Continuous intraocular pressure measurement by telemetry in alpha-chymotrypsin-induced glaucoma model in the rabbit: Effects of timolol, dorzolamide, and epinephrine

Percicot, Christine L.; Schnell, Christian; Debon, Corinne; Hariton, C.

doi:10.1016/s1056-8719(96)00130-x

Cited by 61 publications

(44 citation statements)

References 16 publications

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“…Chronic ocular glaucoma was induced by a single posterior injection of alpha-chymotrypsin (10 mg/ml, 0.1 ml) into posterior segment of eye in rabbits (36). Care was taken to avoid the contact of alpha-chymotrypsin with the surface of the eye.…”

Section: Induction Of Glaucomamentioning

confidence: 99%

Brimonidine Tartrate–Eudragit Long-Acting Nanoparticles: Formulation, Optimization, In Vitro and In Vivo Evaluation

Bhagav

Upadhyay

Chandran³

2011

AAPS PharmSciTech

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Abstract. In the present study, an effort was made to design prolonged release Eudragit nanoparticles of brimonidine tartrate by double emulsion-solvent evaporation technique for the treatment of open-angle glaucoma. The effect of various formulation variables like initial drug amount, lecithin proportion, phase volume and pH, secondary emulsifier and polymer proportion were studied. Various process variables like energy and duration of emulsification, lyophilization on the characteristics of nanoparticles and in vitro drug release profile were studied. The selected formulations were subjected to in vivo intraocular pressure-lowering efficacy studies by administering aqueous dispersion of nanoparticles into the lower cul de sac of glaucomatous rabbits. The prepared Eudragit-based nanoparticles were found to have narrow particle size range and improved drug loading. The investigated process and formulation variables found to have significant effect on the particle size, drug loading and entrapment efficiency, and in vitro drug release profile of nanoparticles. The selected formulations upon in vivo ocular irritability and tolerability tests were found to be well tolerated with no signs of irritation. In vivo pharmacodynamic efficacy studies revealed that the selected nanoparticle formulations significantly improved the therapy as area under the ΔIOP vs. time curve [AUC (ΔIOP vs.t) ] showed several fold increase in intensity and duration of intraocular pressure (IOP) decrease. All the selected nanoparticle formulations were found to prolong the drug release in vitro and prolong IOP reduction efficacy in vivo, thus rendering them as a potential carrier in developing improved drug delivery systems for the treatment of glaucoma.

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Section: Induction Of Glaucomamentioning

confidence: 99%

Brimonidine Tartrate–Eudragit Long-Acting Nanoparticles: Formulation, Optimization, In Vitro and In Vivo Evaluation

Bhagav

Upadhyay

Chandran³

2011

AAPS PharmSciTech

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“…They have demonstrated why it is critical for conscious animals that are being used in anti-glaucoma drug studies to be acclimated to IOP measurements. It is important to recognize that during blinking IOP transiently increases approximately 15 mmHg during lid closure and that this transient spike is followed by a 1-2 mmHg undershoot for a approximately 1 s [62]. Simply moving a rabbit from one room to another (the room in which the animal is housed to another room for tonometry) can cause a 20 % increase in IOP and it may take some animals 4-5 h to return to baseline [31,32].…”

Section: Animalassociated Factorsmentioning

confidence: 99%

“…Rabbits have been reported to respond to most anti-glaucoma drug classes including adrenergics, cholinergics, beta-blockers, carbonic anhydrase inhibitors, rho-kinase inhibitors, melatonin analogues, some cannabinoid analogues, serotonin-2 receptor agonists, and prostaglandin analogues, although the responsiveness to the latter two classes can be quite variable [62,66,70,71,75,[93][94][95].…”

Section: Rabbit (Oryctolagus Cuniculus)mentioning

confidence: 99%

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Study Design and Methodologies for Evaluation of Anti-glaucoma Drugs

Miller

2013

Methods in Pharmacology and Toxicology

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A large number of factors are important in conducting anti-glaucoma drug efficacy studies. It is essential to have an understanding of aqueous humor dynamics and how the tonometer, tonometrist, and animal may affect IOP estimates. Additional critical considerations in the design of an anti-glaucoma drug efficacy studies include the following: (1) selecting the most appropriate species, (2) identifying the rate of nonresponders within the study population, (3) determining whether normotensive or glaucomatous animals should be used, and deciding (4) what secondary endpoints (if any) to include, and (5) whether one eye or both should be dosed. Anti-glaucoma drug efficacy studies have an acclimation phase in which the animal becomes conditioned to the procedures, a predose phase in which baseline data is collected, a dosing phase in which the drug is administered and IOP and possibly other endpoints are monitored, and a recovery phase in which IOP returns to predose values as the drug is washed out before another predose phase is started.

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“…This condition creates an acute elevation of the IOP, which is a glaucoma condition. There are several approaches to destroy the trabecular system: laser irradiation, 19 a-chymotrypsine administration, photocoagulation following India ink injection, 20,21 and aqueous vein obstruction. 22 All these models have the common property of being an artificial model trying to mimic the human disease and have the same weak aspects: (a) creation of acute elevation of IOP, which has no identity to the disease in humans.…”

Section: Introductionmentioning

confidence: 99%

Decrease in reducing power of aqueous humor originating from glaucomatous rabbits

Beit‐Yannai

Trembovler

Solomon

2006

Eye

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Aim To evaluate changes in the reducing power of aqueous humor (AH) with cyclic voltammetry (CV) and HPLC-EC. Methods NZW Rabbits exhibiting a sporadic mutation causing bilaterally buphthalmus eyes were set for intra ocular pressure (IOP) and eye size measurements. AH was obtained under anesthesia, from congenital glaucomatic rabbits (CGR, n ¼ 6) and age-matched controls (CON; n ¼ 6). The AH samples were analysed by CV and HPLC-EC. Results CGR IOP was found to be significantly higher than in CON (33.571.1 and 14.271.0 mmHg, respectively), eye size was 18.25 and 13.9 cm, respectively. CV analysis revealed two anodic currents representing two groups of low molecular weight antioxidant (LMWA). The two anodic potentials were equal for the two tested groups, indicating the same components of LMWA. The first anodic current of CGR was only 30% of the CON rabbits (2.11 vs 7.17 lA/mg protein, t-test: Po0.05). As the main hydrophilic components of the first anodic current are known to be uric acid (UA) and ascorbic acid (AA), they were analysed for exact content by HPLC-EC. UA and AA levels were significantly lower in the CGR group (UA: 17.173.2 and 189.1775.70 lM/mg, AA: 1.170.3 and 4.872.0 lM/mg protein respectively). Conclusions Changes in the reducing power, as indicated by CV analysis, of CGR AH, is probably a result of chronic oxidative stress caused by the pathology. The differences in the first anodic wave are mainly due to a fall in the concentration of UA and AA.

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Continuous intraocular pressure measurement by telemetry in alpha-chymotrypsin-induced glaucoma model in the rabbit: Effects of timolol, dorzolamide, and epinephrine

Cited by 61 publications

References 16 publications

Brimonidine Tartrate–Eudragit Long-Acting Nanoparticles: Formulation, Optimization, In Vitro and In Vivo Evaluation

Brimonidine Tartrate–Eudragit Long-Acting Nanoparticles: Formulation, Optimization, In Vitro and In Vivo Evaluation

Study Design and Methodologies for Evaluation of Anti-glaucoma Drugs

Decrease in reducing power of aqueous humor originating from glaucomatous rabbits

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