Dexamethasone Disodium Phosphate Penetration Into the Human Aqueous Humor After Topical Application

The effect of different potency glucocorticosteroids treatments on tear inflammatory factors and corneal optical density after femtosecond-assisted laser in situ keratomileusis

To assess the impact of glucocorticosteroids with varying potencies on inflammatory mediators in tears and corneal optical density after femtosecond-assisted laser in situ keratomileusis (FS-LASIK). In a prospective study, 110 patients (220 eyes) who underwent FS-LASIK were divided into 2 groups: 55 patients (110 eyes) received dexamethasone, and another 55 patients (110 eyes) received fluorometholone. Visual acuity, intraocular pressure, and corneal optical density were measured before, 1 week, and 1 month after surgery. Tear fluid samples were also collected to assess expression levels of TNF-α, IL-1α, IL-6, and TGF-β1. One week after the procedure, the dexamethasone group exhibited elevated intraocular pressure (IOP) levels (P > .05) and a decreased expression of TNF-α in tears (P < .001) compared to the fluorometholone group. Within the 0 to 2 mm range from the corneal apex, the anterior corneal layer's optical density in the fluorometholone group surpassed that of the dexamethasone group (P < .05). At 1 month post-surgery, the IOP in the fluorometholone group was higher than that in the dexamethasone group (P < .05). In both the 0 to 2 mm and 2 to 6 mm intervals from the corneal apex, the optical density of the anterior corneal layer was significantly higher in the fluorometholone group compared to the dexamethasone group (P < .05). There was no statistically significant difference in visual acuity between the 2 groups at any postoperative time point. Short-term use of potent corticosteroids after FS-LASIK can swiftly address ocular surface inflammation, enhance corneal wound healing, reduce corneal edema, and accelerate the restoration of corneal transparency, in contrast to prolonged use of milder corticosteroids post-surgery.

Assessment of the eye surface and subjective symptoms after using 0.1% dexamethasone drops with and without preservatives in patients after cataract surgery

Cataract surgery can cause dry eye symptoms. One of the many factors compromising the ocular surface is the use of benzalkonium chloride (BAC)-preserved topical eye drops administered during the postoperative period. In this open-label, prospective, randomized, comparative clinical trial, 40 patients not previously affected by dry eye disease were assigned to receive either preservative-free (PFD) or preserved (PD) dexamethasone 0.1% eye drops for two weeks after a standard phacoemulsification procedure. Fluorescein break-up time, ocular surface staining score, Schirmer test, Ocular Surface Disease Index and anterior chamber (AC) cells were evaluated at baseline prior to the surgery and 2 weeks after surgery. No statistically significant differences in baseline assessments were observed between groups. At week 2, a significant increase in corneal staining scores (p = 0.003) and foreign body sensation (p = 0.04) was observed for the PD group only. The conjunctival staining score was significantly higher in both groups. The mean AC cell grading was higher in the PFD group than in the PD group (0.28 ± 0.30 and 0.07 ± 0.18, respectively; p = 0.013). Preservative-free dexamethasone eye drops after cataract surgery caused milder dry eye symptoms as compared with preserved dexamethasone. The AC inflammation control comparison may require a larger study group. Trial registration: ClinicalTrials.gov identifier NCT05753787, 03/03/2023.

Penetration of topically administered dexamethasone disodium phosphate and prednisolone acetate into the normal equine ocular fluids

BACKGROUND

Topical dexamethasone and prednisolone are currently the mainstay treatment for equine ophthalmic inflammatory diseases, such as equine recurrent uveitis. Comparative pharmacokinetic studies in horses are lacking and current guidelines are mainly based on empirical data and extrapolation from other species.

OBJECTIVES

To investigate the penetration and local concentrations of topically applied dexamethasone and prednisolone in normal equine ocular fluids and serum.

STUDY DESIGN

Prospective randomised experimental pharmacokinetic study.

