Development of a rapid and validated stability-indicating UPLC-PDA method for concurrent quantification of impurity profiling and an assay of ipratropium bromide and salbutamol sulfate in inhalation dosage form.

The objective of the proposed work was to develop a rapid and new reverse phase ultra-performance liquid chromatographic (RP-UPLC) method for the simultaneous quantification of related impurities of ipratropium bromide and salbutamol sulfate in the combined inhalation dosage form. Herein, the chromatographic separation was achieved on Acquity BEH C18 (100mm×2.1mm, 1.7µm) column by following gradient elution of solvent A as 2mM potassium dihydrogen phosphate with 0.025% of 1-pentane sulphonic acid sodium salt (pH 3.0 buffer) and solvent B as pH 3.0 buffer, acetonitrile and methanol in the ratio of (32:50:18, v/v/v) at a flow rate of 0.3mL/min. The samples were detected and quantified at 220nm. To prove the stability-indicating potential of the method, forced degradation studies were performed using acidic, basic, oxidative, thermal, and photolytic conditions. After sufficient exposure, the resultant solutions were injected and found that all degradants and impurities formed during stress studies were well separated from each other and from the main peak compounds. The performance of the method was validated according to the present ICH Q2 (R1) guidelines. The method has good linearity (r≥0.999) and consistent recoveries were obtained with a range of 91.3-108.8% for all compounds. The % RSD obtained for the precision experiments was less than 5% and also there is a good sensitivity (LOQ≤0.5µg/mL) for all compounds. The intended method proved its applicability and that it can be beneficial to pharmaceutical industries for quick quantification of related impurities and assay in quality control department for analysis of ipratropium bromide and salbutamol sulfate inhalation dosage form.

Assay of tirofiban and identification of oxidative impurity in aqueous injection by using UPLC-PDA/QDa detectors.

The basic objective of this study is to propose a short, reliable, mass compatible ultra-performance liquid chromatography (UPLC) method to confirm the identity of impurities and to estimate the assay and purity of Tirofiban simultaneously in aqueous injection (5mg/100mL bag). Aqueous formulations are susceptible to oxidation, hence the possible oxidative degradation impurities of Tirofiban were studied in this experiment by using UPLC coupled with photodiode array/Quadrupole Dalton Analyzer (PDA/QDa) detectors. The required separations were achieved in the column: ACQUITY HSS T3 (100×2.1) mm, 1.7µm, operated at 30°C by using 0.02% Triethyl amine (TEA) in water, pH 2.8 with formic acid as solution-A and 0.1% formic acid in 9:1 acetonitrile, water as solution-B. Binary gradient flow is delivered at the rate of 0.5mL/min and the detection of impurities specifically carried out at 227nm using empower3 software. RP-UPLC/PDA with QDa detector was used for the experiment. The method was linear and accurate from the concentrations: 0.04 to 0.38µg/mL for impurity-A and 0.04 to 75µg/mL for Tirofiban. The major unknown degradation impurity generated during the oxidative degradation has been identified as N-oxide derivative (Impurity-B) [(M+H)+ 455.1] by using QDa detector operated in an electro spray positive ion mode by applying a voltage of 0.8kV. This method was further validated as per ICH Q2 (R2) guidelines. Hence, the proposed method is said to be a fast, sensitive and comprehensive technique, which could give a clear idea about the assay and impurity profile of Tirofiban injection.

Single quad mass analyzer coupled UPLC method for impurity profile of Brimonidine tartrate and Timolol maleate: Application in their binary mixture ophthalmic formulation.

The main objective of the study is to develop a suitable and rapid UPLC/PDA method by coupling online to Quadrupole Dalton analyzer (QDa), a mass detector for the identification and impurity profiling of Brimonidine Tartrate (BRIM)/Timolol maleate (TIMO) in the ophthalmic formulation. Chromatographic separation was achieved on ethylene bridged hybrid octadecylsilane column having 1.7µm particle size in gradient mode using high pure heptafluorobutyric acid as a buffer (A) and water, methanol, and acetonitrile (B) as mobile phase with a flow rate of 0.3mlmin-1. Based on the spectral maxima, BRIM and its impurities were monitored at 248nm, and TIMO and its impurities were monitored at 295nm. During evaluation of stress conditions and stability data unknown degradants are observed and identified as m/z 218.01 (DP1) and m/z 390.03 (DP2) using QDa-ESI+ scanning mode technique. The performance of the method was systematically validated according to ICH Q2 (R1) guidelines and the method shown very good sensitivity (≥0.5µg.mL-1) and linearity (r2≥0.999) with consistent recoveries and less than 5% RSD for all compounds. Hence, the proposed UPLC/PDA/QDa method is a simple, sensitive and comprehensive technique where identification and quantification can be done. It gives for complete impurity profile evaluation of BRIM/TIMO in the ophthalmic formulation during quality control in the pharmaceutical industry.