Purchase this article with an account.
Naba Elsaid, Zeeneh Elsaid, Satyanarayana Somavarapu, Timothy L Jackson; A Stable Chitosan-coated Nanomicelle Combination Of Vitamin E-TPGS And Cholesterol-PEG For The Topical Administration And Scleral Retention Of Rapamycin. Invest. Ophthalmol. Vis. Sci. 2012;53(14):328.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The aim of this study was to prepare and characterise chitosan-coated vitamin E-TPGS: cholesterol-PEG (CPEG) nanomicelles and use these in the ocular delivery of the insoluble, hydrophobic drug rapamycin.
Micelles containing vitamin E-TPGS and cholesterol-PEG (CPEG) were prepared and coated with chitosan oligomer using the thin film method. This formulation was analysed for encapsulation efficiency, size and stability (Dynamic Light Scattering- DLS), surface morphology (Transmission Electron Microscopy- TEM) and critical micelle concentration (fluorometry). Furthermore, ex-vivo studies were conducted by mounting porcine sclera in Ussing chambers and measuring the drug content which was retained in and had permeated across the sclera. Sample analysis was carried out using High Performance Liquid Chromatography with a limit of quantification (LOQ) of 12.5ng/mL.
The TPGS:CPEG micelles successfully entrapped rapamycin with an encapsulation efficiency of 78% and a desirable size of 13nm. These micelles remained stable for 7 days, unlike the TPGS micelles which were stable for 3 days. The solution was visibly clear with a polydispersity index of 0.07 and no sign of aggregates. TEM and DLS data confirmed this and showed uniform particle distribution. The critical micelle concentration was found to be 1x10-4% w/v. The addition of CPEG and the chitosan coating of these micelles enabled permeation within the first 30 minutes of tissue exposure and caused a significant increase in scleral retention.
A stable nanomicellar formulation was developed with desirable physiochemical properties and transscleral permeation which occurred within the first 30 minutes of tissue exposure. Furthermore, there is potential for future applications in topical drug delivery as this formulation was retained in the sclera. This carrier system may also enhance the transscleral delivery of drugs that may otherwise not be able to target the posterior segment of the eye.
This PDF is available to Subscribers Only