What is the purpose of a rubber stopper in a Mix-O-Vial?

The purpose of a rubber stopper in a Mix-O-Vial is to separate the diluent from the powder until use. In a Mix-O-Vial system, the design typically includes a compartment for a powdered medication and another compartment for a diluent. The rubber stopper serves as a barrier between these two components. This separation is crucial for preserving the stability and integrity of the medication until it is ready to be mixed and administered. Once the healthcare professional is ready to use the medication, the rubber stopper can be punctured, allowing the diluent to mix with the powdered medication, resulting in a solution that can be drawn up into a syringe for administration. This mechanism ensures that the medication remains effective and safe to use.