Spray-drying as a method for microparticulate controlled release systems preparation: Advantages and limits. I. Water-soluble drugs

Spray-drying was used for the preparation of paracetamol/eudragit RS or RL or ethylcellulose microspheres to verify the possibility of their use in co ntrolled-release solid-dosage forms formulation and try to determine advant ages and limits of the technique of such use. Microspheres were first chara cterized by scanning electron microscopy, differential scanning calorimetry , x-ray diffractometry, and in vitro dissolution studies and then used for the preparation of tablets. During this step, the compressibility of the sp ray-dried powders was also evaluated. In vitro dissolution studies were per formed also on the tablets and their release control was accessed. Although powders were unable to slow down drug release , tablets obtained from micr osphere compression showed a good capability of controlling paracetamol rel ease when eudragit RS or ethylcellulose was used, even at low polymer amoun ts.