal penetration. The main objective of this study was to characterize them and to evaluate in vitro, ex vivo, and in vivo their safety, biopermanence, and transcorneal permeation. Gels A and B are Newtonian fluids and display a viscosity of 13.2 mPa.s and 18.6 mPa.s, respectively, which increases their ocular retention, according to the in vivo biopermanence study by PET/CT. These hydrogels could act as corneal absorption promoters as they allow a higher transcorneal permeation of DXMa through porcine excised cornea, compared to DEXAFREE^® and MAXIDEX^®. Cytotoxicity assays showed no cytotoxic effects on human primary corneal epithelial cells (HCE). Furthermore, Gel B is clearly safe for the eye, but the effect of Gel A on the human eye cannot be predicted. Both gels were also stable 12 months at 25 °C after sterilization by filtration. These results demonstrate that the developed formulations present a high potential for the topical ocular administration of dexamethasone acetate.

A Sensitive Chromatographic Method for Hyaluronate Quantification Applied to Analyze the Desorption Behavior on Contact Lenses

Background:

Sodium hyaluronate (NaHA) is generally supplemented in products related to contact lenses for increasing comfort during wearing. The quantity of sodium hyaluronate and the material of lenses affect the retention of sodium hyaluronate on the contact lenses.

Methods:

We developed a convenient and sensitive but unconventional chromatographic method to quantify sodium hyaluronate and analyze its release behavior from contact lenses. The reverse-phase chromatography eluted sodium hyaluronate with high molecular masses in the shortest time and could separate salt and small compounds from sodium hyaluronate.

Results:

This method could accurately quantify sodium hyaluronate with diverse molecular sizes. Because sodium hyaluronate was eluted in a narrow time frame, sensitivity was significantly enhanced, and the limit of detection of this method was 0.45 μg/mL. According to this quantitation method, the attached quantity of sodium hyaluronate is related to the water content of the material. Furthermore, a material test indicated that the release efficiency of sodium hyaluronate depends on the material of lenses. Nonionic Polymacon had a longer half-life in the sodium hyaluronate release curve than negative Methafilcon A and silicone hydrogel.

Conclusion:

This hyaluronate quantification method is a fast, sensitive and accurate method, making it suitable for the in vitro hyaluronate research without further derivatization.

Effects of Eurya japonica extracts on human corneal epithelial cells and experimental dry eye

Eurya japonica (EJ) leaves have been indicated to exert anti-oxidative and anti-inflammatory effects. Dry eye disease (DED) is a chronic inflammatory disease and oxidative stress is closely associated with DED. The aim of the present study was to analyze the therapeutic efficacy of EJ in DED using human corneal epithelial (HCE) cells and a mouse model of experimental dry eye (EDE). EJ extracts (0.001, 0.01 and 0.1%) were used to treat HCE cells. Cell viability and mitochondrial function were detected using a EZ-Cytox cell viability assay kit and mitochondrial membrane potential assays. Dichlorofluorescein diacetate (DCF-DA) assay was used to measure cellular reactive oxygen species (ROS) levels. Subsequently, eye drops consisting of BSS or 0.001%, 0.01 and 0.1% EJ extracts were applied for treatment of EDE. At 7 days, conjunctival ROS production was measured using a DCF-DA assay. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, 10 kDa interferon gamma-induced protein 10 (IP-10) and monokine induced by interferon-γ (MIG) levels in the conjunctiva were analyzed using a multiplex immunobead assay. Tear film and ocular surface parameters were measured. Treatment with EJ extracts in HCE cells effectively improved cell viability, ROS levels and mitochondrial function. Mice treated with 0.01 and 0.1% EJ extracts indicated a significant decrease in ROS, TNF-α, IL-1β, IP-10 and MIG levels compared with the EDE or BSS groups. Furthermore, a significant improvement in all clinical parameters was observed in the 0.01 and 0.1% EJ extract groups. EJ extracts could decrease cytotoxicity and ROS production in HCE cells. Additionally, topical EJ extracts reduced oxidative damage and inflammation and improved clinical signs of EDE, suggesting that EJ extracts may be used as an adjunctive therapy for DED.

Anti-inflammatory effects of paeoniflorin from Paeonia lactiflora Pall. on human corneal epithelial cells and a mouse model of dry eye disease

Dry eye disease (DED) is characterized by increased osmolality of tears due to a lack of production or increased evaporation of tears.

