Spectrophotometry Microdetermination of Some Antihypertensive Drugs in Pure Form and in Pharmaceutical Formulations

Abstract

Simple, rapid, accurate, precise and sensitive spectrophotometric method for the microdetermination of enalapril maleate (ENM) and lisinopril dihydrate (LIS) has been developed. The method is based on oxidation of the drug by potassium permanganate in acidic medium and determine the unreacted oxidant by measuring the decrease in absorbance for three different acidic dyes; acid red 73 (AR), amaranth dye [acid red 27] (AM) and acid orange 7 (AO) at a suitable λ max (510, 521 and 484 nm for ENM and 509, 521 and 485 nm for LIS), respectively. Regression analysis of Beer's law plots showed good correlation in the concentration ranges 0.7-12, 0.5-7.6 and 0.6-9.5 µg mL -1 and 0.5-9.0, 0.4-6.1 and 0.4-7.2 µg mL -1 for ENM and LIS using AR, AM and AO, respectively. The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits are calculated. Statistical treatment of the results reflects that the proposed procedures are precise, accurate and easily applicable for the determination of ENM and LIS in pure and in pharmaceutical preparations.

New Method for Spectrophotometric Determination of Lisinopril in Pure Form and in Pharmaceutical Formulations

“…It was observed that complete color development was attained at 40 ± 1°C (7 min) ( Figure 2). The effect of Alizarin concentration on the color development was investigated 3 ml of Alizarin reagent produced maximum color intensity ( Figure 3) [36].…”

“…Commercial formulation was successfully analyzed for the lisinopril by the proposed method and the results are compared with reference method (20) (Table 3) did not exceed the theoretical values, which indicates the absence of any difference between the methods compared. The proposed method gives good results for lisinopril in pure and pharmaceutical formulations [35,36]. …”

Determination of Lisinopril in Pure and Tablet form by Using 2-Hydroxynaphthaldehyde as Derivatizing Reagent

“…The literature reveals various analytical methods were described for the determination of LNP such as titrimetric [5,6], Spectrophotometric [7][8][9][10][11][12][13][14][15], spectrofluorometric [16][17][18][19][20], chromatographic [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], derivative UV-spectrophotometric, [39][40] polarography [41][42], radioimmunoassay [43] and fluoroimmunoassay [44].…”

Determination of Enalapril maleate from tablets using a new HPLC method

“…The therapeutic importance of Enalapril maleate has led to its increasing use and thus to the development of numerous methods of determining this drug. The determination of the Enalapril maleate, alone or in combination with other drugs, has been carried out by various analytical techniques, such as spectrophotometric methods, which, in most cases, involves extraction with organic solvents [4,5] and many reagents [6][7][8][9], or by high performance liquid chromatography (HPLC), which it is the most common practical technique for the determination of this drug. HPLC methods have the advantage of determining the drug in a much shorter time than other analytical methods, and the degradation products do not interfere [10][11][12].…”