Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2000-11-02
2002-03-26
Weddington, Kevin E. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C514S560000, C514S895000
Reexamination Certificate
active
06362219
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the formulation of artemisinin derivative (Dihydroartemisinin) for the emergent treatment and control of uncomplicated/severe complicated/cerebral and multi-drug resistance malaria. Dihydroartemisinin is a lactol derivative of artemisinin (Qinghaosu), the principle antimalarial constituent of the plant
Artemisia annua.
BACKGROUND OF THE INVENTION
Malaria is caused by blood protozoa of the genus Plasmodium. The four species of Plasmodium that infect humans are
Plasmodium vivax, P. malariae, P. ovale
and
P. falciparum
, the last one is responsible for producing severe complications and cerebral malaria, which can cause the patient to lapse into a coma and ultimately leads to death. In many parts of the world, strains of
P. falciparum
have emerged which are resistant to chloroquine, mefloquine, halofantrinc, quinine and sulfadoxin+pyrimethamine combination, and sulfa methodpyrazine+pyrimethamine combinations the trusted drugs of choice for control of malaria. Like-wise
P. vivax
infections resistant to chloroquine are emerging in different countries. More than 270 million people suffer from the disease, and 1.2-1.7 million deaths occur yearly. Mortality is more among children under 5 years of age who are specially sensitive because of their lack of immunity to the disease (Ziffer H; Highet RJ and Klayman DL; Artemisinin an endoperoxide antimalarial from
A. annua
. Progress in the chemistry of organic natural product: Herz W (Ed.). Springer-Wien New York, 1997. P. 121-214).
Severe complicated malaria is a life-threatening condition and comatose cerebral malaria cases need emergency parental therapy. Severe
P. falciparum
infections are common in both rural and urban areas and the management of these cases becomes difficult because of emerging problems of drug resistant infections. The comatose cases generally do not survive more than 72 hrs and therefore, require urgent antimalarial drug therapy. The suppository preparations of a variety of antimalarials can be effectively used as emergency treatment in rural areas as well as primary health care centres and these can be easily administered even by unskilled health workers in remote areas. Several reports have been published which support the observation that rectal suppository preparations of artemisinin have powerful effect in reducing the falciparum parasitaemia in critically sick and severe cases including cerebral complications (Vinh et al. (1997); Trans Roy Soc. Trop. Med. Hyg. 91, 465-467; Li et al 1985. J Trad. Chinese Med. 5, 159-161).
The endoperoxides are a promising class of antimalarial drugs which may beet the dual challenges posed by drug parasites and the rapid progression of severe malarial illness and complications which can prove fatal unless emergency treatment is instituted. Artemisinin, is a sesquiterpene lactone containing an endoperoxide bridge (—O—O—C) and is unique among the antimalarial drugs. Dihydroartemisinin (DHA) is the reduced lactol derivative of artemisinin and the semisynthetic derivatives (artemether, arteether, artesunate and artelinate) are ethers or esters of the lactol. In general, the endoperoxides present in all these derivatives, have several advantages over existing antimalarial drugs. These derivatives show little or no cross-resistance to existing anitmalarials. The endoperoxides are fast-acting and clear the periphera blood of parasites more rapidly than other available drugs and finally resistance to the endoperoxides has not yet developed, despite widespread clinical trials. (White N.J., 1994, Artemisinin Current Status: Trans R. Soc. Trop Med Hyg. (88 Suppl). 53-54). The attractive feature of the drugs (arteether, artemether) is the lack of systemic neurotoxicity at the clinically prescribed doses (Looaresuwan, S. et al. 1997 Acta. Tropica. 67, 197-205).
