Become A Member

Background: Bhasmas, the calcined metal and mineral preparations of Rasa Shastra, are now widely described as "ancient nanomedicines". The claim is attractive, but it rests on characterisation data of uneven quality and on terms that are often used loosely. Objective: To examine what the published physicochemical evidence actually shows about particle size in bhasmas, and whether it supports the nanomedicine label. Methods: A critical narrative review of characterisation studies on metal, mineral and marine bhasmas and herbo-mineral formulations, interpreted against current nanomaterial definitions and the known limits of each analytical technique. Results: Most studies report nanometre-scale crystallite domains, usually from Scherrer analysis of X-ray diffraction peaks, while electron microscopy, laser diffraction and dynamic light scattering show that these domains are held in sub-micron to micron-sized aggregates. Representative examples include Swarna bhasma with 28 nm crystallites but hydrodynamic diameters of about 670–720 nm, Naga bhasma with 60 nm lead sulphide crystallites in sub-micron agglomerates, and Swarna Makshika bhasma with particles of 1–2 µm. Number-based size distributions, which current regulatory definitions require, are almost never reported. Commercial Suvarna bhasma samples differ widely in gold content (32–98 wt%), surface area and in vivo bioaccumulation. Conclusion: Crystallite size is not particle size. The evidence supports describing many bhasmas as nanostructured, micron-scale materials rather than as nanoparticle suspensions. A minimum reporting standard combining several orthogonal techniques is proposed.

KEYWORDS: Bhasma; Rasa Shastra; Nanomedicine; Particle size; X-ray diffraction; Characterisation