Neomycin sulfate is available in $1 \mathrm{~g}$ vials of maximum volume of $10 \mathrm{~mL}$ and the dry powder accounts for $0.9 \mathrm{~mL}$ of the final volume of the reconstituted product. Using a 1-g vial of neomycin sulfate and sterile water for injection as a diluent, how would you obtain the antibiotic concentration needed for the following prescription?
$\mathrm{R}$
Neomycin sulfate $\quad 500 \mathrm{mg}$
Water for injection ad $30 \mathrm{~mL}$
Sig. For topical use only.