Characterization and quantitation of PVP content in a silicone hydrogel contact lens produced by dual-phase polymerization processing.

Polyvinylpyrrolidone (PVP) has been incorporated over the years into numerous hydrogel contact lenses as both a primary matrix component and an internal wetting agent to increase lens wettability. In this study, complementary analytical techniques were used to characterize the PVP wetting agent component of senofilcon A and samfilcon A contact lenses, both in terms of chemical composition and amount present. Photo-differential scanning calorimetry (photo-DSC), gas chromatography with a flame ionization detector (GC-FID), and high-resolution/accurate mass (HR/AM) liquid chromatography-mass spectrometry (LC-MS) techniques confirmed dual phase reaction and curing of the samfilcon A silicone hydrogel material.

Comparative studies of hyaluronan in marketed ophthalmic products.

Purpose: Research has indicated that there is a correlation between the molecular weight of hyaluronan or hyaluronic acid (HA) and its biocompatibility/biological functions with high molecular weight HA showing many biological benefits. The purpose of this research was to characterize and compare the molecular weights, molecular weight distributions, and concentrations of HA present in a series of commercially available HA-containing ophthalmic products.

Methods: On-line size-exclusion chromatography with triple detection (SEC-TD) was used to determine the molecular weights and concentration of HA in commercially available products, including marketed contact lens multipurpose solutions and contact lens packaging solutions.

Detailed characterization of hyaluronan using aqueous size exclusion chromatography with triple detection and multiangle light scattering detection.

Hyaluronan (HA) has attracted great interest and attention from ophthalmic surgical and eye care companies owing to its unique properties. A more complete understanding of HA biopolymers has, therefore, become increasingly critical as thorough characterization of raw materials helps promote product quality and process control. Often, such detailed information requires the use of a combination of analytical techniques.