Frontline Combo Spot-On Dog Presentation Spot-on solution. Small: 1 pipette of 0.67 ml contains fipronil 67 mg, (S)-methoprene 60.30 mg. Medium: 1 pipette of 1.34 ml contains fipronil 134 mg, (S)-methoprene 120.60 mg. Large: 1 pipette of 2.68 ml contains fipronil 268 mg, (S)-methoprene 241.20 mg. XL: 1 pipette of 4.02 ml contains fipronil 402 mg, (S)-methoprene 361.80 mg.