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90Sr (T1/2 = 28 y) is always in equilibrium with 90Y in High Level Liquid waste (HLLW) and hence 90Sr is a suitable long lasting source of 90Y, if it is purified suitably for therapeutic applications. A combination of CMPO & TBP was found to be the most suitable solvent system for alpha activity removal. CMPO has high selectivity for alpha contaminants (Pu/Am) w.r.t. 90Sr. For regeneration of spent organic, 3 M Phosphoric acid was most suitable with the ability to strip back more than 98% of gross alpha activity in single contact and thus solvent system was qualified for recycling. [ABSTRACT FROM AUTHOR]

The purpose of the present research was to test the ion pair absorption hypothesis with respect to the topical route of drug delivery. The experiment consisted of preparing various lidocaine-n-alkanoate ion pairs, then characterizing them by proton magnetic resonance spectroscopy, elemental analysis and conductivity. Percutaneous absorption studies through excised hairless mouse skin were carried out using ethanolic solution of radiolabeled 14C-lidocaine-octanoate, 14C-lidocaine-decanoate and 14C-lidocaine-dodecanoate. Studies were conducted under steady-state conditions using Bronaugh's flow-through apparatus and normal saline as the receptor fluid. Ethanolic solution of a lidocaine base served as a control. The apparent differences in flux between lidocaine and the various ion pairs were statistically significant (p less than 0.05). The differences among the fluxes of the various ion pairs were not statistically significant (p greater than 0.05), nor were the differences in lag times (p greater than 0.05). The difference between the flux values of lidocaine-1-14C-dodecanoate and 14C-lidocaine-dodecanoate infers that lidocaine-dodecanoate did not cross the excised, full-thickness, hairless mouse skin as an intact 1:1 ion pair. The formation of weakly associated ion pairs was suggested by the apparent low-association constants (Ka = 15-17 liters/mol) obtained at 25 degrees C in methanol by conductometric analysis.