Development of liquid chromatographic method for simultaneous determination of mycophenolate mofetil and its degradation product mycophenolic acid in dosage form.

In this paper, a chemometrical approach is applied for the development of a reversed-phase high-performance liquid chromatography method for the simultaneous determination of mycophenolate mofetil and its degradation product mycophenolic acid in dosage form. The fractional factorial design is used in screening experiments for selecting the variables that significantly influence the chromatographic procedure. The investigated variables are column type, temperature of the column, and composition of the mobile phase (with respect to pH and the percentage of organic modifier). Investigation is performed using two columns, XTerra (RP 18, 150 mmx3.9 mm) and Chromolith (RP-18e, 100 mmx4.6 mm). Because the column type shows no influence on separation process, the Chromolith column is further used due to its ability to achieve a high-speed separation without loss of column efficiency. Total analysis time is reduced from 8.34 min on XTerra to 1.27 min on Chromolith. The columns' efficiency, analysis cost, and peak symmetries are briefly compared. For both substances, only two variables are found significant: percentage of acetonitrile and pH of the water phase. Afterward, the main variables are optimized using response surface methodology for visualization and easier identification of optimal conditions. The optimal conditions are obtained with mobile phase composition of acetonitrile-15 mM phosphate buffer (pH adjusted to 4.0 with 85% orthophosphoric acid) (35:65, v/v) at the flow rate of 5 mL/min. The temperature of the column is adjusted to 25 degrees C and detection is performed at 254 nm.

Investigation of chromatographic conditions for the separation of ofloxacin and its degradation products.

A sensitive, precise, and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for simultaneous determination of fluoroquinolone antibacterial ofloxacin and its degradation products: decarboxy ofloxacin, 9-piperazino ofloxacin, des-methyl ofloxacin, and ofloxacin-N-oxide. The proposed RP-HPLC method allowed separation of all five compounds simultaneously with the total time of the analysis not more than 15 min. The relative standard deviation (RSD) values for quantification of DOF, POF, MOF, OF, and NOF were of 0.77, 0.58, 0.51, 0.10, and 0.70%, respectively, indicating a good precision of the method. The limits of detection for DOF, POF, MOF, OF, and NOF were 0.10, 0.13, 0.06, 0.03, and 0.03 microg mL(-1), respectively. The described method can be used for simultaneous identification and quantification of all analysed compounds in different pharmaceutical formulations.

Validation of a high-performance liquid chromatographic method for the simultaneous determination of tramadol and its impurities in oral drops as a pharmaceutical formulation.

The novel, rapid high performance liquid chromatographic method for the determination of tramadol hydrochloride and its three impurities was developed and validated. The method can simultaneously assay potassium sorbate, used as preservative, and saccharin sodium, used as sweetener in tramadol pharmaceutical formulation. The separation was carried out on a C(18) XTerra (150 mm x 4.6 mm, 5 mm) column using acetonitrile-0.015 M Na(2)HPO(4) buffer (2:8, v/v) as mobile phase (pH value 3.0 was adjusted with orthophosphoric acid) at a flow rate 1.0 ml min(-1), temperature of the column 20 degrees C and UV detection at 218 nm. The method was found to be linear (r > 0.999) in the range of 0.05-0.8 mg ml(-1) for tramadol hydrochloride, 0.1-1.2 mg ml(-1) for impurities B and C and for impurity A (r > 0.995) in the range 0.15-2.4 mg ml(-1). The low RSD values indicate good precision and high recovery values indicate excellent accuracy of the HPLC method. Developed method was successfully applied to the determination of tramadol hydrochloride, its investigated impurities and potassium sorbate in commercial formulation. The recovery of tramadol hydrochloride was 98.25% and RSD was 1.80%. The method is rapid and sensitive enough to be used to analyse Trodon oral drops.

Validation of liquid chromatographic method for analysis of lidocaine hydrochloride, dexamethasone acetate, calcium dobesilate, buthylhydroxyanisol and degradation product hydroquinone in suppositories and ointment.

In this paper, there was developed a sensitive, precise and accurate reversed-phase liquid chromatographic (RP-HPLC) method and validated for simultaneous determination of lidocaine hydrochloride, dexamethasone acetate (DA) and calcium dobesilate (CD) in suppositories and ointment. Also there was achieved a parallel analysis of buthylhydroxyanisol, as a preservative, and hydroquinone, as a degradation product of calcium dobesilate, present in these dosage forms. The relative standard deviation (RSD) values for all five compounds indicated a good precision and accuracy of the RP-HPLC method. Method is selective, sensitive and reproducible with good recovery values and can be applied in simultaneous determination of all mentioned compounds.

Validation of a high-performance liquid chromatography method for the determination of pancuronium in Pavulon injections.

A new high-performance liquid chromatography (HPLC) method was developed for the quality control of pancuronium bromide and its degradation products. The HPLC method used a 5-microm Supelcogel ODP-50 (150x4 cm) column with acetonitrile-CH3OH-water-F3CCOOH (20.5:74.9:0.1, v/v) as the mobile phase (pH value 2.0 adjusted with trifluoroacetic acid) at a flow-rate 0.8 ml/min and UV detection at 210 nm. The Beer's law plots were found to be linear over the concentration range 0.4-1.2 mg/ml of pancuronium bromide and 0.04-0.08 mg/ml of desacetyl degradation products (R2=0.9995). The RSD of the peak areas was 1.09% and the recovery was 102.43%. The RSD value shows good precision, acceptable accuracy and reproducibility of the new method for the determination of pancuronium bromide in presence of its desacetyl degradation products. The method is rapid and sensitive enough to be used for Pavulon injection analysis.

Application of experimental design to the development of an HPLC method for the analysis of ochratoxin A in Triticum aestivum grain.

Ochratoxin A is a mycotoxin, a natural product of Aspergillus and Penicillium species. It can be present in grain from Triticum aestivum, (Graminae) and other starch-abundant cereals. This paper describes the investigation of ochratoxin A in grain from Triticum aestivum using a statistically optimized HPLC method. The assay was developed using two mathematical statistical models: factorial design and response surface mapping. The final step was to optimize the values of variables by response surface design. The analysis of variance 'ANOVA' method was applied to the analytical results in order to construct an adequate model. The optimal experimental conditions obtained by the response surface diagram method were: pH = 2.5, composition of the mobile phase acetonitrile: water 55:45 v/v and flow rate 1.0 ml/min. with a C18 column. Retention time and capacity factor for ochratotoxin A were 7.46 min. and 1.19, respectively.