RPLC determination of acid dissociation constants and quantitative estimation for sulfasalazine

Abstract

disease-modifying antirheumatic drug (DMARD) used in the treatment of patients with rheumatoid arthritis. Clinical studies during the last two decades have provided evidence of the drug's efficacy in the treatment of both ulcerative colitis and Crohn's disease [1].Acid dissociation constant values (pK a ) are useful physicochemical measurements describing the extent of ionization of functional groups with respect to pH. This parameter is important in pharmaceutical drug discovery and development [2]. Various experimental modalities have been used for the determination of the pK a values, comprising potentiometric titration [3], spectrophotometry [4], high performance liquid chromatography (HPLC) [5, 6] and capillary electrophoresis (CE) methodology [7]. Among these techniques, most of the drugs can be analyzed by reversed-phase liquid chromatography (RPLC) technique because of the several advantages like rapidity, specificity, accuracy, precision and ease of automation in this method.Analysis of the change in retention time of the analyte versus the change in pH of the mobile phase is given an indirect measure of the acid dissociation constant. The theory for studying the pH dependence of chromatographic retention for ionizable compounds in LC was proposed by Horvath et al. and verified by different authors for different type of compounds [8-10]. For a triprotic acid (H 3 A), Eqs. (1), (2) and (3) represent the variation of the retention factors at different pH values.(Abstract Acid dissociation constant value (pK a ) is key parameter for predicting the extent of the ionization of a drug molecule at different pH. The effect of the mobile phase composition on the acid dissociation constant values was studied by measuring the pK a values at different acetonitrile concentrations, ranging from 25 to 35 % (v/v). pK a values and limiting retention factors of SSZ were calculated chromatographically using equations derived. From calculated pK a values, the aqueous pK a values of SSZ were calculated by various approaches. Moreover, the correlation established between retention factors and the pH of the water-acetonitrile mobile phase was used to determine the optimum separation condition. Optimized condition was also validated with respect to system suitability, linearity, precision, accuracy, limit of detection and limit of quantitation, respectively. A Gemini NX C18 column (250 × 4.6 mm I.D., 5 µm particles) was used for all the determinations.

RPLC Method Development and Validation for the Simultaneous Determination of Selective Serotonin Reuptake Inhibitors in Tablet Formulations

“…The insoluble part in the prepared solution was removed by filtration. Finally, the solution obtained was prepared at different dilution rates according to the concentration in the calibration range specified for each compound [16,26,27].…”

Highly luminescent nitrogen‐doped carbon dots for simultaneous determination of chlortetracycline and sulfasalazine

“…Moreover, the proposed sensor was very facile and low-cost, indicating considerably feasible application for CTC and SSZ detection. [20] LC-fluorescence 0.0050-0.10 0.00050 [42] LC-MS 0.0010-0.30 0.0026 [24] CE 0.030-5.0 0.017 [26] Electrochemical sensor 0.046-25.77 0.026 [43] MIP-based ISEs ≥0.11 0.071 [44] N-CDs sensor 0.85-20.38 0.078 This work SSZ HPLC-dad 1-12 0.086 [22] LC-MS/MS 0.010-10.0 - [45] CE 0.050-0.50 0.0063 [27] Poly(3-methylthiophene) film modified GCE 30.0-128.0 10.0 [46] MWCNTCOOH-BA/SPCE 0.40-5.6 0.12 [47] Antimony film electrode 1.2-100 0.30 [48] N-CDs sensor 0.34-6.76 0.032 This work Note: MIP, molecularly imprinted polymer; ISEs, ion-selective electrodes; GCE, glassy carbon electrode; MWCNTCOOH-BA/SPCE, multiwalled carbon nanotubes/benzyl acetate modified screen-printed carbon electrode.…”

“…Up to now, several analytical techniques have been reported in the literature for CTC and SSZ detection including electrochemical , high performance liquid chromatography (HPLC) with UV/photodiode‐array or fluorescence detection , high performance liquid chromatography with mass spectrometry (HPLC‐MS) , capillary electrophoresis (CE) , and ultra‐high performance liquid chromatography coupled to tandem mass spectrometry (UPLC‐MS/MS) . Most of these methods mentioned are highly precise and sensitive, but not appropriate for routine analysis due to the requirements for sophisticated equipment, production of toxic effluents, and time‐consuming pretreatment of samples.…”

A Study on the Retention Behavior of Some Imidazole Antimycotic Drugs in Acetonitrile-Water Binary Mixtures

“…Reversed-phase liquid chromatography (RPLC) is the other preferred method to determine the pKa value of ionizable substances. This method is based on the different retention behavior of the ionized and neutral forms of drug molecules [13,14]. Among the advantages of this method is its necessity for a very small amount of the analyte and high purity of the sample is not required for the LC assays [15].…”