AUTHOR OF THIS BLOG

DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER

Teva Launches Generic Niaspan in U.S.

 GENERIC  Comments Off on Teva Launches Generic Niaspan in U.S.
Sep 212013
 

niaspan

Teva Announces Exclusive Launch of Generic NIASPAN® in the United States

JERUSALEM–(BUSINESS WIRE)–Teva Pharmaceutical Industries Ltd. (NYSE:TEVA) today announced the launch of the generic equivalent to NIASPAN® (niacin extended-release) tablets, 500, 700, and 1000mg in the United States. Teva was first to file, making the product eligible for 180 days of marketing exclusivity.

NIASPAN® is marketed by AbbVie and used with diet to reduce elevated TC, LDL-C, Apo B and TG levels, and to increase HDL-C in patients with primary hyperlipidemia and mixed dyslipidemia. NIASPAN® had annual sales of approximately $1.12 billion in the United States, according to IMS data as of June 30, 2013.  read more at

http://www.pharmalive.com/teva-launches-generic-niaspan-in-us

niacin,  vit B3

Niacin (also known as vitamin B3, nicotinic acid, or less commonly vitamin PP; archaic terms include pellagra-preventive and anti-dermatitis factor) is an organic compound with the formula C
6H
5NO
2 and, depending on the definition used, one of the 40 to 80 essential human nutrients.

Niacin is one of five vitamins (when lacking in human diet) associated with a pandemic deficiency disease: niacin deficiency (pellagra), vitamin C deficiency (scurvy), thiamin deficiency (beriberi), vitamin D deficiency (rickets and osteomalacia), vitamin A deficiency (night blindness and other symptoms). Niacin has been used for over 50 years to increase levels of HDL in the blood and has been found to decrease the risk of cardiovascular events modestly in a number of controlled human trials.[3]

This colorless, water-soluble solid is a derivative of pyridine, with a carboxyl group (COOH) at the 3-position. Other forms of vitamin B3 include the corresponding amide, nicotinamide (“niacinamide”), where the carboxyl group has been replaced by a carboxamide group (CONH
2), as well as more complex amides and a variety of esters. Nicotinic acid and niacinamide are convertible to each other with steady world demand rising from 8500 tonnes per year in 1980s to 40,000 in recent years.[4]

Niacin cannot be directly converted to nicotinamide, but both compounds could be converted to and are precursors of NAD andNADP in vivo.[5] Nicotinic acid, nicotinamide, and tryptophan (via quinoline acid) are co-factors for nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). NAD converts to NADP by phosphorylation in the presence of the enzyme NAD+ kinase. NADP and NAD are coenzyme for many dehydrogenases, participating in many hydrogen transfer processes.[6] NAD is important in catabolism of fat, carbohydrate, protein, and alcohol, as well as cell signaling and DNA repair, and NADP mostly in anabolism reactions such as fatty acid and cholesterol synthesis.[6] High energy requirements (brain) or high turnover rate (gut, skin) organs are usually the most susceptible to their deficiency.[7]

Although the two are identical in their vitamin activity, nicotinamide does not have the same pharmacological effects (lipid modifying effects) as niacin. Nicotinamide does not reduce cholesterol or cause flushing.[8] Nicotinamide may be toxic to the liver at doses exceeding 3 g/day for adults.[9] Niacin is involved in both DNA repair, and the production of steroid hormones in theadrenal gland.

 

  1. “Niacin”. DrugBank: a knowledgebase for drugs, drug actions and drug targets. Retrieved 14-January-2012.
  2.  PubChem 938
  3.  Bruckert, E; Labreuche, J; Amarenco, P (2010 Jun). “Meta-analysis of the effect of nicotinic acid alone or in combination on cardiovascular events and atherosclerosis”.Atherosclerosis 210 (2): 353–61. doi:10.1016/j.atherosclerosis.2009.12.023.PMID 20079494.
  4.  Cantarella, L; Gallifuoco, A; Malandra, A; Martínková, L; Spera, A; Cantarella, M (2011). “High-yield continuous production of nicotinic acid via nitrile hydratase-amidase cascade reactions using cascade CSMRs”. Enzyme and microbial technology 48 (4–5): 345–50. doi:10.1016/j.enzmictec.2010.12.010. PMID 22112948.
  5.  Cox, Michael; Lehninger, Albert L; Nelson, David R. (2000). Lehninger principles of biochemistry. New York: Worth Publishers. ISBN 1-57259-153-6.
  6. ^ Jump up to:a b Wan, P; Moat, S; Anstey, A (2011). “Pellagra: A review with emphasis on photosensitivity”. The British journal of dermatology 164 (6): 1188–200.doi:10.1111/j.1365-2133.2010.10163.x. PMID 21128910.
  7.  Ishii, N; Nishihara, Y (1981). “Pellagra among chronic alcoholics: Clinical and pathological study of 20 necropsy cases”. Journal of neurology, neurosurgery, and psychiatry 44 (3): 209–15. doi:10.1136/jnnp.44.3.209. PMC 490893.PMID 7229643.
  8.  Jaconello P (October 1992). “Niacin versus niacinamide”. CMAJ 147 (7): 990.PMC 1336277. PMID 1393911.
  9.  Knip M, Douek IF, Moore WP, et al. (2000). “Safety of high-dose nicotinamide: a review”. Diabetologia 43 (11): 1337–45. doi:10.1007/s001250051536.PMID 11126400.

Food sources

“Food Data Chart – Niacin”. Retrieved 7 September 2012.

Niacin is found in variety of foods, including liver, chicken, beef, fish, cereal, peanuts and legumes, and is also synthesized from tryptophan, an essential amino acid found in most forms of protein.

Animal products:

Fruits and vegetables:

Seeds:

Fungi:

Other:

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Synthetic drug Tramadol found in nature,pin cushion tree

 Ayurveda, drugs  Comments Off on Synthetic drug Tramadol found in nature,pin cushion tree
Sep 182013
 

The bark of Nauclea latifolia contains tramadol at medicinal concentrations © imagebroker / Alamy

http://www.rsc.org/chemistryworld/2013/09/african-plant-natural-source-tramadol

In another example of nature beating chemists, the African plant Nauclea latifolia has been found to be a natural source of the synthetic opioid tramadol. First marketed in 1977, tramadol is frequently used to relive moderate to moderately-severe pain. While other synthetic drugs have later been found in nature, this is the first instance where the discovery involves clinically viable concentrations.

