Highly compressible paracetamol: I: crystallization and characterization

It was found that polyvinylpyrrolidone (PVP) is an effective additive durin g crystallization of paracetamol and significantly influenced the crystalli zation and crystal habit of paracetamol. These effects were attributed to a dsorption of PVP onto the surfaces of growing crystals. It was found that t he higher molecular weights of PVP (PVP 10 000 and PVP 50 000) were more ef fective additives than lower molecular weight PVP (PVP 2000). Paracetamol p articles obtained in the presence of 0.5% w/v of PVP 10 000 or PVP 50 000 h ad near spherical structure and consisted of numerous rod-shaped microcryst als which had agglomerated together. Particles obtained in the presence of PVP 2000 consisted of fewer microcrystals. Differential scanning calorimetr y (DSC) and X-ray powder diffraction (XPD) experiments showed that paraceta mol particles, crystallized in the presence of PVP, did not undergo structu ral modifications. By increasing the molecular weight and/or the concentrat ion of PVP in the crystallization medium the amount of PVP incorporated int o the paracetamol particles increased. The maximum amount of PVP in the par ticles was 4.32% w/w. (C) 2000 Elsevier Science B.V. All rights reserved.