Most stock lists are archaeological. They record what was ordered at various points for various reasons, and nobody has revisited the whole of it since. A formulary is the same list made deliberately: an explicit decision about what is held, how much, and from where.
The exercise usually pays for itself the first time it is done, because it surfaces both the items quietly expiring unused and the ones that stock out repeatedly.
Segment by pattern of use, not by category
Compounds group naturally by how they are consumed rather than by what they are.
- Core items, drawn on continuously and predictably. These justify holding safety stock, buying in larger single lots and negotiating on volume.
- Periodic items, used in defined blocks of work with gaps between. Better ordered against a known schedule than held continuously.
- Occasional items, needed rarely and often unpredictably. Holding these ties up capital and storage against a low probability of use, and supplier lead time usually matters more than stock level.
Pulling six to twelve months of order history and sorting it by frequency of reorder rather than by spend puts most items into one of the three almost immediately.
Size against storage and stability, not just against demand
Two constraints bound order quantity independently of usage, and both are routinely forgotten until a delivery arrives.
- Storage capacity at the required condition. Cold storage is the binding constraint in most practices, and a volume discount that does not fit in the freezer is not a discount.
- Stability and re-test dating. Material held beyond its supported period is a write-off regardless of how well it was priced. Quantity should be bounded by what will realistically be consumed within that window.
Where a single larger lot is attractive for consistency reasons, those two constraints set the ceiling.
Supplier concentration
Consolidating onto fewer suppliers simplifies documentation, makes pricing clearer and reduces the number of relationships to maintain. It also concentrates risk: a single supplier with a stock problem becomes your stock problem.
A common structure is a primary supplier for core items, with a qualified secondary already evaluated and set up for the items that would hurt most to be without. Qualifying a backup supplier before it is needed is far easier than doing it during a shortage, and most of that work is the audit described separately.
What a formulary record holds per item
- Compound, strength and the supplier catalogue reference.
- Segment: core, periodic or occasional.
- Target stock level and reorder point, where one applies.
- Storage condition and location.
- Supported shelf life or re-test interval.
- Primary supplier, lead time, and qualified alternative where one exists.
- Documentation required on receipt, which for most items means a lot-specific certificate.
A review cadence
A formulary reviewed annually drifts; one reviewed at every order never settles. Quarterly suits most practices, and the review is short if the questions are fixed.
- Which items did not move at all this quarter, and should they be held?
- Which items stocked out, and was the reorder point wrong or the lead time?
- Which items are approaching their supported date with stock remaining?
- Did any supplier's lead time, pricing or documentation change?
- Is the qualified alternative still qualified?
Why this connects to everything else
A formulary is where the other practices become operational. Lot consistency argues for fewer, larger purchases of core items. Traceability requires the documentation column to be enforced rather than aspirational. Cold chain limits order size. Supplier audit determines who appears in the supplier column at all.
Built that way, it stops being an inventory list and becomes the place the decisions are recorded.
A formulary is a standing decision about what to stock, and it only holds if the quantities are honest. Inventory levels and reorder points covers the arithmetic, and minimum order quantities covers what to do when the smallest order available exceeds what can be used.
For how this fits with everything else that happens to a vial between delivery and use, peptide storage and handling for clinics covers the full picture.