Simultaneous Estimation of Paracetamol, Ambroxol Hydrochloride, Levocetirizine Dihydrochloride, and Phenylephrine Hydrochloride in Combined Tablet Formulation by First-Order Derivative Spectrophotometry

Paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride are used in combination for the treatment of chronic sinusitis, rhinitis, fever, nasal discharge, sore throat, and wheezing. The present work deals with method development for simultaneous estimation of paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride in tablet formulation by first-order derivative spectrosphotometry. For determination of sampling wavelength, 10？μg/mL of each of paracetamol, ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride was scanned in 200–400？nm ranges and sampling wavelengths were found to be 305.5？nm for paracetamol, 321？nm for ambroxol hydrochloride, 244？nm for levocetirizine dihydrochloride, and 280？nm for phenylephrine hydrochloride in first-order derivative spectrophotometry. In this method, linearity was observed in the ranges of 20–140？μg/mL for paracetamol and 10–70？μg/mL for ambroxol hydrochloride, levocetirizine dihydrochloride, and phenylephrine hydrochloride. The % recovery was within the range between 98 and 102%, and % relative standard deviation for precision and accuracy of the method was found to be less than 2%. The method is validated as per International Conference on Harmonization Guidelines. The method can be successfully applied for the simultaneous analysis of these drugs in pharmaceutical dosage forms. 1. Introduction Paracetamol (PARA), chemically known as N-(4-hydroxyphenyl)ethanamide (Figure 1(a)), inhibits the cyclooxygenase (COX) used as an analgesic, antipyretic, and nonnarcotic agent. Ambroxol hydrochloride (AMB), chemically known as trans-S-4-(2-Amino-3, 5-dibrombenzylamino)-cyclohexanol (Figure 1(b)), is an active N-desmethyl metabolite of the mucolytic bromhexine used as an oral mucolytic expectorant. Levocetirizine dihydrochloride (LEVO), chemically known as [2-[4-[(R)-(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]-acetic acid dihydrochloride (Figure 1(c)), is L-enantiomer of cetirizine racemate. It works by blocking H1 histamine receptors; it is used for allergic rhinitis and conjunctivitis, hay fever, and pollinosis; it controls sneezing, runny but not blocked nose, and red, watering, and itchy eyes. Phenylephrine hydrochloride (PHEN), chemically known as (R)-3-hydroxy-alpha [(methylamino)methyl]benzenemethanol hydrochloride (Figure 1(d)), is a direct acting sympathomimetic agent. It is a selective adrenoceptor agonist and has negligible action and is used as a nasal decongestant and for producing