Laboratory glassware cleaning validation in pharmaceutical industry: a case study

Glassware cleaning is an essential part of pharmaceutical industry’s quality process, although, to date, no precise methodology is recommended by the pharmaceutical regulations. This study focuses on developing a detailed validation procedure for laboratory glassware cleaning and applying it routinely in quality control labs. The first step was the determination of the worst-case among raw materials controlled on a pharmaceutical site by using the failure mode effects analysis (FMEA) approach based on water solubility (WS), flask volume (FV), concentration (C), detectability (D) according to the absorptivity, and the probability (P) of the occurrence of the risk based on raw material analysis frequency. The adopted manual cleaning method was validated on three series of six flasks. Absorbances at λ_max of cleaned and worst-case flasks were compared to the limit of detection (LOD). Methylparaben was found to be the worst-case. Cleaning validation was carried out on 50 mL flasks containing aqueous solutions at 0.11 g/L after a contact time of 20 min under stirring. A prewash with tap water, a proper wash with a 95-V/5-V water/detergent solution (quaternary ammonium), and a final wash with purified water were carried out. The absorbances of all the cleaned flasks were lower than those of the worst-case LOD (< 0.0112). The selected cleaning procedure has been successfully validated. The proposed approach precisely describes the steps to be followed and can be adapted by other pharmaceutical industries as part of their laboratory glassware cleaning validation methodology.