Indian Journal of Chemistry
Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical
Total visitors: 1,318 since 25-07-06
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VOLUME 45A |
NUMBER 7 |
July 2006 |
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CONTENTS |
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Papers |
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1601 |
On distribution of π-electrons in rhombus-shaped benzenoid
hydrocarbons Ivan Gutman*, Nedžad Turković & Boris
Furtula |
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The distribution of π-electrons into rings of rhombus-shaped benzenoid hydrocarbons is reported here. In this class of benzenoid systems, the unique Clar formula represents only a minute fraction of the total number of Kekulč structures, and therefore, a breakdown of the Clar model could be expected.
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1605 |
NMR and thermal studies of A S Brar* & Pravin
Kumar Singh |
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Copolymers with different compositions of |
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1611 |
Homogeneous catalysis of
aquachloro-ruthenium(III) complex and evaluation of individual kinetic and
thermodynamic parameters of bromate-mandelic acid reaction Ch Sanjeeva Reddy* & T
Vijaya Kumar |
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Aquachlororuthenium(III) complex catalysed bromate-mandelic acid reaction involves complex formation between mandelic acid and ruthenium(III), which in turn forms a ternary complex with two moles of bromate. The slow decomposition of the ternary complex to form products constitutes the rate-determining step.
Rate constants involved in each step of the reaction have been evaluated along with their thermodynamic parameters. |
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1619 |
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Pure cerium hydroxide has been prepared by
pseudo-template method and sulphate modification has been carried out by wet
impregnation method using H2SO4. Modified catalysts
have been prepared by incorporating varying amounts of molybdenum (5, 10 and
15%) into pure as well as sulphated cerium hydroxide. The oxydehydrogenation of ethyl
benzene proceeds efficiently over molybdenum incorporated pure as well as
sulphated ceria systems yielding styrene as the major product. Benzene,
toluene and |
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1626 |
D S Rajmane,
K V Kapashikar & G S Gokavi* |
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The oxidation of various aliphatic alcohols by oxone catalyzed by Keggin type [CoIIW12O40]6- has been studied.
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1631 |
Effect of temperature on
the viscosities of some divalent transition metal sulphates and magnesium
sulphate in water and water+ethylene glycol mixtures |
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Relative viscosities for the solutions of some divalent
transition metal sulphates at different concentrations have been determined
in water and in water + ethylene glycol mixtures. The data have been analysed
using |
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1638 |
Synthesis, spectroscopic
(IR, electronic and FAB-mass) and magnetic studies of some mixed ligand
complexes of chromium (III) |
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Some new mixed ligand complexes of chromium (III) of
the type [Cr(L)2(L˘)Cl].2H2O [where LH = Schiff bases derived
from the condensation of
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Notes |
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1643 |
Substituent
effects on catalytic activity of transition metal phthalocyanine complexes Hassan Hosseini Monfared*,
Saeid Dini, Naser Safari & Mahtab
Pirouzmand |
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The effects of chloro
substituents on catalytic activityof Fe(II), Co(II), and Cu(II) phthalocyanine
(MCl16Pc and MCl8Pc)complexes in olefin epoxidation are
reported. Performance of these catalystshas been tested for the oxidation of
cyclohexene, cyclooctene and styrenewith iodosylbenzene. In cyclohexene
oxidation, epoxide selectivity (22-56%for MCl8Pc and 32-55% for
MCl16Pc) follows the order: Fe(II)>Co(II)>Cu(II)complexes.
In the catalytic oxidation of cyclooctene and styrene, only thecorresponding
epoxides are obtained. |
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1646 |
Hydrogenation of
cinnamaldehyde over Pt/ZrO2 catalyst modified by Cr, Mn, Fe, Co,
Ni and Sn |
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Hydrogenation of cinnamaldehyde has been studied over
Pt/ZrO2 and PtM/ZrO2 catalysts (M= Cr, Mn, Fe, Co, Ni,
Sn) in ethanol at 343 K and 2.0 MPa.
