Assessing the ex vivo permeation behaviour of functionalised contact lens coatings engineered using an electrohydrodynamic technique

Abstract

In vitro testing alone is no longer considered sufficient evidence presented solely with respect to drug release and permeation testing. These studies are thought to be more reliable and representative when using tissue or animal models; as opposed to synthetic membranes. The release of anti-glaucoma drug timolol maleate from electrically atomised coatings was assessed here using freshly excised bovine corneal tissue. Electrohydrodynamic processing was utilised to engineer functionalised fibrous polyvinylpyrrolidone-Poly (N-isopropylacrylamide) coatings on the outer side of commercial silicone contact lenses. Benzalkonium chloride, ethylenediaminetetraacetic acid, Brij ® 78 and borneol were employed as permeation enhancers to see their effect on ex vivo permeation of timolol maleate through the cornea. Formulations containing permeation enhancers showed a vast improvement with respect to cumulative amount of drug permeating through the cornea as shown by a six fold decrease in lag time compared to enhancer-free formulations. Most drug delivery systems require the drug to pass or permeate through a tissue or biological membrane. This study has shown that to fully appreciate and understand how a novel drug delivery system will behave not only within the device but with the external environment or tissue, it is imperative to have in vitro and ex vivo data in conjunction.

A Meta-Analysis of Wearable Contact Lenses for Medical Applications: Role of Electrospun Fiber for Drug Delivery

“…By using a special mixing ratio of permeation enhancers and polymers, Mehta et al (2018) presented the capability of utilizing electrohydrodynamic atomization (EHDA) in engineering strong coverings to improve the permeation of pharmaceuticals, thus increasing the bioavailability of ocular drugs ( Supplementary Table S5 ). Their ex vivo analyses indicated that by adding permeation enhancers, a substantial increase in TM permeation in comparison to an additive-free setup could be achieved (53.39 ± 3.95 μg cm − 2 ) after 24 h. This significant improvement in drug permeation resulted in a decline in ocular toxicity due to the lower systematic absorption over an appropriate time frame [ 27 ].…”

“…Scientists have created a range of fiber networks to focus on both drug delivery and the engineering of corneal tissue. One of the main challenges when dealing with electrospun fibers for drug loading and release is the fine-tuning of the fiber matrix and its morphology, porosity, and wettability, as drug particles may get trapped within the network of fibers, which may act as barriers to hinder the drug diffusion instead of promoting it [ 22 , 26 , 27 ]. Furthermore, the low efficacy and systemic side effects of these electrospun release systems are additional aspects to be thoroughly studied [ 143 ].…”

“…For each specific drug, the release rate and profile have to be carefully controlled with respect to the natural optical and diffusive characteristics of corneal tissue to overcome dose management issues and limitations associated with poor delivery [ 21 , 22 ]. Several reports of the literature highlight the design and fabrication of polymer/co-polymer fiber networks for drug delivery applications [ 20 , 21 , 22 , 25 , 26 , 27 , 28 ]. Regardless of these advancements, however, several issues are yet to be addressed.…”

Recent applications of electrical, centrifugal, and pressurised emerging technologies for fibrous structure engineering in drug delivery, regenerative medicine and theranostics

“…chitosan [152][153][154][155][156], collagen [157][158][159][160], SF [161][162][163][164], gelatin [165][166][167][168][169][170]) and synthetic polymers (e.g. PGA [171][172][173], poly lactic acid (PLA) [174][175][176][177][178][179], PLGA [180][181][182][183][184][185][186][187][188], poly vinylpyrrolidone (PVP) [77,[189][190][191][192][193][194], PCL [195][196][197][198][199][200]<...…”

Bio-responsive materials for tissue regeneration

“…This topical review highlights progress with different functional stimuli based on molecular design, with prospective comments on their future in health application. Keeping with the advanced biomaterials design for medical therapeutics, our next original article by Mehta et al [2], De Montfort University, United Kingdom, describes the development of a new fibrous coating on tissue via electrohydrodynamic technique, which is applicable for ex vivo drug testing model. Another interesting contribution is from Konishi et al [3] who investigated the effects of an amorphous hydrated layer in bioceramics fabrication using nuclear magnetic resonance spectroscopy.…”