Buchi 190 Spray Dryer

Melamine-formaldehyde (MF) resins of a molar ratio F/M = 1.70 were prepared at 95°C by dissolving 505 g melamine in 592 g formalin (34.5 wt% aqueous formaldehyde with a pH of 9.2). The reaction was stopped when the reaction mixture reached the cloud point [75]. At 25°C, the pH of the MF resin was adjusted to 7.5 and 9.5. These resins were spray-dried using a Buchi spray dryer and further dried for half an hour in a vacuum oven at 60° C before each MTDSC experiment. Liquid C-NMR spectra showed that more methylene bridges and ether bridges and fewer residual methylol groups (see section 2.2.1 were present in MF pH 7.5 compared to MF pH 9.5. 

Fig. 7 Buchi/Brinkmann Lab Scale Spray-Dryer. A stock solution or suspension is pumped from the beaker through a nozzle which sits above the large glass particle formation vessel on the left-hand side. The nozzle atomizes the feedstock at temperatures ranging from ambient to 250° C into the particle formation vessel, using air or an inert gas such as nitrogen to dry and move particles into the cyclone and collection chamber on the right-hand side. Product temperature is monitored by a temperature probe mounted between the particle formation vessel and the cyclone. Solvent or water are exhausted through a fine particle filter bag in series with the cyclone, which also collects fines.

Salbutamol sulfate Spray-drying of an aqueous solution in Buchi 90 spray dryer 1121]... 

Drying technology Lab-scale Buchi 190 mini spray dryer T" 140°C 7 80°C. 

The conventional method to control the particle size is by adjusting the atomization parameter of the drug formulation liquid used. Higher atomization driving force (high pressure or disk rotation) will result in smaller particles from the spray dryer and vice versa. Lower feed concentration will also result in smaller particles as there will be less solid for the particle formation however, this is normally determined by the allowable drug formulation. Small-scale spray dryers such as the Buchi can produce particles in the range of... 

Lab unit (Buchi B-290 Advance), pilot unit (Niro Mobile Minor) commercial unit (Niro PSD4) Fig. 8.1 Lab-, pQot-, and commercial-scale spray dryers at Hovione... 

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