Journal of Chromatography A, 870 (2000) 69–75 www.elsevier.com / locate / chroma Validation of the removal of acetylsalicylic acid Recovery and determination of residues on various surfaces by high performance liquid chromatographic * ´ ´ ´ ´ ´ Marıa J. Nozal , Jose L. Bernal, Laura Toribio, Juan J. Jimenez, Marıa T. Martın Department of Analytical Chemistry, Faculty of Sciences, University of Valladolid, E-47005 Valladolid, Spain Abstract The validation of a procedure to clean glass, vinyl and stainless steel surfaces that have been exposed to acetylsalicylic acid during its manufacture is described. The cleaning procedure using two cotton swabs moistened with the mobile phase was validated using a wipe-test and a high-performance liquid chromatography (HPLC) method developed to determine low quantities of the acid. The HPLC method involves an octadecylsilane column at 558C, a mixture of water–acetonitrile– orthophosphoric acid (779:220:1, v / v) as mobile phase and detection at 226 nm. Recoveries of 86%, 90% and 94% were obtained from vinyl, glass and stainless steel plates respectively. The validation gave acceptable levels of sensitivity, recovery, precision and linearity.  2000 Elsevier Science B.V. All rights reserved. Keywords: Validation; Pharmaceutical analysis; Acetylsalicylic acid 1. Introduction methods used to wipe the surfaces and to measure residuals have an special importance. In pharmaceutical manufacturing it is well estab- Acetylsalicylic acid (ASA) is a very common lished that equipment and production areas must be compound, moderately water soluble, that appears as thoroughly cleaned after each manufacturing cam- main ingredient in many formulations, being the paign, regulatory authorities recommend that those aspirin the most well known, and it is manufactured procedures must be validated [1–6]. Cleaning valida- world wide by many drug companies. To determine tion is the process of assuring that cleaning pro- ASA, apart from acid-base titration, usually HPLC cedures effectively remove the residues from manu- methods are recommended, generally using C 18 facturing equipment / facilities below a predetermined columns with acidic mobile phases at room tempera- level, usually related to the dose. This is necessary ture and detection at 275 nm, although obviously not only to assure the quality of future products but there are other alternatives [7–12]. The sensitivity of also to prevent cross-contamination and also as a those methods is not frequently appropriate when World Health Organization Good Manufacturing measuring low quantities of ASA is needed because Practice requirement. Among the most important those methods are not focused to determine trace components of any cleaning validation strategy the levels, as happens in cleaning validation studies, so it is necessary to have methods adapted to those concentrations. *Corresponding author. For sampling the residues from the surfaces, 0021-9673 / 00 / $ – see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S0021-9673(99)01134-6