PTCB Certified Pharmacy Technician (PTCE)MedicationsMedium
A pharmacy technician is preparing to compound a non-sterile oral solution. The master formulation record specifies 'Purified Water, USP' as a solvent. What is the primary characteristic of Purified Water, USP, that makes it suitable for this purpose?
- AIt contains added minerals for taste.
- BIt is sterile and pyrogen-free.
- CIt is free of particulate matter and dissolved solids.
- DIt has a high concentration of electrolytes.
Show answer & explanationAnswer & explanation
Correct answer: C. It is free of particulate matter and dissolved solids.
Purified Water, USP, is water that has been treated to remove most chemical contaminants, including dissolved solids and organic matter, making it suitable for pharmaceutical compounding where the presence of these impurities could affect stability or efficacy. It is not necessarily sterile or pyrogen-free unless specifically treated further.
Why the other options are wrong
- A. Purified Water, USP, has most minerals removed, not added.
- B. While it is often used as a starting material for sterile products, Purified Water, USP, itself is not required to be sterile or pyrogen-free.
- D. It has a very low concentration of electrolytes, as most dissolved solids have been removed.
Purified Water, USP
Purified Water, USP, is water that has been processed to remove chemical impurities and dissolved solids. It is suitable for use in non-sterile compounding and as a starting material for further processing into sterile water.
- Prepared by distillation, ion-exchange, or reverse osmosis.
- Contains no added substances.
- Not necessarily sterile or pyrogen-free unless specified.
Memory trick: Purified water is 'clean' water for compounding.