Critical appraisal of ophthalmic ketorolac in treatment of pain and inflammation following cataract surgery

Loteprednol-Loaded Nanoformulations for Corneal Delivery by Quality-by-Design Concepts: Optimization, Characterization, and Anti-inflammatory Activity

Loteprednol etabonate (LE) is a topical corticosteroid that uses inflammatory conditions of the eye. It has a low ocular bioavailability and side effects such as corneal disorder, eye discharge, and ocular discomfort. Therefore, it was decided to select the delivery systems, which are solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nanoemulsion (NE). Design of experiments (DoE) of SLN, NLC, and NE formulations were formulated by using the quality by design (QbD) approach. Precirol® ATO 5 and oleic acid were used as solid and liquid lipids, respectively, in SLN, NLC, and NE formulations. Physiochemical characterization was performed on the formulations. The optimized formulations' inflammatory effects have been appraised on human corneal epithelial cells employing the ELISA test. Physicochemical characterization studies and inflammatory effects were appraised. The sizes of optimized formulations of SLN, NLC, and NE were 86.19 nm, 82.38 nm, and 126.35 nm, respectively, with minimum polydispersity. The release behavior of the formulations is composed of both diffusion and erosion. ELISA test results proved that the formulations significantly reduced IL-1 and IL-6 levels (p < 0.05). D-optimal mixture experimental design allowed us to develop the most precise formulations of SLN, NLC, and NE. Furthermore, the optimized formulations could be promising candidates for treating an inflammation-based corneal disease of the eye.

The effects of addition of functional monomers and molecular imprinting on dual drug release from intraocular lens material

Although cataract surgery is considered a safe procedure, post-surgery complications such as endophthalmitis and ocular inflammation, may occur. To prevent this, antibiotics and anti-inflammatories are prescribed in the form of eye drops during the post-operatory period, but they lead to a low drug bioavailability in target tissues. The objective of this work is to develop an intraocular lens (IOL) material to deliver simultaneously one antibiotic, moxifloxacin (MXF), and one anti-inflammatory, diclofenac (DFN), in therapeutic concentrations to prevent both complications. The IOL material was modified through the incorporation of functional monomers, as well as molecular imprinting with both drugs using the same functional monomers, namely acrylic acid (AA), methacrylic acid (MAA), 4-vinylpiridine (4-VP) and a combination of MAA + 4-VP. The best results were obtained with MAA. Molecular imprinting did not influence the drug release, except with AA. Application of a mathematical model predicted that the released MXF and DFN concentrations would stay above the pre-determined MIC of S. aureus and S. epidermidis and the minimum values of IC50 of COX-1 and COX-2, for 9 and 14 days, respectively. Antibacterial tests showed that the released antibiotic remained active. The physical properties of the drug-loaded MAA-hydrogel remained adequate. The developed system proved to be non-irritant and non-cytotoxic.

Metformin attenuated histopathological ocular deteriorations in a streptozotocin-induced hyperglycemic rat model

Diabetes mellitus (DM) often causes ocular disorders leading to vision loss. Metformin is commonly prescribed for type 2 diabetes. This study assessed the effect of metformin on hyperglycemic histopathological eye abnormalities and some possible pathways involved. Male rats were divided into 3 groups (N = 6), namely, healthy control, hyperglycemic non-treated control, and hyperglycemic rats treated with 200 mg/kg metformin. Two weeks after diabetes induction by an intraperitoneal streptozotocin (60 mg streptozotocin (STZ)/kg) injection, the rats develop ocular abnormalities, and metformin (200 mg/kg) treatment was administered daily. Rats underwent dilated retinal digital ophthalmoscope examination and graded for diabetic retinopathy. Rats were sacrificed at 12 weeks, and the cornea, lens, sclera, ciliary body, iris, conjunctiva, retinal, and optic nerve were examined histologically. Rats' fasting blood glucose and body weight were monitored. Serum tumor necrosis factor-α (TNF-α), vascular endothelial growth factor (VEGF), claudin-1, and glutathione/malondialdehyde ratios were analyzed. Metformin significantly attenuated diabetes-related histopathological ocular deteriorations in the cornea, lens, sclera, ciliary body, iris, conjunctiva, retina, and optic nerve partly by restoring serum TNF-α, VEGF, claudin-1, and glutathione/malondialdehyde ratios without significantly affecting the fasting blood glucose levels or body weight in these hyperglycemic rats. Metformin attenuated hyperglycemia-associated histopathological eye deteriorations, possibly partly by ameliorating vascular leakage, oxidative stress, inflammation, and neovascularization, without affecting the fasting blood glucose levels or body weights in these STZ-induced diabetic rats.

