NAD+: Form, Reconstitution and Storage (Research Format)

Form and specification

NAD+ is supplied as a lyophilized powder in a vial with a nominal 1000 mg fill. It is a white to faintly cream, hygroscopic powder, freely soluble in water. The material is labeled for research use only (RUO) and not for administration to humans or animals.

Reconstitution (solution chemistry)

Before opening, the vial is brought to room temperature, which limits moisture condensation on the hygroscopic powder. The solvent in lab-handling practice is often bacteriostatic water (water with 0.9% benzyl alcohol), or sterile water for analytical purposes. The chosen volume of liquid is added slowly, directing the stream down the inner vial wall rather than onto the cake. Dissolve by gentle swirling; avoid vigorous shaking, which causes foaming. NAD+ dissolves quickly to give a clear, colorless to faintly yellow solution; noticeable turbidity or strong color is a reason to check material quality.

Storage: lyophilizate versus solution

The dry lyophilizate is the most stable form. Keep it capped, dry, protected from light and moisture, and cold; for long-term storage use a freezer. Because the powder is hygroscopic, open the vial as few times as possible and reseal it immediately.

Reconstituted NAD+ is considerably less stable. Keep solutions chilled and protected from light and use them within a short window. If longer storage is required, aliquot the solution and freeze it to avoid repeated freeze-thaw cycles.

Stability

In aqueous media NAD+ hydrolyzes slowly; the rate of degradation rises at alkaline pH and elevated temperature. Solutions are most stable at mildly acidic-to-neutral pH and low temperature. The oxidized form (NAD+) does not absorb at 340 nm whereas NADH does, so spectrophotometry at 340 nm is a convenient way to assess redox state and preparation suitability.

Lab applications

NAD+ is used as a cofactor and reference substrate: in dehydrogenase enzyme assays, in work with sirtuins and PARPs, in calibrating redox measurements and in studying NAD-metabolism pathways. Work with solutions cold and use freshly prepared aliquots for reproducibility. All procedures are strictly for research.