Are there any benefits of Betoptic S (betaxolol HCl ophthalmic suspension) over other beta-blockers in the treatment of glaucoma?

Suppression of trabecular meshwork phagocytosis by norepinephrine is associated with nocturnal increase in intraocular pressure in mice

Intraocular pressure (IOP) is an important factor in glaucoma development, which involves aqueous humor (AH) dynamics, with inflow from the ciliary body and outflow through the trabecular meshwork (TM). IOP has a circadian rhythm entrained by sympathetic noradrenaline (NE) or adrenal glucocorticoids (GCs). Herein, we investigated the involvement of GC/NE in AH outflow. Pharmacological prevention of inflow/outflow in mice indicated a diurnal outflow increase, which was related to TM phagocytosis. NE showed a non-self-sustained inhibition in phagocytosis of immortalized human TM cells, but not GC. The pharmacological and reverse genetic approaches identified β1-adrenergic receptor (AR)-mediated exchange proteins directly activated by cyclic adenosine monophosphate (EPAC)-SHIP1 signal activation by ablation of phosphatidylinositol triphosphate, regulating phagocytic cup formation. Furthermore, we revealed the phagocytosis involvement in the β1-AR-EPAC-SHIP1-mediated nocturnal IOP rise in mice. These suggest that TM phagocytosis suppression by NE can regulate IOP rhythm through AH outflow. This discovery may aid glaucoma management.

[Pharmacogenetics of timolol]

In recent years, β-adrenergic blockers have become the first choice drugs for glaucoma treatment. Timolol holds the main position among them, being a part of most combined antiglaucoma preparations. The use of timolol maleate in clinical practice may be accompanied by severe side effects affecting different organs and systems. The fact that cells with β-adrenergic receptors are widely common within the human body explains pharmacodynamic effects of timolol maleate. Because of these undesirable side effects, timolol maleate often evokes negative reaction from doctors and patients, which to certain extent limits its usage in ophthalmological practice. Obviously, efficacy and safety of timolol administration depends on individual characteristics making personalized approach necessary for every patient. Such particular approach, being the foundation of personalized medicine, increases efficacy and safety of timolol while reducing costs by using targeted doses.

Impact of Combination Glaucoma Therapies on β-Blocker Exposure

PURPOSE

β-adrenergic receptor antagonists (β-blockers) used in the treatment of glaucoma are an often-overlooked source of systemic adverse events. Ophthalmic timolol has been associated with severe systemic adverse events including numerous cases resulting in death. In recent years the number of fixed-dose combination therapies for glaucoma has grown rapidly, and among available combination therapies only the nonselective β-blocker timolol is used as the β-blocker component.

METHODS

A population-based study was conducted in Ontario, Canada between January 1, 2001 and December 31, 2012 to assess the shift to combination therapies in the management of glaucoma, and to investigate the impact of this shift on the relative use of selective and nonselective β-blockers in patients with this disease.

RESULTS

Between 2001 and 2012 timolol (nonselective β-blocker) use grew at an average annual rate of 2.2% (P<0.0001), whereas betaxolol (selective β-blocker) use declined by 14.1% per year (P<0.0001). These changes in the relative use of betaxolol and timolol coincided with changes in the relative use of combination and single-drug therapies. Over the study period, the use of β-blockers as single-drug therapy decreased by 7.7% annually (P<0.0001). In contrast, the use of combination therapies containing a β-blocker increased by 7.6% annually (P<0.0001).

CONCLUSIONS

The introduction of fixed combination glaucoma therapies has been associated with a significant shift to greater use of nonselective β-blockers. In vulnerable older populations, this may have an important impact on patient safety that warrants further study.

