Comparing molecular lengths, the pachycurares dimethyltubocurarine and d-tubocurarine both are very rigid and measure close to 1.8 nm in total length. Pancuronium and vecuronium measure 1.9 nm, whereas pipecuronium is 2.1 nm. The potency of these compounds follows the same rank of order as their length. Likewise, the leptocurares prefer a similar length. Decamethonium, which measures 2 nm, is the most potent in its category, whereas C11 is slightly too long. Gallamine despite having low bulk and rigidity is the most potent in its class, and it measures 1.9 nm. Based on this information one can conclude that the optimum length for neuromuscular blocking agents, depolarizing or not, should be 2 to 2.1 nm.