Development and validation of an ecofriendly chemiluminescence method for the determination of citalopram in pharmaceutical preparations using Cu2+-grafted oxidized multiwall carbon nanotubes

Abstract

Anovel and sensitive chemiluminescence (CL) method was developed and validated for the determination of citalopram in bulk dosage form and in pharmaceutical preparations. The method is based on the use of Cu²⁺-grafted oxidized multiwall carbon nanotubes (Cu/ox-MWCNTs). The weak CL signal arising fromthe reaction of an alkaline luminol-H₂O₂ system was significantly enhanced by the addition of citalopram in the presence of ox-MWCNTs/Cu²⁺. Furthermore, ox-MWCNTs/Cu²⁺ exhibited exceptional catalytic activity towards the oxidation of luminol in the luminol-H₂O₂ CL reaction. Multiwalled carbon nanotubes (MWCNTs) were characterized by scanning electron microscopy (SEM), which also showed the attachment of Cu²⁺ toMWCNTs. Various factors affecting CL intensity were carefully investigated and optimized for citalopram quantitation. The CL intensity was proportional to citalopram concentration in the range 0.2–8.0 μg mL^–1, with a correlation coefficient of 0.996. The limit of detection (LOD) and limit of quantification were 2.29 × 10^–5 μg mL^–1 and 7.64 × 10^–5 μg mL^–1, respectively, and its reproducibility was satisfactory with a relative standard deviation (RSD) of 2.59 % (n = 5). The interference effects of common excipients were studied, and the developed method was effectively applied for the determination of citalopram in pure formand in pharmaceutical preparations. Percentage recoveries were calculated and ranged from 98.67 to 101.46 % for the pure form and from 97.38 to 101.72 % for pharmaceutical preparations.

Keywords: Chemiluminescence, Citalopram, Luminol, oxidized multiwall carbon nanotubes