Colloquially known as the ‘African peach’ or ‘pin cushion tree’, N. latifolia is a flowering, sub-Saharan evergreen that grows widely across Central and West Africa and is used by local populations to treat a wide variety of ailments – including epilepsy, malaria, general pain and many infectious diseases………………………. READ ALL AT

http://www.rsc.org/chemistryworld/2013/09/african-plant-natural-source-tramadol

 

tramadol

tramadol hydrocloride

The chemical name for tramadol hydrochloride is (±)cis-2-[(dimethylamino)methyl]-1-(3methoxyphenyl) cyclohexanol hydrochloride

Tramadol (marketed as the hydrochloride salt by Janssen Pharmaceutica as Ultram in the United States, Ralivia by Biovail in Canada and many other companies throughout the world) is a centrally acting synthetic opioid analgesic used to treat moderate to moderately severe pain. The drug has a wide range of applications, including treatment of rheumatoid arthritis, restless legs syndrome, motor neurone disease and fibromyalgia.[citation needed] It was launched and marketed as Tramal by the German pharmaceutical company Grünenthal GmbH in 1977.

Tramadol is a weak μ-opioid receptor agonist, a serotonin releaser and a reuptake inhibitor of norepinephrine. Tramadol is metabolized to O-desmethyltramadol, a significantly more potent μ-opioid agonist. Tramadol and its major metabolite(s) are distinguished from other more potent opioid agonists by relative selectivity for μ-opioid receptors.

Chemistry

Characteristics

Structurally, tramadol closely resembles a stripped down version of codeine. Both codeine and tramadol share the 3-methyl ether group, and both compounds are metabolized along the same hepatic pathway and mechanism to the stronger opioid, phenol agonist analogs. For codeine, this is morphine, and for tramadol, it is the O-desmethyltramadol.

When administered through IV, patients notice very little clinical difference in subjective potency compared to morphine.

Comparison with related substances

Structurally, tapentadol is the closest chemical relative of tramadol in clinical use. Tapentadol is also an opioid, but unlike both tramadol and venlafaxine, tapentadol represents only one stereoisomer and is the weaker of the two, in terms of opioid effect. Both tramadol and venlafaxine are racemic mixtures. Structurally, tapentadol also differs from tramadol in being a phenol, and not an ether. Also, both tramadol and venlafaxine incorporate a cyclohexyl moiety, attached directly to the aromatic, while tapentadol lacks this feature.

Synthesis and stereoisomerism

(1R,2R)-Tramadol   (1S,2S)-Tramadol
(1R,2R)-Tramadol     (1S,2S)-Tramadol
(1R,2S)-Tramadol   (1S,2R)-Tramadol
(1R,2S)-Tramadol     (1S,2R)-Tramadol

The chemical synthesis of tramadol is described in the literature.[62] Tramadol [2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol] has two stereogenic centers at the cyclohexane ring. Thus, 2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol may exist in four different configurational forms:

  • (1R,2R)-isomer
  • (1S,2S)-isomer
  • (1R,2S)-isomer
  • (1S,2R)-isomer

The synthetic pathway leads to the racemate (1:1 mixture) of (1R,2R)-isomer and the (1S,2S)-isomer as the main products. Minor amounts of the racemic mixture of the (1R,2S)-isomer and the (1S,2R)-isomer are formed as well. The isolation of the (1R,2R)-isomer and the (1S,2S)-isomer from the diastereomeric minor racemate [(1R,2S)-isomer and (1S,2R)-isomer] is realized by the recrystallization of the hydrochlorides. The drug tramadol is a racemate of the hydrochlorides of the (1R,2R)-(+)- and the (1S,2S)-(–)-enantiomers. The resolution of the racemate [(1R,2R)-(+)-isomer / (1S,2S)-(–)-isomer] was described[63] employing (R)-(–)- or (S)-(+)-mandelic acid. This process does not find industrial application, since tramadol is used as a racemate, despite known different physiological effects[64] of the (1R,2R)- and (1S,2S)-isomers, because the racemate showed higher analgesic activity than either enantiomer in animals[65] and in humans.[66]

  1. 62…..Pharmaceutical Substances, Axel Kleemann, Jürgen Engel, Bernd Kutscher and Dieter Reichert, 4. ed. (2000) 2 volumes, Thieme-Verlag Stuttgart (Germany), p. 2085 bis 2086, ISBN 978-1-58890-031-9; since 2003 online with biannual actualizations.
  2. 63………Zynovy, Zinovy; Meckler, Harold (2000). “A Practical Procedure for the Resolution of (+)- and (−)-Tramadol”. Organic Process Research & Development 4 (4): 291–294. doi:10.1021/op000281v.
  3. 64……..Burke D, Henderson DJ (April 2002). “Chirality: a blueprint for the future”. British Journal of Anaesthesia 88 (4): 563–76. doi:10.1093/bja/88.4.563. PMID 12066734.
  4. 65…Raffa, R. B.; Friderichs, E.; Reimann, W.; Shank, R. P.; Codd, E. E.; Vaught, J. L.; Jacoby, H. I.; Selve, N. (1993). “Complementary and synergistic antinociceptive interaction between the enantiomers of tramadol”. The Journal of Pharmacology and Experimental Therapeutics 267 (1): 331–340. PMID 8229760.  
  5. 66 ..Grond, S.; Meuser, T.; Zech, D.; Hennig, U.; Lehmann, K. A. (1995). “Analgesic efficacy and safety of tramadol enantiomers in comparison with the racemate: a randomised, double-blind study with gynaecological patients using intravenous patient-controlled analgesia”. Pain 62 (3): 313–320. doi:10.1016/0304-3959(94)00274-I. PMID 8657431.  
  • tramadol hydrochloride, which is (RR, SS)-2-dimethylaminomethyl-1-(3-methoxyphenyl)cyclohexanol hydrochloride (trans), from a mixture of its (RS, SR) (cis) and trans bases, and to an improved process for the preparation of tramadol (base) monohydrate, sometimes used as an intermediate in the preparation of tramadol hydrochloride.
  • Tramadol is a well-established drug disclosed in US patent specification no. 3 652 589, which is used in the form of its hydrochloride salt as a non-narcotic analgesic drug. Tramadol is the pharmacologically active trans isomer of 2-dimethylaminomethyl-1-(3-methoxyphenyl)cyclohexanol, as opposed to the corresponding cis isomer, namely, (RS, SR)-2-dimethylaminomethyl-1-(3-methoxyphenyl)cyclohexanol.
  • Various processes for the synthesis of tramadol hydrochloride have been described in the prior art. For example, US 3 652 589 and British patent specification no. 992 399 describe the preparation of tramadol hydrochloride. In this method, Grignard reaction of 2-dimethylaminomethyl cyclohexanone (Mannich base) with metabromo-anisole gives an oily mixture of tramadol and the corresponding cis isomer, along with Grignard impurities. This oily reaction mixture is subjected to high vacuum distillation at high temperature to give both the geometric isomers of the product base as an oil. This oil, on acidification with hydrogen chloride gas, furnishes insufficiently pure tramadol hydrochloride as a solid. This must then be purified, by using a halogenated solvent and 1,4-dioxane, to give sufficiently pure tramadol hydrochloride. The main drawback of this process is the use of large quantities of 1,4-dioxane and the need for multiple crystallizations to get sufficiently pure trans isomer hydrochloride (Scheme – 1).
  • The use of dioxane for the separation of tramadol hydrochloride from the corresponding cis isomer has many disadvantages, such as safety hazards by potentially forming explosive peroxides, and it is also a category 1 carcinogen (Kirk and Othmer, 3rd edition, 17, 48). Toxicological studies of dioxane show side effects such as CNS depression, and necrosis of the liver and kidneys. Furthermore, the content of dioxane in the final tramadol hydrochloride has been strictly limited; for example, the German Drug Codex (Deutscher Arzneimittel Codex, DAC (1991)) restricts the level of dioxane in tramadol hydrochloride to 0.5 parts per million (ppm).