Optimization of structures, biochemical properties of ketorolac and its degradation products based on computational studies

BACKGROUND

Ketorolac (KTR) is used as an analgesic drug with an efficacy close to that of the opioid family. It is mainly used for the short term treatment of post-operative pain. It can inhibit the prostaglandin synthesis by blocking cyclooxygenase (COX).

METHODS

In this investigation, the inherent stability and biochemical interaction of Ketorolac (KTR) and its degradation products have been studiedon the basis of quantum mechanical approaches. Density functional theory (DFT) with B3LYP/ 6-31G (d) has been employed to optimize the structures. Thermodynamic properties, frontier molecular orbital features, dipole moment, electrostatic potential, equilibrium geometry, vibrational frequencies and atomic partial charges of these optimized structureswere investigated. Molecular docking has been performed against prostaglandin H2 (PGH2) synthase protein 5F19 to search the binding affinity and mode(s). ADMET prediction has performed to evaluate the absorption, metabolism and carcinogenic properties.

RESULTS

The equilibrium geometry calculations support the optimized structures. Thermodynamic results disclosed the thermal stability of all structures. From molecular orbital data, all the degradents are chemically more reactive than parent drug (except K3). However, the substitution of carboxymethyl radicalin K4 improved the physicochemical properties and binding affinity. ADMET calculations predict the improved pharmacokinetic and non-carcinogenic properties of all degradents.

CONCLUSION

Based on physicochemical, molecular docking, and ADMET calculation, this study can be helpful to understand the biochemical activities of Ketorolac and its degradents and to design a potent analgesic drug.

Principles of pharmacology in the eye

The eye is a highly specialized organ that is subject to a huge range of pathology. Both local and systemic disease may affect different anatomical regions of the eye. The least invasive routes for ocular drug administration are topical (e.g. eye drops) and systemic (e.g. tablets) formulations. Barriers that subserve as protection against pathogen entry also restrict drug permeation. Topically administered drugs often display limited bioavailability due to many physical and biochemical barriers including the pre-corneal tear film, the structure and biophysiological properties of the cornea, the limited volume that can be accommodated by the cul-de-sac, the lacrimal drainage system and reflex tearing. The tissue layers of the cornea and conjunctiva are further key factors that act to restrict drug delivery. Using carriers that enhance viscosity or bind to the ocular surface increases bioavailability. Matching the pH and polarity of drug molecules to the tissue layers allows greater penetration. Drug delivery to the posterior segment is a greater challenge and, currently, the standard route is via intravitreal injection, notwithstanding the risks of endophthalmitis and retinal detachment with frequent injections. Intraocular implants that allow sustained drug release are at different stages of development. Novel exciting therapeutic approaches include methods for promoting transscleral delivery, sustained release devices, nanotechnology and gene therapy.

A comparative study of various topical nonsteroidal anti-inflammatory drugs to steroid drops for control of post cataract surgery inflammation

BACKGROUND

Postoperative inflammation continues to be a cause of patient discomfort, delayed recovery, and in some cases, suboptimal visual results. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) and steroid are commonly used in the management and prevention of noninfectious ocular inflammation following cataract surgery.

AIMS

The aim was to study the safety and efficacy of various NSAIDs drops for control of postoperative inflammation following cataract surgery and compare with steroid eye drops in a patient following cataract surgery.

SUBJECTS AND METHODS

Totally, 200 patients undergoing phacoemulsification with posterior chamber intraocular lens implantation were randomly assigned to receive either nepafenac 0.1% 3 times daily, bromfenac 0.09% twice daily, ketorolac 0.5% 4 times daily for 1 month or 1% prednisolone eye drops as their postoperative anti-inflammatory medication with 50 cases in each group. The patients were examined at the 1^st day (baseline), 1^st week, 2^nd week, and 4^th week after surgery. Postoperative inflammation was evaluated subjectively by intraocular pressure, slit-lamp assessment of signs of inflammation, including conjunctival hyperemia, ocular pain, and aqueous cells and flare.

