1. A. N. Saab, L. W. Dittert and A. A. Hussain, J. Pharm. Sci., 1988, 77, 906.

2. A. N. Saab, A. A. Hussain, I. H. Patel and L. W. Dittert, J. Pharm. Sci., 1990, 79, 802.

3. I. Saikawa, M. Tai, H. Sakai, Y. Yamamoto, Y. Sugimoto, K. Demachi, K. Kanai, J. Nakano and K. Sadaki, Yakugaku Zasshi, 1986, 106, 452.

4. T. Sugioka, T. Asano, Y. Chikaraishi, E. Suzuki, A. Sano, T. Kuriki, M. Shirotsuka and K. Saito, Chem. Pharm. Bull., 1990, 38, 1998.

5. M.J.S. Dewar, E.G. Zoebisch, E.F.Healy and J.J.P. Stewart, J. Am. Chem. Soc., 1985, 107, 3902.

6. AMPAC 5.0 (c) 1994 Semichem, 7128 Summit, Shawnee, KS 66216.

7. D. Goldfarb, Math.Comput., 1970, 24, 23.

8. D.F. Shanno, J. Opt. Theory Applic., 1985, 46, 87.

9. D.F. Shanno, Math. Comput., 1970, 24, 647.

10. R. Fletcher, Comput. J., 1970, 13, 317.

11. C.G. Broyden, J. Inst. Math. Applic., 1970, 6, 222.

12. M. I. Page, Acc. Chem. Res., 1984, 17, 144.

13. T. Yamana, A. J. Tsuji, J. Pharm. Sci., 1976, 65, 1563.

14. E. Pop, M.J. Huang, M.E. Brewster and N. Bodor, J. Mol. Struct. (THEOCHEM), 1994, 315, 1; and references cited therein.

15. R. B. Morin and B. G. Jackson, Forstsch. Chem. Org. Naturst, 1970, 28, 343.

16. C. J. Cramer and D. G. Truhlar, J. Comp. Aided Molec. Des., 1992, 6, 629.

17. H. S. Harned and W. J. Hamer, J. Am. Chem. Soc., 1933, 55, 2194.