title: Andrographolide: solving chemical instability and poor solubility by means of cocrystals.
abstract: The bioactive agent andrographolide was screened with pharmaceutically acceptable coformers to discover a novel solid form that will solve the chemical instability and poor solubility problems of this herbal medicine. Liquid-assisted grinding of andrographolide with GRAS (generally regarded as safe) coformers in a fixed stoichiometry resulted in cocrystals with vanillin (1:1), vanillic acid (1:1), salicylic acid (1:1), resorcinol (1:1), and guaiacol (1:1). All the crystalline products were characterized by thermal, spectroscopic, and diffraction methods. Interestingly, even though the cocrystals are isostructural, their physicochemical properties are quite different. The andrographolide-salicylic acid cocrystal completely inhibited the chemical transformation of andrographolide to its inactive sulfate metabolite, and moreover, the cocrystal exhibited a dissolution rate that was three times faster and a drug release that was two times higher than pure andrographolide.
authors.affiliation: School of Chemistry, University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Central University P.O. Hyderabad 500 046 (India).
authors.forename: Kuthuru
authors.initials: K
authors.lastname: Suresh
authors.forename: N Rajesh
authors.initials: NR
authors.lastname: Goud
authors.forename: Ashwini
authors.initials: A
authors.lastname: Nangia
mesh_terms: D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D012995:Solubility
chemical_list: D004224:Diterpenes; C030419:andrographolide
keywords: X-ray diffraction; crystal engineering; isostructurality; medicinal chemistry; natural products