Spectrofluorimetric determination of piroxicam in the presence and absence of β-cyclodextrin

Abstract

The complexation between β-cyclodextrin (β-CD) and piroxicam (PX) was investigated by both fluorescence and absorption spectrometry. A 1:2 guest:host stoichiometry for the complex was established, and its association constant was calculated by applying a non-linear regression method to the changes brought about by the presence of β-CD in both the fluorescence and absorbance spectra of PX. During the study of the influence of the pH on the fluorescence emission of the complex, an efficient enhancement of the signals at acidic pH was observed. This suggests that the protonated form of PX is included more effectively than the ionized form in the β-CD cavity. Based on the results obtained, spectrofluorimetric methods for the determination of PX were developed. The best limits of detection and quantification were obtained using β-CD at an acidic pH. The dynamic range in this latter case was 0.02–1 µg ml^–1. The method was applied satisfactorily to the determination of piroxicam in a pharmaceutical preparation.

References

1. Y. H. Chang and S. H. Dromgoole, in Drugs for Rheumatic Disease, ed. H. E. Paulus, D. E. Furst and S. H. Dromgoole, Churchill Livingstone, New York, 1987, ch. 18.
2. R. N. Brogden, R. C. Heel, T. M. Speight and G. S. Avery, Drugs, 1981, 22, 165.
3. J. A. Acuna, C. Delafuente, M. D. Vazquez and M. L. Tascon, Talanta, 1993, 40, 1637.
4. E. Hackmann, E. Gianotto and M. I. Santoro, Anal. Lett., 1993, 26, 259.
5. M. A. El-Ries, Anal. Lett., 1998, 31, 793.
6. A. Avgerinos, S. Axarlis, J. Dragatsis, Th. Karidas and S. Malamataris, J. Chromatogr. B, 1995, 673, 142.
7. P. C. Damiani, M. Bearzotti, M. A. Cabezón and A. C. Olivieri, J. Pharm. Biomed. Anal., 1998, 17, 233.
8. S. A. Soper, I. M. Warner and L. B. McGown, Anal. Chem., 1998, 70, 477R.
9. S. Scypinski and L. J. Cline Love, Anal. Chem., 1984, 56, 331.
10. S. Hamai, J. Phys. Chem., 1988, 92, 6140.
11. A. Muñoz de la Peña, T. T. Ndou, J. B. Zung, K. L. Greene, D. H. Live and I. M. Warner, J. Am. Chem. Soc., 1991, 113, 1572.
12. A. Muñoz de la Peña, I. Durán-Merás, F. Salinas, I. M. Warner and T. T. Ndou, Anal. Chim. Acta, 1991, 255, 351.
13. G. M. Escandar and A. Muñoz de la Peña, Anal. Chim. Acta, 1998, 370, 199.
14. R. J. Hurtubise, Phosphorimetry. Theory, Instrumentation and Applications, VCH, New York, 1990.
15. I. Durán-Merás, A. Muñoz de la Peña, F. Salinas and I. Rodríguez Cáceres, Analyst, 1994, 119, 1215.
16. J. C. Márquez, M. Hernández and F. García Sánchez, Analyst, 1990, 115, 1003.
17. S. Panadero, A. Gómez-Hens and D. Pérez-Bendito, Talanta, 1993, 40, 225.
18. O. Jules, S. Scypinski and L. J. Cline Love, Anal. Chim. Acta, 1985, 169, 355.
19. J. Szejtli, Cyclodextrins and Their Inclusion Complexes, Akadémiai Kiadó, Budapest, 1982.
20. C. L. Araujo, G. A. Ibañez, G. N. Ledesma, G. M. Escandar and A. C. Olivieri, Comput. Chem., 1998, 22, 161.
21. A. C. Olivieri and G. M. Escandar, Anal. Lett., 1997, 30, 1967.
22. The Merck Index, ed. M. Windholz, Merck, Rahway, NJ, 1983, p. 1082.
23. R. L. VanEtten, J. F. Sebastian, G. A. Clowes and M. L. Bender, J. Am. Chem. Soc., 1967, 89, 3242.
24. M. J. S. Dewar, E. G. Zoebisch, E. F. Healy and J. J. P. Stewart, J. Am. Chem. Soc., 1985, 107, 3902.
25. A. Muñoz de la Peña, T. Ndou, J. B. Zung and I. M. Warner, J. Phys. Chem., 1991, 95, 3330.
26. D. A. Skoog, Principles of Instrumental Analysis, Saunders College Publishing, Philadelphia, 3rd edn., 1985, p. 22.
27. J. Mandel and R. D. Stiehler, J. Res. Natl. Bur. Stand. (US), 1964, A53, 155.
28. L. Cuadros Rodríguez, A. M. García Campaña, C. Jimenez Linares and M. Román Ceba, Anal. Lett., 1993, 26, 1243.
29. D. Dell, in Analysis of Drugs and Metabolites Including Anti-infective Agents, ed. E. Reid and I. D. Wilson, Methodogical Surveys in Biochemistry and Analysis, Royal Society of Chemistry, Cambridge, 1990, vol. 20, p. 14.