Methods of analysis .nilhhhhhhhhhhh

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Methods of analysis .nilhhhhhhhhhhh

  1. 1. METHODS OF ANALYSIS For β CD COMPLEX Guided By: Mrs. S.P. CHAUDHRI Prepared By: Mr. NILESH K. GAWARE Marathwada Mitra Mandals’s College of Pharmacy, Pune-33 1
  2. 2. METHODS OF ANALYSIS  There are 6 methods to analyse the β cd complex. 1. 2. 3. 4. 5. 6. 2 Method of continuous variation Spectroscopy method Distribution method pH titration methods Solubility methods General method NILESH GAWARE MM COLLEGE OF PHARMACY.
  3. 3. 1. METHOD OF CONTINUOUS VARIATION  In this we measured additive property.  JOB suggested the use of additive property such as spectrophotometric extinction coefficient (dielectric constant & square of R.I)  If the property for two species is different and when they are mixed no interaction is occur  The value of the property is calculated by taking mean of there individual species in mixture 3 NILESH GAWARE MM COLLEGE OF PHARMACY.
  4. 4.  If the additive property such as dielectric constant is plotted Vs mole fraction from 0-1  If there is no complex formation then it will give linear relationship. 4 NILESH GAWARE MM COLLEGE OF PHARMACY.
  5. 5.  If the solution of two species A & B are of equal molar conc. are mix & if complex is form between them then value of additive property will pass from maximum.  For a constant total conc. of A & B the complex is at highest conc. at point where the species A & B are combined in the ratio in which they occur in the complex.  The line show a change in slope occurs at the mole fraction corresponding to the complex .  The change in slope occur at a mole fraction indicate a type of complex . 5 NILESH GAWARE MM COLLEGE OF PHARMACY.
  6. 6. Spectrophotometric approach  In this method measure the absorbance of the solutions of various mole fraction in which the complex is form.  Measure the absorbance of another same mole fraction of solution in which the complex is not form.  Take the absorbance difference of this solutions and plot a graph Vs mole fractions.  Extrapolate the intersect point on x axis gives the conk . of mole fraction require to form stable complex of cd’s. 6 NILESH GAWARE MM COLLEGE OF PHARMACY.
  7. 7. 7 NILESH GAWARE MM COLLEGE OF PHARMACY.
  8. 8.  Another relation can be used that is absorbance is proportional to the only conc. of the complex MAn,the molar ratio of ligand A to metal M and stability constant can be calculated as follows. M + nA 8 NILESH GAWARE MAn MM COLLEGE OF PHARMACY.
  9. 9. Log[Man]=log k + log [M]+nlog [A] where,  Log[MAn]=conc. of complex  Log k = equm.constant  N= no. of ligand  Log[M]= conc. of uncomplex metal ion  In this the conc. of metal ion is kept constant while the conc. of ligand varried & corrsponding to the formation of complex is obtained from the spectrophotometric analysis.  If we plot the graph of log[MAn] Vs log[A] then slope of line gives no. of ligand mole require to form complex & intercept gives the stability constant. 9 NILESH GAWARE MM COLLEGE OF PHARMACY.
  10. 10. pH titration methods  This is a method used in which the complexation is achieve by change in pH.  Eg.chelation of cupric ion by glycine. 10 NILESH GAWARE MM COLLEGE OF PHARMACY.
  11. 11. CONTINUE……  As the two proton are formed in the reaction of equation the addition of glycine to a solution containing cupric ion should result in a decrease in pH .  Titration curve can be obtained by adding a strong base to solution of glycine & to another solution containing glycine & cupric ion.  Plot the graph of pH Vs no. of ml strong base added.  The curve for glycine metal mix is well below that for the glycine alone & decreased in pH show that complexation is occur is throughout most of the neutralization range. 11 NILESH GAWARE MM COLLEGE OF PHARMACY.
  12. 12. 12 NILESH GAWARE MM COLLEGE OF PHARMACY.
  13. 13.  The results can be treated to obtain stability constant for the complex.  The 2 successive equilibrium between the cu ion M, and glycine or ligand A, so M + A= MA k1=[MA]/ [M].[A] MA+A =MA2 k2=[MA2]/ [MA]. [A] 13 NILESH GAWARE MM COLLEGE OF PHARMACY.
  14. 14. M + 2A =MA2;β β= K1.K2=[MA2]/ [M].[2A] Where , k1 & k2=formation constant, β = equilibrium constant 14 NILESH GAWARE MM COLLEGE OF PHARMACY.
  15. 15.  The average number of ligand group bound per metal ion present is given by  The denominator gives the total conc. of metal present in in all form. 15 NILESH GAWARE MM COLLEGE OF PHARMACY.
  16. 16. [MA]+ 2[MA2] =[M] + [MA] +[MA2] [M] =[MA2] β=K1.K2=1/[A]2 P[A]= ½ log β n =1 P[a]=log k1 n=1/2 P[A]= log k2 n=3/2 16 NILESH GAWARE MM COLLEGE OF PHARMACY.
  17. 17.  If we know the value of n & β we can determine the individual complex formation constant & stability constant.  When graph is plotted of n Vs p[A] w.r.t to pHs 17 NILESH GAWARE MM COLLEGE OF PHARMACY.
