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  • 1 University of Szeged Faculty of Pharmacy, Department of Pharmaceutical Technology Eötvös u. 6. 6720 Szeged Hungary
  • | 2 Martin-Luther-University Halle-Wittenberg FB Ingenieurwissenschaften, Institut für Verfahrenstechnik/TVT 06099 Halle/Saale Germany
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The aim of this work was to investigate the influence of different levels of microwave irradiation on the structure and particle size characteristics of α-lactose monohydrate. The structural study of the samples was carried out by XRD, the presence of lactose polymorphs in the test samples was determined by DSC and the particle size distribution was measured by laser diffraction. The samples subjected to microwave irradiation retained their original X-ray patterns. No significant differences in thermal transition characteristics and particle size were observed. Hence, neither the occurrence of crystalline-amorphous transition resulted by microwave irradiation nor the presence of lactose polymorphs in the test samples can be assumed. The unmodified properties can be attributed to the fact that the water of crystallization is very difficult to remove from the crystal structure and is not free to move during microwave treatment, which results in stability to microwaves. Our results allow the conclusion that microwave processing of α-lactose monohydrate has no influence on further pharmaceutical technological properties, which are related to the structure and the particle size distribution of this substance.