Chromatographic analysis of some drugs employed in erectile dysfunction therapy: Qualitative and quantitative studies using calixarene stationary phase

Abstract

In this study, the effect of change in chromatographic process variables on the retention behavior of four drugs employed in erectile dysfunction therapy on a calixarene stationary phase is described. Three of these drugs are known to treat erectile dysfunction, namely, sildenafil citrate, tadalafil, and apomorphine hydrochloride, and one drug that is used as opioid analgesic, tramadol hydrochloride, which is quiet widely misused to treat premature ejaculation. The results indicate the importance of considering the structure and pKa values of drugs to be separated along with mobile phase composition. A new optimized, rapid, and accurate liquid chromatography method is also established for simultaneous determination of sildenafil citrate, tadalafil, and apomorphine hydrochloride in pharmaceutical preparations and bulk powders. The chromatographic separation of the three pharmaceuticals was achieved on a calixarene column in less than 10 min using a binary mobile phase of 35% acetonitrile and 65% 50 mM sodium perchlorate pH2.5 at 1 mL/min flow rate. The method was validated for system efficiency, linearity, accuracy, precision, limits of detection and quantitation, specificity, stability, and robustness. Statistical analysis proved that the method enabled reproducible and selective quantification of all three analytes in bulk drugs and in pharmaceutical preparations.

Assessment of sexual behaviour and fertility indices in male rabbits following chronic codeine use

“…Tramadol also caused a significant decline in Leydig cells activities (Nna et al, 2017) with a possible reduction in testosterone biosynthesis. Although tramadol has been reported to improve premature ejaculation but adversely affect male reproduction (Hashem et al, 2014;Martyn-St James et al, 2015;Nna et al, 2017), it is structurally different from other members of the opioid family (McMillan, 2018). Leon & Wexler (1973) documented the relationship between heroin addiction and sexual behaviour.…”

A novel stability indicating HPLC-method for simultaneous determination of atenolol and nifedipine in presence of atenolol pharmacopeoial impurities

“…Mobile phase including water without any salt as aqueous part gave bad separation due to tailing of peaks and this is why NaClO 4 is added to aqueous part of the mobile phase. In previous studies, it was found that usage of NaClO 4 as aqueous mobile additive (chaotropic mobile phase additive) led to reduction of retention times and enhancement of separation of basic analytes via decreasing of tailing (Elhenawee et al, 2014;Hashem et al, 2014). The method was validated according to ICH guidelines (Guidance for Industry: ICH 1996) for system suitability, linearity, precision, limits of detection and quantitation, specificity, stability and robustness.…”

Core–shell particles and monolithic columns; tools for simultaneous LC analysis of avanafil, sildenafil, apomorphine, trazodone, yohimbine, tramadol and dapoxetine in pharmaceutical dosage forms, counterfeit products and human plasma

“…Literature survey revealed that individual determination of the drugs under study was reported extensively. Some papers were reported for simultaneous determination of drugs used in treatment of ED [16][17][18] and some others were reported for simultaneous determination of some antidepressant drugs that can be abused in treatment of PE. 19,20 However, as discussed before, the co-administration of drugs for treatment of ED and PE is possible.…”