ICH Q2(R2) describes analytical-procedure performance characteristics such as specificity or selectivity, accuracy, precision, detection limit, quantitation limit, linearity, range, and robustness, as applicable to the intended use of the procedure
Multiple strengths are available as separate variants: 2 mg per vial , 5 mg per vial and 10 mg per vial
References Chang CH, Tsai WC, Lin MS, Hsu YH, Pang JH
This produces a 5mg/ml concentration that is easier to measure accurately on a standard U-100 insulin syringe , especially at lower starting doses like 2.5mg
Oral B12 looks cheap, but if your body absorbs very little of each pill because of low stomach acid or a gut condition, much of that spending does not translate into results, and you keep buying bottle after bottle