USP <1229.6> covers Liquid-Phase Sterilization. The traditional methods for sterilization include steam and dry heat, whereas Liquid-Phase sterilization requires immersion in a chemical solution. Per USP, “a number of chemical agents, such as aldehydes, acids, bases, and strong oxidants in solution, under the appropriate conditions, are capable of destroying bacteria and fungi, including both vegetative cells and spores in a quantitative fashion.” In order for this to work, after sterilization the chemical agent must be removed from any exposed surfaces. This process must allow the item(s) to remain sterile, post-processing.
Examples of the liquids that can be used in this manner include: Aldehydes (glutaraldehyde, formaldehyde), acids (peracetic acid, nitric acid, sulfuric acid), bases (sodium hydroxide, potassium hydroxide), oxygenating compounds (hydrogen peroxide, ozone, chlorine dioxide) and halides (sodium hypochlorite, chlorine). To identify the appropriate sterilant, you must consider the effect on any materials, components, and equipment prior to use.
Also discussed within this section:
- Validation of sterilization by liquids
- Equipment qualification
- Component and load definition
- Biological indicators
- Process confirmation/Microbiological challenge
- Agent neutralization/removal
- Routine process control