The polymorphs of nimodipine, Modification I (Mod I), the metastable racemate, and Modification II (Mod II), the stable conglomerate, were evaluated by means of the intrinsic dissolution procedure. For this purpose, a hydro alcoholic solution (ethanol:water, 50:50, v/v) was selected as the dissolution medium, maintained at 37±0.5°C. Different rotation speeds were tested (50, 75 and 100 rpm) and the lower one was chosen for the test validation. Although the sample initially characterized as polymorph Mod I presented higher intrinsic dissolution rates in all the conditions tested, no statistical differences were noticed between the two polymorphs. This result can be attributed to the partial solution-mediated phase transformation from Mod I to Mod II, detected through X-ray powder diffraction and differential scanning calorimetry. Also, reliable intrinsic dissolution rate data were acquired for the polymorph Mod II. The dissolution method was validated, being considered stable, specific, linear, sensible, accurate and precise. 相似文献
An HPLC method was developed and validated for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in pharmaceutical formulations. The chromatographic separation was carried out on an RP-C18 column using a mobile phase gradient of methanol, 0.015 M phosphate buffer (pH 3.0), and 0.03 M phosphoric acid at a flow rate of 1.0 mL/min and UV detection at 230, 280, and 360 nm, respectively, for buclizine, tryptophan, pyridoxine, and cyanocobalamin. The method validation yielded good results with respect to linearity (r>0.999), specificity, precision, accuracy, and robustness. The RSD values for intraday and interday precision were below 1.82 and 0.63%, respectively, and recoveries ranged from 98.11 to 101.95%. The method was successfully applied for the QC analysis of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension. 相似文献
An accurate, simple, reproducible, and sensitive liquid chromatographic method was developed and validated for the captopril determination in controlled release tablets. The analyses were performed at room temperature on a reversed-phase Phenomenex Luna C18 column (250 mm × 4.6 mm). The mobile phase was composed of water:methanol (45:55; v/v) pH 2.5, and it was eluted isocratically at a 1.0 mL min−1 flow rate. The method was validated in terms of specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. The response was linear in the range 0.3–1.5 mg mL−1 (r2 = 0.9983). The relative standard deviation values for inter-and intra-day precision were 0.77% and 0.50%, respectively. Recoveries ranged between 97.7 and 99.1%. The method was successfully applied for the determination of captopril in the developed formulations.
An accurate, simple, reproducible, and sensitive liquid chromatographic method was developed and validated for the captopril
determination in controlled release tablets. The analyses were performed at room temperature on a reversed-phase Phenomenex
Luna C18 column (250 mm × 4.6 mm). The mobile phase was composed of water:methanol (45:55; v/v) pH 2.5, and it was eluted isocratically at a 1.0 mL min−1 flow rate. The method was validated in terms of specificity, linearity, quantification limit, detection limit, accuracy,
precision and robustness. The response was linear in the range 0.3–1.5 mg mL−1 (r2 = 0.9983). The relative standard deviation values for inter-and intra-day precision were 0.77% and 0.50%, respectively. Recoveries
ranged between 97.7 and 99.1%. The method was successfully applied for the determination of captopril in the developed formulations. 相似文献
A high performance liquid chromatographic method was developed and validated for the quantitative determination of carbamazepine
in intravenous nanoemulsions. The method validation yielded good results with respect to linearity, specificity, precision
and accuracy. The method was carried out on a RP-18 column with a mobile phase composed of methanol–water (70:30 v/v) subjected to a gradient of acetonitrile after drug elution, and detection at 286 nm. The linearity in the range of 10.0–50.0 μg mL−1 presented a determination coefficient (r2) of 0.9996, calculated by least-squares regression; the RSD values for intra-day and inter-day precision for % recovered
were <0.44 and <1.21%, respectively; and the recovery of carbamazepine from the sample matrix ranged from 94.3 to 104.9%. 相似文献
A stability-indicating reversed-phase high-performance liquid chromatography (LC) method was developed and validated for the
determination of hydrochlorothiazide in an oral suspension. Isocratic chromatography was performed on a C18 column with 0.1 M sodium phosphate buffer pH 3.0/acetonitrile (70:30 v/v) as mobile phase, at a flow rate of 1.3 mL min−1, and UV detection at 254 nm. The method was linear (r2 = 0.9998), accurate (mean recovery = 100.3%), and precise (RSD <2%). It was also validated for specificity and robustness.
The method was successfully applied for the quality control analysis of a new pharmaceutical formulation of HCTZ for pediatric
use. 相似文献