Case Study: Residual Solvents per USP method 
PROBLEM: Residual Solvents per USP method <467>
SOLUTION: Developed and Validated a Modified <467> Method for the Client's Product
A medical device company with a drug-delivery patch needed a method for residual solvents. Testing under USP method <467> was desired, but the test article was not applicable for the preparation conditions listed in the method.
SOLUTION & RESULTS:
Impact Analytical developed and validated a method for residual solvents under cGMP. USP method <467> was modified to accommodate the test material, but the core of the method was retained. A headspace GC-FID method for residual solvents was developed. The method achieved a detection limit of 0.1 ppm, and was linear throughout a range from 1 ppm (LOQ) to 1000 ppm. Recoveries were between 97 and 102%, and precision was 5% RSD for injection of standards at the specification level of the test material. The resulting submission to the FDA was accepted without need for further explanation or response.