Pharmaceutical compositions containing donepezil hydrochloride - Patent 6734195 The invention provides a pharmaceutical composition for the treatment of dementia or Alzheimer's disease in which the active therapeutical agent is donepezil hydrochloride in an amorphous state. Donepezil hydrochloride was found as an efficient drug for the treatment of dementia and Alzheimer's disease. Its cholinergic enhancement property is considered to be the reason for the alleviation of symptoms in patients. The drug, formulated as 5 and 10 mg film coated tablets is given once daily to the patients. Amorphous donepezil hydrochloride is mentioned in U.S. Pat. No. 5,985,864 and U.S. Pat No. 6,140,321. However, it is claimed that this form is chemically unstable and develops impurities on standing. Thus, it is described that at 40° C. the content of the impurities of crystalline donepezil hydrochloride (forms I to IV) did not change during a 12 week period, whereas the impurity content in amorphous donepezil hydrochloride changed from an initial value of 0.1% to 0.2% after 4 weeks and to 0.4% after 12 weeks. At higher temperatures even more extensive decomposition was reported. Therefore, these patents recommend the use of crystalline forms of donepezil hydrochloride only.
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