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2775736 
Technical Report 
On the rate of release of active ingredient from polyvinylpyrrolidone (PVP) tablets. I. The release of benzoic acid and o-, m-, and p-hydroxybenzoic acids 
Kahela, P; Krogerus, VE 
1970 
IPA/71/37065 
Aikak 
REF 21 
74-94 
English 
IPA COPYRIGHT: ASHP The purpose of this study was to determine what effect the position of the hydroxyl group in the benzoic acid ring had on the rate of release of a drug from polyvinylpyrrolidone (PVP) tablets. Tablets were prepared containing approximately 20 mg. of either benzoic acid, o-hydroxybenzoic acid (salicylic acid), m- or p-hydroxybenzoic acid. The inactive ingredient in each tablet was either 250 mg. PVP or 250 mg. potato starch. Tablets were compressed at 180 or 1800 kg. The results of the study indicated that all of the active ingredients formed complexes with PVP. The compression force appeared to affect these interactions. The effect of the compression force seems to increase in the following order: benzoic acid(salicylic)acid(p-hydroxybenzoic)acid(m-hydroxybenzoic)acid. The active ingredients also interacted to form complexes with starch; however, this effect was not as great as the interactions with PVP. In this study starch did not form complexes with m-hydroxybenzoic acid. It was thought that this lack of complex formation was due to the steric structure of m-hydroxybenzoic acid which prevented the penetration of the active ingredient into the starch.