What is NAD+ Dissolving Strips?
NAD+ is not a peptide. It is a dinucleotide coenzyme built from a nicotinamide mononucleotide joined to an adenosine monophosphate through a pyrophosphate bridge. It carries hydride in redox reactions, cycling between the oxidized NAD+ and reduced NADH forms, and it is consumed as a substrate by sirtuins, PARP enzymes and CD38, which is the link between this molecule and the metabolic and aging literature.
Because the molecule is a charged dinucleotide rather than a peptide, its formulation behaviour differs from the rest of this library. It is highly water soluble, labile at alkaline pH, and more stable dry than in solution, which is one reason a cast film is an interesting format to study. Films are produced by dissolving the solute into an aqueous casting solution containing a film former and plasticizer, then evaporating solvent to leave a uniform sheet.
What is not established is transmucosal recovery of an intact charged dinucleotide from a film. The molecule is large and polar for passive diffusion, published absorption data for this route are limited, and whether NAD+ itself or its degradation products cross a mucosal surface is unresolved.
Reconstitution & handling
No reconstitution applies, since the strip is a dry solid rather than a lyophilized powder. The analytical procedure is extraction. A strip is dissolved in a measured volume of cold buffer at mildly acidic to neutral pH, since NAD+ degrades quickly in alkaline conditions, then clarified by filtration before injection. Concentration follows from declared content per strip divided by extraction volume.
Storage & stability
Sealed moisture-barrier packs are kept refrigerated at 2 to 8 degrees Celsius or at controlled room temperature, away from light and humidity. Moisture is the principal liability, because the hygroscopic matrix takes up water, the film turns tacky, and hydration accelerates hydrolysis of the pyrophosphate linkage. Packs should be opened briefly and resealed. Freezing is unnecessary and creates a condensation risk. Alkaline residues on glassware are avoided during handling.
How it's tested
Content uniformity is the governing measure, since a cast sheet is cut into discrete units. Strips are extracted and assayed by reverse-phase or ion-pair HPLC with detection near 260 nanometres, the adenine absorbance maximum, rather than at the 214 and 220 nanometres used for peptide bonds. Identity is confirmed by mass spectrometry, degradation products including nicotinamide are quantified, and mean content with strip-to-strip variation is reported per lot.