Discovery and development of direct Xa inhibitors Xa was identified as a promising target for the development of new anticoagulants in the early 1980s. In 1987 the first factor Xa inhibitor, the naturally occurring compound antistasin, was isolated from the salivary glands of the Mexican leech "Haementeria officinalis". Antistasin is a polypeptide and a potent Xa inhibitor. In 1990 another naturally occurring Xa inhibitor was isolated, tick anticoagulant peptide (TAP) from extracts of the tick "Ornithodoros moubata". TAP and antistasin were used to estimate factor Xa as a drug target. Blood coagulation is a complex process by which the blood forms clots. It is an essential part
Renin inhibitor normal conditions, stimulation of the RAAS occurs in response to threats that compromise blood pressure stability, such as hypotension, blood loss and excessive loss of sodium and water. Blood pressure depends on total peripheral resistance and cardiac output. The highly selective aspartic protease renin is secreted from the juxtaglomerular apparatus, which is the only source of active renin, although its precursor, prorenin, can be secreted by other tissues, such as the salivary glands, brain, heart and blood vessels. Renin is a circulating enzyme that acts on a circulating peptide, angiotensinogen. Renin cleaves the peptide at the Leu10–Val11 bond, and this