Five Years' Outcomes of Trabeculectomy with Cross-linked Sodium Hyaluronate Gel Implantation for Chinese Glaucoma Patients

Background:

Trabeculectomy is the most efficient surgical treatment. Prevention failure of bleb cicatrix would lead to unsatisfactory postoperative intraocular pressure (IOP) controlling and unsatisfactory success rate. The aim of this study was to evaluate the 5-year outcomes of trabeculectomy with a cross-linked sodium hyaluronate gel implantation for Chinese glaucoma patients.

Methods:

This is a prospective, case-controlled study. Patients who were to be applied first-time trabeculectomy in the Department of Ophthalmology of Peking University Third Hospital between 2010 and 2012 were included in the study. Totally, 60 eyes were randomly assigned to the trabeculectomy group (TA group) or the trabeculectomy with cross-linked sodium hyaluronate gel implantation group (TH group). Follow-up was finished at 1 week, 1 month, 3 months, 1 year, 3 years, and 5 years after the operation. The statistical index of demographic data, IOP, bleb shape, and any complications or medications or surgical procedures were recorded and assessed by SPSS 19.0 software through independent t-test, one-way analysis of variance (ANOVA) and Pearson's Chi-square test, respectively.

Results:

The baseline IOP was comparable between the two groups (t= −1.00, P= 0.32) while the postoperative IOP was significantly lower in the TH group at 1, 3 and 5 years' time points (P = 0.00, P= 0.01 and P = 0.01, respectively). According to the Indiana Bleb Appearance Grading Scale, the height and extent of bleb were better in the TH group at all follow-up time points (P < 0.05), however, the comparison of bleb vascularity showed no statistical difference (P > 0.05). TA group had a higher percentage of complications (13% vs. 3%) compared to TH group; however, there was no statistical difference in the comparison of each statistical item (P > 0.05, respectively). The complete success at 5 years was higher in the TH group than that in the TA group (78% vs. 54%, P = 0.03).

Conclusion:

Our results suggested that implantation of cross-linked sodium hyaluronate gel with trabeculectomy was more efficient and would improve the prognosis of glaucoma patients.

Comparison of 0.1%, 0.18%, and 0.3% Hyaluronic Acid Eye Drops in the Treatment of Experimental Dry Eye

PURPOSE

To compare the efficacy of 0.1%, 0.18%, and 0.3% hyaluronic acid (HA) artificial tear in the treatment of experimental dry eye (EDE).

METHODS

EDE was established in female C57BL/6 mice through an air draft and subcutaneous scopolamine injection. The mice were divided into 5 groups according to topical treatment regimens (n = 5 each): EDE control, balanced salt solution (BSS), preservative-free 0.1% HA, 0.18% HA, and 0.3% HA. The tear film break-up time (TBUT) and corneal fluorescein staining scores were measured 5, 10, 14, 21, and 28 days after treatment. The corneal smoothness scores were measured. In addition, periodic acid-Schiff (PAS) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed.

RESULTS

The values for TBUT and corneal fluorescein staining showed greater improvements in all the HA groups (P < 0.05) than in the EDE and BSS groups after 10 days of treatment. Mice treated with 0.3% HA showed a more significant improvement in all clinical parameters than did those in the EDE control, BSS, 0.1% HA, and 0.18% HA groups (all P < 0.05) after 28 days of treatment. The goblet cell counts were higher in the 0.3% and 0.18% HA groups than in the 0.1% HA group. The number of TUNEL-positive cells was the lowest in the 0.3% HA group.

CONCLUSIONS

In EDE, 0.3% HA artificial tears are more effective than the 0.1% and 0.18% HA in improving tear film instability and ocular surface staining and irregularity, in increasing the number of conjunctival goblet cells, and in decreasing corneal epithelial apoptosis.

Osmoprotectants, carboxymethylcellulose and hyaluronic acid multi-ingredient eye drop: a randomised controlled trial in moderate to severe dry eye

Purpose

To assess the safety and efficacy of an eye drop combining osmoprotectants, carboxymethylcellulose and hyaluronic acid (O/CMC/HA) in reducing symptomatic, moderate to severe dry eye, compared with HA.

Methods

In this investigator-masked, randomised study, patients instilled 1–2 drops/eye of O/CMC/HA or HA (2–6 times/day) for 3 months. Primary endpoint: mean change in Global Ocular Staining Score (GOSS) from baseline at day 35. Noninferiority of O/CMC/HA was tested in the per-protocol population; if achieved, superiority was tested in the intent-to-treat population. Secondary efficacy endpoints: mean change from baseline in GOSS, Ocular Surface Disease Index (OSDI), Schirmer score, tear break-up time (TBUT), corneal/conjunctival staining, conjunctival hyperaemia, symptoms, and patient/investigator assessments.

