Résumé
Connexin43 mimetic peptide (Cx43MP) has been intensively investigated for its therapeutic effect in the management of inflammatory eye conditions, spinal cord injury, wound healing and ischemia-induced brain damage. Here, we report on a validated stability–indicating reversed-phase high performance liquid chromatography(RP-HPLC)method for the quantification of Cx43MP under stress conditions.These included exposure to acid/base, light, oxidation and high temperature. In addition, the degradation kinetics of the peptide were evaluated in bovine vitreous and drug-free human plasma at 37 ℃. Detection of Cx43MP was carried out at 214 nm with a retention time of 7.5 min. The method showed excellent linearity over the concentration range of 0.9–250μg/mL(R2≥0.998),and the limits of detection(LOD)and quantification(LOQ) were found to be 0.90 and 2.98 μg/mL, respectively. The accuracy of the method determined by the mean percentage recovery at 7.8, 62.5 and 250μg/mL was 96.79%, 98.25% and 99.06% with a RSD of<2.2%. Accelerated stability studies revealed that Cx43MP was more sensitive to basic conditions and completely degraded within 24 h at 37 ℃(0% recovery)and within 12 h at 80 ℃(0.34% recovery).Cx43MP was found to be more stable in bovine vitreous(t1/2slow=171.8 min)compared to human plasma(t1/2slow=39.3 min)at 37 ℃ according to the two phase degradation kinetic model. These findings are important for further pre-clinical development of Cx43MP.
Résumé
A stability indicating simple, selective, accurate high Performance Liquid Chromatographic (HPLC) method was developed and validated for the combined tablet formulation of pyrimethamine & sulphadoxine. Chromatographic separation was optimized by gradient HPLC on a C18 column [Inertsil Silica, 250 x 4.6 mm, 5μ] utilizing a mobile phase of potassium dihydrogen phosphate and acetonitrile taken in the ratio 70:30 at a flow rate of 1.0 ml/min with UV detection at 221nm. The retention time of pyrimethamine and sulphadoxine was 2.77 and 6.57 min respectively. The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantitation, robustness and stress degradation studies. Validation of the method was done in accordance with ICH guidelines for the assay of active ingredients. Thus validated method can be recommended for the routine laboratory analysis.
Résumé
A simple, RP-HPLC stability indicating method was developed for determination of mefenamic acid in pharmaceutical formulations and its degradation products using C8 column with the mobile phase containing mixture of Buffer : Acetonitrile + THF in the ratio of 55:45 v/v at a flow rate of 1.0 ml/min was found to yield satisfactory retention time of about 18.253 min with sharp symmetrical peak at a detection wavelength of 285 nm. The method was validated using ICH guidelines and was found to be linear in the range 0.5-2 μg/ mL. The proposed method shows good separation of mefenamic acid and its degradation products. The developed method can be applied successfully for the determination of mefenamic acid and its degraded products.