Bioperformance Improvement: Small Particles and Optimal Polymorphs

The average molar mass of active substances in crop protection as well as in pharmaceuticals has grown almost tenfold in the last century. In general, large molar masses are a drawback when looking at bioavailability. There are several strategies to overcome the problem of low bioavailability. Two of those strategies will be discussed in this paper: (i) Increasing the dissolution rate of the solids by increasing the specific surface and (ii) increasing the solubility by choosing an optimal polymorph or an amorphous substance. It will be shown what physicochemical measurements are useful to predict which excipients will stabilize suspensions of particles as small as 500 nm. In relation to optimal polymorphs, the importance of the optimal choice will be highlighted and examples of reliable stabilization of the amorphous form will be given.