Soft contact lenses functionalized with pendant cyclodextrins for controlled drug delivery
TL;DR: The hydrogels with pendant betaCDs are particularly useful for the development of cytocompatible medicated implants or biomedical devices, such as drug-loaded SCLs, and to sustain drug delivery in lacrimal fluid for two weeks.
About: This article is published in Biomaterials.The article was published on 2009-03-01. It has received 148 citations till now. The article focuses on the topics: Self-healing hydrogels & Contact lens.
Citations
More filters
TL;DR: This review provides an advanced perspective on contact lens materials, with an emphasis on materials science employed in developing new CLs, and provides viewpoints of precision manufacturing in CL development.
Abstract: More is demanded from ophthalmic treatments using contact lenses, which are currently used by over 125 million people around the world. Improving the material of contact lenses (CLs) is a now rapidly evolving discipline. These materials are developing alongside the advances made in related biomaterials for applications such as drug delivery. Contact lens materials are typically based on polymer- or silicone-hydrogel, with additional manufacturing technologies employed to produce the final lens. These processes are simply not enough to meet the increasing demands from CLs and the ever-increasing number of contact lens (CL) users. This review provides an advanced perspective on contact lens materials, with an emphasis on materials science employed in developing new CLs. The future trends for CL materials are to graft, incapsulate, or modify the classic CL material structure to provide new or improved functionality. In this paper, we discuss some of the fundamental material properties, present an outlook from related emerging biomaterials, and provide viewpoints of precision manufacturing in CL development.
188 citations
TL;DR: The adsorption kinetics and isotherms of the polymers toward a mixture of ten distinct pesticides clearly demonstrate that the adsorbents with a homogeneous open network structure can absorb pesticides via multiple adsorbent-adsorbate interactions such as CD inclusion, loading into swelling water and physical Adsorption on network.
176 citations
TL;DR: The possible new ways to incorporate hydrophobic drugs within hydrogel structures that have been developed through research are discussed.
Abstract: Hydrogels have been shown to be very useful in the field of drug delivery due to their high biocompatibility and ability to sustain delivery. Therefore, the tuning of their properties should be the focus of study to optimise their potential. Hydrogels have been generally limited to the delivery of hydrophilic drugs. However, as many of the new drugs coming to market are hydrophobic in nature, new approaches for integrating hydrophobic drugs into hydrogels should be developed. This article discusses the possible new ways to incorporate hydrophobic drugs within hydrogel structures that have been developed through research. This review describes hydrogel-based systems for hydrophobic compound delivery included in the literature. The section covers all the main types of hydrogels, including physical hydrogels and chemical hydrogels. Additionally, reported applications of these hydrogels are described in the subsequent sections.
173 citations
Cites background or methods from "Soft contact lenses functionalized ..."
...showed that hydrogel-based contact lenses containing CDs were able to deliver diclofenac for 25 days [75]....
[...]
...Subsequently, β-CD was grafted to the network by reaction with the glycidyl groups [75]....
[...]
...HEMA-based hydrogels containing CDs Diclofenac Ocular inflammatory disorders Ocular (contact lenses) [75]...
[...]
TL;DR: The present review focuses on the approaches tested to synthesize nano- to macro-size covalently cross-linked CD networks and the advantages of having the CDs chemically bound among themselves and to substrates are provided and their applicability in therapeutics discussed.
160 citations
TL;DR: This review provides an expert opinion on different methodology to develop therapeutic contact lenses with special remark of their advantages and limitations.
Abstract: Contact lenses for ophthalmic drug delivery have become very popular, due to their unique advantages like extended wear and more than 50% bioavailability. To achieve controlled and sustained drug delivery from contact lenses, researchers are working on various systems like polymeric nanoparticles, microemulsion, micelle, liposomes, use of vitamin E, etc. Numerous scientists are working on different areas of therapeutic contact lenses to treat ocular diseases by implementing techniques like soaking method, molecular imprinting, entrapment of drug-laden colloidal nanoparticles, drug plate/film, ion ligand polymeric systems, supercritical fluid technology, etc. Though sustained drug delivery was achieved using contact lens, the critical properties such as water content, tensile strength (mechanical properties), ion permeability, transparency and oxygen permeability were altered, which limit the commercialization of therapeutic contact lenses. Also issues like drug stability during processing/fabrication (drug integrity test), zero order release kinetics (prevent burst release), drug release during monomer extraction step after fabrication (to remove un-reacted monomers), protein adherence, drug release during storage in packaging solution, shelf life study, cost-benefit analysis, etc. are still to be addressed. This review provides an expert opinion on different methodology to develop therapeutic contact lenses with special remark of their advantages and limitations.