  18. 18.  It is seen that value of n is reach up to certain value which indicate that maximum no of glycine mole that can combine with cu ion. 18 NILESH GAWARE MM COLLEGE OF PHARMACY.
  19. 19. SOLUBILITY METHOD  Higuchi & Lach used this method for detection of complex.  Take a container with closure system. Add drug in to the container along with the solution of complexing agent.  Make series of solution of different conc.of complexing agent & the bottle's are agitated in a constant temperature bath.  Aliquid portion is removed & analyzed. 19 NILESH GAWARE MM COLLEGE OF PHARMACY.
  20. 20.  In this p-amino benzoic acid(PABA) is drug & caffeine is complexing agent.  The results of above experiments is plotted as molar conc.of PABA Vs. molar conc. of caffeine.  The point A at which the line crosses the vertical axis show the solubility of drug in water.  Add caffeine then observed. There is increase in solubility of PABA linearly owing to complexion. 20 NILESH GAWARE MM COLLEGE OF PHARMACY.
  21. 21. 21 NILESH GAWARE MM COLLEGE OF PHARMACY.
  22. 22.  At point B the solution is saturated w.r.t. the complex & to the     22 drug itself. The complex continue to form & precipitate from the saturated system as more caffeine is added. At point ‘C’ all excess solid PABA has passed into solution & has converted to the complex. Although the solid drug is exhausted and the solution is no longer saturate some of the PABA remain uncomplexd in solution. It is further combine with caffeine to form higher complex as shown in fig. NILESH GAWARE MM COLLEGE OF PHARMACY.
  23. 23. Distribution Methods  The method of distributing a solute, between two immiscible solvent can be used to determine the stability constant for certain compound.  The complexion of iodide by Potassium iodide may be used as.  E.g. To explain this method equation I2 + I- 23 NILESH GAWARE I3 --- MM COLLEGE OF PHARMACY.
  24. 24.  Higuchi investigate the complexing action of caffeine, glycols on number of acidic drugs using this method.  According to Higuchi & Zuck the reaction between caffeine & benzoic acid to form the B.A– caffeine complex K= [B.A - caffeine]/ [B.A - caffeine] K=37.5 24 NILESH GAWARE at 0 MM COLLEGE OF PHARMACY.
  25. 25. SPECTROSCOPY & CHARGE TRANSFER COMPLEXATION  It is used for charge transfer complexation.  When iodine is analyzed in a noncomplexing solvent such as CCL4 a curve is obtained with single peak at about 520nm having violet color.  A solution of iodine in benzene exhibits a max. shift to 475nm & peak considerably intensity for the charge shifted band appears at 300nm.  A solution of iodine in diethyl ether shows a still greater shift to lower wavelength & the appearance of a new max. solution is red to brown. 25 NILESH GAWARE MM COLLEGE OF PHARMACY.
  26. 26.  In benzene & ether iodine is electrons accepter accepter & the     26 organic solvent is donor in in ccl4;no complex is formed. The shift towards the u.v. region becomes greater as the electron donor solvents becomes a strong electron releasing agents. This spectra arise from the transfer of an electron from donor to the accepter in close contact contact in the in the excited state of the complex. The more easily a donor release its electrons as measured by its ionization potential, the stronger it is as a donor. Ionization potential of a series of donor produce a straight line, when plotted against the charge transfer energy for solution of iodine in the donor solvent. NILESH GAWARE MM COLLEGE OF PHARMACY.
  27. 27.  The complexation constant K can be obtained by use of UV spectroscopy.  The association between the donor D & accepter A is given as K1 D + A DA K-1  Where, k1/k-1 = equilibrium constants for complexation k1& k-1 =interaction rate constant. 27 NILESH GAWARE MM COLLEGE OF PHARMACY.
  28. 28. The Benesi-Hildebrand eq.given relation of k that is. A0/A=1/€+1/K €*1/D0 A0 & D0 = initial conc. in mole/lit. € = molar .absorptivity of the charge transfer complex. K= stability constant L/mole 28 NILESH GAWARE MM COLLEGE OF PHARMACY.
  29. 29. result in a straight line with slope of 1/K € is observe  A plot of A0/A Vs 1/D0 29 NILESH GAWARE MM COLLEGE OF PHARMACY.
  30. 30. GENERAL METHODS  It include Nuclear magnetic resonance ,infra red spectroscopy, polarography x-ray diffraction , kinetics etc & many more.  NMR SPECTROSCOPY ;  EG.complexation of caffeine with tryptophan in aq.solution was given by Nishijo et.al using H1 NMR  Caffeine interacts with L-tryptophan at a molar ratio of 1:1 by parallel stacking 30 NILESH GAWARE MM COLLEGE OF PHARMACY.
  31. 31. 31 NILESH GAWARE MM COLLEGE OF PHARMACY.
  32. 32. 32 NILESH GAWARE MM COLLEGE OF PHARMACY.
  33. 33. 33 NILESH GAWARE MM COLLEGE OF PHARMACY.

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