A Comparison of Two Methods for the Preparation Cefquinome-Loaded Gelatin Microspheres for Lung Targeting

The aim of this study was to prepare CEQ-loaded gelatin microspheres and compare two preparation methods, evaluate targeting to the lungs.

Gelatin microspheres containing CEQ were prepared by an emulsion cross-linking method (ECLM) and a spray-drying method (SDM) and were characterized in terms of morphology, size, drug-loading coefficient, encapsulation ratio and in vitro release.

The microspheres prepared by ECLM gave a drug loading (DL) of 19.4 ± 2.4% and an entrapment efficiency (EE) of 80.8 ± 3.2%. The microspheres prepared by SDM resulted in a DL value of 20.8 ± 2.7% and an EE of 95.3 ± 3.8%. The average particle size of microspheres was 7-30 μm by both methods and both preparations sustained CEQ release for 36 h in the target tissue (lungs). The in vitro release profile of the microspheres matched the Korsmeyer-Peppas release pattern. In vivo studies identified the lung as the target tissue and the region of maximum CEQ release. Histopathological examination showed a partial lung inflammation that disappeared spontaneously as the microspheres were biodegraded. In general, the formulations were safe.

The well-sustained CEQ release from the microspheres revealed its suitability as a drug delivery vehicle that minimized injury to healthy tissues while achieving the accumulation of therapeutic drug for lung targeting. The intravenous administration of CEQ gelatin microspheres prepared by SDM is of potential value in treating lung diseases in animals.