Notwithstanding any other provision of state law, DMSO (dimethyl sulfoxide) may be introduced into intrastate commerce as long as (1) it is manufactured or distributed by persons licensed pursuant to chapter
18.64 RCW or chapter
18.92 RCW, and (2) it is used, or intended to be used, in the treatment of human beings or animals for any ailment or adverse condition: PROVIDED, That DMSO intended for topical application, consistent with rules governing purity and labeling promulgated by the pharmacy quality assurance commission, shall not be considered a legend drug and may be sold by any retailer.