For the prevention and treatment of osteoporosis in post-menopausal women, as well as prevention and treatment of corticosteroid-induced bone loss. Also for the reduction in the incidence of invasive breast cancer in postmenopausal women with osteoporosis or have a high risk for developing breast cancer.
Raloxifene, a selective estrogen receptor modulator (SERM) of the benzothiophene class, is similar to tamoxifen in that it produces estrogen-like effects on bone and lipid metabolism, while antagonizing the effects of estrogen on breast and uterine tissue. Raloxifene differs chemically and pharmacologically from naturally occuring estrogens, synthetic steroidal and nonsteroidal compounds with estrogenic activity, and antiestrogens. Estrogens play an important role in the reproductive, skeletal, cardiovascular, and central nervous systems in women, and act principally by regulating gene expression. When estrogen binds to a ligand-binding domain of the estrogen receptor, biologic response is initiated as a result of a conformational change of the estrogen receptor, which leads to gene transcription through specific estrogen response elements of target gene promoters. The subsequent activation or repression of the target gene is mediated through 2 distinct transactivation domains of the receptor: AF-1 and AF-2. The estrogen receptor also mediates gene transcription using different response elements and other signalling pathways. The role of estrogen as a regulator of bone mass is well established. In postmenopausal women, the progressive loss of bone mass is related to decreased ovarian function and a reduction in the level of circulation estrogens. Estrogen also has favourable effects on blood cholesterol.
Mode of Action:
Raloxifene binds to estrogen receptors, resulting in differential expression of multiple estrogen-regulated genes in different tissues. Raloxifene produces estrogen-like effects on bone, reducing resorption of bone and increasing bone mineral density in postmenopausal women, thus slowing the rate of bone loss. The maintenance of bone mass by raloxifene and estrogens is, in part, through the regulation of the gene-encoding transforming growth factor-_3 (TGF-_3), which is a bone matrix protein with antiosteoclastic properties. Raloxifene activates TGF-_3 through pathways that are estrogen receptor-mediated but involve DNA sequences distinct from the estrogen response element. The drug also binds to the estrogen receptor and acts as an estrogen agonist in preosteoclastic cells, which results in the inhibtion of their proliferative capacity. This inhibition is thought to contribute to the drug's effect on bone resorption. Other mechanisms include the suppression of activity of the bone-resorbing cytokine interleukin-6 promoter activity. Raloxifene also antagonizes the effects of estrogen on mammary tissue and blocks uterotrophic responses to estrogen. By competing with estrogens for the estrogen receptors in reproductive tissue, raloxifene prevents the transcriptional activation of genes containing the estrogen response element. As well, raloxifene inhibits the estradiol-dependent proliferation of MCF-7 human mammary tumor cells in vitro. The mechansim of action of raloxifene has not been fully determined, but evidence suggests that the drug's tissue-specific estrogen agonist or antagonist activity is related to the structural differences between the raloxifene-estrogen receptor complex (specifically the surface topography of AF-2) and the estrogen-estrogen receptor complex. Also, the existence of at least 2 estrogen receptors (ER_, ER_) may contribute to the tissue specificity of raloxifene.
Hepatic, raloxifene undergoes extensive first-pass metabolism to the glucuronide conjugates: raloxifene-4'-glucuronide, raloxifene-6-glucuronide, and raloxifene-6, 4'-diglucuronide. No other metabolites have been detected, providing strong evidence that raloxifene is not metabolized by cytochrome P450 pathways
A STARring role for raloxifene? Lancet Oncol. 2006 Jun;7(6):443. Pubmed Heringa M: Review on raloxifene: profile of a selective estrogen receptor modulator. Int J Clin Pharmacol Ther. 2003 Aug;41(8):331-45. Pubmed Barrett-Connor E: Raloxifene: risks and benefits. Ann N Y Acad Sci. 2001 Dec;949:295-303. Pubmed Khovidhunkit W, Shoback DM: Clinical effects of raloxifene hydrochloride in women. Ann Intern Med. 1999 Mar 2;130(5):431-9. Pubmed Cummings SR, Eckert S, Krueger KA, Grady D, Powles TJ, Cauley JA, Norton L, Nickelsen T, Bjarnason NH, Morrow M, Lippman ME, Black D, Glusman JE, Costa A, Jordan VC: The effect of raloxifene on risk of breast cancer in postmenopausal women: results from the MORE randomized trial. Multiple Outcomes of Raloxifene Evaluation. JAMA. 1999 Jun 16;281(23):2189-97. Pubmed Bryant HU, Glasebrook AL, Yang NN, Sato M: An estrogen receptor basis for raloxifene action in bone. J Steroid Biochem Mol Biol. 1999 Apr-Jun;69(1-6):37-44. Pubmed Balfour JA, Goa KL: Raloxifene. Drugs Aging. 1998 Apr;12(4):335-41; discussion 342. Pubmed Clemett D, Spencer CM: Raloxifene: a review of its use in postmenopausal osteoporosis. Drugs. 2000 Aug;60(2):379-411. Pubmed Silverman SL: New selective estrogen receptor modulators (SERMs) in development. Curr Osteoporos Rep. 2010 Sep;8(3):151-3. Pubmed Diez-Perez A: Selective estrogen receptor modulators (SERMS). Arq Bras Endocrinol Metabol. 2006 Aug;50(4):720-34. Pubmed
Products currently covered by valid US Patents are offered for R&D use in accordance with 35 USC 271(e)+A13(1). Any patent infringement and resulting liability is solely at buyer risk.
API’s From Quality Manufacturers:
Cost effective materials based on specific requirements
Small quantities for initial research and larger development quantities towards product commercialization
Technical packages, letters of access to filed DMFs