What visible defects require discarding a vial of the Brown & Burk UK Ltd caffeine citrate 20 mg/ml solution for infusion and oral solution product before administration?

A vial of the Brown & Burk UK Ltd caffeine citrate 20 mg/ml solution for infusion and oral solution product must be discarded if the solution is discoloured or contains visible particulate matter; both undiluted and diluted parenteral solutions must be inspected before administration.