scholarly journals Soft Contact Lenses as Drug Delivery Systems: A Review

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5577
Author(s):  
Iwona Rykowska ◽  
Iwona Nowak ◽  
Rafał Nowak

This review describes the role of contact lenses as an innovative drug delivery system in treating eye diseases. Current ophthalmic drug delivery systems are inadequate, particularly eye drops, which allow about 95% of the active substance to be lost through tear drainage. According to the literature, many interdisciplinary studies have been carried out on the ability of contact lenses to increase the penetration of topical therapeutic agents. Contact lenses limit drug loss by releasing the medicine into two layers of tears on either side of the contact lens, eventually extending the time of contact with the ocular surface. Thanks to weighted soft contact lenses, a continuous release of the drug over an extended period is possible. This article reviewed the various techniques to deliver medications through contact lenses, examining their advantages and disadvantages. In addition, the potential of drug delivery systems based on contact lenses has been extensively studied.

2014 ◽  
Vol 679 ◽  
pp. 118-127 ◽  
Author(s):  
Deirdre M. McElroy ◽  
Luke M. Geever ◽  
Clement L. Higginbotham ◽  
Sinead M. Devery

Hydrogel soft contact lenses have been investigated as delivery systems for ophthalmic drug products in response to the need for more efficient ophthalmic drug delivery systems. Ocular drugs delivered via eye drops have a low residence time in the eye resulting in as low as 5% bioavailability of the therapeutic agent. This study investigates the effect of varying concentrations of the photoinitiator diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (TPO) on the physicochemical properties of hydrogel soft contact lenses for ophthalmic drug delivery purposes. Contact lens samples were synthesised via photopolymerisation with a range of initiator concentration. Gel fraction and swelling results indicated that increasing the photoinitiator concentration increased the efficiency of the gel network and reduced the water content of contact lens samples. Fourier transform infra-red spectroscopy (FTIR) analysis was employed to confirm polymerisation of the lenses and also indicated the presence of residual photoinitiator in lenses with higher TPO concentrations.


2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaohong Hu ◽  
Lingyun Hao ◽  
Huaiqing Wang ◽  
Xiaoli Yang ◽  
Guojun Zhang ◽  
...  

Soft contact lenses can improve the bioavailability and prolong the residence time of drugs and, therefore, are ideal drug carriers for ophthalmic drug delivery. Hydrogels are the leading materials of soft contact lenses because of their biocompatibility and transparent characteristic. In order to increase the amount of load drug and to control their release at the expected intervals, many strategies are developed to modify the conventional contact lens as well as the novel hydrogel contact lenses that include (i) polymeric hydrogels with controlled hydrophilic/hydrophobic copolymer ratio; (ii) hydrogels for inclusion of drugs in a colloidal structure dispersed in the contact lenses; (iii) ligand-containing hydrogels; (iv) molecularly imprinted polymeric hydrogels; (v) hydrogel with the surface containing multilayer structure for drugs loading and releasing. The advantages and disadvantages of these strategies in modifying or designing hydrogel contact lenses for extended ophthalmic drug delivery are analyzed in this paper.


2015 ◽  
Vol 18 (5) ◽  
pp. 683 ◽  
Author(s):  
Andreza Maria Ribeiro ◽  
Ana Figueiras ◽  
Francisco Veiga

Conventional ophthalmic systems present very low corneal systemic bioavailability due to the nasolacrimal drainage and the difficulty to deliver the drug in the posterior segment of ocular tissue. For these reasons, recent advances have focused on the development of new ophthalmic drug delivery systems. This review provides an insight into the various constraints associated with ocular drug delivery, summarizes recent findings in soft contact lenses (SCL) and the applications of novel pharmaceutical systems for ocular drug delivery. Among the new therapeutic approaches in ophthalmology, SCL are novel continuous-delivery systems, providing high and sustained levels of drugs to the cornea. The tendency of research in ophthalmic drug delivery systems development are directed towards a combination of several technologies (bio-inspired and molecular imprinting techniques) and materials (cyclodextrins, surfactants, specific monomers). There is a tendency to develop systems which not only prolong the contact time of the vehicle at the ocular surface, but also at the same time slow down the clearance of the drug. Different materials can be applied during the development of contact lenses and can be combined with natural inspired strategies of drug immobilization and release, providing successful tools for ocular drug delivery systems. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.


2020 ◽  
Vol 13 (11) ◽  
pp. 351
Author(s):  
Yu-Chi Liu ◽  
Molly Tzu-Yu Lin ◽  
Anthony Herr Cheun Ng ◽  
Tina T. Wong ◽  
Jodhbir S. Mehta

Allergic conjunctivitis is one of the most common external eye diseases and the prevalence has been increasing. The mainstay of treatment is topical eye drops. However, low bioavailability, low ocular drug penetration, transient resident time on the ocular surface due to tear turnover, frequent topical applications and dependence on patient compliance, are the main drawbacks associated with topical administration. Nanotechnology-based medicine has emerged to circumvent these limitations, by encapsulating the drugs and preventing them from degradation and therefore providing sustained and controlled release. Using a nanotechnology-based approach to load the drug is particularly useful for the delivery of hydrophobic drugs such as immunomodulatory agents, which are commonly used in allergic conjunctival diseases. In this review, different nanotechnology-based drug delivery systems, including nanoemulsions, liposomes, nanomicelles, nanosuspension, polymeric and lipid nanoparticles, and their potential ophthalmic applications, as well as advantages and disadvantages, are discussed. We also summarize the results of present studies on the loading of immunomodulators or nonsteroidal anti-inflammatory drugs to nano-scaled drug delivery systems. For future potential clinical use, research should focus on the optimization of drug delivery designs that provide adequate and effective doses with safe and satisfactory pharmacokinetic and pharmaco-toxic profiles.


