TRANSDERMAL IONTOPHORESIS OF SODIUM NONIVAMIDE ACETATE .2. OPTIMIZATION AND EVALUATION ON SOLUTIONS AND GELS

Sodium nonivamide acetate (SNA) is a newly designed derivative of caps aicin which reveals marked antinociceptive activity without producing an overt pungent sensation and skin irritation. The following iontopho retic drug delivery issues have been examined in this paper: (1) the c ompetitive ion effect; (2) transdermal iontophoretic delivery from gel base; and (3) maximization of iontophoretic application mode from gel base. According to the theory of molal volume, divalent salt ions sho w higher buffering capacity on SNA iontophoretic transport than did mo novalent salt ions. However, this effect also causes a great reduction of SNA transdermal flux. The experimental result of transdermal ionto phoresis of gel indicated the flux of SNA decreased following the incr ease of viscosity. Using various polymers incorporated in gel formulat ions, indicated methyl cellulose and hydroxypropyl methyl cellulose sh owed higher capacity for SNA iontophoretic transport than the other ma terials. After a series of evaluation and optimization on the iontopho retic delivery of SNA, transdermal iontophoresis has provided a great capacity of enhancing SNA transport across the skin. The result of the present study is particularly helpful in the development of SNA trans dermal delivery system and holds promise for the successful clinical d evelopment of an antinociceptive therapeutic regimen. Copyright (C) 19 96 Elsevier Science B.V.