Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings

Prina Mehta, Ali A. Al-Kinani, Rita Haj-Ahmad, Muhammad Sohail Arshad, Ming Wei Chang, Raid G. Alany, Zeeshan Ahmad

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Advances in nanotechnology have enabled solutions for challenging drug delivery targets. While the eye presents numerous emerging opportunities for delivery, analysis and sensing; issues persist for conventional applications. This includes liquid phase formulation localisation on the ocular surface once administered as formulated eye-drops; with the vast majority of dosage (>90%) escaping from the administered site due to tear production and various drainage mechanisms. The work presented here demonstrates a single needle electrohydrodynamic (EHD) engineering process to nano-coat (as an on demand and controllable fiber depositing method) the surface of multiple contact lenses rendering formulations to be stationary on the lens and at the bio-interface. The coating process was operational based on ejected droplet charge and glaucoma drug timolol maleate (TM) was used to demonstrate surface coating optimisation, bio-surface permeation properties (flux, using a bovine model) and various kinetic models thereafter. Polymers PVP, PNIPAM and PVP:PNIPAM (50:50%w/w) were used to encapsulate the active. Nano-fibrous and particulate samples were characterised using SEM, FTIR, DSC and TGA to confirm structural and thermal stability of surface coated formulations. More than 52% of nano-structured coatings (for all formulations) were <200 nm in diameter. In vitro studies show coatings to exhibit biphasic release profiles; an initial burst release followed by sustained release; with TM-loaded PNIPAM coating releasing most drug after 24 h (89.8%). Kinetic modelling (Higuchi, Korsmeyer-Peppas) was indicative of quasi-Fickian diffusion whilst biological evaluation demonstrates adequate ocular tolerability. Results from permeation studies indicate coated lenses are ideal to reduce dosing regimen, which in turn will reduce systemic drug absorption. Florescent microscopy demonstrated probe and probe embedded coating behaviour from lens surface in vitro. The multiple lens surface coating method demonstrates sustained drug release yielding promising results; suggesting both novel device and method to enhance drug activity at the eyes surface which will reduce formulation drainage.

LanguageEnglish
Pages170-184
Number of pages15
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
Volume119
Early online date15 Jun 2017
DOIs
Publication statusPublished - 1 Oct 2017

Fingerprint

Timolol
Crystalline Lens
Lenses
Pharmaceutical Preparations
Drainage
Nanotechnology
Surface Properties
Ophthalmic Solutions
Contact Lenses
Fourier Transform Infrared Spectroscopy
Tears
Glaucoma
Needles
Microscopy
Hot Temperature
Equipment and Supplies
poly-N-isopropylacrylamide

Keywords

  • Contact lens
  • Drug delivery
  • Electrospinning
  • Fiber
  • Glaucoma
  • Timolol maleate

Cite this

Mehta, Prina ; Al-Kinani, Ali A. ; Haj-Ahmad, Rita ; Arshad, Muhammad Sohail ; Chang, Ming Wei ; Alany, Raid G. ; Ahmad, Zeeshan. / Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings. In: European Journal of Pharmaceutics and Biopharmaceutics. 2017 ; Vol. 119. pp. 170-184.
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abstract = "Advances in nanotechnology have enabled solutions for challenging drug delivery targets. While the eye presents numerous emerging opportunities for delivery, analysis and sensing; issues persist for conventional applications. This includes liquid phase formulation localisation on the ocular surface once administered as formulated eye-drops; with the vast majority of dosage (>90{\%}) escaping from the administered site due to tear production and various drainage mechanisms. The work presented here demonstrates a single needle electrohydrodynamic (EHD) engineering process to nano-coat (as an on demand and controllable fiber depositing method) the surface of multiple contact lenses rendering formulations to be stationary on the lens and at the bio-interface. The coating process was operational based on ejected droplet charge and glaucoma drug timolol maleate (TM) was used to demonstrate surface coating optimisation, bio-surface permeation properties (flux, using a bovine model) and various kinetic models thereafter. Polymers PVP, PNIPAM and PVP:PNIPAM (50:50{\%}w/w) were used to encapsulate the active. Nano-fibrous and particulate samples were characterised using SEM, FTIR, DSC and TGA to confirm structural and thermal stability of surface coated formulations. More than 52{\%} of nano-structured coatings (for all formulations) were <200 nm in diameter. In vitro studies show coatings to exhibit biphasic release profiles; an initial burst release followed by sustained release; with TM-loaded PNIPAM coating releasing most drug after 24 h (89.8{\%}). Kinetic modelling (Higuchi, Korsmeyer-Peppas) was indicative of quasi-Fickian diffusion whilst biological evaluation demonstrates adequate ocular tolerability. Results from permeation studies indicate coated lenses are ideal to reduce dosing regimen, which in turn will reduce systemic drug absorption. Florescent microscopy demonstrated probe and probe embedded coating behaviour from lens surface in vitro. The multiple lens surface coating method demonstrates sustained drug release yielding promising results; suggesting both novel device and method to enhance drug activity at the eyes surface which will reduce formulation drainage.",
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Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings. / Mehta, Prina; Al-Kinani, Ali A.; Haj-Ahmad, Rita; Arshad, Muhammad Sohail; Chang, Ming Wei; Alany, Raid G.; Ahmad, Zeeshan.

In: European Journal of Pharmaceutics and Biopharmaceutics, Vol. 119, 01.10.2017, p. 170-184.

Research output: Contribution to journalArticle

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T1 - Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings

AU - Mehta, Prina

AU - Al-Kinani, Ali A.

AU - Haj-Ahmad, Rita

AU - Arshad, Muhammad Sohail

AU - Chang, Ming Wei

AU - Alany, Raid G.

AU - Ahmad, Zeeshan

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AB - Advances in nanotechnology have enabled solutions for challenging drug delivery targets. While the eye presents numerous emerging opportunities for delivery, analysis and sensing; issues persist for conventional applications. This includes liquid phase formulation localisation on the ocular surface once administered as formulated eye-drops; with the vast majority of dosage (>90%) escaping from the administered site due to tear production and various drainage mechanisms. The work presented here demonstrates a single needle electrohydrodynamic (EHD) engineering process to nano-coat (as an on demand and controllable fiber depositing method) the surface of multiple contact lenses rendering formulations to be stationary on the lens and at the bio-interface. The coating process was operational based on ejected droplet charge and glaucoma drug timolol maleate (TM) was used to demonstrate surface coating optimisation, bio-surface permeation properties (flux, using a bovine model) and various kinetic models thereafter. Polymers PVP, PNIPAM and PVP:PNIPAM (50:50%w/w) were used to encapsulate the active. Nano-fibrous and particulate samples were characterised using SEM, FTIR, DSC and TGA to confirm structural and thermal stability of surface coated formulations. More than 52% of nano-structured coatings (for all formulations) were <200 nm in diameter. In vitro studies show coatings to exhibit biphasic release profiles; an initial burst release followed by sustained release; with TM-loaded PNIPAM coating releasing most drug after 24 h (89.8%). Kinetic modelling (Higuchi, Korsmeyer-Peppas) was indicative of quasi-Fickian diffusion whilst biological evaluation demonstrates adequate ocular tolerability. Results from permeation studies indicate coated lenses are ideal to reduce dosing regimen, which in turn will reduce systemic drug absorption. Florescent microscopy demonstrated probe and probe embedded coating behaviour from lens surface in vitro. The multiple lens surface coating method demonstrates sustained drug release yielding promising results; suggesting both novel device and method to enhance drug activity at the eyes surface which will reduce formulation drainage.

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