A kinetic study of biotransformation from valencene to nootkatone in an oscillatory baffled reactor.

In this paper we report our kinetic study of an oxidation reaction from valencene to nootkatone using enzyme in an oscillatory baffled reactor. The aims of this work are to elucidate the reaction mechanism and evaluate reaction kinetics. Towards these objectives, a full kinetic model using the Langmuir-Hinshelwood method was established and applied to the experimental data, allowing reactor schemes and orders to be confirmed and reaction rate constants to be extracted. Our full kinetic analysis suggests that most of the reversible reaction steps can be treated as irreversible, simplifying the overall reaction schemes. The effect of mass transfer on the kinetics was also investigated. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Investigation of dissolution rate kinetics of bulk pharmaceutical feed streams within a stirred tank vessel and a twin screw extruder.

The introduction of continuous manufacturing of pharmaceuticals has highlighted the challenging area of continuous dissolution of solids for work ups to flow chemistry systems. In this study, the use of a 16 mm twin screw extruder (TSE) as a platform technology for solid feeds is investigated using four solid pharmaceutical ingredients (PI) in a mixture of water and IPA. In order for comparison, the same experiments were also carried out in a batch traditional stirred tank vessel (STV). The objectives of this work are to gain further scientific understanding on dissolution kinetics and to compare kinetics in both a batch and continuous system. The concentration of each PI during dissolution is monitored using an in-line UV-ATR probe, allowing the extraction of dissolution kinetics. Faster dissolution rates are achieved in the TSE than in the STV due to higher power dissipation generated by the aggressive shear mixing and thermal energy within the TSE. Complete dissolution of paracetamol is obtained within the residence time of the TSE; complete dissolution of benzoic acid and acetylsalicylic acid are achieved at higher barrel temperatures; however full dissolution of nicotinic acid is not achievable in the TSE under the experimental conditions.