Simple and sensitive spectrophotometric methods for the determination of acebutolol hydrochloride in bulk sample and pharmaceutical preparations

Ethylcellulose assisted exfoliation of graphite by the ultrasound emulsification: An application in electrochemical acebutolol sensor

This work reports the sonochemical exfoliation of graphite (bath sonication with the frequency of 37/80 kHz and power of 60 W) and its electrocatalytic properties to the β-blocker drug. The pencil graphite (PG) was exfoliated by the ultrasound emulsification with the support of ethyl cellulose (EC). Herein, EC act as an emulsifier which aids to the exfoliation and also stabilizing the exfoliated graphite. This EC assisted PG (ECPG) was characterized by various analytical techniques which showed that ECPG has high crystalline graphene sheets. In some places, EC submerged to the graphene sheets which improve the dispersibility of graphene in water. The performance of ECPG was evaluated to the electrocatalysis of acebutolol (ACE) which exhibited good electrochemical signal. Therefore, the ECPG was utilized to the detection of ACE as the electrochemical sensor electrode. It showed notable sensitivity (2.87 µA μM^-1 cm^-2) appreciable linear range (0.01-200 µM) and satisfactory detection limit (4 nM). Furthermore, it displays acceptable anti-interference properties with other interfering ions.

Effect of cavitation erosion in the sonochemical exfoliation of activated graphite for electrocatalysis of acebutolol

This study mainly covered the cavitation erosion in probe sonication and its electrochemical behavior. The activated graphite was exfoliated by the probe sonication wherein the titanium alloy (TA) is used as a probe (micro-tip). The sonication performed in the aqueous solution contains a mixture of sulfuric acid and nitric acid (1:1). The exfoliated graphite (EG) was examined by field emission scanning electron microscope, Raman and X-ray diffraction pattern analysis. The results showed that some TA particles dissolute from the TA micro-tip accompanied with graphite exfoliation. This dissolution experienced from the cavitation erosion, because the acoustic cavitation makes severe deformation on probe tips due to the bubble collapse. The dissolution rate increased when increasing sonication time; the resultant TA particles are randomly distributed over the EG. These EGTAs applied to the electrochemical oxidation of acebutolol which revealed an appreciable electrochemical performance and also exhibited better analytical performances to the electrochemical determinations. The obtained analytical parameters viz., sensitivity (0.234 µA µM^-1 cm^-2), linear range (0.01-15.1 µM), and limit of detection (0.003 µM) are highly comparable with the previous reports. Moreover, it has an acceptable tolerance with the interfering substances.

Use of Two Sulfonphthalein Dyes for the Sensitive and Selective Extraction-Free Spectrophotometric Assay of Albendazole in Bulk Drug and in Tablets

Albendazole (ALB) is a potent benzimidazole anthelmintic used in the treatment of human intestinal helmintiasis as well as of hytatid cysts and neurocysticercosis. Two rapid, simple, sensitive, and selective spectrophotometric methods are presented for the determination of ALB in pharmaceuticals. The methods are based on the formation of dichloromethane soluble 1 : 1 ion-pair complexes (ALB : dye) formed between ALB and sulfonphthalein dyes, bromophenol blue BPB, (method A) and bromothymol blue BTB, (method B). The complexes formed were measured directly (without extraction) at 445 nm (method A) and 460 nm (method B). The experimental conditions were optimized and the systems obey Beer’s law for 1.5–21.0 and 2.0–32.0 μg mL−1 ALB for method A and method B respectively. The molar absorptivity and Sandell's sensitivity were calculated to be  L mol−1 cm−1 and 0.0209 ng cm−2, and  L mol−1 cm−1 and 0.0350 ng cm−2 using BPB and BTB, respectively. The limits of detection and quantification were calculated to be 0.01 and 0.03, and 0.16, and 0.49 μg mL−1 using BPB and BTB, respectively. The relative standard values for intra-day and inter-day precision were less than 3%, and the accuracy was better than 3% for both methods.

Use of two sulfonthalein dyes in the extraction-free spectrophotometric assay of tramadol in dosage forms and in spiked human urine based on ion-pair reaction

Tramadol is a centrally acting analgesic used in the prevention and treatment of moderate to severe pain. Two sensitive, selective, and rapid spectrophotometric methods are described for the determination of tramadol in its dosage forms and in spiked human urine. The methods are based on formation of yellow ion-pairs between tramadol and two sulfonthalein dyes; bromocresol purple (BCP) and bromocresol green (BCG) in dichloromethane medium followed by absorbance measurement at 400 and 410 nm, respectively. Under the optimum conditions, tramadol could be assayed in the concentration ranges, 1-15 and 1-16 µg ml(-1) with correlation coefficient greater than 0.999 in both cases. The molar absorptivity values are calculated to be 1.84 × 10(4) and 1.97 × 10(4) l mol(-1) cm(-1) for BCP and BCG methods, respectively; and the corresponding Sandell sensitivity values are 0.0143 and 0.0134 µg cm(-2). The limits of detection (LOD) and quantification (LOQ) have also been reported. The stoichiometry of the reaction was found to be 1:1 in both cases and the conditional stability constant (K(f)) values of the ion pairs have been calculated. The within-day and between-day RSD were 0.9-1.96% and 1.56-3.21%, respectively. The methods were successfully applied to the determination of tramadol in tablets and injections and also in spiked human urine with good recoveries. The procedures are simple, accurate, and suitable for quality control application.