Diphenhydramine Hydrochloride Injectable,Stability and Inpurities

Diphenhydramine Hydrochloride having chemical name 2-(diphenylmethoxy)-N,N-dimethyl ethylamine hydrochloride.It is white ,crystalline powder,is freely soluble in water and alchol.The molcular formula is C17H21NO.HCl and molcular weight is 291.82. Diphenhydramine Hydrochloride in the parentral form is a sterile,pyrogen-free solution.Each ml contains a concentration of 50 mg of Diphenhydramine Hydrocholoride and water for injection,for intermuselar and interavenous use.The solution for paretnral use has been adjusted to a PH between4 and 6.5 with either sodium hydroxide or hydrochloric acid.Diphenhydramine Hydrochloride is an antihistamine drug,clear and colorless solution available as 50 mg/ml in a1ml ampules.Diphenhydramine Hydrochloride contains NLT98.0% and NMT102.0% of Diphenhydramine Hydrochloride calculated on the dried basis[1]. For identificatin 3 methods is used[1]: 1-Infrared Absorption 2-HPLC:the retention time of the major peak of sample solution crosseponds to that of the standard solution,as obtained in the Assay. 3-Identification Test-General-Choloride[1]For calculating Assay, gradiant HPLC method with a buffer of monobasic potassium phosphate,that adjust with phosphoric acid to a PH of 3.0 and Dilluent(Acetonitrile and Buffer(35:65) with a L7 column is used[1],Tailing factor NMT1.8. There are seven khnown inpurities for Diphenhydramine Hydrochloride[2,3,4].These inpurities decrease Assay during the stability time.Inpurities measured by HPLC method[1].In order to more stability manufacturing conditions must be controlled.For calculating inpurities, HPLC method with a buffer of monobasic potassium phosphate,that adjust with phosphoric acid to a PH of 3.0 and Mobile phase(Acetonitrile and Buffer(35:65) with a L7 column is used[1].