Polymers (Polyvinylpyrrolidones) As Active Additives Modifying the Lubricating Properties of Water

Co-formulations of adalimumab with hyaluronic acid / polyvinylpyrrolidone to combine intraarticular drug delivery and viscosupplementation

Polymer-based formulations present an attractive strategy in intraarticular drug-delivery to refrain biologicals from early leakage from the joint. In this study, co-formulations of hyaluronic acid and polyvinylpyrrolidone were investigated for their potential as viscosupplements and their influence on the transsynovial loss of adalimumab. For this purpose, polymer mixtures were evaluated for their viscosity and elasticity behavior while their influence on the permeation of adalimumab across a porcine ex-vivo synovial membrane was determined. Hyaluronic acid showed strong shear thinning behavior and exhibited high viscosity and elasticity at low motions, while combinations with polyvinylpyrrolidone provided absorption and stiffness at high mechanical stress, so that they can potentially restore the rheological properties of the synovial fluid over the range of joint motion. In addition, the formulations showed significant influence on transsynovial permeation kinetics of adalimumab and hyaluronic acid, which could be decelerated up to 5- and 3-fold, respectively. Besides viscosity effects, adalimumab was retained primarily by an electrostatic interaction with hyaluronic acid, as detected by isothermal calibration calorimetry. Furthermore, polymer-mediated stabilization of the antibody activity was detected. In summary, hyaluronic acid - polyvinylpyrrolidone combinations can be efficiently used to prolong the residence of adalimumab in the joint cavity while simultaneously supplying viscosupplementation.

THE EFFECT OF THE FORMATION OF POLYMER /SURFACTANT COMPLEXES ON SELECTED TRIBOLOGICAL PROPERTIES OF THEIR AQUEOUS SOLUTIONS

Aqueous solutions of sodium alkyl sulphate (surfactant) and polyvinylpyrrolidone (polymer) whose physicochemical properties, including complexing ability, have been widely described in the literature were proposed as a model lubricant. It has been assumed that aqueous solutions of these compounds will favourably modify lubricating properties of water under high load conditions. For this purpose, measurements were made on a four-ball apparatus (T-02 Tester) for aqueous solutions of these compounds. Two kinds of tests were carried out: at constant loads (2, 3, and 4 kN) and variable loads within the range of 0 to 7.2 kN. Unexpectedly, high decreases in motion resistance and wear as well as an increase in antiseizure properties were found in relation to water as a base. The results obtained are so promising that solutions with an optimized composition can find practical applications. The surprisingly high effectiveness of the additives used results from the formation of surfactant/polymer complexes. These adducts adsorb at the interface, and, under friction conditions, they form a lubricant film capable of carrying high loads.

Friction-lowering capabilities and human subject preferences for a hydrophilic surface coating on latex substrates: implications for increasing condom usage

Personal lubricants can increase user satisfaction with male condoms by reducing friction and yielding a slippery sensation. However, lubricants pose disadvantages of dilution in physiologic fluids and sloughing away over repeated articulations. To address these drawbacks, a latex surface modification, which becomes lubricious in the presence of physiologic fluid, has been developed and evaluated. This study assesses (i) the frictional performance of the lubricious coating compared to non-coated latex and latex lubricated by personal lubricant, (ii) the level of agreement between human-perceived slipperiness and machine-measured friction, and (iii) human preference for a hypothetical male condom containing the lubricious coating. Friction coefficient of the lubricious coating was 53% lower than that of non-coated latex and approximately equal to that afforded by personal lubricant. A touch test and survey of a small population sample (N = 33) revealed a strong correlation (R ² = 0.83) between human-perceived slipperiness and machine-measured friction. A majority of participants (73%) expressed a preference for a condom containing the lubricious coating, agreeing that an inherently slippery condom that remained slippery for a long duration would increase their condom usage. Such a coating shows potential to be an effective strategy for decreasing friction-associated pain, increasing user satisfaction and increasing condom usage.

Overgrowth of Silver Nanodisks on a Substrate into Vertically Aligned Nanopillars for Chromatic Light Polarization

Vertically aligned and well-separated 1D silver nanopillars (AgNPLs) are prepared on a large-area quartz surface using a robust colloidal chemical technique. Silver nanodisk (AgND) monolayers were first deposited on quartz using the Langmuir-Blodgett technique, and the presence of the substrate induced asymmetric chemical overgrowth of the AgNDs into AgNPLs. The height and diameter of the prepared AgNPLs were controlled by changing the rate of the overgrowth reaction. Chloride ions were used during overgrowth to etch the silver atoms that formed sharp features on the sides of the AgNDs and to limit growth in the lateral direction. The grown AgNPLs displayed two surface plasmon resonance modes corresponding to the transverse and longitudinal electron oscillations. The intensity of the longitudinal mode increased by a factor of 9 while the intensity of the transverse mode decreased by a factor of 2.5 upon increasing the angle of incidence of the exciting light from 0° to 60°. This interesting property makes these AgNPL arrays on quartz useful as chromatic light polarizers.