STATISTICAL ANALYSIS

Statistical analysis was performed by the SPSS program for Windows, version 17.0.

RESULTS AND CONCLUSIONS

In our study, we found that prednisolone 1% was more effective in controlling postoperative intraocular inflammation in terms of reducing anterior chamber cells and flare. We found that ketorolac 0.5% and nepafenac 0.1% were equally effective in controlling postoperative ocular pain and inflammation. All four drugs are effective in controlling post cataract surgery ocular inflammation. Intraocular inflammation is best controlled with prednisolone 1%, while ocular pain and hyperemia are better controlled with NSAIDs in the early postoperative periods.

Intracameral phenylephrine and ketorolac injection (OMS302) for maintenance of intraoperative pupil diameter and reduction of postoperative pain in intraocular lens replacement with phacoemulsification

BACKGROUND

The purpose of this study was to evaluate the effect of OMS302 on intraoperative pupil diameter and early postoperative ocular pain when administered during intraocular lens replacement surgery.

METHODS

Four hundred and six patients (406 study eyes; 202 in the OMS302 group and 204 in the placebo group) were entered into this randomized, double-masked, placebo-controlled, multicenter Phase III study, which was conducted at 15 centers in the USA and the Netherlands. The patients received OMS302 (60.75 mM phenylephrine HCl and 11.25 mM ketorolac tromethamine) or placebo in irrigation solution during intraocular lens replacement. No other changes in procedure were required. Coprimary endpoints were change in pupil diameter over time from surgical baseline to end of procedure and patient-reported ocular pain during the first 12 hours postoperatively. Secondary endpoints included additional measures of pupil diameter and postoperative pain.

RESULTS

OMS302 was superior to placebo in maintaining intraoperative mydriasis, preventing miosis, and reducing postoperative pain. The weighted mean (standard error) difference (OMS302 - placebo) in change in the area under the curve from baseline for pupil diameter was 0.590 ([0.049]; 95% confidence interval 0.494 to 0.686; P<0.0001). For ocular pain scores, the weighted mean (standard error) difference was -4.580 ([1.192]; 95% confidence interval -6.917 to 2.244; P=0.0002). All secondary efficacy results favored OMS302. Specifically, analyses supporting prevention of miosis (patients with ≥6 mm pupil diameter at completion of cortical clean-up and those with <6 mm diameter at any time during surgery) were significant for OMS302 (95.9% versus 77.0% and 9.2% versus 38.0%, respectively; P<0.0001 for each endpoint). OMS302 was well tolerated and not associated with any unexpected adverse events.

CONCLUSION

OMS302 maintained mydriasis, prevented miosis, and reduced early postoperative pain when administered in irrigation solution during intraocular lens replacement, with a safety profile similar to that of placebo. OMS302 is preservative-free and bisulfite-free, and its administration does not require any modification to the surgical procedure.

Non steroidal anti-inflammatory drugs in the prevention of cystoid macular edema after uneventful cataract surgery

BACKGROUND

Cystoid macular edema (CME) remains an important complication after cataract surgery. There is no consensus about how to prevent this frequent complication. The purpose of this study was to conceive an effective anti-inflammatory strategy using nonsteroidal anti-inflammatory drugs (NSAIDs) together with regular treatment with corticosteroids to prevent CME and improve visual acuity after cataract surgery in patients without risk factors.

MATERIALS AND METHODS

We searched the PubMed, Cochrane, and Google Scholar databases focused on prospective, controlled, randomized, double-blind clinical trials published in the last 10 years, with a minimum follow-up of 4 weeks.

RESULTS

A total of nine clinical trials, one systematic review, and two reviews satisfied our search criteria. Most studies highlighted that NSAIDs are as powerful as corticosteroids to diminish postoperative inflammation, and demonstrated an additional benefit when used in combination with standard corticosteroid postsurgical therapy. In addition, the use of NSAIDs in the perioperative period seems to significantly improve the outcome after surgery and helps prevent CME in low-risk patients.

CONCLUSION

The prophylactic use of NSAIDs in combination with the standard postoperative steroid scheme appears to be a positive course of action for preventing CME after cataract surgery. We suggest a therapeutic scheme based on the administration of one drop four times a day, beginning the day before surgery and for 4 weeks after the procedure. It is also advisable to administer one drop every 15 minutes in the hour prior to surgery in order to obtain better anti-inflammatory efficacy.

