Two sensitive and reproducible methods were developed and validated for the determination of ziprasidone (ZIP) in the presence of its degradation products in pure form and in pharmaceutical formulations. The fi rst method was based on reversed-phase high-performance liquid chromatography (HPLC), on a Lichrosorb RP C(18) column using water:acetonitrile:phosphoric acid (76:24:0.5 v/v/v) as the mobile phase at a fl ow rate of 1.5 mL min(-1) at ambient temperature. Quantification was achieved with UV detection at 229 nm over a concentration range of 10-500 micro g mL(-1) with mean percentage recovery of 99.71 +/- 0.55. The method retained its accuracy in presence of up to 90% of ZIP degradation products. The second method was based on TLC separation of ZIP from its degradation products followed by densitometric measurement of the intact drug spot at 247 nm. The separation was carried out on aluminium sheet of silica gel 60 F(254) using choloroform:methanol:glacial acetic acid (75:5:4.5 v/v/v) as the mobile phase, over a concentration range of 1-10 micro g per spot and mean percentage recovery of 99.26 +/- 0.39. Both methods were applied successfully to laboratory prepared mixtures and pharmaceutical capsules.
Specific stability indicating reverse-phase liquid chromatography (RP-LC) assay method (SIAM) was developed for the determination of cinnarizine (Cinn)/piracetam (Pira) and cinnarizine (Cinn)/heptaminol acefyllinate (Hept) in the presence of the reported degradation products of Cinn. A C18 column and gradient mobile phase was applied for good resolution of all peaks. The detection was achieved at 210 nm and 254 nm for Cinn/Pira and Cinn/Hept, respectively. The responses were linear over concentration ranges of 20–200, 20–1000 and 25–1000 μgmL−1 for Cinn, Pira, and Hept respectively. The proposed method was validated for linearity, accuracy, repeatability, intermediate precision, and robustness via statistical analysis of the data. The method was shown to be precise, accurate, reproducible, sensitive, and selective for the analysis of Cinn/Pira and Cinn/Hept in laboratory prepared mixtures and in pharmaceutical formulations.
Simple, rapid and sensitive spectroscopic methods were developed and validated for the determination of antiviral agents, namely, penciclovir (PCV) and entecavir (ETV). The first method is based on measuring the native fluorescence of each of the cited drugs at its optimum excitation and emission wavelengths. The fluorescence intensity was measured for PCV & ETV at 363 nm and 370 nm upon excitation at 260 nm and 254 nm, respectively. The calibration curves were linear over the concentration range 0.1-0.8, 0.025-0.4 lg ml À1 for PCV and ETV, respectively. The second method is based on measuring the amplitude of ETV in the fourth derivative with Dk = 8 and scaling factor = 100 at 256.4 nm at which its acidic degradation showed zero reading over the concentration range 5-60 lg ml À1 . The proposed methods were applied for the determination of the cited drugs in bulk and pharmaceutical preparations. ICH guidelines were used for method validation. Ó 2016 Production and hosting by Elsevier B.V. on behalf of Faculty of Pharmacy, Cairo University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).
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