Advanced drug delivery and targeting technologies for the ocular diseases

INTRODUCTION

Ocular targeted therapy has enormously been advanced by implementation of new methods of drug delivery and targeting using implantable drug delivery systems (DDSs) or devices (DDDs), stimuli-responsive advanced biomaterials, multimodal nanomedicines, cell therapy modalities and medical bioMEMs. These technologies tackle several ocular diseases such as inflammation-based diseases (e.g., scleritis, keratitis, uveitis, iritis, conjunctivitis, chorioretinitis, choroiditis, retinitis, retinochoroiditis), ocular hypertension and neuropathy, age-related macular degeneration and mucopolysaccharidosis (MPS) due to accumulation of glycosaminoglycans (GAGs). Such therapies appear to provide ultimate treatments, even though much more effective, yet biocompatible, noninvasive therapies are needed to control some disabling ocular diseases/disorders.

METHODS

In the current study, we have reviewed and discussed recent advancements on ocular targeted therapies.

RESULTS

On the ground that the pharmacokinetic and pharmacodynamic analyses of ophthalmic drugs need special techniques, most of ocular DDSs/devices developments have been designed to localized therapy within the eye. Application of advanced DDSs such as Subconjunctival insert/implants (e.g., latanoprost implant, Gamunex-C), episcleral implant (e.g., LX201), cationic emulsions (e.g., Cationorm™, Vekacia™, Cyclokat™), intac/punctal plug DDSs (latanoprost punctal plug delivery system, L-PPDS), and intravitreal implants (I-vitaion™, NT-501, NT- 503, MicroPump, Thethadur, IB-20089 Verisome™, Cortiject, DE-102, Retisert™, Iluvein™ and Ozurdex™) have significantly improved the treatment of ocular diseases. However, most of these DDSs/devices are applied invasively and even need surgical procedures. Of these, use of de novo technologies such as advanced stimuli-responsive nanomaterials, multimodal nanosystems (NSs)/nanoconjugates (NCs), biomacromolecualr scaffolds, and bioengineered cell therapies need to be further advanced to get better compliance and higher clinical impacts.

CONCLUSION

Despite mankind successful battle on ocular diseases, our challenge will continue to battle the ocular disease that happen with aging. Yet, we need to understand the molecular aspects of eye diseases in a holistic way and develop ultimate treatment protocols preferably as non-invasive systems.

The management of glaucoma and intraocular hypertension: current approaches and recent advances

In the last decade, numerous novel ocular hypotensive agents have been introduced for the control of intraocular pressure (IOP). Clinicians now have more options than ever in the selection of medical therapy for the treatment of glaucoma and ocular hypertension. When selecting an ocular hypotensive medication for their patients, clinicians should consider not only the IOP-lowering efficacy of an agent, but also the ability of the drug to allow patients to achieve target levels of IOP that are low enough to stop the progression of glaucomatous damage. Other considerations should include how well the drug controls diurnal IOP, the likelihood of serious adverse events, the versatility of the medication for use as an adjunctive agent, as well as other potential attributes (ie, neuroprotection).

Penetration of betaxolol HCL ionic suspension 0.25% and betaxolol HCL solution 0.50% into the aqueous humor

PURPOSE

To determine the intraocular penetration of topical drops of betaxolol HCl 0.25% suspension and betaxolol HCl 0.50% solution into the aqueous humor.

METHODS

Fifteen patients were randomly assigned to receive topical betaxolol HCl 0.25% suspension (n=7) or topical betaxolol HCl 0.50% solution (n=8) the day before cataract surgery. Aqueous samples were collected 2 hours after the administration of the morning dose during cataract surgery. Drug concentrations were determined by high-performance liquid chromatography with fluorescence detection.

RESULTS

The mean aqueous humor concentration of topical betaxolol HCl 0.25% suspension was 275.1+/-168.8 micro g/mL (range 570-70 micro g/mL) and the mean aqueous humor concentration of topical betaxolol HCl 0.50% solution was 195.4+/-102.4 micro g/mL (range 334-50 micro g/mL) (p=0.281).

CONCLUSIONS

The mean aqueous humor concentration of betaxolol 0.25% suspension was higher than betaxolol 0.50% solution; however, the difference was not statistically significant. With twofold reduced concentration and similar anterior chamber penetration, betaxolol 0.25% suspension could be first choice for Beta 1 selective blocker therapy when considered for patients with glaucoma.