Research on drying characteristics of soft gelatin-capsules

In order to research the drying characteristics of soft gelatin-capsules, the experiment was engaged in convective drying apparatus. The surface temperature of soft gelatin-capsules was measured by an infrared thermal imager and the mass was tested by high accuracy electronic balance. The results show that with the increase of air temperature the rate of heat transfer increases, but the drying rate in the second falling period is decreased, which causes higher final water mass fraction in soft capsules; with the increase of the air velocity both the heat transfer rate and the drying rate in the first falling period increases, and the final water mass fraction of soft capsules is slightly dropped; the change of hot air humidity has very small influenced on heat transfer, but the drying rate raises as decreasing the air humidity, which leads to the obvious dropping of final water mass fraction in soft capsules. The experimental results can be used for guiding the manufacture of soft gelatin-capsules in the pharmaceutical industry.