    Figure 00020001
  • In another process, disclosed in US patent specification no. 5 414 129, the purification and separation of tramadol hydrochloride is undertaken from a reaction mixture containing the trans and cis isomers, and Grignard reaction side products, in which the reaction mixture is diluted in isopropyl alcohol and acidified with gaseous hydrogen chloride to yield (trans) tramadol hydrochloride (97.8%) and its cis isomer (2.2%), which is itself crystallized twice with isopropyl alcohol to give pure (trans) tramadol hydrochloride (Scheme – 2). This process relies on the use of multiple solvents to separate the isomers (ie butylacetate, 1-butanol, 1-pentanol, primary amyl alcohol mixture, 1-hexanol, cyclohexanol, 1-octanol, 2-ethylhexanol and anisole). The main drawback of this process is therefore in using high boiling solvents; furthermore, the yields of tramadol hydrochloride are still relatively low and the yield of the corresponding cis hydrochloride is relatively high in most cases.

    Figure 00030001
  • PCT patent specification no. WO 99/03820 describes a method of preparation of tramadol (base) monohydrate, which involves the reaction of Mannich base with metabromo-anisole (Grignard reaction) to furnish a mixture of tramadol base with its corresponding cis isomer and Grignard impurities. This, on treatment with an equimolar quantity of water and cooling to 0 to -5°C, gives a mixture of tramadol (base) monohydrate with the corresponding cis isomer (crude). It is further purified with ethyl acetate to furnish pure (trans) tramadol (base) monohydrate, which is again treated with hydrochloric acid in the presence of a suitable solvent to give its hydrochloride salt (Scheme – 2). The drawback of this method is that, to get pure (trans) tramadol hydrochloride, first is prepared pure (trans) tramadol (base) monohydrate, involving a two-step process, and this is then converted to its hydrochloride salt. The overall yield is low because of the multiple steps and tedious process involved.
  • More recently, a process for the separation of tramadol hydrochloride from a mixture with its cis isomer, using an electrophilic reagent, has been described in US patent specification no. 5 874 620. The mixture of tramadol hydrochloride with the corresponding cis isomer is reacted with an electrophilic reagent, such as acetic anhydride, thionyl chloride or sodium azide, using an appropriate solvent (dimethylformamide or chlorobenzene) to furnish a mixture of tramadol hydrochloride (93.3 to 98.6%) with the corresponding cis isomer (1.4 to 6.66%), (Scheme – 3). The product thus obtained is further purified in isopropyl alcohol to give pure (trans) tramadol hydrochloride. However, the drawback of this process is that a mixture of tramadol base with its cis isomer is first converted into the hydrochloride salts, and this is further reacted with toxic, hazardous and expensive electrophilic reagents to get semi-pure (trans) tramadol hydrochloride. The content of the cis isomer is sufficiently high to require further purification, and this therefore results in a lower overall yield.

 

 

Synthesis and stereoisomerism
The chemical synthesis of tramadol is described in the literature. Tramadol [2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol] has two stereogenic centers at the cyclohexane ring. Thus, 2-(dimethylaminomethyl)-1-(3-methoxyphenyl)cyclohexanol may exist in four different configurational forms:
  • (1R,2R)-isomer
  • (1S,2S)-isomer
  • (1R,2S)-isomer
  • (1S,2R)-isomer

 

The synthetic pathway leads to the racemate (1:1 mixture) of (1R,2R)-isomer and the (1S,2S)-isomer as the main products. Minor amounts of the racemic mixture of the (1R,2S)-isomer and the (1S,2R)-isomer are formed as well. The isolation of the (1R,2R)-isomer and the (1S,2S)-isomer from the diastereomeric minor racemate [(1R,2S)-isomer and (1S,2R)-isomer] is realized by the recrystallization of the hydrochlorides. The drug tramadol is a racemate of the hydrochlorides of the (1R,2R)-(+)- and the (1S,2S)-(–)-enantiomers. The resolution of the racemate [(1R,2R)-(+)-isomer / (1S,2S)-(–)-isomer] was described[62] employing (R)-(–)- or (S)-(+)-mandelic acid. This process does not find industrial application, since tramadol is used as a racemate, despite known different physiological effects of the (1R,2R)- and (1S,2S)-isomers, because the racemate showed higher analgesic activity than either enantiomer in animals and in humans.
……………………………………………………
EP 1346978 A1
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The first generic version of the oral chemotherapy drug Xeloda (capecitabine) has been approved by the U.S. Food and Drug Administration to treat cancers of the colon/rectum or breast

 cancer  Comments Off on The first generic version of the oral chemotherapy drug Xeloda (capecitabine) has been approved by the U.S. Food and Drug Administration to treat cancers of the colon/rectum or breast
Sep 172013
 

capecitabine

154361-50-9

  • R-340, Ro-09-1978, Xeloda

pentyl [1-(3,4-dihydroxy-5-methyltetrahydrofuran-2-yl)-5-fluoro-2-oxo-1H-pyrimidin-4-yl]carbamate

MONDAY Sept. 16, 2013 — The first generic version of the oral chemotherapy drug Xeloda (capecitabine) has been approved by the U.S. Food and Drug Administration to treat cancers of the colon/rectum or breast, the agency said Monday in a news release.

