Soluble polyvinylpyrrolidone Povidone

Modern acetylene chemistry is based on the work of Reppe. One of the many products of this work is N-vinylpyrrolidone (Fig. 1). 

The first polymerization product of N-vinylpyrrolidone was soluble polyvinylpyrrolidone, which was patented in 1939. Fig. 2 and 3 show mechanisms of polymerization free-radical polymerization in water using hydrogen peroxide as initiator or in 2-propanol using an organic peroxide as initiator [1,141]. 

The mechanism for terminating the polymerization reaction makes it possible to produce soluble polyvinylpyrrolidone of almost any molecular weight. 

Apart from the method of production in water shown in Fig. 2, it is also possible to conduct the polymerization in an organic solvent, e.g. 2-propanol, an with 

The low and medium-molecular weight grades of soluble polyvinylpyrrolidone are spray-dried to produce the pharmaceutical-grade povidone powders, while the high-molecular weight grades are roller-dried. 

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Today, soluble polyvinylpyrrolidone (povidone) is one of the most versatile and widely used pharmaceutical auxiliaries (see Section 2.4). 

In systematic investigations into the dependence of complex formation on structure, no difference was found between soluble polyvinylpyrrolidone (povidone) and insoluble polyvinylpyrrolidone (crospovidone) for complexes with organic compounds [192]. 

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