Results

Baseline characteristics were comparable between groups (n=40 each). O/CMC/HA was noninferior (and not superior) to HA based on similar GOSS reductions from baseline at day 35 and month 3 in both groups (P=0.778, day 35, per-protocol population). Overall, O/CMC/HA and HA provided similar reductions in OSDI, Schirmer score, TBUT, corneal staining and hyperaemia from baseline at 35 days (P≥0.155). More patients reported less severe stinging/burning, sandiness/grittiness, and painful/sore eyes at month 3 with O/CMC/HA (P≤0.039), and more rated the dropper bottle easy to use (87.5%), compared with HA (46.2% P=0.002). Other patient and investigator assessments were similar between groups. O/CMC/HA and HA were well tolerated.

Conclusions

O/CMC/HA is noninferior to HA in improving objective signs of dry eye, with potential advantages for subjective symptoms and patient acceptance.

Comparison of 0.3% Hypotonic and Isotonic Sodium Hyaluronate Eye Drops in the Treatment of Experimental Dry Eye

PURPOSE

To compare the efficacy of 0.3% hypotonic and isotonic sodium hyaluronate (SH) eye drops in the treatment of experimental dry eye.

METHODS

Experimental dry eye was established in female C57BL/6 mice by subcutaneous scopolamine injection and an air draft. The mice were divided into three groups (n = 15): control, preservative-free 0.3% isotonic SH, and preservative-free 0.3% hypotonic SH. The tear volume, tear film break-up time, and corneal fluorescein staining scores were measured 5 and 10 days after treatment. After conjunctival tissues were excised at 10 days, the levels of interleukin (IL)-6, IL-17, interferon (IFN)-γ, and IFN-γ inducible protein-10 were determined using the multiplex immunobead assay. In addition, PAS staining and flow cytometry were performed to evaluate the counts of conjunctival goblet cells and CD4+ IFN-γ+ T cells.

RESULTS

Mice treated with 0.3% hypotonic SH showed a significant decrease in corneal staining scores (P = 0.04) and the levels of IL-6 (16.7 ± 1.4 pg/mL, P = 0.02) and IFN-γ (46.5 ± 11.5 pg/mL, P = 0.02) compared to mice treated with 0.3% isotonic SH (IL-6; 32.5 ± 8.8 pg/mL, IFN-γ; 92.0 ± 16.0 pg/mL) at day 10. Although no significant difference in CD4+ IFN-γ+ T cell numbers was observed, goblet cell counts were higher in the hyopotonic SH group than in the isotonic SH group (P = 0.02).

CONCLUSIONS

When compared to 0.3% isotonic SH eye drops, 0.3% hypotonic SH eye drops can be more effective by improving corneal staining scores, decreasing inflammatory molecules, and increasing goblet cell counts for experimental dry eye. These data suggest that hypotonic artificial tears may be useful as an adjunctive treatment for inflammatory dry eye.

Increased concentration of hyaluronan in tears after soaking contact lenses in Biotrue multipurpose solution

Purpose

This study was conducted to determine 1) the concentration of hyaluronan (HA) in the tear films of contact lens (CL) wearers versus non-CL wearers and 2) whether HA sorbed from Biotrue, an HA-containing multipurpose solution (MPS), onto senofilcon A lenses affects the concentration of HA in tears after 2 hours of wear.

Patients and methods

Tears of habitual CL wearers and non-CL wearers were collected on Schirmer strips at baseline and after 2 hours of wear of senofilcon A CLs that had first been either rinsed with Sensitive Eyes Saline or soaked in Biotrue MPS for 14 hours. HA concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and adjusted for sample volumes.

Results

No difference in baseline concentrations of HA in tears was found between CL wearers and non-CL wearers (P=0.07), nor between males and females (P=0.06). However, age was significantly negatively associated with HA concentration (P<0.01), and mostly, CL wear contributed to a significant association (P<0.01). Among saline-rinsed CL wearers, no change in HA concentration in tears was observed after 2 hours of wear (P=0.38). By contrast, a significant increase in HA concentration was observed in the tears from eyes that had worn CLs soaked in Biotrue MPS when compared to baseline (P=0.01) or to saline-rinsed control (P=0.03).

Conclusion

1) In this study population, no difference in baseline concentration of HA was observed between CL wearers and non-CL wearers, and 2) after 2 hours of wear of senofilcon A lenses that were soaked in Biotrue MPS, HA concentrations in the tear films of CL wearers increased.

Influence of Light Emitting Diode-Derived Blue Light Overexposure on Mouse Ocular Surface

Purpose

To investigate the influence of overexposure to light emitting diode (LED)-derived light with various wavelengths on mouse ocular surface.

