For best results and reproducibility, rehydrate peptide just before use. Do not attempt to weigh out smaller portions. Do not refreeze any unused portions.

Potent, long-lasting, morphine-like analgesic - C.B. Pert et al., Science 194, 330 (1976); A. Pert, OPIATES AND ENDOGENOUS OPIOID PEPTIDES, H. W. Kosterlitz, Ed., Elsevier/North-Holland, Amsterdam, 87-94 (1976); D. H. Coy et al., BBRC 73, 632 (1976).