Format is not packaging. A lyophilized vial, an atomized solution and a dissolving film put the same molecule into three different chemical situations, and the practical differences are larger than the price difference.

Lyophilized vial

Dry, sealed and cold, a peptide is about as stable as it gets. The clock does not really start until it is reconstituted, which is why the certificate carries a valid-until date measured in years and a reconstituted vial is measured in weeks. The cost is that you do the arithmetic yourself, which is where net peptide content starts to matter.

Liquid spray

Already in solution, so already on the clock: the shelf life quoted is for the sealed bottle, and the open life once the pump has been primed is shorter. What you gain is that the concentration is fixed and known, and nothing has to be weighed or diluted.

Dissolving strip

A fixed amount per film in a solid matrix, which sidesteps both the reconstitution arithmetic and the open-life problem. The trade is granularity: the amount is whatever one film carries, and a film is not divisible in any way you would want to write down.