Various cleaning solutions are used in the pharmaceutical industry to wash reactor chambers in between production batches. Obtaining instantaneous measurement of the active ingredient’s concentration in the cleaning solution is of great importance.

The washing process consists of several cycles, in each a certain amount of methanol (or any other cleaning material) is recycled through the system. For maximum efficiency the cycling of methanol should be stopped when the concentration of the active ingredient reaches steady state.

Validation of cleaning procedures are of utmost importance to the pharmaceutical, food and specialty chemicals industry. The OMA-517, an industrial spectrophotometer is utilized to monitor traces of active material in the development stages, validation routines and to the control of a Clean In Place (CIP) process.

Benefits in continuous monitoring:

• Validation of cleaning and final purity level.
• Greater availability of reactor volume
• Detect possible faulty valves & pipes in the flow system

Washing cycle - setup

Washing cycle timing diagram

The concentration of the active ingredient in the methanol increases until it reaches a plateau. The same occurs for each wash. The 1st derivative of the concentration with time (dc/dt) approaches zero when the process reaches steady state. The UCL (Upper Control Limit) is also shown 

Effective cleaning strategies

Most active materials have a distinct UV or SWNIR absorbance spectra, and therefore can be monitored by spectroscopic methods. The OMA product line consist of  industrial spectrophotometers, which are installed on-line and programmed to measure trace impurities in a washing cycle

UV Absorbance spectra

UV absorbance spectrum of several active materials: The absorbance spectrum of some active materials are shown below, the low detection levels of the method should be noted.