Biphalin
 | |
 | |
| Clinical data | |
|---|---|
| ATC code |
|
| Identifiers | |
| |
JSmol) | |
| |
| |
Biphalin is a
δ opioid receptors (with an EC50 of about 1–5 nM for both μ and δ receptors), therefore it has analgesic activity.[2]
Biphalin presents a considerable intraperitoneal administration. The extraordinary in vivo potency shown by this compound is coupled with low side-effects, in particular, to produce no dependency in chronic use.[3] For these reasons, several efforts have been carried out in order to obtain more information about structure-activity relationship (SAR). Results clearly indicate that, at least for μ receptor binding, the presence of two pharmacophores is not necessary;[2] Tyr1 is indispensable for analgesic activity, while replacing Phe at the position 4 and 4' with non-aromatic, but lipophilic amino acids does not greatly change the binding properties[2] and in general 4,4' positions are found to be important to design biphalin analogues with increased potency and modified μ/δ selectivity.[4][5] The hydrazide linker is not fundamental for activity or binding, and it can be conveniently substituted by different conformationally constrained cycloaliphatic diamine linkers.[6]