INAUGURAL–DISSERTATION zur Erlangung der Doktorwürde der ...

4 1. Introduction
Fig. 1.3: SEM images of spray dried PVP [11].
porosity and shape [1]. To produce PVP powder with specific required properties
is very important, for example, a uniform particle size distribution of PVP powder
in pharmaceuticals not only helps in flowability of the powder but also improves the
appealing of the final product.
Similar to PVP, mannitol has several useful applications. Mannitol is a sugar
alcohol and it is widely used as a carrier particle in tablets. Mannitol is commonly
produced via the hydrogenation of fructose, which is formed from either starch or
sucrose (common table sugar) [13]. Although starch is a cheaper source than sucrose,
the transformation of starch is much more complicated. Hydrogenation of starch yields
a syrup containing about 42% fructose, 52% dextrose, and 6% maltose [13]. Sucrose is
simply hydrolyzed into an invert sugar syrup, which contains about 50% fructose. In
both cases, the syrups are chromatographically purified to contain 90–95% fructose [13].
The fructose is then hydrogenated over a nickel catalyst into mixture of isomers sorbitol
and mannitol with a typical yield of 50% sorbitol and 50% mannitol [13]. The chemical
structure of mannitol is shown in Fig. 1.4 [12].
For many years active pharmaceutical ingredients (APIs) are delivered to the lung
Fig. 1.4: Chemical structure of mannitol (C 6 H 8 (OH) 6 ) [12].