A filter assembly is provided that includes an immobilized base material in combination with a slow release mechanism for introducing an additive base material into a lubrication fluid flowing through the filter assembly. The introduced base material is a weaker base material than the base material of the immobilized base material. The combination of the immobilized base material and the additive base material provides a system that would work to neutralize acids for all lube formulations commonly used in the field. As a result, oil drain intervals can be extended.