Pharmaceutica Analytica Acta

Abstract

Effect of Povacoat or Soluplus on Solid-State Characterization of Indomethacin-Nicotinamide Co-Crystal Formation

Shan-Yang Lin, Hong-Liang Lin, Ru-Ying Hung, Yu-Ting Huang and Chi-Yu Kao

Novel pharmaceutical polymers named Povacoat and Soluplus were used to investigate whether both polymers could influence the co-crystal formation between indomethacin (IMC) and nicotinamide (NIC) or the solid-state characterization of IMC-NIC mixture after co-grinding or solvent evaporation. Different weight ratios of Povacoat or Soluplus to IMC-NIC (molar ratio = 1:1) were respectively co-ground or dissolved in different solvents via ultrasonication, and then co-evaporated under a hood at ambient temperature. All the samples were determined by thermo analytical and FTIR spectroscopic studies. The results indicate that Povacoat or Soluplus added did not induce any interaction among Povacoat or Soluplus, IMC and NIC after co-grinding process. It is also found that Povacoat did not induce the IMC-NIC co-crystal formation but only caused the amorphous formation of IMC in the Povacoat/IMC-NIC evaporates prepared by 4:1 (w/w) weight ratio of Povacoat to IMC:NIC (1:1 molar ratio) with final volume ratio of 1:9 (v/v) water to ethanol via ultrasonication and evaporation. On the other hand, the Soluplus/IMCNIC evaporates after co-evaporation from acetone solution exhibited either IMC-NIC co-crystal or amorphous IMC formation, which was dependent on the amounts of Soluplus added. The former IMC-NIC co-crystal was prepared in the formulations with less amount of Soluplus, implies that Soluplus did not interfere the IMC-NIC co-crystal formation after co-evaporation. While a large amount of Soluplus added might directly interrupt the IMC-NIC cocrystal formation but cause the amorphous IMC formed in the Soluplus solid dispersion.