Increasingly high cell density, high product titer cell cultures, containing mammalian cells are placing a larger burden on traditional downstream clarification and purification operations due to higher product and impurity levels. EMD Millipore has addressed these challenges by developing a proprietary single-use technology to improve primary and secondary direct depth filtration of flocculated high cell density mammalian cell cultures. The use of graded depth filters, combined with pre-treatment technologies, have achieved higher primary throughput capacities and lower flushing volumes as compared to traditional depth filters. The primary clarification (PC) family of devices represent three media grades for three particle size distributions: Clarisolve® 20MS Depth Filters: Acid Precipitation (Smaller aggregated particles – 20 μm) Clarisolve® 40MS Depth Filters: Traditional Flocculants (Medium aggregated particles – 40 μm) Clarisolve® 60HX Depth Filters: Smart Polymer-SmP ( Larger aggregated particles – 60 μm)