METHODS

Twenty-one Shetland ponies without ophthalmic disease were treated bilaterally topically every 2 hours during 24 hours to obtain steady state drug concentrations. One eye was treated with 0.15 mg of dexamethasone disodium phosphate (0.1%), and the other eye was simultaneously treated with 1.5 mg of prednisolone acetate (1%). Serum samples were taken prior to the induction of general anaesthesia. Aqueous and vitreous humour samples were taken during euthanasia at time points after administration of the last dose (t = 5 min, t = 15 min, t = 30 min, t = 60 min, t = 90 min, t = 120 min, t = 180 min). Each pony was randomly assigned to one time point, and three ponies were sampled per time point. Dexamethasone and prednisolone concentrations were measured by liquid chromatography-mass spectrometry.

RESULTS

The mean dexamethasone concentration in aqueous humour was 32.4 ng/mL (standard deviation [SD] 10.9) and the mean prednisolone concentration was 321.6 ng/mL (SD 96.0). In the vitreous and in serum samples concentrations of both corticosteroids were below the limit of detection (LOD 2.5 ng/mL).

MAIN LIMITATIONS

The study group was limited to subjects without evidence of current ophthalmic disease. A limited number of time points were measured.

CONCLUSIONS

Potentially effective dexamethasone and prednisolone concentrations were measured in the anterior chamber, but vitreal concentrations were negligible. Systemic uptake was low. Therefore, treatment with only topically administered corticosteroids is deemed insufficient in horses in cases of posterior uveitis. Further studies evaluating other routes of administration are warranted.

Kinetics of hydrocortisone sodium phosphate penetration into the human aqueous humor after topical application

AIM OF THE STUDY

Hydrocortisone is a soft steroid with low anti-inflammatory properties and a short duration of action, used to manage several ocular conditions. The clinical benefits and side effects associated with hydrocortisone are well documented, but its basic pharmacokinetic in the eye is yet to be fully elucidated. The purpose of this study is to investigate the anterior chamber penetration capabilities of hydrocortisone when used in different concentrations as eye drops treatment.

MATERIALS AND METHODS

This is a double-blind, single-centre, randomised clinical trial performed at the Department of Medicine and Surgery of the University of Perugia (Italy) on consecutive patients who undergone phacoemulsification with intraocular lens implantation. Patients were randomly assigned on the morning of surgery to receive a single instillation of 0.33% (group A) or 0.001% (group B) hydrocortisone sodium phosphate solution. Group of patients C did not receive any treatment and was used to measure the hydrocortisone endogenous levels. Before surgery, one aliquot of aqueous humor for each patient was aspirated. The time of collection for each sample was recorded. Hydrocortisone concentrations were then stratified into six interval classes of 30 minutes each.

RESULTS

The mean concentration of hydrocortisone was significantly higher in group A (25.2 ± 12.4 ng/mL) compared with group B (7.11 ± 1.51 ng/mL) and compared with the mean hydrocortisone endogenous levels (3.92 ± 1.18 ng/mL) (P < .0001). No statistically significant differences of hydrocortisone mean concentrations between group B and the mean endogenous levels were found.

CONCLUSIONS

Considering the frequent need for prolonged topical steroid therapies and the possible consequent undesirable side effects, ophthalmologists should consider the lowest clinically effective dose of hydrocortisone useful to obtain the desired therapeutic effect and in an adequate time, to minimise the amount of steroids into the anterior chamber and to avoid side effects like intra-ocular pressure increase or cataract development.

Corneal delivery of moxifloxacin and dexamethasone combination using drug-eluting mucoadhesive contact lens to treat ocular infections

