Quality control in residual solvent analysis: the static headspace gas chromatographic method

 Residual solvent testing of raw materials and drug products constitutes part of a quality control programme. Static headspace gas chromatography (HS/GC) is suggested in current pharmacopoeias as a general tool for residual solvent testing. But the main obstacles to using HS/GC procedures are the absence of performance tests, suitable reference solvents and matrix standards, and reference methods. Harmonized regulations for residual solvent testing allow the use of a cumulative approach to estimate the residual solvent content in drug products. The supplier data may be appropriate. Therefore, in a quality control programme the main accent is put on the definition of specification limits (in accordance with toxicological data, and the influence of residual solvents on the physical properties and stability of the product) and supplier qualification. This paper focuses on two main problems linked to supplier qualification: system performance and matrix effect. HS/GC of a mixture containing solvents of different volatility and polarity is proposed as a performance test. The test can be done in three ways in accordance with the residual solvents characteristics, the test sample solubility and the specification levels required. The use of the test as a diagnostic tool is demonstrated and sources of uncertainty of the recovery determination are discussed. Received: 12 December 1998 · Accepted: 25 January 1999