Figure 12. Optimization algebraic ramps outlining the optimal solution meeting the criteria of desired PQAs. The factor Figure 12. Optimization algebraic ramps outlining the optimal solution meeting the criteria of desired PQAs. The factor settings of ( a ) drug–stabilizer, ( b ) drug–mannitol ratios, ( c ) inlet temperature are shown by the red dots and ( d ) the CQA settings of ( a ) drug–stabilizer, ( b ) drug–mannitol ratios, ( c ) inlet temperature are shown by the red dots and ( d ) the CQA selected response prediction for ζ -potential values are displayed in blue. selected response prediction for ζ -potential values are displayed in