Prior art
Dihydroartemisinin (DHA) is the simplest semisynthetic derivative of Artemisinin, the principle antimalarial constituent of medicinal plant
Armeisia annua
(Warburton, D. (1984) Handbook of Experimental Pharmacology, MaCmillan NY pp. 471-495; Hoffman, S. L. (1986). Clin. Trop. Med. Communicable Dis. 1, 171-274). It has considerable activity in vivo and in vitro and is 3.8 to 5 times more potent than artemisinin (de Vries, P. et al (1996). Drugs 52, 818-836; China Cooperative Research group on Qinghaosu, (1982b) J. Trad. Chin. Med. 2, 17-24); Gu, H. M. et al, (1984) Trans. Roy. Soc. Trop. Med. Hyg, 78, 265-270). In vitro bioassay against drug-resistant
P. falciparum
cultures (W-2 Indo-China and D-6 Sierre Lone strains) showed that direct antimalarial activity of DHA is superior to that of artemether and arteether &bgr; (Lin, A. J. et al (1987) J. Med. Chem. 30, 2147-2150). However, because of its poor solubility in water, DHA had only been formulated as an oral preparation (Tablet) (Li, Q. G. et al (1998) J. Pharm. Pharmacol. 50, 173-182). DHA has been chiefly used for making semisynthetic derivatives such as artemether (AM) and arteether (AE) which are soluble in oil, and the water soluble drug artesunate (AS) (Luo, X. et al, (1984) Helv. Chem. Acta. 67, 1515-1522; Lin, A. J. et al, (1987) J. Med. Chem. 30, 2147-2150; Brossi, A. et al, (1988) J. Med. Chem. 31, 645-650). Zhao and Song (1993 Yao Hsuch Pao, 28, 342-346) compared the pharmacokinetics of oral dihydroartemisinin (DHA) and qinghaosu (QHS) Tablets in human volunteers and reported very high bioavailability of DHA (oral tablets) as compared to QHS (oral) and serum level after QHS were only 1.6-10.8% that of oral DHA preparation. For oral administration DHA was reported to be far superior blood schizontocide compared to QHS. Qi-Gui Li et al (1998 J. Pharm. Pharmacol. 50, 173-182) compared the oral bioactivity of dihydroartemisinin (DHA) with artemether, arteether and artesunic acid in rats and concluded that maximum plasma concentration was produced by oral DHA (769±218) in comparison to artemether (381±113), arteether (324±10) and artesunic acid (208±25 ng ml
−1
). Further area under plasma concentration time curve (ngh ml
−1
) was highest with oral DHA
9
615±56) as compared to artemether (306±52), arteether (298±68) and artesunic acid (217±34). Elimination half life (h) was longer for DHA (4.94±0.73) as compared to artemether (2.04±0.18), arteether (1.79±0.47) and artesunic acid (1.34±26 h). DHA was reported to be active metabolite of other artemisinin derivatives such as artemether (AM), arteether (AE), Artesunate (AS) Artelinic acid (AL).
Benakis et al (1996) administered (60 mg dose representing half of daily dose) oral dihydroartemisinin tablets to six uncomplicated falciparum malaria cases and the peak plasma levels of dihydroartemisinin (0.26-0.71 &mgr;g/ml) were recorded between 1‥2 hrs in four subjects. Thereafter, plasma level dropped and there was complete excretion by 6 hrs. Elimination half-life of DHA was 0.71-1.45 h, drug was well tolerated in 2 subjects while 4 subjects experienced mild headache, nausea or vomiting. One subject showed gastrointestinal hemorrhage and stupor 30 min after drug (Tablet) administration. Benakis et al (1996 J. Trop. Med. Hyg. 24, Suppl 1, 7-11) suggested that the development of a sustained release form of DHA could overcome the adverse drug reaction of table form of drug.
Benakis et al (1977) also reported that following oral artesunate administration, the maximum dihydroartemisinin, plasma level produced was much higher 0.57±0.18 &mgr;g/ml compared to that of parent compound artesunate which recorded peak level of 0.12±0.11 &mgr;g/ml. It may be emphasized, that DHA level was 5-fold higher compared to that of artesunate and that DHA is the main antimalarial principle following artesunate administration. Further it was pointed out that for artesunate type of antimalarials, dose administration (every 3 hourly) would be necessary because of a very short half-life of the drug. However, Bethell et al (1977 Trans R. Soc. Trop. Med. Hyg. 91, 1
Bhakuni Rajendra Singh
Dutta Guru Prakash
Jain Dharam Chand
Kumar Sushil
Sharma Ram Prakash
Council of Scientific and Industrial Research
Ladas & Parry
Weddington Kevin E.
LandOfFree
Process for the preparation of a formulation of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the preparation of a formulation of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of a formulation of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2826355