Wednesday, September 26, 2012

Abstract: Working towards a safer cyclosporine delivery

This is 'early-stage' stuff with test tubes and bunny eyes but it's interesting stuff from an excellent research group in France looking at what makes or mars the delivery of cyclosporine for dry eye, concluding that cationic emulsion is better.

Topical preparations of cyclosporine (CsA) are common therapeutics for the treatment of dry eye. However, they are not devoid of side effects, such as allergy and irritation. The present study aimed at evaluating the safety profile of a new CsA formulation in cationic emulsion (CEm) in vitro with a dynamic corneal wound healing assay using human corneal epithelial (HCE) cells, and in vivo in a rabbit acute toxicity model.
THREE DIFFERENT CSA FORMULATIONS WERE TESTED: 1) 0.05%CsA-CEm, 2) commercial 0.05%CsA-Anionic emulsion (CsA-AEm, Restasis(®)), and 3) 0.05%CsA-Oil solution. Phosphate buffered saline (PBS) was used as negative control and 0.02% benzalkonium chloride (BAK) as the toxic control. In vitro, a wound was created by scratching through a confluent HCE cell layer and exposed 30 min to 1/10 dilutions of the different formulations. Cytotoxicity, cell migration, and proliferation were performed to analyze the recovery at days 1, 2, and 3. In vivo, the eye drops were applied to rabbit eyes 15 times at 5-min intervals. The ocular surface structures were examined with a slit-lamp and by corneal in vivo confocal microscopy (IVCM) for detailed examination of corneal epithelium, stroma, limbus, and conjunctiva-associated lymphoid tissue (CALT) structures.
The in vitro study confirmed that a 0.02% BAK solution delayed the corneal healing process (-57%) by severely damaging the remaining HCE cells. The other formulations maintained a normal healing rate with a similar behavior for CsA-CEm, CsA-AEm, and PBS with no significant differences (at D3, 66%-74% closure). In the rabbit, 0.02%BAK showed the highest toxicity, inducing redness, chemosis with damaged corneal epithelium, and inflammatory cell infiltrations. CsA-AEm and CsA-Oil induced moderate infiltrations of inflammatory cells around the CALT. CsA-CEm presented the lowest toxicity with patterns similar to PBS.
The combination of these in vitro and in vivo models evaluated the tolerance/cytotoxicity and the dynamic wound healing potential of CsA in different formulations. While CsA-AEm, CsA-CEm, and CsA-Oil are generally well tolerated, only CsA-CEm appeared to maintain the HCE cells' normal healing rate in vitro and low levels of inflammation in vivo.

Mol Vis. 2012;18:2195-204. Epub 2012 Aug 8.
Liang H, Baudouin C, Daull P, Garrigue JS, Brignole-Baudouin F.

Abstract: Diquafosol vs. sodium hyaluronate

Hm... I wonder what the osmolarity figures would have been for the two groups.

To compare the efficacy and safety of 3% diquafosol ophthalmic solution with those of 0.1% sodium hyaluronate ophthalmic solution in dry eye patients, using mean changes in fluorescein and rose bengal staining scores as endpoints. TRIAL
In this multicenter, randomised, double-masked, parallel study of 286 dry eye patients with fluorescein and rose bengal staining scores of ≥3 were randomised to the treatment groups in a 1:1 ratio. Efficacy and safety were evaluated after drop-wise instillation of the study drug, six times daily for 4 weeks.
After 4 weeks, the intergroup difference in the mean change from baseline in fluorescein staining score was -0.03; this verified the non-inferiority of diquafosol. The mean change from baseline in rose bengal staining score was significantly lower in the diquafosol group (p=0.010), thus verifying its superiority. The incidence of adverse events was 26.4% and 18.9% in the diquafosol and sodium hyaluronate groups, respectively, with no significant difference.
Diquafosol (3%) and sodium hyaluronate (0.1%) exhibit similar efficacy in improving fluorescein staining scores of dry eye patients, whereas, diquafosol exhibits superior efficacy in improving rose bengal staining scores. Diquafosol has high clinical efficacy and is well tolerated with a good safety profile.

Br J Ophthalmol. 2012 Oct;96(10):1310-1315. Epub 2012 Aug 21.
Takamura E, Tsubota K, Watanabe H, Ohashi Y; for The Diquafosol Ophthalmic Solution Phase 3 Study Group.
Department of Ophthalmology, Tokyo Women's Medical University, School of Medicine, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan;