Method development and validation for the analysis of didanosine using micellar electrokinetic capillary chromatography

Abstract

A selective MEKC method was developed for the analysis of didanosine in bulk samples. Successful separation of didanosine from 13 of its potential impurities, derived from the various synthetic preparation procedures, was achieved. As CZE gave poor separation selectivity, MEKC was preferable. The use of EKC allowed achievement of the separation in a significantly shorter time than conventional HPLC. An anionic long-chain surfactant, lithium dodecyl sulfate (LiDS), was used as the pseudostationary phase and sodium tetraborate buffer as the aqueous phase. In order to obtain the optimal conditions and to test the method robustness, a central composite response surface modeling experiment was performed. The optimized electrophoretic conditions include the use of an uncoated fused-silica capillary with a total length of 40 cm and an ID of 50 microm, a BGE containing 40 mM sodium tetraborate and 110 mM LiDS at pH 8.0, an applied voltage of 18.0 kV, and the capillary temperature maintained at 15 degrees C. The method was found to be robust. The parameters for validation such as linearity, precision, and sensitivity are also reported. Three commercial bulk samples were analyzed with this system.

Theoretical models of separation selectivity for charged compounds in micellar electrokinetic chromatography

“…In the case of analytes with a difference in their electrophoretic mobility (m 0 ) at zero concentration of surfactant or CZE, the MEKC separation is based on the differences in both k and m 0 . In comparison with the CZE separation of charged analytes, the addition of surfactant to the MEKC buffer may result in improved separation for some analytes, but lowered degree of separation for other analytes [4,10,[13][14][15][16][17][23][24][25][26]. These dual effects are similar to those seen in chiral separation using dual cyclodextrins as reported in our previous work [27].…”

Nucleoside reverse transcriptase inhibitors and their phosphorylated metabolites in human immunodeficiency virus-infected human matrices

“…Mallampati et al [63] presented a selective MEKC method for the analysis of ddI in bulk samples. Successful separation of ddI from 13 of its potential impurities that were derived from the various synthetic preparation procedures was achieved.…”

“…An anionic long-chain surfactant, namely lithium dodecyl sulfate (LiDS), was used as the pseudostationary phase and the sodium tetraborate buffer as the aqueous phase. The optimized electrophoretic conditions included the use of an uncoated fusedsilica capillary with a total length of 40 cm and an ID of 50 m, a background electrolyte (BGE) containing 40 mM sodium tetraborate and 110 mM LiDS at pH 8.0, an applied voltage of 18.0 kV, and the capillary temperature maintained at 15 • C [63]. Fan and Stewart developed a MEKC method to separate and quantify the anti-HIV drug mixtures A and B containing d4T/ddI/saquinavir and d4T/ddI/efavirenz, respectively, in human serum [64].…”

Analysis of dideoxyadenosine triphosphate by CE with fluorescence detection. I. Derivatization through the phosphate group

“…The uncharged compounds are separated according to their distribution between the aqueous phase and the micellar pseudostationary phase. Since LiDS showed promising results for the separation of 13 potential impurities of didanosine in our previous work [19], we have applied it for the separation of the dansyl EDA derivatives of ddATP, dATP and ATP. Optimum separations were targeted by varying the concentrations of LiDS in the range of 10-90 mM in combination with 100 mM ammonium acetate (pH 9.0).…”