USP Reference Standards are specified for use in conducting official USP–NF tests and assays. To confirm accuracy and reproducibility, USP Reference Standards are rigorously tested and evaluated by multiple independent laboratories including USP, commercial, regulatory, and academic labs. USP also provide publicly available, official documentary standards for pharmaceutical ingredients in the USP–NF that link directly with our primary reference standards.

A mixture containing abacavir sulfate and trans-abacavir