Hybrid modeling of roll compaction processes with the Styl’One Evolution
Roll compaction/dry granulation is a widely used and cost effective dry granulation method. To save time and material in formulation development, some approaches have been made to predict the most important parameters in roll compaction (RC) like gap width, specific compaction force (SCF) and ribbon solid fraction (SF).
A novel approach is the hybrid modeling of roll compaction with the Styl’One Evolution. It combines a mechanical mimicking by uniaxial compression of the powder with a mathematical model that converts the applied compaction pressure into a computed SCF.
It was tested whether the Styl’One Evolution can mimic a RC process correctly. Powder was compacted at different gap widths and SCFs, both on a Mini-Pactor (Gerteis) and on the Styl’One Evolution. Two excipients, lactose and microcrystalline cellulose (MCC), were used for the trials. The ribbons and ribbon like tablets, called ribblets, were characterised regarding their SF.
Compaction of lactose prepared at a certain SCF resulted in ribbons and ribblets with higher SF than for MCC. The Styl’One Evolution provided results with similar curve shapes but with systematically higher SF. Nevertheless, the results for ribbons and ribblets from both materials were aligned by adjusting the roll compactor specific correction factor Kp in the mathematical model. The SF of lactose ribblets was more accurately predicted than of MCC ribblets. That could be due to the bigger elastic recovery of MCC. The findings also suggest that mechanical mimicking gives hints whether a material is suitable for RC.
In conclusion, hybrid modeling can identify the appropriate settings to obtain ribbons with the desired SF.