Continuous melt granulation: Influence of process and formulation parameters upon granule and tablet properties.

The pharmaceutical industry has a growing interest in alternative manufacturing models allowing automation and continuous production in order to improve process efficiency and reduce costs. Implementing a switch from batch to continuous processing requires fundamental process understanding and the implementation of quality-by-design (QbD) principles. The aim of this study was to examine the relationship between formulation-parameters (type binder, binder concentration, drug-binder miscibility), process-parameters (screw speed, powder feed rate and granulation temperature), granule properties (size, size distribution, shape, friability, true density, flowability) and tablet properties (tensile strength, friability, dissolution rate) of four different drug-binder formulations using Design of experiments (DOE). Two binders (polyethylene glycol (PEG) and Soluplus®) with a different solid state, semi-crystalline vs amorphous respectively, were combined with two model-drugs, metoprolol tartrate (MPT) and caffeine anhydrous (CAF), both having a contrasting miscibility with the binders. This research revealed that the granule properties of miscible drug-binder systems depended on the powder feed rate and barrel filling degree of the granulator whereas the granule properties of immiscible systems were mainly influenced by binder concentration. Using an amorphous binder, the tablet tensile strength depended on the granule size. In contrast, granule friability was more important for tablet quality using a brittle binder. However, this was not the case for caffeine-containing blends, since these phenomena were dominated by the enhanced compression properties of caffeine Form I, which was formed during granulation. Hence, it is important to gain knowledge about formulation behavior during processing since this influences the effect of process parameters onto the granule and tablet properties.

An analytical quality by design (aQbD) approach for a L-asparaginase activity method.

L-asparaginase is an effective anti-tumor agent for acute lymphoblastic leukemia. This work presents the development of an activity determination of L-ASNase preparations for pharmaceutical quality control purposes, in accordance with analytical Quality by Design principles. Critical method attributes, the absorbance at 450 nm (A450) of the Nessler product as well as its variability, were evaluated as a function of critical method variables, by using experimental designs. The design space of the enzyme activity assay was defined (Nessler method: C(KI)/C(HgI2) of 1.90-1.95, C(NaOH)/C(HgI2) of 17.0-18.0, C(HgI2final) of 20-40 mM and time of 10-40 min; enzyme activity conditions: temperature range of 36.6-37.4 °C, pH range of the KH2PO4 buffer from 7.1 to 7.7, KH2PO4 buffer concentration: 0.18-0.22 M and L-Asn concentration of 18-22 mM), leading to a final enzyme activity assay method. A control strategy was ultimately implemented using system suitability tests.