Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, University of Alexandria, Elmessalah, Alexandria 21521, Egypt.
Pharmaceutical Chemistry Department, Faculty of Pharmacy and Drug Manufacturing, Pharos University in Alexandria, Alexandria, Egypt.
Ann Pharm Fr. 2020 Sep;78(5):368-378. doi: 10.1016/j.pharma.2020.04.006. Epub 2020 May 11.
Two chromatographic methods were developed for the assay of the FDA approved lozenges containing dextromethorphan hydrobromide (DXT) and menthol (MNT). The first was a green HPTLC method which uses a mobile phase of methanol-ammonia (10:0.1, v/v). The densitometric measurements of the spots which were retained at 0.28±0.01 for DXT and 0.76±0.02 for MNT was done at 210nm. The other method was RP-HPLC method with stability indicating merits at which a mixture of 20mM phosphate buffer pH 3 and acetonitrile as mobile phase in isocratic mode was used. The cited drugs were resolved in RP-HPLC method using isocratic elution using 20mM phosphate buffer: acetonitrile (65:35 v/v) with retention times of 2.21 and 3.47min for MNT and DXT, respectively and quantified using 215nm. Both methods were entirely validated and both methods were successfully able to analyze both drugs in presence of lozenges inactive ingredients. HPLC method had the advantage of being stability indicating at which resolution of the drugs from their forced degradation products was successfully attained. For HPTLC method, both drugs showed reasonable RF values when compared to rapidly eluted MNT in RP-HPLC; also it was more environmentally friendly than RP-HPLC as it used solvents which are less toxic and greener.
两种色谱方法被开发用于测定 FDA 批准的含有右美沙芬氢溴酸盐（DXT）和薄荷醇（MNT）的锭剂。第一种是绿色 HPTLC 方法，使用甲醇-氨水（10:0.1，v/v）作为流动相。在 210nm 处对保留时间为 0.28±0.01 的 DXT 和 0.76±0.02 的 MNT 斑点进行了分光光度测量。另一种方法是具有稳定性指示优点的反相高效液相色谱法，其中使用 20mM 磷酸盐缓冲液 pH 3 和乙腈作为等度模式的流动相。在反相高效液相色谱法中，使用 20mM 磷酸盐缓冲液：乙腈（65:35 v/v）作为等度洗脱剂，MNT 和 DXT 的保留时间分别为 2.21 和 3.47min，并在 215nm 处进行定量。两种方法均经过全面验证，均能成功分析锭剂中活性成分和非活性成分的两种药物。HPLC 方法具有稳定性指示的优点，能够成功地从药物的强制降解产物中分离出药物。对于 HPTLC 方法，与反相高效液相色谱中快速洗脱的 MNT 相比，两种药物的 RF 值都相当合理；与反相高效液相色谱相比，它也更加环保，因为它使用的溶剂毒性较小且更环保。
