Particle Design of Drugs by Spherical Crystallization Techniques

Abstract

Direct tabletting technique is the most easy and simplest way of making tablets. Good flowability and compressibility is prerequisite for drug to be prepared by direct compression. There are several techniques available to impart desired compressibility to drugs. Spherical crystallization techniques are the promising techniques in which the drug crystals are modified using different solvents to directly compressible spherical agglomerates, which can save money and time for tabletting. The two mostly commonly used spherical crystallization techniques are wet spherical agglomeration method (WSA), quasi-emulsion solvent diffusion method (QESD, Transient emulsion). But there are two extensions of these techniques, ammonia diffusion system (ADS) and crystal-co-agglomeration technique (CCA).The ammonia diffusion system technique is mainly meant for amphoteric drugs and the crystal-co-agglomeration technique is used for direct co-agglomeration of two drugs or drug with excipient simultaneously. Another technique of this process is the Neutralization technique, where first fine crystals form by neutralization then it will agglomerate by the help of a bridging liquid. By any of the above technique crystallization and agglomeration can be carried out simultaneously in one step and which has been successfully utilized for improvement of flowability and compactability of crystalline drugs.