Coprecipitation of nicotinic acid in PVP by gas antisolvent technique using Box-Behnken design

Nicotinic acid is a water-soluble compound recognized in the medical field for its ability to decrease low-density lipoprotein cholesterol levels. Additionally, nicotinic acid is used to alleviate the effects of heat stress in ruminant animals. The supercritical gas antisolvent technique was employed using carbon dioxide to encapsulate nicotinic acid in polyvinylpyrrolidone (PVP) using ethanol + acetone. Encapsulation efficiency, process yield and crystallite size data were evaluated using the Box-Behnken design. Gas chromatography-mass spectrometry quantified the encapsulation efficiency at (13.1 to 66.9)%, and the same technique was used to determine that the encapsulation of nicotinic acid increased the dissolution rate compared to the pure compound. A residual solvent level was quantified at least 33 times lower than the maximum permitted level. The encapsulation was shown to protect the active ingredient in thermal degradation tests in a climatic chamber. XRPD showed the stability of the crystalline structure of niacin after encapsulation, and the effects on its microstructure were evaluated using Rietveld analysis. Spectroscopic analysis showed evidence of intermolecular bonding between nicotinic acid particles and PVP. An average particle size of (80.4 to 238.9) mu m was obtained by SEM analysis.