Manufacture of fibrous dosage forms by wet micro-patterning and drying.

Recently, we have introduced fibrous dosage forms prepared by the predictable deposition, or 3D-micro-patterning, of a drug-laden fibrous melt on a surface. Such dosage forms enable precisely controlled microstructures and drug release rates, and can be manufactured by an efficient, continuous melt process. However, the applicability of melt-processing to manufacture pharmaceutical dosage forms is limited because the temperatures at which suitable excipients plasticize by melting are greater than the degradation or melting temperatures of many kinds of drugs. In this work, therefore, a continuous wet micro-patterning process is presented for the manufacture of fibrous dosage forms, wherein the excipient is plasticized by solvation and solidified by drying. Models are developed to illustrate the effects of the fiber radius, the inter-fiber spacing, the drying conditions, and the viscosity of the drug-excipient-solvent mixture on microstructure, drug release properties, and process time of the dosage forms. Experimental results show that the microstructure can be well controlled by the above parameters. They also confirm that the drug release behaviour of the dosage forms is predictable. Furthermore, the small excipient particles and the thin fibers are solvated, micro-patterned, and dried rapidly, in a few seconds or about a minute, respectively, which affords short process times. Thus it is demonstrated that fibrous dosage forms with predictable properties can be readily prepared by a continuous wet micro-patterning process.