Characterization and Drug Release Properties of Curcumin Loaded Native and Nano-Sized Starches of Pigeon Pea (Cajanus cajan) and Bambara Nut (Vigna subterranean)

Starches from underutilized sources such as Bambara nut (BAM) and pigeon pea (PP) can serve as new sources of starch. Starch nanoparticles (SNP) of BAM (BAMnp) and PP (PPnp) are prepared by nanoprecipitation. The physicochemical and pasting properties of the native and SNP are evaluated. The scanning electron microscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), drug loading, and release studies of curcumin-loaded starches and SNP are carried out. The flow, swelling, and solubility of the native starches improve with nanoparticle fabrication. Setback viscosities of the starches are in the order PPnp < BAMnp < PP < BAM. The integrity of the starch granules is maintained after modification. The FTIR of loaded starches shows no interaction between the entities. Reduction in crystallinity of the SNP is observed in the XRD diffractogram. The drug loading efficiency of BAM, PP, BAMnp, and PPnp are 48.55 +/- 0.11, 49.00 +/- 0.11, 55.44 +/- 0.40, and 54.72 +/- 0.11, respectively. The drug release is improved when curcumin is loaded on the SNP. The release after 6 h is 33%, 25%, and 2% for BAMnp, PPnp, and pure curcumin, respectively. The properties of the SNP showed that they are potential candidates for the delivery of curcumin, a poorly water soluble drug.