This year, an estimated 142,820 people will be diagnosed with cancer of the colon/rectum, and 50,830 are predicted to die from the disease, the FDA said, citing the U.S. National Cancer Institute. An estimated 232,340 women will be diagnosed with cancer of the breast this year, and some 39,620 will die from it.

The most common side effects of the drug are diarrhea, vomiting; pain, redness, swelling or sores in the mouth; fever and infection, the FDA said.

The agency stressed that approved generics have the same high quality and strength as their brand-name counterparts.

License to produce the generic drug was given to Israel-based Teva Pharmaceuticals. The brand name drug is produced by the Swiss pharma firm Roche.

Capecitabine (INN) /keɪpˈsaɪtəbiːn/ (Xeloda, Roche) is an orally-administeredchemotherapeutic agent used in the treatment of metastatic breast andcolorectal cancers. Capecitabine is a prodrug, that is enzymatically converted to 5-fluorouracil in the tumor, where it inhibits DNA synthesis and slows growth of tumor tissue. The activation of capecitabine follows a pathway with three enzymatic steps and two intermediary metabolites, 5′-deoxy-5-fluorocytidine (5′-DFCR) and 5′-deoxy-5-fluorouridine (5′-DFUR), to form 5-fluorouracil

Indications

Capecitabine is FDA-approved for:

  • Adjuvant in colorectal cancer Stage III Dukes’ C – used as first-line monotherapy.
  • Metastatic colorectal cancer – used as first-line monotherapy, if appropriate.
  • Metastatic breast cancer – used in combination with docetaxel, after failure of anthracycline-based treatment. Also as monotherapy, if the patient has failed paclitaxel-based treatment, and if anthracycline-based treatment has either failed or cannot be continued for other reasons (i.e., the patient has already received the maximum lifetime dose of an anthracycline).

In the UK, capecitabine is approved by the National Institute for Health and Clinical Excellence (NICE) for colon and colorectal cancer, and locally advanced or metastatic breast cancer.[1] On March 29, 2007, the European Commission approved Capecitabine, in combination with platinum-based therapy (with or without epirubicin), for the first-line treatment of advanced stomach cancer.

Capecitabine is a cancer chemotherapeutic agent that interferes with the growth of cancer cells and slows their distribution in the body. Capecitabine is used to treat breast cancer and colon or rectum cancer that has spread to other parts of the body.

Formulation

Capecitabine (as brand-name Xeloda) is available in light peach 150 mg tablets and peach 500 mg tablets.

 

 

WO2009066892A1

Capecitabine is an orally-administered anticancer agent widely used in the treatment of metastatic breast and colorectal cancers. Capecitabine is a ribofuranose-based nucleoside, and has the sterochemical structure of a ribofuranose having an β-oriented 5-fluorocytosine moiety at C-I position.

US Patent Nos. 5,472,949 and 5,453,497 disclose a method for preparing capecitabine by glycosylating tri-O-acetyl-5-deoxy-β-D-ribofuranose of formula I using 5-fluorocytosine to obtain cytidine of formula II; and carbamoylating and hydrolyzing the resulting compound, as shown in Reaction Scheme 1 :

Reaction Scheme 1

Figure imgf000002_0001

1

The compound of formula I employed as an intermediate in Reaction

Scheme 1 is the isomer having a β-oriented acetyl group at the 1 -position, for the reason that 5-fluorocytosine is more reactive toward the β-isomer than the α-isomer in the glycosylation reaction due to the occurrence of a significant neighboring group participation effect which takes place when the protecting group of the 2-hydroxy group is acyl.

Accordingly, β-oriented tri-O-acetyl-5-deoxy-β-D-ribofuranose (formula

I) has been regarded in the conventional art to the essential intermediate for the preparation of capecitabine. However, such a reaction gives a mixture of β- and α-isomers from which cytidine (formula II) must be isolated by an uneconomical step.

Meanwhile, US Patent No. 4,340,729 teaches a method for obtaining capecitabine by the procedure shown in Reaction Scheme 2, which comprises hydrolyzing 1-methyl-acetonide of formula III to obtain a triol of formula IV; acetylating the compound of formula IV using anhydrous acetic anhydride in pyridine to obtain a β-/α-anomeric mixture of tri-O-acetyl-5-deoxy-D-ribofuranose of formula V; conducting vacuum distillation to purify the β-/α-anomeric mixture; and isolating the β-anomer of formula I therefrom:

Reaction Scheme 2

Figure imgf000003_0001

III IV

However, the above method is also hampered by the requirement to perform an uneconomical and complicated recrystallization steps for isolating the β-anomer from the mixture of β-/α-anomers of formula V, which leads to a low yield of only about 35% to 40% (Guangyi Wang et al., J. Med. Chem., 2000, vol. 43, 2566-2574; Pothukuchi Sairam et al., Carbohydrate Research, 2003, vol. 338, 303-306; Xiangshu Fei et al., Nuclear Medicine and Biology, 2004, vol. 31, 1033-1041; and Henry M. Kissman et al., J. Am. Chem. Soc, 1957, vol. 79, 5534-5540).

Further, US Patent No. 5,476,932 discloses a method for preparing capecitabine by subjecting 5′-deoxy-5-fluorocytidine of formula VI to a reaction with pentylchloroformate to obtain the compound of formula VII having the amino group and the 2-,3-hydroxy groups protected with C5Hi1CO2 groups; and removing the hydroxy-protecting groups from the resulting compound, as shown in Reaction Scheme 3 :

Reaction Scheme 3

Figure imgf000004_0001

Vl VII 1

However, this method suffers from a high manufacturing cost and also requires several complicated steps for preparing the 5′-deoxy-5-fluorocytidine of formula VI: protecting the 2-,3-hydroxy groups; conducting a reaction thereof with 5-fluorocytosine; and deprotecting the 2-,3-hydroxy groups.