159 citations
Cites background from "Soft contact lenses functionalized ..."
...Improvement in drug (diclofenac) loading by 1300% and sustained drug delivery up to two weeks was detected in lacrimal fluids (Dos Santos et al., 2009)....
[...]
References
More filters
TL;DR: Cyclodextrins are still regarded as novel excipients of unexplored potential and, thus, 100 years after their discovery, new cyclodextrin-based technologies are constantly being developed.
1,394 citations
"Soft contact lenses functionalized ..." refers background in this paper
...The guest molecule can establish favorable interactions with the hydrophobic inner face of the cavity and hydrogen bonds with the outer –OH groups of the cyclodextrin [23]....
[...]
TL;DR: This review summarizes the compositional and structural effects of polymers on swelling, loading, and release and approaches to characterize solute release behavior in a dynamic state.
Abstract: Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability The desired kinetics, duration, and rate of solute release from hydrogels are limited to specific conditions, such as hydrogel properties, amount of incorporated drug, drug solubility, and drug-polymer interactions This review summarizes the compositional and structural effects of polymers on swelling, loading, and release and approaches to characterize solute release behavior in a dynamic state A new approach is introduced to compensate drug effects (solubility and loading) with the release kinetics by varying the structure of heterogeneous polymers Modulated or pulsatile drug delivery using functional hydrogels is a recent trend in hydrogel drug delivery
590 citations
"Soft contact lenses functionalized ..." refers methods in this paper
...In order to further understand the role of the interaction of diclofenac with cyclodextrin units, the partition coefficient, K, between the polymer network and the drug loading solution was estimated from the following expression [50]:...
[...]
TL;DR: A critique of the literature, the own work, and various simulations suggests that drug release from cyclodextrin complexes is rapid and quantitative in most cases.
375 citations
"Soft contact lenses functionalized ..." refers background in this paper
...However, when solutions of drug:CD complexes are diluted in the physiological fluids, the decomplexation is practically instantaneous and controlled release cannot be achieved; such is the case of ophthalmic solutions containing CDs [24,25]....
[...]
TL;DR: Particle-laden hydrogels are promising candidates for ophthalmic drug delivery because they are transparent and can release drugs for extended periods and can be controlled by varying the loading of nanoparticles in the gel.
Abstract: Purpose Currently available ophthalmic drug delivery systems are inefficient and may lead to side effects. To increase efficiency and reduce side effects, the authors propose disposable particle-laden soft contact lenses for ophthalmic drug delivery. Methods The essential idea is to encapsulate the ophthalmic drug formulations in nanoparticles and to disperse these drug-laden particles in the lens material, such as poly-2-hydroxyethyl methacrylate (p-HEMA) hydrogels. The drug-laden p-HEMA hydrogels were synthesized by free radical solution polymerization of the monomers in presence of nanoparticles. The particle-laden hydrogels were characterized by light-transmission and electron microscopy studies. Release profiles of lidocaine, a model hydrophobic drug, were measured by UV-Vis spectrophotometry. Results Microemulsions of hexadecane in water stabilized with a silica shell around the particles produced transparent hydrogels. Contact lenses made with particle-laden hydrogels released therapeutic levels of drug for a few days. Conclusions Particle-laden hydrogels are promising candidates for ophthalmic drug delivery. They are transparent and can release drugs for extended periods. The drug delivery rates can be controlled by varying the loading of nanoparticles in the gel.
290 citations
TL;DR: The challenge of improving ocular compatibility and ensuring the longevity of indwelling ocular devices is addressed along with the need to improve the physicochemical and mechanical properties of existing ocular biomaterials.
276 citations
"Soft contact lenses functionalized ..." refers background in this paper
...Since the main monomers used to prepare the hydrogels (HEMA and EGDMA) are common components of FDA approved contact lenses [2,45] and bCD is regarded as non-irritant to the eyes [46], good compatibility with the ocular surface is foreseeable for the hydrogels with pendant bCD....
[...]