CRANBURY, N.J., June 21, 2011 /PRNewswire/ -- Palatin Technologies, Inc. (NYSE Amex: PTN) announced today that the U.S. Patent and Trademark Office issued U.S. Patent No. 7,964,181, titled "Amino Acid Surrogates for Peptidic Constructs." The claims in the issued patent cover a series of small molecule mimics for naturally occurring amino acids which can be used as building blocks in drug development. A small molecule mimic claimed in the issued patent is used in making PL-3994, Palatin's lead peptide mimetic natriuretic peptide receptor A agonist, which is in development for treatment of acute exacerbations of asthma, heart failure and refractory or difficult-to-control hypertension. "The small molecule mimetics we have developed should help in the commercialization of peptide-based drugs," said Carl Spana, Ph.D., Palatin's President and CEO. "Compounds such as our PL-3994 which use small molecule mimetics have extended half-lives, and are resistant to normal clearance mechanisms. This results in a drug candidate that is very potent and has a pharmacological effect much longer than is typically seen with peptides." PL-3994 and the related family of compounds were discovered and developed by Palatin scientists and are solely owned by Palatin. In addition to this issued U.S. patent, Palatin has a U.S. patent on the PL-3994 composition of matter, and pending applications or issued patents in selected countries outside the United States. About PL-3994 PL-3994 is a natriuretic peptide receptor A (NPR-A) agonist compound in development for treatment of acute exacerbations of asthma, heart failure and refractory hypertension. PL-3994 activates NPR-A, a receptor known to play a role in cardiovascular homeostasis. PL-3994, one of a number of natriuretic peptide receptor agonist compounds Palatin has developed, is a synthetic molecule incorporating a novel and proprietary amino acid mimetic structure. It has an extended half-life, with reduced affinity for the endogenous natriuretic peptide clearance receptor and significantly increased resistance to neutral endopeptidase, an endogenous enzyme that degrades natriuretic peptides.