Accordingly, the present inventors have endeavored to develop an efficient method for preparing capecitabine, and have unexpectedly found an efficient, novel method for preparing highly pure capecitabine using a trialkyl carbonate intermediate, which does not require the uneconomical β-anomer isolation steps.

synthesis

WO2010065586A2

more info and description

Aspects of the present invention relate to capecitabine and processes for the preparation thereof.

The drug compound having the adopted name “capecitabine” has a chemical name 5′-deoxy-5-fluoro-N-[(pentyloxy) carbonyl] cytidine and has structural formula I.

H

Figure imgf000002_0001

OH OH I

This compound is a fluoropyrimidine carbamate with antineoplastic activity. The commercial product XELODA™ tablets from Roche Pharmaceuticals contains either 150 or 500 mg of capecitabine as the active ingredient.

U.S. Patent No. 4,966,891 describes capecitabine generically and a process for the preparation thereof. It also describes pharmaceutical compositions, and methods of treating of sarcoma and fibrosarcoma. This patent also discloses the use of ethyl acetate for recrystallization of capecitabine. The overall process is summarized in Scheme I.

Figure imgf000002_0002

Scheme I

U.S. Patent No. 5,453,497 discloses a process for producing capecitabine that comprises: coupling of th-O-acetyl-5-deoxy-β-D-hbofuranose with 5- fluorocytosine to obtain 2′,3′-di-O-acetyl-5′-deoxy-5-fluorocytidine; acylating a 2′, 3′- di-O-acetyl-5′-deoxy-5-fluorocytidine with n-pentyl chloroformate to form 5′-deoxy- 2′,3′-di-O-alkylcarbonyl-5-fluoro-N-alkyloxycarbonyl cytidine, and deacylating the 2′ and 3′ positions of the carbohydrate moiety to form capecitabine. The overall process is summarized in Scheme II.

Figure imgf000003_0001

Capecitabine

Scheme Il

The preparation of capecitabine is also disclosed by N. Shimma et al., “The Design and Synthesis of a New Tumor-Selective Fluoropyrimidine Carbamate, Capecitabine,” Bioorganic & Medicinal Chemistry, Vol. 8, pp. 1697-1706 (2000). U.S. Patent No. 7,365,188 discloses a process for the production of capecitabine, comprising reacting 5-fluorocytosine with a first silylating agent in the presence of an acid catalyst under conditions sufficient to produce a first silylated compound; reacting the first silylated compound with 2,3-diprotected-5- deoxy-furanoside to produce a coupled product; reacting the coupled product with a second silylating agent to produce a second silylated product; acylating the second silylated product to produce an acylated product; and selectively removing the silyl moiety and hydroxyl protecting groups to produce capecitabine. The overall process is summarized in Scheme III. te

Figure imgf000004_0001

R: hydrocarbyl

Figure imgf000004_0002

Scheme III

Further, this patent discloses crystallization of capecitabine, using a solvent mixture of ethyl acetate and n-heptane. International Application Publication No. WO 2005/080351 A1 describes a process for the preparation of capecitabine that involves the refluxing N4– pentyloxycarbonyl-5-fluorocytosine with trimethylsiloxane, hexamethyl disilazanyl, or sodium iodide with trimethyl chlorosilane in anhydrous acetonitrile, dichloromethane, or toluene, and 5-deoxy-1 ,2,3-tri-O-acetyl-D-ribofuranose, followed by hydrolysis using ammonia/methanol to give capecitabine. The overall process is summarized in Scheme IV.

Figure imgf000004_0003

Scheme IV

International Application Publication No. WO 2007/009303 A1 discloses a method of synthesis for capecitabine, comprising reacting 5′-deoxy-5- fluorocytidine using double (trichloromethyl) carbonate in an inert organic solvent and organic alkali to introduce a protective lactone ring to the hydroxyl of the saccharide moiety; reacting the obtained compound with chloroformate in organic alkali; followed by selective hydrolysis of the sugar component hydrolytic group using an inorganic base to give capecitabine. The overall process is summarized in Scheme V.

Figure imgf000005_0001

Scheme V

Even though all the above documents collectively disclose various processes for the preparation of capecitabine, removal of process-related impurities in the final product has not been adequately addressed. Impurities in any active pharmaceutical ingredient (API) are undesirable, and, in extreme cases, might even be harmful to a patient. Furthermore, the existence of undesired as well as unknown impurities reduces the bioavailability of the API in pharmaceutical products and often decreases the stability and shelf life of a pharmaceutical dosage form.

nmr

1H NMR(CD3OD) δ 0.91(3H5 t), 1.36~1.40(4H, m), 1.41(3H, d), 1.68~1.73(2H, m), 3.72(1H, dd), 4.08(1H, dd), 4.13~4.21(3H, m), 5.7O(1H, s), 7.96(1H, d)

 

  • The acetylation of 5′-deoxy-5-fluorocytidine (I) with acetic anhydride in dry pyridine gives 2′,3′-di-O-acetyl-5′-deoxy-5-fluorocytidine (II), which is condensed with pentyl chloroformate (III) by means of pyridine in dichromethane yielding 2′,3′-di-O-acetyl-5′-deoxy-5-fluoro-N4-(pentyloxycarbonyl)cytidine (IV). Finally, this compound is deacetylated with NaOH in dichloromethane/water. The diacetylated cytidine (II) can also be obtained by condensation of 5-fluorocytosine (V) with 1,2,3-tri-O-acetyl-5-deoxy-beta-D-ribofuranose (VI) by means of trimethylchlorosilane in acetonitrile or HMDS and SnCl4 in dichloromethane..
    • EP 602454, JP 94211891, US 5472949.
      • Capecitabine. Drugs Fut 1996, 21, 4, 358,
        • Bioorg Med Chem Lett2000,8,(7):1697,
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Novartis’ Breakthrough Therapy For A Rare Muscle-Wasting Disease

 drugs  Comments Off on Novartis’ Breakthrough Therapy For A Rare Muscle-Wasting Disease
Sep 162013
 

 

 

On August 20, 2013, Novartis announced in a press release that the FDA had granted breakthrough therapy designation to its experimental agent BYM338 (bimagrumab) for treatment of the rare muscle wasting disease sporadic inclusion body myositis (sIBM).

sIBM is a rare–but increasingly prevalent–disease. It is the most common cause of inflammatory myopathy in people over 50. sIBM has a yearly incidence of 2 to 5 per million adults with a peak at ages 50 to 70, with male predominance. Muscle wasting caused by sIBM is superimposed upon the sarcopenia (degenerative loss of muscle mass) that typically occurs with aging.

