Abstract
Purpose :
To evaluate and compare the ex-vivo (rabbit and porcine) transscleral diffusion permeability profile of dexamethasone sodium phosphate (Dex SP) and triamcinolone acetonide (TA) in solution and lyophilized dry form.
Methods :
The sclerae were harvested from fresh porcine and albino rabbit globes. The effect of solution and a lyophilized formulation on the transscleral permeability was investigated using Franz-type vertical diffusion cells after delivery of Dex SP and TA at 6 and 9 mg/ml concentrations in the donor side and its quantification by HPLC in the recipient side. The transscleral flux and permeability coefficient were calculated. Permeability parameters were determined and compared with ANOVA (p<0.05).
Results :
It was demonstrated that both solutions and lyophilized formulations of Dex SP and TA at 6 and 9 mg/mL could diffuse across the sclera and that permeation decreased over time in porcine and rabbit. The flux of Dex SP in solution and lyophilized formulation at 6 mg were 2.22 and 6.92 ug/cm2Hr respectively in porcine. After 48 hours, in average 62.8% and 42.8% of the initial 6 mg solution and dry Dex SP, respectively had been recovered in the recipient side (p = 0.00014).
The flux of TA in porcine sclera after exposure to 6 mg in solution and lyophilized formulations was 0.1568 and 0.0089 ug/cm2Hr, respectively, and the permeability coefficients were 7.29 x 10-9 and 4.23 x 10-10 cm/s. After 48 hours of diffusion, the recovery of TA 6 mg were 0.8% and 0.2%, respectively, for solution and lyophilized forms of TA (p = 0.0131). The majority of the lyophilized dry form was found in the donor chambers with 60.9% of total recovery of TA 6 mg.
Conclusions :
We have shown that transscleral diffusion of hydrophilic and lipophilic steroidal anti-inflammatory drugs in solution and dry-lyophilized formulations. Both formulations were able to provide drug permeation through the sclerae in different species. It indicates that soluble and insoluble drugs can benefit from the use of liquid and dry formulations for episcleral delivery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.