Pharmaceutical plants must have visually clean equipment to operate according to good manufacturing practices. Formulators must visually inspect manufacturing equipment for cleanliness before formulation work begins (1). Manufacturers establish and perform visible cleanliness and analytical methods to ensure regulatory compliance. An analyst conducts a visual inspection and confirms visible cleanliness before taking swab samples for chemical analysis (2). The formulator of the subsequent batch conducts a visual inspection before manufacturing work begins. A correlation between available analytical data and visible cleanliness of manufacturing equipment over an extended period of time can expand the practice of performing visual inspections in lieu of swab sampling.
Application of Visible-Residue Limit for Cleaning Validation Richard J. Forsyth and Vincent Van Nost