Assignment:
Transport of pilocarpine across the corneal membrane
Obtain the delta H and delta S in the example 3 - 14 on page 71 of Martin's Physical Pharmacy. A set of data (log Ka v. 1/T x 10^3) is plotted and the linear form of the van't hoff equation should be used to calculate delta H and delta S. The equation in this form is:
ln K = -(delta H/R)1/T + delta S/R or y = mx + b where: delta H/R = m and delta S/R = b.
Question-1
In the study of the transport of pilocarpine across the corneal membrane of the eye, Mitra and Mikkelson presented a van't Hoff
Problem
1/K' pH
0.2315 3.3
0.2801 3.4
0.4 3.6
0.6993 3.9
1.0526 4.11
2 Anhydrous
ln/X 1/T
-1.1394 0.1
-0.9676 0.04
-0.6162 0.027
Did not convert to mole fraction first!
2 Dihydrate
ln/X 1/T
Question-2
Cg (g/L) π / cg (l-atm g-1)
1.25 7.76E-03
2.5 7.90E-03
3.75 8.03E-03
5 8.16E-03
Question-3
|
|
|
|
|
|
|
C |
K |
1/T |
log X |
X |
|
|
|
|
|
|
Ibuprofen |
75 |
348.15 |
0.002872 |
2.579784 |
380 |
Alclofenac |
92 |
365.15 |
0.002739 |
2.875061 |
750 |
Ketoprofen |
94 |
367.15 |
0.002724 |
2.845098 |
700 |
Fenclofenac |
134 |
407.15 |
0.002456 |
2.146128 |
140 |
Diclofenac |
155 |
428.15 |
0.002336 |
0.90309 |
8 |
Indomethicin |
155 |
428.15 |
0.002336 |
-1 |
0.1 |
Naproxen |
155 |
428.15 |
0.002336 |
1.845098 |
70 |
Sulidac |
182 |
455.15 |
0.002197 |
1 |
10 |
Fenbuprofen |
185 |
458.15 |
0.002183 |
0.69897 |
5 |
Indoprofen |
213 |
486.15 |
0.002057 |
1.176091 |
15 |
75
|
348.15
|
0.002872
|
2.579784
|
380
|
|
92
|
365.15
|
0.002739
|
2.875061
|
750
|
|
94
|
367.15
|
0.002724
|
2.845098
|
700
|
|
134
|
407.15
|
0.002456
|
2.146128
|
140
|
|
110
|
383.15
|
0.00261
|
2.376577
|
238
|
|
155
|
428.15
|
0.002336
|
1.845098
|
70
|
?????
|
155
|
428.15
|
0.002336
|
0.90309
|
8
|
|
155
|
428.15
|
0.002336
|
-1
|
0.1
|
|
182
|
455.15
|
0.002197
|
1
|
10
|
|
185
|
458.15
|
0.002183
|
0.69897
|
5
|
|
213
|
486.15
|
0.002057
|
1.176091
|
15
|
|
75 |
348.15 |
0.002872 |
2.579784 |
380 |
206 |
2.313867 |
92 |
365.15 |
0.002739 |
2.875061 |
750 |
226 |
2.354108 |
94 |
367.15 |
0.002724 |
2.845098 |
700 |
254 |
2.404834 |
134 |
407.15 |
0.002456 |
2.146128 |
140 |
297 |
2.472756 |
|
|
|
|
|
|
|
110 |
383.15 |
0.00261 |
2.477121 |
300 |
305 |
2.4843 |
Alpha-Methyls |
C |
K |
1/T |
log X |
X |
Indomethicin |
155 |
428.15 |
0.002336 |
-1 |
0.1 |
Fenbuprofen |
185 |
458.15 |
0.002183 |
0.69897 |
5 |
Indoprofen |
213 |
486.15 |
0.002057 |
1.176091 |
15 |
Ketoprofen |
94 |
367.15 |
0.002724 |
2.845098 |
700 |
Ibuprofen |
75 |
348.15 |
0.002872 |
2.579784 |
380 |
Naproxen |
155 |
428.15 |
0.002336 |
1.845098 |
70 |
|
|
|
|
|
|
Question-4
1/T x 103 log Ka
3.47 -7.13
3.41 -6.97
3.35 -6.9
3.3 -6.8
3.24 -6.67
3.19 -6.53
3.14 -6.4
In the study of the transport of pilocarpine across the corneal membrane of the eye, Mitra and Mikkelson presented a van't Hoff
plot of the log of the ionization constant, log Ka, of pilocarpine versus the recipocal of the absolute temperature, 1/T. Using the data in
Table 1 above, regress log Ka versus 1/T. With reference to the van't Hoff equation below :
ln K = - (delta Ho/R)1/T + deltaSo/R
obtain the standard heat (enthalpy), delta H, of inoization for pilocarpine and the standard entropy for the ionization
process.