A client is receiving 500 mg of metronidazole IVPB q8h. The metronidazole has been placed in 100 mL D5W to infuse over 45 minutes. The administration set delivers 10 gtt/mL. At what rate in gtt/min should the IV infuse? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)