Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.

Enantiomeric differentiation by synthetic helical polymers.

Recent advances in the synthesis of helical polymers and their applications as chiral materials, in particular chiral stationary phases (CSPs), for high-performance liquid chromatography (HPLC) are reviewed with an emphasis on the key role of the helical conformations with one-handedness for the prominent chiral recognition of enantiomers. The historical background of artificial optically active helical polymers is also briefly described.

Using light scattering to locate less than a microgram of protein per band in polyacrylamide tube gels after isoelectric focusing.

After separation by isoelectric focusing (IEF) or non-equilibrium pH gradient electrophoresis (NEPHGE) in 9.2 M urea polyacrylamide tube gels, proteins with Mr > 20,000 can be precipitated by shaking the gels in 25% methanol. When a fiber-optic illuminator is placed in contact with the end of the gel, the cylindrical gel transmits light by internal reflection. In regions of the gel where protein is precipitated, this light is scattered, making it visible when the gel is viewed in a darkened room against a black background. The sensitivity of the method is moderate: less than 1 microgram protein per band (in a 3-mm diameter gel) can be detected. Because the protein in the bands precipitates rapidly (30 min), the solution used (25% methanol) is fairly benign to proteins, and the apparatus is not expensive, this technique should be useful in several situations including electrophoretic purification schemes. This method is especially useful for evaluating the quality of an IEF or NEPHGE tube gel before using it for the second dimension of a two-dimensional gel.