572 Razzak Mageed et al.
Asian J. Chem.
TABLE-1
PHYSICAL PROPERTIES OF PREPARED POLYMERS
Polymer
Colour
T (°C)
tD,WS
TunkS
dunk
dD.W
ηD.w poise
ηunk poise
Yellow
Brown
Light yellow
Brown light
–
–
25
–
–
–
62
–
54
58
54
53
0.786
0.782
0.783
0.786
–
–
0.99
–
–
0.904
–
0.62
0.67
0.61
0.60
F8
F9
F14
F15
–
Swelling ratio: The swelling ratio was determined by
immersing xerogel (0.05 g) from homo- and hetero polymers,
in 50 mL of different buffer solutions (pH = 2.2, 7.0 and 8.0).
It was allowed to soak for different period of time at constant
temperature (310 K). After each 1 h and 24 h, hydrogel was
removed from the water, blotted with filter paper to remove
surface water weighed and then the swelling ratio was calcu-
lated using following equation [24]:
ance signal at δ 8 ppm for (C=C-H)Ph, at δ 6 ppm for (C=C-H)
maleimide and at δ 3 ppm for (C-H). The 13C NMR spectrum
for monomer (F3) showed the disappearance of signal for
(C=O) acid and shows the signals at δ 130 ppm for (C=C)Ph
and at δ 40 ppm for (C-C).
Characterization of homopolymers (F8 and F9): The
FT-IR spectra of homopolymers (F8 and F9) show the disapp-
earance absorption band of C=C-H maleimide at 3100 and
3009 cm-1 respectively and the absorption bands at 2992 cm-1
C=C-H benzamide (F8) and C-C-H aliph at 2885 cm-1 (F9).
The absorption band at 2885 cm-1 of C=C-H ring of drug (F8)
is clearly visible. The absorption peaks of C=O amide at 1712
(F8) and 1711 cm-1 (F9), similarly C-N-C at 1693 (F8) and 1530
cm-1 (F9); at 1586 (C=C maleimide) (F8) and 1600 cm-1 (F9).
The 1H NMR of polymer (F8) shows the single peak at δ
10 ppm for (O=C-H), multi-signals at δ 7-8 ppm for (C=C-H,
H-Ar), at δ 3-4 ppm for (C-C-H)maleimide and at δ 1-3 ppm
for (N-H). Similarly, 1H NMR of polymer (F9) shows the multi-
signals at δ 7-8 ppm for (C=C-H)Ph, at δ 3-4 ppm for (C-C-H)-
maleimide and at δ 1-3 ppm for (C-H3).
Characterization of heteropolymers (F14 and F15): The
FT-IR spectra of heteropolymer (F14) show the disappear-
ance absorption band of O-H and the appearance of absorption
peaks at 3105 cm-1 C=C-H benzamide (F14). Similarly, hetero-
polymer (F15) shows the peak at 2929 cm-1 C-H aliph. The
disappearance of absorption peak of C=C-H maleimide was
found in both heteropolymers. Similarly, the absorption peaks
at 3075 (F14) and 3010 cm-1 (F15) of C=CH acrylic acid, at
2981 cm-1 (F14) of C-C-H aliph, 1714 (F14) and 1711 cm-1
(F15) C=O amide; at 1602 cm-1 (F14 and F15) C-N-C; at 1173
(F14 and F15) C-O; at 1256 (F14) and 1381 cm-1 (F15) C-N
were observed.
wt. of hydrogel − wt. of xerogel
Swelling ratio (%) =
×100
wt. of hydrogel
Release of drugs: By using UV-visible spectrophoto-
meter, the release of drug from the prepared polymers (both
homo- and hetero polymers) was determined in three different
buffer solutions (pH 2.2, 7.0 and 8.0) at constant temperature
310 K. By immersing xerogel (0.05 g) from homo- and hetero
polymers in 50 mL of different buffer solutions, it was allowed
to soak for different invertal of time at constant temperature
310 K. The hydrogel was removed from the buffer solution at
the stipulated time and measure the absorbance of buffer solu-
tion in order to determine the amount of drug release [25].
RESULTS AND DISCUSSION
Characterization of compound F1: The appearance of
characteristic absorption broad bands at 3500 ν(O-H), 3100
ν(C=C-H maleimide), 1705 ν(C=O carboxylic acid), 1602
ν(C=C benzoic acid). 1514 ν(C=C maleimide), 1380 ν(C-N-C),
1175 ν(C-O) 824 ν(p-substituted of benzene ring) and 697 ν(o-
1
substituted of benzene ring) and 542 ν(C-C) [26]. H NMR
shows single-signal at δ 13 ppm for (OH) acid, and signal
doublet at 8 ppm for (Ph-H), single-signal at 4 ppm for (C=C-
H)maleimide and single-signal at 3.5 ppm for (N-C=C-H).
13C NMR shows the signal at 166.60 ppm for (C=O) carboxylic
acid and doublet signal at 130 ppm for (C=C)Ph, and single
signal at 40 ppm for (C-O) carboxylic acid [27].
The 1H NMR of polymer (F14 and F15) shows the multi-
signals at δ 7-8 ppm for (C=C-H)Ph, at δ 3-4 ppm for (C-C-
H)maleimide, at δ 2-3 ppm for (C-OH)aliph and at δ 1 ppm
for (C-H)aliph. For polymer F15, the single peak was observed
at δ 10 ppm for (O=C-H).
Solubility: The solubility properties of prepared mono-
mers and polymers in different solvents (H2O, ethanol, CHCl3,
ether, toluene, DMSO, hexane, petroleum ether and acetone)
were studied. The solubility results are shown in Table-2.
Swelling ratio: The swelling ratio was determined by
immersing 0.05 g polymers in 50 mL of different buffer solutions
(pH 2.2, 7.0 and 8.0) and allowed to soak for different period
of time at 310 K. Table-3 represents the swelling ratio of homo
and hetero polymers in different period of time.
Characterization of monomers (F2 and F3): The FTIR
spectra of monomer (F2 and F3) show the disappearance
absorption band of O-H and appearance of absorption band of
NH2 at 3306 cm-1, 3100 cm-1 C=C-H maleimide, 2997 cm-1
C=C-H benzamide (F2) and 2926 cm-1 (F3), 2923 cm-1 C=C-H
ring of drug, 1710 cm-1 C=O amide, 1600 cm-1 (C-N-C), 1532
cm-1 C=C amide, 1381 cm-1 C-N, 1311 cm-1 C-N drug, 1256
cm-1 S=O, 1172 cm-1 C-O, 947 cm-1 C-S and 697 cm-1 S-N. The
1H NMR shows the disappearance signal for (O-H) acid and
appearance of a single signal at δ 11 ppm for (OH) drug, doublet
signal at δ 8 ppm for (C=C-H)Ph, a single signal at δ 5 ppm for
(C=C-H), δ 2 ppm for CH3. The 13C NMR also shows the disapp-
earance signal at δ 170.67 ppm (C=O) acid and signal at δ 130
ppm for (C=C)Ph and at δ 40 ppm for (C-H3).
Release of drug: By using UV-visible spectrophotometer,
drug release from the prepared polymers (homo and hetero)
was determined in three different buffer solutions (pH 2.2, 7.0
and 8.0) at 310 K. Table-4 represents the drug release from
the prepared polymer.
The 1H NMR spectrum for monomer (F3) shows disapp-
earance a single signal at δ 13 ppm for (OH) acid and appear-