read all

http://biopharmconsortium.com/blog/2013/09/04/novartis-breakthrough-therapy-rare-muscle-wasting-disease/

 

bimagrumab

immunoglobulin G1-lambda2, anti-[Homo sapiens ACVR2B (activin
A receptor type IIB, ActR-IIB)], Homo sapiens monoclonal antibody;
gamma1 heavy chain (1-445) [Homo sapiens VH (IGHV1-2*02
(91.80%) -(IGHD)-IGHJ5*01 [8.8.8] (1-115) -IGHG1*03 (CH1 (116-
213), hinge (214-228), CH2 L1.3>A (232), L1.2>A (233) (229-338),
CH3 (339-443), CHS (444-445)) (116-445)], (218-216′)-disulfide with
lambda light chain (1′-217′) [Homo sapiens V-LAMBDA (IGLV2-
23*02 (90.90%) -IGLJ2*01) [9.3.11] (1′-111′) -IGLC2*01 (112′-217′)];
dimer (224-224”:227-227”)-bisdisulfide
myostatin inhibitor
bimagrumab immunoglobuline G1-lambda2, anti-[Homo sapiens ACVR2B
(récepteur type IIB de l’activine A, ActR-IIB)], Homo sapiens
anticorps monoclonal;
chaîne lourde gamma1 (1-445) [Homo sapiens VH (IGHV1-2*02
(91.80%) -(IGHD)-IGHJ5*01 [8.8.8] (1-115) -IGHG1*03 (CH1 (116-
213), charnière (214-228), CH2 L1.3>A (232), L1.2>A (233) (229-
338), CH3 (339-443), CHS (444-445)) (116-445)], (218-216′)-
disulfure avec la chaîne légère lambda (1′-217′) [Homo sapiens
V-LAMBDA (IGLV2-23*02 (90.90%) -IGLJ2*01) [9.3.11] (1′-111′) –
IGLC2*01 (112′-217′)]; dimère (224-224”:227-227”)-bisdisulfure
inhibiteur de la myostatine

inmunoglobulina G1-lambda2, anti-[Homo sapiens ACVR2B
(receptor tipo IIB de la activina A, ActR-IIB)], anticuerpo monoclonal
de Homo sapiens;
cadena pesada gamma1 (1-445) [Homo sapiens VH (IGHV1-2*02
(91.80%) -(IGHD)-IGHJ5*01 [8.8.8] (1-115) -IGHG1*03 (CH1 (116-
213), bisagra (214-228), CH2 L1.3>A (232), L1.2>A (233) (229-338),
CH3 (339-443), CHS (444-445)) (116-445)], (218-216′)-disulfuro con
la cadena ligera lambda (1′-217′) [Homo sapiens V-LAMBDA
(IGLV2-23*02 (90.90%) -IGLJ2*01) [9.3.11] (1′-111′) -IGLC2*01
(112′-217′)]; dímero (224-224”:227-227”)-bisdisulfuro
inhibidor de la miostatina
1356922-05-8

Heavy chain / Chaîne lourde / Cadena pesada
QVQLVQSGAE VKKPGASVKV SCKASGYTFT SSYINWVRQA PGQGLEWMGT 50
INPVSGSTSY AQKFQGRVTM TRDTSISTAY MELSRLRSDD TAVYYCARGG 100
WFDYWGQGTL VTVSSASTKG PSVFPLAPSS KSTSGGTAAL GCLVKDYFPE 150
PVTVSWNSGA LTSGVHTFPA VLQSSGLYSL SSVVTVPSSS LGTQTYICNV 200
NHKPSNTKVD KRVEPKSCDK THTCPPCPAP EAAGGPSVFL FPPKPKDTLM 250
ISRTPEVTCV VVDVSHEDPE VKFNWYVDGV EVHNAKTKPR EEQYNSTYRV 300
VSVLTVLHQD WLNGKEYKCK VSNKALPAPI EKTISKAKGQ PREPQVYTLP 350
PSREEMTKNQ VSLTCLVKGF YPSDIAVEWE SNGQPENNYK TTPPVLDSDG 400
SFFLYSKLTV DKSRWQQGNV FSCSVMHEAL HNHYTQKSLS LSPGK 445
Light chain / Chaîne légère / Cadena ligera
QSALTQPASV SGSPGQSITI SCTGTSSDVG SYNYVNWYQQ HPGKAPKLMI 50
YGVSKRPSGV SNRFSGSKSG NTASLTISGL QAEDEADYYC GTFAGGSYYG 100
VFGGGTKLTV LGQPKAAPSV TLFPPSSEEL QANKATLVCL ISDFYPGAVT 150
VAWKADSSPV KAGVETTTPS KQSNNKYAAS SYLSLTPEQW KSHRSYSCQV 200
THEGSTVEKT VAPTECS 217
Disulfide bridges location / Position des ponts disulfure / Posiciones de los puentes disulfuro
Intra-H 22-96 142-198 259-319 365-423
22”-96” 142”-198” 259”-319” 365”-423”
Intra-L 22′-90′ 139′-198′
22”’-90”’ 139”’-198”’
Inter-H-L 218-216′ 218”-216”’
Inter-H-H 224-224” 227-227”
N-glycosylation sites / Sites de N-glycosylation / Posiciones de N-glicosilación
H CH2 N84.4

Bimagrumab

http://www.who.int/medicines/publications/druginformation/innlists/PL108_Final.pdf

Novartis announced that the US Food and Drug Administration (FDA) has granted breakthrough therapy designation to BYM338 for sporadic inclusion body myositis (sIBM). This designation is based on the results of a phase 2 proof-of-concept study that showed BYM338 substantially benefited patients with sIBM compared to placebo.

read all at

http://www.dddmag.com/news/2013/08/novartis-muscle-drug-gets-breakthrough-status?et_cid=3433957&et_rid=523035093&type=headline

Novartis receives FDA breakthrough therapy designation for BYM338 (bimagrumab) for sporadic inclusion body myositis (sIBM)

•    Designation highlights potential of BYM338 to address an unmet medical need in a serious disease
•    If approved, BYM338 has the potential to be the first treatment for sIBM patients
•    BYM338 is the third Novartis investigational treatment this year to receive a breakthrough therapy designation by the FDA, highlighting Novartis’ leadership in the industry in breakthrough therapy designations

