Varian launches dissolution system for drug-device combinations
testing small drug volumes in medical devices such as implants or
drug-eluting stents.
The Varian 400-DS Apparatus VII is the first compendial small-volume dissolution system for medical devices and is designed to simplify the testing of drug formulations with extremely low quantities of active ingredient, the US company says. The new unit can run up to 13 samples at a time and is available in both 5 mL and 10mL versions - significantly smaller media volumes than is usual with traditional dissolution apparatuses, Varian notes. Sampling volumes can go even lower, to 1-4mL. Dissolution testing is used to determine bioavailability, or the rate at which pharmaceutical active ingredients become available for absorption within the body. It is required throughout the pharmaceutical manufacturing process to ensure product quality and long-term stability. As dissolution tests routinely run at 37 degrees Celsius and can be conducted over several days, the Varian 400-DS features an evaporation cover that sits on top of (and seals) the small-volume dissolution cells and ensures more accurate test results. Varian is claiming minimal evaporation rates of less than 0.2 per cent volume loss per 24 hours, even with mixed aqueous-organic solution media. The dissolution cells themselves consist of a glass tube placed on top of a sampling manifold. Heater jackets surround each dissolution cell and connect to temperature probes at the bottom of the cells to provide stable temperature control ranging up to 50 degrees Celsius for extended periods of dissolution testing. The closed-cell design of the 400-DS also features Varian's patent-pending magnetically driven reciprocation mechanism, which is capable of providing dip rates of between five and 35 DPM. Media replacement and sampling capabilities are built into the instrument, which can switch between up to four different types of media, including organic solvents. As many as four 400-DS units can be controlled independently by a single Windows-based PC, which incorporates Varian software compliant with US 21 CFR Part 11 requirements for pharmaceutical laboratories. The new apparatus is ideal for dissolution testing of extended-release products that either contain and/or release small amounts of active pharmaceutical ingredient over time, Varian says. Its addition to the company's existing dissolution product range means Varian can "assist customers with challenging drug delivery scenarios, such as implants, stents and intra-ocular devices," commented Martin O'Donoghue, senior vice-president, scientific instruments.
