NMR method for the determination of Nevirapine in pharmaceutical formulations.

Results shown

The poster shows the use of absolute Proton NMR signal intensities for the quantification of Nevirapine in mixtures. The concentration of Nevirapine is correlated with the number of scans and receiver gain, taking into account the delay between scans. We observe that, assuming a minimum delay of 15s, the signal intensity increase with each scan is linear, as long as the receiver gain is above 200. Hence we can calculate the concentration from this parameters.

The calibration value determined remains untouched by mixtures, as long as signals do not overlap. But, we assume there will be influence of the shim and the size of the molecule. The shim influences by changing the line shapes and therefore the integral. The molecule's size influences the T1 time, larger molecules with shorter relaxation times will have lower intensities. This influences remain to be analysed.

Literature cited

The following literature references are used for this poster:

  1. van Heeswijket al., J. Chromatogr B 1998, 713, 395; Murphy, R.L. e Montaner, J.; Exp. Opin. Invest. Drugs 1996, 5, 1183.
  2. Langmann et al., J. Chromatogr B 2002, 767, 69; van Heeswijket al., J. Chromatogr B 1998, 713, 395-399; Lopez et al., J. Chromatogr B 2001, 751, 371; Hollanders et al., J. Chromatogr B 2000, 744, 65; Pav et al., J. Pharm. Biomed. Anal. 1999, 20, 91; Chi et al., J. Pharm. Biomed. Anal. 2003, 31, 953.
  3. Kaul et al., Talanta 2004, 62, 843; Sarkar et al., J. Chromatogr B 2006, 830, 349; Sekar et al., Chromatographia 2008, 67, 389.
  4. Robins et al., Nucleos Nucleot 1998, 17, 785-790; F. Malz and, H. Jancke, J Pharmaceut Biomed 2005, 38, 813-823.
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