Bimagrumab (BYM338) is a human monoclonal antibody developed by Novartis to treat pathological muscle loss and weakness. On August 20, 2013 it was announced that bimagrumab was granted breakthrough therapy designation for sporadic inclusion body myositis(sIBM) by US Food and Drug Administration.[1]

 

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LEVOCETRIZINE

 drugs  Comments Off on LEVOCETRIZINE
Sep 152013
 

File:Levocetirizine structure 2.svg
LEVOCETRIZINE

Levocetirizine (as levocetirizine dihydrochloride) is a third-generation non-sedative antihistamine, developed from the second-generation antihistamine cetirizine. Chemically, levocetirizine is the active enantiomer of cetirizine. It is the R-enantiomer of the cetirizine racemate. Levocetirizine works by blocking histamine receptors. It does not prevent the actual release of histamine from mast cells, but prevents it binding to its receptors. This in turn prevents the release of other allergy chemicals and increased blood supply to the area, and provides relief from the typical symptoms of hay fever.
The manufacturers claim it to be more effective with fewer side effects than the second-generation drugs; however, there have been no published studies supporting this assertion, although other studies have concluded it may be more effective.[1]

History and formulations

Levocetirizine was first launched in 2001 by Belgian pharmaceutical company UCB. It is sold under the brand name Xyzal/ˈzaɪzæl/ in Australia, Czech Republic, Austria, Finland, France, Ireland, Netherlands, Portugal, Romania, Taiwan, Turkey, United States, South Africa and UK; Xuzal in Mexico; Xusal in Germany; and Xozal in Greece. In Hungary it is marketed by Richter Gedeon under the Zilola brand name.

In India, levocetirizine is marketed by GlaxoSmithKline under the brand name Vozet and Xyzal. On May 25, 2007, theUnited States Food and Drug Administration approved Xyzal, where it is co-marketed by Sanofi-Aventis. Torrent Pharma launched UVNIL in rural market of India. It is also available as LEZYNCET 5 mg tablets through Unichem in India. In India, generic name of Lev-Cit 5 mg is manufactured by VIP Pharmaceuticals. Also marketed in India by Croslands (Ranbaxy Laboratories Ltd.) under the brand name Teczine. In Brazil it is marketed under the brand name ‘Zyxem’ by Farmalab. It is marketed in Egypt by BORG Pharma under the brand name ‘Xaltec’, Allear by western pharmaceuticals and levcet by marcryl.
In Pakistan levocetirizine was first launched in liquid formulation by Novartis Consumer Health Division by the name of T-Day Syrup. It is available as 5 mg-strength tablets and a 0.5 mg/mL oral solution. In Pakistan levocetirizine is available in liquid formulation as well with the name of OCITRA and T-Day 2.5 mg/5 mL. In Bangladesh levocetirizine is available in 5 mg tablet & 2.5 mg/5 mL oral liquid formulation with the brand name of Alcet marketed by Healthcare Pharmaceuticals and Seasonix marketed by Incepta Pharmaceuticals. In Nepal levocetirizine is available in 5 mg tablet with brand name ofCurin manufactured by Beximco Pharma.[2]

Side effects

levocetirizine is called a non-sedating antihistamine as it does not enter the brain in significant amounts, and is therefore unlikely to cause drowsiness. However, some people may experience some slight sleepiness, headache, mouth dryness,lightheadedness, vision problems (mainly blurred vision), palpitations and fatigue.[3]

Research

latest research shows levocetirizine reduces asthma attacks by 70% in children.[4]

Availability]

The drug is currently available by prescription in the United States. Although the drug was only authorized by the FDA on 25 May 2007, it was already available in most European countries. Like many new drugs it entered the market at a higher price than currently available third and second generation antihistamines. In India, one form of the drug is available as Crohist MK tablets and syrup, a formulation of levocetirizine hydrochloride and montelukast. In India, Crohist MK is a Schedule ‘H’ drug and may only be prescribed by a registered medical practitioner. In Finland, the drug is sold over-the-counter.

Different brands (Actavis, Glenmark, UCB) Levocetirizine tablets and oral solution.

  1. ^ Grant, JA; Riethuisen, JM; Moulaert, B; DeVos, C; Gamalero, C.; Descalzi, D.; Folli, C.; Passalacqua, G. et al. (2002-02). “A double-blind, randomized, single-dose, crossover comparison of levocetirizine with ebastine, fexofenadine, loratadine, mizolastine, and placebo: suppression of histamine-induced wheal-and-flare response during 24 hours in healthy male subjects.”. Ann Allergy Asthma Immunol 88 (2): 190–197. doi:10.1016/S1081-1206(10)61995-3. PMID 11868924.
  2. ^ http://www.beximco-pharma.com/allergic-disorders/147-curin.html
  3. ^ XOZAL technical specifications booklet.
  4. ^ Pasquali, M; Baiardini, I; Rogkakou, A; Riccio, AM; Gamalero, C; Descalzi, D; Folli, C; Passalacqua, G et al. (2006-09).“Levocetirizine in persistent allergic rhinitis and asthma: effects on symptoms, quality of life and inflammatory parameters.”.Clinical & Experimental Allergy 36 (9): 1161–7. doi:10.1111/j.1365-2222.2006.02548.x. PMID 16961716.