The important causes of loss of vision are ocular infections, including keratitis and conjunctivitis. Attaining an adequate concentration of topically applied antibiotics to prevent or treat infections within the cornea is challenging. The study aimed to design and develop a drug-eluting polymeric contact lens for the effective delivery of moxifloxacin (MF) and dexamethasone (DM). The polymeric contact lens was prepared using chitosan, glycerol, and polyethylene glycol. MF and DM were loaded into the contact lens, both separately and in combination. The MF and DM loaded contact lenses were characterized for thickness, swelling index, surface topography, and mucoadhesion strength. Furthermore, studies were performed to understand the in vitro drug release behavior, ex vivo corneal permeation, and in vitro and in vivo antimicrobial activity. The drug-loaded contact lens was compared with the standard drug solutions. The physical characteristics of the polymeric contact lens were similar to the commercially available contact lens. Compared to the topically applied standard drug solutions, the drug-loaded contact lens showed significantly (p < 0.05) greater corneal drug distribution after 24 h incubation. In vitro and in vivo antimicrobial activity of the MF loaded contact lens was superior to the standard drug solution. In vivo drug distribution studies showed greater tissue concentration of MF in cornea, sclera, and aqueous humor with contact lens application compared with drug solutions. Overall, the polymeric contact lens was efficient in delivering MF and DM at required therapeutic concentrations. The findings from the present study show that drug-eluting contact lenses could be used in post-operative conditions to prevent ocular infections.

Comparison of anti-inflammatory effects of eye drops formulations after uncomplicated cataract surgery

Aim:

The aim of this study is to compare the efficacy of different dexamethasone eye drops formulations in controlling postoperative inflammation.

Methods:

Cataract surgery was carried out in 72 patients (35 males) divided into two groups: group A (36 patients, mean age = 78.0 ± 5.6) received four times daily for 2 weeks a suspension containing tobramycin 0.3% mg/ml + dexamethasone 0.1% mg/ml, and group B (36 patients, mean age = 76.2 ± 6.8) a solution containing tobramycin 0.3% mg/ml + dexamethasone 0.1% mg/ml. Both groups received ofloxacin 0.5% four times daily for 7 days, and nepafenac 0.1% three times daily for 3 weeks. Best-corrected visual acuity, intraocular pressure, corneal thickness, endothelial cells count, aqueous flare and macular thickness were evaluated preoperatively and at 1 day, 15 days, 1 and 2 months.

Results:

In group A, intraocular pressure, corneal thickness and aqueous humour flare values preoperatively and at the end of follow-up were 14.3 ± 1.8 and 13.2 ± 1.8 mmHg, 546.4 ± 34.6 and 539.6 ± 36.1 µm, 11.84 ± 4.44 and 13.52 ± 5.54 ph/ms, respectively, with no statistically significant difference. In group B, intraocular pressure, corneal thickness and aqueous humour flare values preoperatively and at the end of follow-up were 14.3 ± 1.5 and 13.1 ± 1.7 mmHg, 552.9 ± 37.4 and 548.1 ± 39.3 µm, 11.45 ± 4.06 and 13.73 ± 4.99 ph/ms, respectively, with no statistically significant difference. No difference was detected in the macular thickness values in the parafoveal area preoperatively and at 2 months follow-up in group A (332.18 ± 16.19 and 337.71 ± 16.33 µm) and group B (329.11 ± 18.28 and 334.37 ± 20.86 µm), respectively.

Conclusion:

The two different formulations of dexamethasone eye drops reached the same anti-inflammatory effects.

Thermo- and pH-sensitive glycosaminoglycans derivatives obtained by controlled grafting of poly(N-isopropylacrylamide)

Poly(N-isopropyl acrylamide) grafted heparin and chondroitin sulfate were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers were characterized by NMR, IR, SEC, DLS, SLS and NTA methods. High grafting densities were reached for both glycosaminoglycans. The temperature, pH and polymer concentration affected the low critical solution temperatures values. The increased pNIPAAm chain length, grafting density and concentration led to the sharp phase transition at 35 °C. Spherical nanogels were formed around this temperature. Terminal dodecyl trithiocarbonate groups of the copolymers were reduced to thiols that allowed formation of sensitive nanogels with sharp phase transitions induced by pNIPAAm chains. The copolymers showed no toxicity to the ocular cells and they provided the prolonged release of dexamethasone phosphate at 37 °C. These copolymers are interesting alternatives for ocular drug delivery.

