SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF THIAMINE HYDROCHLORIDE IN PURE FORM, PHARMACEUTICAL AND BIOLOGICAL FLUIDS

Thiamine hydrochloride, also known as Vitamin B₁, is a water-soluble vitamin which is important biologically and pharmaceutically. A new simple and sensitive spectrophotometric method has been developed for the determination of Thiamine Hydrochloride (Vitamin B₁) in pure form and biological fluids. The method is based on the diazotization reaction of Thiamine Hydrochloride with Procaine HCl which reacted with sodium nitrate and hydrochloric acid to form a red water-soluble azo dye in basic medium, that has a maximum absorption at λ_max = 507 nm. Beer’s law is obeyed over the concentration range (2-60 µg.ml^-1), the molar absorptivity of 4.047×10⁴ L.mol^-1 .cm^-1 and Sandell sensitivity of 7.417×10^-3 µg .cm^-2 and the method have an accuracy and precision between (0.02-0.16) while the relative standard deviation between (0.805-2.049). The structure of dye showed that (1:2) product was formed between the drug and diazotized reagent. The method was applied successfully for the determination of Vitamin B₁ in pharmaceutical preparations and biological samples. The results showed that the concentration of vitamin B₁were decreased, in both blood and urine samples, with time after taken a therapy.