Experiences towards the indigenous development of colloidal samarium [32P] phosphate in

In continuation of the on going development work of radio colloidal samarium [32P] phosphate injection for radiosynoviorthesis applications, 11 clinical trial batches of the radio colloid were prepared following the established production protocol with precise batch process yields as evident from the radiochemical yields, not less than 95%. Preparation involves the reaction of carrier SmCl3 with phosphoric acid mixed with required quantities of radio 32PH3PO4, followed by the addition of 3.5% gelatin solution to have true colloidal dispersion. Pure product recovered by dialysis was formulated in isotonic saline solution, dispensed and sterilized by heating in an autoclave, under aseptic conditions. This method is convenient, easily adaptable, for handling large batch sizes of about 100–150 mCi with adequate shielding and the typical batch recovery was around 85%. The RCP of the product was not less than 98% and the product complied with respect to sterility and BET tests as per the USP specifications and other specifications as per the QC monograph.

Multi centric clinical trials involving the participation of seven nuclear medicine institutes, and a total dose of 250 mCi of colloidal samarium [32P] phosphate injection was supplied during these trials. In these studies randomized dose of 1mCi per knee joint was instilled and distribution scintigrams were acquired at 0h and 24h post instillation. Also in these studies aliquots of blood was with drawn at 24h for estimating the systemic leakage of radio colloid and estimating the radioactivity in comparison with the test blood sample of normal adult with no radioactivity using liquid scintillation analyzer.

Results of 100 joints treated in cases of Hemophiliacs, Pigmented villonodular synovitis and Rheumatoid arthritis following the approved protocol, are satisfactory and very encouraging as evident from the summary reports given by the participating institutes.

Plans are in the final stages for the regular production and supply of this therapeutic product after RPC's approval, and make available on monthly basis to all the Nucl. Med. Cents. in India by the end of December 2006.