xyzal_structure.png
Figure 1-The chemical structure of Xyzal
BACKGROUND

Cetirizine, chemically [2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid is an antihistamine non-sedating type histamine H1-receptor antagonist, indicated for relief of symptoms associated with seasonal allergic rhinitis, perennial allergic rhinitis and related diseases.
Figure US20110184174A1-20110728-C00003
U.S. Pat. No. 4,525,358 and its equivalent EP 58146 disclose cetirizine and its pharmaceutically acceptable salts. The process for the synthesis of cetirizine comprises condensation of 1-[(4-chlorophenyl)-phenylmethyl]piperazine with 2-chloroethoxy acetamide to obtain 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]-ethoxy acetamide which on hydrolysis gives cetirizine.
It was found later that the pharmacological activity resides primarily in (R)-isomer or (−) form known as levocetirizine. GB 2225321 describes a process for the preparation of the dextro and levorotatory isomers of cetirizine comprising hydrolysis of 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazynyl]-ethoxy acetonitrile.
Figure US20110184174A1-20110728-C00004
(−)-1-[(4-chlorophenyl)-phenylmethyl]piperazine is a very important intermediate in the synthesis of levocetirizine. U.S. Pat. No. 5,478,941 discloses a process for the synthesis of (−)-1-[(4-chlorophenyl)-phenylmethyl]piperazine involving hydrolyzing 1-[(4-chlorophenyl)-phenylmethyl]-4-(4-methylphenyl)sulfonyl piperazine with hydrobromic acid in the presence of 4-hydroxybenzoic acid.
Figure US20110184174A1-20110728-C00005
The alternative routes of synthesis of (−)-1-[(4-chlorophenyl)-phenylmethyl]piperazine disclosed in the prior art involve the use of bis chloro ethylamine which is carcinogenic in nature.
Levocetirizine is a highly-potent non-sedating anti-allergic agent. Hence, there are continuous attempts to develop new processes for the synthesis of levocetirizine and its intermediates. The present invention describes a new process for the preparation of the key intermediate (−)-1-[(4-chlorophenyl)-phenylmethyl]piperazine.
Levorotatory [2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid, also known by the generic name of levocetirizine, has proven useful as a therapeutic agent for the treatment of allergic disease.
Levocetirizine and its salts including its dihydrochloride are known and are effective in the treatment of allergies, including but not limited to, chronic and acute allergic rhinitis, allergic conjunctivitis, pruritus, urticaria and the like. Levocetirizine belongs to the second generation of H1 histamine receptor antagonists, which are believed to offer significant advantages over first generation compounds. Studies have shown that levocetirizine provides safe and effective symptomatic relief of seasonal allergies. Levocetirizine is used also for treating chronic idiopathic urticaria.
GB 2,225,321 describes a process for the preparation of cetirizine in the levorotatory form, dextrorotatory form or a mixture thereof comprising the hydrolysis of enantiomerically pure [2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetonitrile. Hydrolysis takes place in aqueous, alcoholic or aqueous-alcoholic medium by a base or by an acid; the acid thus obtained is converted to its dihydrochloride. Optically active starting material 1-[(4-chlorophenyl)phenylmethyl]piperazine is obtained by resolution of the corresponding racemic compound, preferably by conversion to its diastereoisomeric salt with tartaric acid. The yield of resolution is rather low, namely only 12.7%. The obtained optically active intermediate is further converted with chloroethoxyacetonitrile in 69% yield.
EP 0 617 028 and EP 0 955 295 disclose a process for the preparation of optically active 1-[(4-chlorophenyl)phenylmethyl]piperazine and its conversion to cetirizine in the levorotatory form or dextrorotatory form or to derivative thereof. The process for the preparation is shown in the following scheme:
Figure US08049011-20111101-C00001
The drawback of the disclosed reaction is that it requires protection of N,N-bis(2-haloethyl)amine, and consequently deprotection of the intermediate obtained.
Preparation of Cetirizine in its Levorotatory Form Proceeds in most known syntheses from enantiomerically pure 1-[(4-chlorophenyl)phenylmethyl]piperazine. Consequently it appears to be very desirable to provide new routes to prepare the enantiomers thereof with improved optical purity and good yields.
Polymorphic form I of crystalline levorotatory dihydrochloride salt of cetirizine and amorphous form thereof are disclosed in WO 2004/050647 and WO 2004/065360. Crystalline form is prepared by crystallization from ketone-containing solvent, such as acetone, methyl ethyl ketone, dimethylketone, 2-pentanone and mixtures thereof. Amorphous form was prepared by solvent evaporation.
There still exists a need for an efficient synthesis of levocetirizine, new intermediates used in the process, suitable for large-scale production.
Synthesis of Xyzal:
Figure 2 displays the synthesis of Cetirizine (Zyrtec). Levocetirizine, the R-enantiomer of cetirizine, is then formed from pyroglutamate salts in a synthesis that does not have attainable details.

REAL_ceterizine_synthesis.png
(Figure 2)

The synthesis of Cetrizine begins by reducing molecule 33 with a catecholborane. This reaction yields molecule 34, which is then treated with tetraflouroboric acid and reacted with an amine, compound 35. In order to remove the chromium group, the compound is refluxed in pyridine and undergoes an acid hydrolysis. This results in a yield of cetrizine.

Identification of all chirality centers:
Stereogenic centers are carbon atoms that are bonded to 4 groups. Tetrahedral stereogenic centers are stereogenic centers that are not only bonded to 4 groups but are more importantly bonded to 4 different groups. If a molecule contains 1 tetrahedral stereogenic center it is said to be chiral (nonsuperimposable on its mirror image).If a given compound contains more than 1 stereogenic center it must be further analyzed to determine if it is chiral or achiral(superimosable on its mirror image). The carbon atom bonded to the phenyl groups was found to be a tetrahedral stereogenic center. Therefore,xyzal,which was found to contain only 1 tetrahedral stereogenic center is generally considered a chiral compound because it meets the requirements of chirality and does not have a plane of symmetry that superimposes one half of the molecule on the other and is not super imposable on its mirror image.

Spectral data for Xyzal (IR and NMR):
cetirizine_IR.png
xyzal_nmr.png

 

– See more at: http://worlddrugtracker.blogspot.in/#sthash.6Ndn04WU.dpuf

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The strategy of enantiomer patents of drugs

 Uncategorized  Comments Off on The strategy of enantiomer patents of drugs
Sep 152013
 

The strategy of enantiomer patents of drugs

Drug Discovery Today, Volume 15, Issues 5–6, March 2010, Pages 163-170

http://www.sciencedirect.com/science/article/pii/S1359644610000310

  • Organic Chemistry, Institute of Chemistry, The Hebrew University of Jerusalem, Philadelphia Building 201/205, Edmond J. Safra Campus, Jerusalem 91904, Israel

Enantiomer patents (ENPTs), constituents of chiral switches, claim single enantiomers of chiral drugs previously claimed as racemates. In this article, the strategy of ENPTs and recent court decisions and trends in case law worldwide are highlighted. ENPTs are challenged frequently (e.g. anticipation, obviousness, double patenting and insufficient disclosure), even though the novelty of enantiomers is not destroyed by the description of racemates. For establishing inventiveness (nonobviousness), the description in ENPTs should include superior pharmacological and/or pharmaceutical properties of enantiomer vis-á-visracemate, above the expected 2:1 ratio. ENPTs were ‘obvious-to-try’ (unless taught away) since the mid-1980s. General concern about evergreening by ENPTs is not justified. ENPTs should be evaluated on a case-by-case basis. ENPT litigations are especially susceptible to settlements.

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