A Radiolabeling Method for Precise Quantification of Polymers.

Radiolabeling a protein, molecule, or polymer can provide accurate and precise quantification in biochemistry, biomaterials, pharmacology, and drug delivery research. Herein, we describe a method to I label two different polymers for precise quantification in different applications. The surfaces of model contact lenses were modified with phenylboronic acid to bind and release the natural polymer, hyaluronic acid (HA); HA uptake and release were quantified by radiolabeling.

Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery.

Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients.

An Injectable Hydrogel Prepared Using a PEG/Vitamin E Copolymer Facilitating Aqueous-Driven Gelation.

Hydrogels have been widely explored for biomedical applications, with injectable hydrogels being of particular interest for their ability to precisely deliver drugs and cells to targets. Although these hydrogels have demonstrated satisfactory properties in many cases, challenges still remain for commercialization. In this paper, we describe a simple injectable hydrogel based on poly(ethylene glycol) (PEG) and a vitamin E (Ve) methacrylate copolymer prepared via simple free radical polymerization and delivered in a solution of low molecular weight PEG and Ve as the solvent instead of water.

Hydrophobically-modified poly(vinyl pyrrolidone) as a physically-associative, shear-responsive ophthalmic hydrogel.

The potential of hydrophobically-modified poly(vinyl pyrrolidone) as a shear-responsive, self-associative hydrogel for ophthalmic applications is demonstrated. Hydrophobic modification was achieved via random copolymerization of N-vinylpyrrolidone with N-vinylformamide, the latter of which can be hydrolyzed to expose a desired degree of reactive amine groups permitting grafting of alkyl chlorides of varying alkyl chain lengths. The resulting materials formed highly shear-responsive physical hydrogels, exhibiting tunable shear thinning over 4-5 decades of viscosity from infinite shear to zero shear conditions that facilitates lubrication upon blinking and/or facile injection or drop-based delivery to the anterior or posterior segments of the eye.

Strategies for ocular siRNA delivery: Potential and limitations of non-viral nanocarriers.

Controlling gene expression via small interfering RNA (siRNA) has opened the doors to a plethora of therapeutic possibilities, with many currently in the pipelines of drug development for various ocular diseases. Despite the potential of siRNA technologies, barriers to intracellular delivery significantly limit their clinical efficacy. However, recent progress in the field of drug delivery strongly suggests that targeted manipulation of gene expression via siRNA delivered through nanocarriers can have an enormous impact on improving therapeutic outcomes for ophthalmic applications.

Cell-adhesive thermogelling PNIPAAm/hyaluronic acid cell delivery hydrogels for potential application as minimally invasive retinal therapeutics.

Copolymers of N-isopropylacrylamide (NIPAAm) and acrylic acid N-hydroxysuccinimide (NAS) were synthesized via free radical polymerization and conjugated with amine-functionalized hyaluronic acid (HA) and cell adhesive RGDS peptides. These novel copolymers were designed to facilitate noninvasive delivery of a liquid suspension of cells into the delicate subretinal space for treatment of retinal degenerative diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. The various synthesized copolymers all displayed subphysiological phase transition temperatures, thereby allowing temperature-induced scaffold formation and subsequent entrapment of transplanted cells within an adhesive support matrix.