Spray-dried diclofenac-loaded poly(epsilon-caprolactone) nanocapsules and nanospheres. Preparation and physicochemical characterization.

The aims of the present study were to prepare spray-dried polymeric nanocapsules (NC) and nanospheres (NS) from poly(epsilon-caprolactone) (P epsilon C) suspensions containing diclofenac (DIC) and to determine the physicochemical properties of the formulations. NC or NS suspensions were prepared by interfacial deposition of the polymer. DSC-thermograms of raw materials and NC or NS suspensions (evaporated or spray-dried) were obtained using a PL-DSC. Spray-dried powders were prepared by addition of 3% (w/v) Aerosil 200 into suspensions of NC or NS. These mixtures were fed into a spray-dryer. DIC was assayed by HPLC. NC and NS spray-dried powders were examined under SEM (Jeol Scanning Microscope, JSM-5800). NC and NS suspensions had acceptable diameter, 340 and 247 nm respectively. The yields of NC and NS spray-dried powders were 80% and 75% and the recovery of the DIC was 99% and 93%, respectively. The melting peak of P epsilon C in NC and NS was observed at a temperature about 10 degrees C lower than in the raw material. In the NC thermograms the maximum of the oil (Miglyol 810) melting peak (+1.6 degrees C) was lowered about 7 degrees C. For spray-dried NC formulations, the SEM analyses of powders showed spherical microparticles of silicon dioxide, covered by nanoparticles (300 nm), while for spray-dried NS formulations the microparticles presented a rugged surface at the same magnification.