Methods

LEDs with various wavelengths were used to irradiate C57BL/6 mice at an energy dose of 50 J/cm², twice a day, for 10 consecutive days. The red, green, and blue groups represented wavelengths of 630 nm, 525 nm, and 410 nm, respectively. The untouched group (UT) was not exposed to LED light and served as the untreated control. Tear volume, tear film break-up time (TBUT), and corneal fluorescein staining scores were measured on days 1, 3, 5, 7, and 10. Levels of interferon (IFN)-γ, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were measured in the cornea and conjunctiva using a multiplex immunobead assay at day 10. Levels of malondialdehyde (MDA) were measured with an enzyme-linked immunosorbent assay. Flow cytometry, 2’7’-dichlorofluorescein diacetate (DCF-DA) assay, histologic analysis, immunohistochemistry with 4-hydroxynonenal, and terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) staining were also performed.

Results

TBUT of the blue group showed significant decreases at days 7 and 10, compared with the UT and red groups. Corneal fluorescein staining scores significantly increased in the blue group when compared with UT, red, and green groups at days 5, 7, and 10. A significant increase in the corneal levels of IL-1β and IL-6 was observed in the blue group, compared with the other groups. The blue group showed significantly increased reactive oxygen species production in the DCF-DA assay and increased inflammatory T cells in the flow cytometry. A significantly increased TUNEL positive cells was identified in the blue group.

Conclusions

Overexposure to blue light with short wavelengths can induce oxidative damage and apoptosis to the cornea, which may manifest as increased ocular surface inflammation and resultant dry eye.

Prolonged Ocular Retention of Mucoadhesive Nanoparticle Eye Drop Formulation Enables Treatment of Eye Diseases Using Significantly Reduced Dosage

Eye diseases, such as dry eye syndrome, are commonly treated with eye drop formulations. However, eye drop formulations require frequent dosing with high drug concentrations due to poor ocular surface retention, which leads to poor patient compliance and high risks of side effects. We developed a mucoadhesive nanoparticle eye drop delivery platform to prolong the ocular retention of topical drugs, thus enabling treatment of eye diseases using reduced dosage. Using fluorescent imaging on rabbit eyes, we showed ocular retention of the fluorescent dye delivered through these nanoparticles beyond 24 h while free dyes were mostly cleared from the ocular surface within 3 h after administration. Utilizing the prolonged retention of the nanoparticles, we demonstrated effective treatment of experimentally induced dry eye in mice by delivering cyclosporin A (CsA) bound to this delivery system. The once a week dosing of 0.005 to 0.01% CsA in NP eye drop formulation demonstrated both the elimination of the inflammation signs and the recovery of ocular surface goblet cells after a month. Thrice daily administration of RESTASIS on mice only showed elimination without recovering the ocular surface goblet cells. The mucoadhesive nanoparticle eye drop platform demonstrated prolonged ocular surface retention and effective treatment of dry eye conditions with up to 50- to 100-fold reduction in overall dosage of CsA compared to RESTASIS, which may significantly reduce side effects and, by extending the interdosing interval, improve patient compliance.

Therapeutic Efficacy of Topically Applied Antioxidant Medicinal Plant Extracts in a Mouse Model of Experimental Dry Eye

Purpose. To investigate the therapeutic effects of topical administration of antioxidant medicinal plant extracts in a mouse model of experimental dry eye (EDE). Methods. Eye drops containing balanced salt solution (BSS) or 0.001%, 0.01%, and 0.1% extracts were applied for the treatment of EDE. Tear volume, tear film break-up time (BUT), and corneal fluorescein staining scores were measured 10 days after desiccating stress. In addition, we evaluated the levels of interleukin- (IL-) 1β, tumor necrosis factor- (TNF-) α, IL-6, interferon- (IFN-) γ, and IFN-γ associated chemokines, percentage of CD4+C-X-C chemokine receptor type 3 positive (CXCR3+) T cells, goblet cell density, number of 4-hydroxy-2-nonenal (4-HNE) positive cells, and extracellular reactive oxygen species (ROS) production. Results. Compared to the EDE and BSS control groups, the mice treated with topical application of the 0.1% extract showed significant improvements in all clinical parameters, IL-1β, IL-6, TNF-α, and IFN-γ levels, percentage of CD4+CXCR3+ T cells, goblet cell density, number of 4-HNE-positive cells, and extracellular ROS production (P < 0.05). Conclusions. Topical application of 0.1% medicinal plant extracts improved clinical signs, decreased inflammation, and ameliorated oxidative stress marker and ROS production on the ocular surface of the EDE model mice.