Preparation of Powdered Phospholipid Nanospheres by Spray Drying in an Aqueous System with Sugars

Abstract

Phospholipid nanosphere dispersion was prepared from phosphatidylcholine with or without vitamin E by the heating method. The dispersed particles had diameters of 8.6-150 nm. These nanosphere dispersions were powdered with sugars such as sucrose, lactose and mannitol by spray drying in an aqueous system. The resultant powders, except coformulation with mannitol, consisted of spherical, homogeneous and freely flowing particles, in which the sugar was amorphous. The powder yielded a nanosphere dispersion having almost the same particle size and optical density as the original dispersion, when rehydrated with water. The particle size of rehydrated nanospheres with vitamin E increased with the increasing amount of vitamin E coformulated. A water-soluble drug, 5-fluorouracil, could be entrapped in the nanospheres by rehydrating the powdered nanospheres with an aqueous solution of the drug. All the steps from the preparation of the original nanosphere dispersion to spray drying were performed in an aqueous system without using any organic solvent. The procedures described here should be suitable for the production of stable powdered nanosphere which can be rehydrated to form phospholipid nanosphere dispersions as required.