Aqueous humour concentrations after topical apPlication of combinEd levofloxacin-dexamethasone eye dRops and of its single components: a randoMised, assEssor-blinded, parallel-group study in patients undergoing cataract surgery: the iPERME study

Purpose

To evaluate the penetration of levofloxacin and dexamethasone sodium phosphate into the aqueous humour (AH) after administration in combination and as single molecules. Evaluation of the penetration of those agents in the site of action and their pharmacodynamic potential activity in view of the intended clinical use after cataract surgery.

Methods

Randomised, assessor-blinded, parallel-group. Patients scheduled for cataract surgery were assigned in a 1:1:1 ratio to: levofloxacin + dexamethasone sodium phosphate (L-DSP), Levofloxacin (L) or Dexamethasone sodium phosphate (DSP) eye drops. Either test or reference drugs were instilled in the cul-de-sac twice, 90 and 60 min before paracentesis.

Results

A total of 125 patients completed the study. Fraction of dose absorbed in the anterior chamber was 3.8–4.2 · 10⁻⁴ for levofloxacin and 0.3–0.4 · 10⁻⁴ for dexamethasone, respectively. No notable differences in concentration of levofloxacin were found between L-DSP arm (1.970 nmol/ml) and L arm (2.151 nmol/ml). The concentrations of levofloxacin were well above the MICs for the most frequent Gram-positive and Gram-negative eye pathogens. Dexamethasone concentrations were slightly lower in L-DSP arm (0.030 nmol/ml) than in DSP arm (0.042 nmol/ml), but still in the pharmacodynamically active range in the site of action. The difference was not clinically relevant. DSP was not detected in any HA sample, suggesting its full hydrolysis to free dexamethasone.

Conclusion

Our results confirm that no interaction is evident on the corneal penetration of levofloxacin and dexamethasone which reach pharmacologically active concentrations when instilled as fixed combination eye drops to patients undergoing cataract surgery.

Trial registration

ClinicalTrials.gov Identifier: NCT03740659

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02863-7) contains supplementary material, which is available to authorized users.

Validation of direct method to quantify dexamethasone in human aqueous humor by LC–MS/MS

Aim: Dexamethasone (Dex) has been used for the treatment of ocular diseases, presenting concentrations up to 150 ng/ml in the biological matrix. Drug sampling has been performed from aqueous humor (AH), which the volume varies from 50 to 200 μl, becoming a challenge for analytical analyses. Results: We developed and validated a direct and sensitive method by LC–MS/MS for Dex measurement in human AH, using water as surrogate matrix to reduce the sample volume applied in some validation assays. With accuracies of 99.6% and precision within 15% in the range of 0.1–150 ng/ml, Dex had an 87-day stability. Conclusion: Our method is robust and sensitive enough to be applied in bioequivalence studies with human AH using only 20 μl of biological sample.

Pharmaceutical technology can turn a traditional drug, dexamethasone into a first-line ocular medicine. A global perspective and future trends

Dexamethasone is one of the most prescribed glucocorticoids. It is effective and safe in the treatment of a wide variety of ocular conditions, including anterior and posterior segment inflammation. However, its half-life in the vitreous humor is very short, which means that it typically requires frequent administrations, thus reducing patient adherence and causing therapeutic failure. Innovative dexamethasone delivery systems have been designed in an attempt to achieve sustained release and targeting. The FDA has approved dexamethasone implants for the treatment of macular edema secondary to retinal vein occlusion and posterior segment noninfectious uveitis. Lenses, micro- and nanoparticles, liposomes, micelles and dendrimers are also proving to be adequate systems for maintaining optimal dexamethasone levels in the site of action. Pharmaceutical technology is turning a classical drug, dexamethasone, into a fashionable medicine.

Pharmacologic Treatment of Noninfectious Uveitis

Uveitis encompasses a spectrum of diseases whose common feature is intraocular inflammation, which may be infectious or noninfectious in etiology (Nussenblatt and Whitcup 2010). Infectious causes of uveitis are typically treated with appropriate antimicrobial therapy and will not be discussed in this chapter. Noninfectious uveitides are thought have an autoimmune component to their etiology and are thus treated with anti-inflammatory agents.