Structural and elemental characterization of traditional Indian Siddha formulation: Thalagak karuppu

Background The traditional Indian medicine ‘Siddha’ uses metals, metalloids and minerals including toxic ones with no proven toxicity. Thalagak karuppu (TK) is remarkably stable over a century and used for treating Suram (Fever), Kaasam (Cough), Elai (Tuberculosis) and Eraippu Erumal (Bronchial Asthma). Objective The present study addresses elemental and morphological characterization of therapeutic Siddha formulation: Thalagak karuppu (TK). Materials and methods TK was purchased from the Indian Medical Practitioners Co-operative Pharmacy and Stores (IMCOPS) Ltd, Chennai, Tamilnadu, India. The physicochemical properties were evaluated using UV–visible spectrophotometer, Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM) with Energy Dispersive X-ray analysis (EDX), Zeta sizer and X-ray diffractometer (XRD). Results The mixed nature of arsenic was analyzed using UV–visible spectroscopy. The fingerprint region for arsenic derivatives was inferred from IR spectroscopy and X-ray diffraction patterns. The shape and size heterogeneity in the anisotropic mixture was observed in SEM images and the polydispersity was analyzed by Zeta sizer. Conclusions The structural, elemental and morphological analyses suggests that the arsenic may predominantly exist either as orpiment (As₂S₂) or realgar (As₂S₄) form. The possibility is less for the toxic arsenolite. Hence, the formulation may be considered safe.