Normotensive New Zealand White Rabbits Research Articles

NCX 667, a Novel Nitric Oxide Donor, Lowers Intraocular Pressure in Rabbits, Dogs, and Non-Human Primates and Enhances TGFβ2-Induced Outflow in HTM/HSC Constructs.

PurposeNCX 667, a novel nitric oxide (NO) donor with an isomannide core, was characterized for its IOP-lowering ability in animal models of ocular hypertension and glaucoma. Bioengineered human trabecular meshwork/Schlemm's canal (HTM/HSC) constructs were used to explore the mode of action.MethodsOcular normotensive New Zealand white (NZW) rabbits (ONT-rabbits), spontaneously ocular hypertensive pigmented Dutch-belted rabbits (sOHT-rabbits), hypertonic saline (5%)–induced transient ocular hypertensive NZW rabbits (tOHT-rabbits), ocular normotensive Beagle dogs (ONT-dogs), and laser-induced ocular hypertensive cynomolgus monkeys (OHT-monkeys) were used. NCX 667 or vehicle (30 µL) was instilled in a crossover, masked fashion and intraocular pressure (IOP) measured before dosing (baseline) and for several hours thereafter. The ONT-rabbits were used for cyclic guanosine monophosphate (cGMP) determination in ocular tissues after ocular dosing with NCX 667. Transforming growth factor-beta2 (TGFβ2) (2.5 ng/mL, six days)–treated HTM/HSC constructs were used to address changes in outflow facility.ResultsNCX 667 resulted in robust and dose-dependent IOP decrease in all models used. Maximal IOP-lowering efficacy at 1% was −4.1 ± 0.6, −12.2 ± 2.7, −10.5 ± 2.0, −5.3 ± 0.8, and −6.6 ± 1.9 mmHg, respectively, in ONT-dogs, sOHT-rabbits, tOHT-rabbits, ONT-rabbits, and OHT-monkeys. In ONT-rabbits NCX 667 (1%) increased cGMP in aqueous humor (AH) but not in retina and iris/ciliary body. NCX 667 concentration-dependently increased outflow facility in TGFβ2-treated HTM/HSC constructs (outflow facility, 0.10 ± 0.06 and 0.30 ± 0.10 µL/min/mmHg/mm2, respectively, in vehicle- and NCX 667–treated constructs).ConclusionsNCX 667 leads to robust IOP lowering in several animal models. Evidence in HTM/HSC constructs indicate that the IOP reduction likely results from NO-mediated increase of the conventional outflow pathway. Other mechanisms including changes in AH production and episcleral vein pressure may not be excluded at this time.

Comparative efficacy study of brimonidine tartrate 0.15% and timolol maleate 0.5% ophthalmic solution (benzalkonium chloride free) versus Brimolol® (with benzalkonium chloride) following single ocular instillation in New Zealand white rabbits

Background: Benzalkonium chloride (BKC) is the most used preservative in topical eye drops but it causes effects such as dry eye and trabecular meshwork degeneration. Polyhexamethylene biguanide (PHMB) is a polymeric biguanide is a less harmful preservative used in ophthalmic solutions. The objective of this study to com-pare the efficacy of PHMB preserved versus BKC preserved ophthalmic solutions containing brimonidine tartrate and timolol maleate on intraocular pressure (IOP) following single ocular instillation in New Zealand white (NZW) rabbits.Methods: This study was conducted on 12 normotensive male NZW rabbits (2.9-3.6 kg) between 6-9 months of age. Animals received single ocular instillation of 35 µl ophthalmic solution containing brimonidine tartrate 0.15 %w/v and timolol maleate 0.5% w/v with PHMB as preservative (n=6, test) or BKC as preservative (n=6, reference) as per the randomization. Intraocular pressure (IOP) was measured before and 2, 4, 6, 8 and 24 hours after instillation using a pneumatonometer. Percentage change in IOP from pre-instillation values were calculated. Changes in IOP were analysed using the repeated-measures analysis of variance followed by Bonferroni post-test.Results: Single ocular instillation of PHMB and BKC formulations show significant IOP reduction up to 6 hours as compared with baseline (p<0.05). Reduction in IOP was 35.8% and 32.0% at 2 hours with PHMB and BKC formulations respectively. No differences were observed between the test and reference groups for change in IOP from baseline.Conclusions: PHMB preserved brimonidine tartrate 0.15% w/v and timolol maleate 0.5% w/v ophthalmic solution was comparable to BKC preserved solution in normotensive NZW rabbits.

3-[2-(Aminomethyl)-5-[(pyridin-4-yl)carbamoyl]phenyl] benzoates as soft ROCK inhibitors

Clinical development of ROCK inhibitors has so far been limited by systemic or local ROCK-associated side effects. A soft drug approach, which involves predictable metabolic inactivation of an active compound to a nontoxic metabolite, could represent an attractive way to obtain ROCK inhibitors with improved tolerability. We herein report the design and synthesis of a new series of soft ROCK inhibitors structurally related to the ROCK inhibitor Y-27632. These inhibitors contain carboxylic ester moieties which allow inactivation by esterases. While the parent esters display strong activity in enzymatic (ROCK2) and cellular (MLC phosphorylation) assays, their corresponding carboxylic acid metabolites have negligible functional activity. Compound 32 combined strong efficacy (ROCK2 IC50=2.5nM) with rapid inactivation in plasma (t1/2 <5′). Compound 32 also demonstrated in vivo efficacy when evaluated as an IOP-lowering agent in ocular normotensive New-Zealand White rabbits, without ocular side effects.