Diclofenac sodium ion exchange resin complex loaded melt cast films for sustained release ocular delivery

Abstract

Purpose: The goal of the present study is to develop polymeric matrix films loaded with a combination of free diclofenac sodium (DFS_free) and DFS:Ion exchange resin complexes (DFS:IR) for immediate and sustained release profiles, respectively.

Methods: Effect of ratio of DFS and IR on the DFS:IR complexation efficiency was studied using batch processing. DFS:IR complex, DFS_free, or a combination of DFS_free+DFS:IR loaded matrix films were prepared by melt-cast technology. DFS content was 20% w/w in these matrix films. In vitro transcorneal permeability from the film formulations were compared against DFS solution, using a side-by-side diffusion apparatus, over a 6 h period. Ocular disposition of DFS from the solution, films and corresponding suspensions were evaluated in conscious New Zealand albino rabbits, 4 h and 8 h post-topical administration. All in vivo studies were carried out as per the University of Mississippi IACUC approved protocol.

Results: Complexation efficiency of DFS:IR was found to be 99% with a 1:1 ratio of DFS:IR. DFS release from DFS:IR suspension and the film were best-fit to a Higuchi model. In vitro transcorneal flux with the DFS_free+DFS:IR_(1:1)(1 + 1) was twice that of only DFS:IR_(1:1) film. In vivo, DFS solution and DFS:IR_(1:1) suspension formulations were not able to maintain therapeutic DFS levels in the aqueous humor (AH). Both DFS_free and DFS_free+DFS:IR_(1:1)(3 + 1) loaded matrix films were able to achieve and maintain high DFS concentrations in the AH, but elimination of DFS from the ocular tissues was much faster with the DFS_free formulation.

Conclusion: DFS_free+DFS:IR combination loaded matrix films were able to deliver and maintain therapeutic DFS concentrations in the anterior ocular chamber for up to 8 h. Thus, free drug/IR complex loaded matrix films could be a potential topical ocular delivery platform for achieving immediate and sustained release characteristics.

Keywords:

• Ion exchange resins
• immediate release formulations
• ocular drug delivery
• diclofenac sodium and polymeric matrix films

Declaration of interest

The authors report no declarations of interest.

This publication was supported by Grant 1R01EY022120-01A1 from the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Supplementary materials available online