The safety, pharmacokinetics, and efficacy of intraocular celecoxib

PURPOSE

To determine safety, pharmacokinetics, and anti-inflammatory effects of intraocular celecoxib.

METHODS

The right eye of animals was injected with 1.5, 3, or 6 mg celecoxib prepared in dimethyl sulfoxide (DMSO). Left eyes served as controls and received 0.1 mL DMSO. Electroretinograms (ERG) were obtained at baseline and at 1, 4, and 12 weeks, and eyes were enucleated afterward for histopathologic analysis. For pharmacokinetics, 3 mg celecoxib was injected, and vitreous and retina/choroid drug levels were then analyzed at specific time points. For efficacy, 1 μg lipopolysaccharide was injected to induce inflammation; the right eye was then injected with 3 mg celecoxib (six eyes) or 2 mg triamcinolone acetonide (six eyes) and the left eye with saline. Twenty-four hours later, aqueous fluid was removed, and total leukocyte concentration and prostaglandin E2 (PGE2) concentration were determined.

RESULTS

Histologic and ERG studies demonstrated no signs of retinal or optic nerve toxicity. After a single 3-mg injection, vitreous (0.06 μg/mL) and retina/choroid (132.31 μg/g) celecoxib concentrations at 8 weeks exceeded median inhibitory concentration. Treatment with celecoxib and triamcinolone significantly reduced total leukocyte count by 40% (P = 0.02) and 31% (P = 0.01), respectively. Reduction in PGE2 levels paralleled reduction in leukocyte counts (P < 0.05). There was no increase in intraocular pressure, but cataract formation was observed at higher concentrations.

CONCLUSIONS

Intraocular injection of celecoxib appeared to be nontoxic and demonstrated excellent penetration into the retina/choroid and sustained drug levels out to 8 weeks. Celecoxib demonstrated potent anti-inflammatory effects, but there was an association with cataract formation at higher doses.

Efficacy and tolerability of a gatifloxacin/prednisolone acetate fixed combination for topical prophylaxis and control of inflammation in phacoemulsification: a 20-day-double-blind comparison to its individual components

OBJECTIVE

To compare the efficacy and tolerability of a fixed combination of 0.3% gatifloxacin and 1% prednisolone(ZypredH) versus the individual components used separately (Zymar® and Predfort® ) for infection prophylaxis and inflammation control after cataract surgery with intraocular lens implantation [corrected].

METHODS

A prospective, randomized, double-blind, parallel-group study of 108 patients who underwent phacoemulsification and intraocular lens implantation was conducted. After random assignment, 47 eyes received the fixed combination of topical 0.3% gatifloxacin/1% prednisolone drops, and 61 eyes received the same doses of the individual components as separate solutions four times a day for 15 days. Baseline and postoperative assessments were made on postoperative days 1, 7, 15, and 20.

RESULTS

All objective (best corrected visual acuity, sign of active ocular inflammation, central and incisional corneal edema, the number of cells per high-power field in the anterior chamber, and intraocular pressure) and subjective (eye pain, photophobia, burning sensation, itching, and foreign body sensation) criteria of efficacy were similar in both groups, with no significant differences. Group I included 47 eyes that received the fixed combination of gatifloxacin/prednisolone acetate eye drops and a placebo eye drop solution. Group II included 61 eyes that were treated with 0.3% gatifloxacin and 1% prednisolone acetate eye drops separately. The intraocular pressure was slightly higher in Group II (p<0.05).

CONCLUSION

Treatment with the fixed-dose combination of gatifloxacin/prednisolone eye drops was as effective as the non-fixed combination in preventing infection and controlling inflammation after phacoemulsification and intraocular lens implantation.

Nonsteroidal anti-inflammatory drugs for retinal disease

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used extensively in ophthalmology for pain and photophobia after photorefractive surgery and to reduce miosis, inflammation, and cystoid macular edema following cataract surgery. In recent years, the US Food and Drug Administration has approved new topical NSAIDs and previously approved NSAIDs have been reformulated. These changes may allow for greater drug penetration into the retina and thereby offer additional therapeutic advantages. For example, therapeutic effects on diabetic retinopathy and age-related macular degeneration may now be achievable. We provide an updated review on the scientific rationale and clinical use of NSAIDs for retinal disease.