FOXO4-DRI (Proxofim) Reference

Reconstitution and handling

Sterile water is the default solvent. The product page describes a second, positively charged segment appended to the chain, and a strongly cationic peptide should dissolve readily.

Add diluent slowly down the inside wall of the vial, swirl gently, and let the solution clarify. Do not vortex. Where a vial resists, mildly acidic conditions raise the net positive charge and assist.

Buffer choice deserves care, since alkaline conditions catalyze racemization and identity here rests on configuration at every chiral residue. Neutral to mildly acidic is safer.

A peptide carrying this much positive charge also binds negatively charged surfaces, so at low concentration borosilicate glass is a poor choice and low-protein-binding polypropylene better.

This is laboratory preparation chemistry, not dosing, administration, or protocol guidance of any kind.

Storage and stability

Store the lyophilized powder at -20 degrees C, sealed, desiccated and protected from light, and let a cold vial warm before opening so moisture does not condense onto it. Reconstituted, hold at 2 to 8 degrees C, or aliquot and freeze rather than thawing repeatedly.

Epimerization is the liability specific to this molecule. Racemization is base-catalyzed and heat-accelerated, so alkaline conditions and warmth are what to avoid and near-neutral cold storage is the control. Detection is the awkward part: the epimer has the same mass as the starting material, so a stability study resting on mass alone will not see it. A chromatographic profile can, where the epimer resolves from the parent.

Desiccation matters more than average, since heavily charged lyophilized material takes up moisture quickly once opened.

These are storage conditions for the material, not dosing or administration guidance.

How FOXO4-DRI is tested

The product page states HPLC and MS-UPLC. Reversed-phase HPLC establishes chromatographic purity as area percent, and here it carries unusual weight, being the method that may resolve the impurity mass spectrometry cannot.

Greater than 99 percent is demanding on a chain of this length. Long solid-phase syntheses accumulate deletion and truncation products from incomplete couplings; those shift the mass, so mass spectrometry sees them. Epimers it does not.

A further stereochemical question sits outside both methods: the enantiomeric purity of the D-configured building blocks, since contamination at monomer level propagates into the product. Chiral analysis of the hydrolysate answers that, not chromatography of the intact chain.

Area percent is a chromatographic measure rather than peptide content by weight, and the counter-ion burden on a strongly basic peptide is substantial; the page states that labeled quantity is net peptide content.

At around 5.4 kilodaltons the isotope envelope is broad and the monoisotopic peak is not the tallest, so the two mass conventions differ and should not be conflated.

These describe general methodology, not a claim about any particular batch.