HPTLC and RP-HPLC methods for simultaneous determination of Paracetamol and Pamabrom in presence of their potential impurities

• HPTLC and RP-HPLC methods for determination of PCM and PAM were developed.
• The two developed methods are validated and met ICH requirements.
• Developed methods are able to determine PCM and PAM in presence of their impurities.

Two chromatgraphic methods were developed for determination of Paracetamol (PCM) and Pamabrom (PAM) in presence of P-aminophenol (PAP) and Theophylline (THEO) as potential impurities of both drugs respectively. First method is HPTLC which depends on separation and quantitation of the studied drugs on aluminum plates pre-coated with silica gel 60 F254 as a stationary phase using chloroform:methanol:ethyl acetate:glacial acetic acid (8:0.8:0.6:0.2, v/v/v/v) as mobile phase followed by densitometric measurement of the bands at 254 nm. Second method is RP-HPLC which comprises separation of the studied drugs on a Phenomenex C8 column by gradient elution using mobile phase consisting of sodium dihydrogen phosphate buffer (0.05 M): methanol:acetonitrile (85:10:5, v/v/v) at a flow rate of 1 mL/min for first 7.5 min and (70:20:10, v/v/v) at a flow rate of 1.5 mL/min for the next 5 min. The proposed methods were successfully applied for determination of the potential impurities of PCM and PAM after resolving them from the pure drugs. The developed methods have been validated and proved to meet the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated methods were successfully applied for determination of the studied drugs in their pharmaceutical formulation. The results were statistically compared to those obtained by the reported RP-HPLC method where no significant difference was found; indicating the ability of proposed methods to be used for routine quality control analysis of these drugs.

3D HPTLC chromatogram of resolved mixture of P-aminophenol (Rf = 0.11), Paracetamol (Rf = 0.33), Theophylline (Rf = 0.48) and Pamabrom (Rf = 0.65) using (chloroform:methanol:ethyl acetate:glacial acetic acid) (8:0.8:0.6:0.2, by volume) as a developing system and scanning at 254 nm.RP-HPLC chromatogram of separated peaks of P-aminophenol (Rt = 3.21 min), Paracetamol (Rt = 7.11 min), Theophylline (Rt = 8.26 min) and Pamabrom (Rt = 11.49 min) by gradient elution using phosphate buffer: methanol:acetonitrile (85:10:5, by volume) as a mobile phase delivered at a flow rate of 1 mL/min for first 7.5 min and (70:20:10) at a flow rate of 1.5 mL/min for the next 5 min and scanning at 277 nm.Figure optionsDownload as PowerPoint slide