Triamcinolone Acetonide-Loaded PEGylated Microemulsion for the Posterior Segment of Eye

Present work investigates the possibility of a polyethyleneglycolylated (PEGylated) microemulsion (ME) to deliver drug to the posterior segment of eye. Triamcinolone acetonide (TA), a widely used drug in intraocular diseases, was selected as the model drug. Based on solubility and emulsification capacity, components of microemulsion were selected and optimum formulation was obtained using a pseudoternary phase diagram. The optimized ratio of Capmul MCM C8 (oil): AccononMC8-2 (surfactant): Transcutol (cosurfactant): deionized water was 5:35.5:4.5:55. This was further PEGylated using 1,2-distearoylphosphatylethanolamine-polyethyleneglycol 2000 (DSPE-PEG 2000). This PEGylated ME loaded with TA was characterized and evaluated in vitro, ex vivo, and in vivo for topical ocular use. The developed PEGylated ME loaded with TA was homogenous, stable, and nonirritable to eye and had the ability to reach the posterior segment of eye on topical instillation.

Conclusion

It was a known and accepted fact that PEGylation always enhances the retention/residence time of ligand/molecule/nanoformulation to which it is attached, in fluidic medium whether oral or parenteral route were considered. Drug delivery to retina is hamstrung by two kinds of barriers: membranous and fluidic. The ME system was well reported to overcome the membranous barrier. To surpass the fluidic barrier, these MEs were PEGylated using PEGylated phospholipid. This adjuvant is biodegradable and nontoxic and can attach to interface of ME leaving its PEG chain in aqueous dispersion phase of ME for eliciting its longer circulatory effect in fluids. Developed PEGylated ME in present investigation was capable enough to maintain circulation of loaded dye up to 6 h and that too, in higher amount as compared to plain dye solution and non-PEGylated ME. PEGylation was also proven true for its utility in topical ocular ME for retinal drug delivery. Download the full publication here: Triamcinolone Acetonide-Loaded PEGylated Microemulsion for the Posterior Segment of Eye

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