Author(s):  
Bibhu Prasad Panda ◽  
N.S Dey ◽  
M.E.B. Rao

Over the past few decades, there has been an increased interest for innovative drug delivery systems to improve safety, efficacy and patient compliance, thereby increasing the product patent life cycle. The discovery and development of new chemical entities is not only an expensive but also time consuming affair. Hence the pharmaceutical industries are focusing on the design and development of innovative drug delivery systems for existing drugs. One such delivery system is the fast disintegrating oral film, which has gained popularity among pediatric and geriatric patients. This fast disintegrating film with many potential benefits of a fast disintegrating tablet but devoid of friability and risk of choking is more acceptable to pediatric and geriatric patients. Formulation of fast disintegrating film can be achieved by various techniques, but common methods of preparation include spraying and casting. These film forming techniques use hydrophilic film former in combination with suitable excipients, which allow the film to disintegrate or dissolve quickly in the mouth within a few seconds without the administration of water. In view of the advantages of the fast disintegrating films over the fast disintegrating tablets and other dosage forms, it has the potential for commercial exploitation. The oral film dosage form not only has certain advantages of other fast disintegrating systems but also satisfies the unmet needs of the market. The present review emphasizes on the potential benefits, design and development of robust, stable, and innovative orally fast- disintegrating films and their future scenarios on a global market as a pharmaceutical dosage form.  


2019 ◽  
Vol 26 (14) ◽  
pp. 2502-2513 ◽  
Author(s):  
Md. Iqbal Hassan Khan ◽  
Xingye An ◽  
Lei Dai ◽  
Hailong Li ◽  
Avik Khan ◽  
...  

The development of innovative drug delivery systems, versatile to different drug characteristics with better effectiveness and safety, has always been in high demand. Chitosan, an aminopolysaccharide, derived from natural chitin biomass, has received much attention as one of the emerging pharmaceutical excipients and drug delivery entities. Chitosan and its derivatives can be used for direct compression tablets, as disintegrant for controlled release or for improving dissolution. Chitosan has been reported for use in drug delivery system to produce drugs with enhanced muco-adhesiveness, permeation, absorption and bioavailability. Due to filmogenic and ionic properties of chitosan and its derivative(s), drug release mechanism using microsphere technology in hydrogel formulation is particularly relevant to pharmaceutical product development. This review highlights the suitability and future of chitosan in drug delivery with special attention to drug loading and release from chitosan based hydrogels. Extensive studies on the favorable non-toxicity, biocompatibility, biodegradability, solubility and molecular weight variation have made this polymer an attractive candidate for developing novel drug delivery systems including various advanced therapeutic applications such as gene delivery, DNA based drugs, organ specific drug carrier, cancer drug carrier, etc.


2020 ◽  
Vol 17 ◽  
Author(s):  
Marina Gallarate ◽  
Daniela Chirio ◽  
Giulia Chindamo ◽  
Elena Peira ◽  
Simona Sapino

: Osteomyelitis is a bone marrow infection which generally involves cortical plates and which may occur after bone trauma, orthopedic/maxillofacial surgery or after vascular insufficiency episodes. It mostly affects people from the Third World Countries, elderly and patients affected by systemic diseases e.g. autoimmune disorders, AIDS, osteoporosis and microvascular disease. The highest percentage of osteomyelitis cases (almost 75%) is caused by Staphylococcus spp., and in particular by Staphylococcus aureus (more than 50%). The ideal classification and the diagnosis of osteomyelitis are two important tools which help the physicians to choose the best therapeutic strategies. Currently, common therapies provide an extensive debridement in association with intravenous administration of antibiotics (penicillin or clindamycin, vancomycin and fluoroquinolones among all for resistant microorganisms), to avoid the formation of sequestra. However, conventional therapeutic approach involves several drawbacks like low concentration of antibiotic in the infected site, which can lead to resistance and adverse effects due to the intravenous administration. For these reasons, in the last years several studies have been focused on the development of drug delivery systems such as cement, beads, scaffold and ceramics made of hydroxyapatite (HA), calcium phosphate (CaP) and β-tricalcium phosphate (β-TCP) which demonstrated to be biocompatible, poorly toxic and capable to allow osteointegration and a prolonged drug release. The aim of this review is to provide a focus on current therapies and latest developed drug delivery systems with particular attention on those based on CaP and its derivatives, hoping that this work could allow further direction in the field of osteomyelitis.


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