Dead mass in continuous blending

• Published in: Powder technology 2019-10, Vol.355, p.67-71
• Main Authors: Kauppinen, Ari, Karhu, Hannu, Lakio, Satu
• Format: Article
• Language: English
• Subjects: Blending; Continuous blending; Continuous manufacturing; Dead mass; Effective residence mass; Manufacturing; New technology; Process parameters; Quality management; Residence mass; Residence time distribution
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2019.07.028

Continuous manufacturing is an emerging technology in secondary pharmaceutical manufacturing of oral solid dosage forms such as tablets. Continuous blending is a crucial process step in continuous manufacturing. Residence mass (i.e. fill level or hold-up mass) is a critical process parameter of continuous blending and it is defined as amount of material in the blender at controlled state conditions. Residence mass affects for example on the blending efficiency and the residence time distribution. Aim of the study was to elucidate the characteristics of residence mass and its implications. Results showed that residence mass can consist of proportions that are involved in blending process (i.e. effective residence mass) and proportions that are not involved in the blending process (i.e. dead mass). The dead mass has several implications related to the quality attributes of the finished product, detection and segregation of nonconforming material and raw material traceability. [Display omitted] •Dead mass is defined as a proportion of residence mass not taking part to blending.•Dead mass was found to be adhered onto the low or no shear zones of the blender.•Amount of dead mass was quantified by residence time distribution experiments.•Dead mass has implications on finished product quality and material traceability.