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1651 |
Solid phase extraction and spectrophotometric
determination of gold |
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A sensitive, selective and rapid method for the determination
of gold based on the rapid reaction of gold with 5-(p-aminobenzylidene)-thiorhodanine and the solid phase extraction
of the colored chelate has been developed. This method has been applied for
determination of gold in water and ore with good results. |
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1655 |
6-Chloro-3-hydroxy-2-[2'-(5'-methylfuryl)]-4H-chromen-4-one as an analytical
reagent for the spectrophotometric determination of tungsten(VI) |
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A 1:2 light yellow complex of tungsten(VI) is formed
with 6-chloro-3-hydroxy-2-[2'-(5'-methylfuryl)]-4H-chromen-4-one in 0.18-0.32 M
HClO4 medium. The complex is extractable into chloroform and
absorbs maximally at |
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1659 |
Spectrophotometric
determination of copper(II) in alloys and edible oils using 2-acetylthiophene
thiosemicarbazone M Sayaji Rao, N B L Prasad, & K Hussain Reddy* |
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The reagent, 2-acetylthiophene thiosemicarbazone has been synthesized and characterized. It gives intense yellowish green coloured complex (λ max = 370 nm) with copper(II) in sodium acetate-acetic acid buffer (pH 5-7) medium. The molar absorptivity and Sandell’s sensitivity of the copper(II) complex are 1.83 ´ 104 L. mol-1 cm-1 and 0.0034 μg of Cu(II) cm-2, respectively. The method has been used for the determination of copper(II) in alloys, edible oils and seeds. |
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1663 |
TLC separation of l-tryptophan using microemulsion mobile phase and its
spectrophotometric determination |
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The TLC system comprising
silica gel as the stationary phase, and water-in-oil microemulsion (SDS +
water + heptane + n-pentanol; as
the mobile phase, has been used for selective separation of L-tryptophan from other amino acids in the presence of
metal cation impurities. The proposed method is applied to L-tryptophan in drug samples. The quantitative estimation
of L-tryptophan by
spectrophotometry (lmax 570 nm) after
separation from other amino acids has been done. The recovery of tryptophen
is around 98% and its limit of
detection on silica gel layer is 0.13 mg. |
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1667 |
Solubility
enhancement of rofecoxib in water in the presence of hydrophilic polymers,
surfactants, K H Desai, A R Kulkarni, S A Agnihotri, |
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Solubility
enhancement of rofecoxib in water has been studied in presence of different
concentrations of hydrophilic polymers like polyethylene glycol-4000
polyethylene glycol-6000 and polyvinylpyrrolidone (PVP- K30); surfactants
like Span-20, Tween-80 and sodium lauryl sulfate (SLS); co-solvents like
ethanol, propylene glycol and glycerol and small molecules like urea,
mannitol and b-cyclodextrin at 310.15 K. Drug analysis has
been carried out by HPLC method using UV detector at 254 nm. Drug solubility
is greatly enhanced in the presence of PVP-K30, SLS, and ethanol. In the
presence of small molecules, urea enhances the solubility much more than
mannitol or b-cyclodextrin. |
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1670 |
Announcement |
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Authors for correspondence are indicated by (*)
AUTHOR INDEX
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Agnihotri N |
1655 |
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Agnihotri R |
1655 |
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Agnihotri S A |
1667 |
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Aminabhavi T M |
1667 |
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Bhawani Showkat Ahmad |
1663 |
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Brar A S |
1605 |
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Desai K H |
1667 |
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Dini Saeid |
1643 |
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Dubey R K |
1638 |
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Dubey U K |
1638 |
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Fincy Jose P |
1619 |
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Furtula Boris |
1601 |
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Gokavi G S |
1626 |
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Gudasi K B |
1667 |
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Gutman Ivan |
1601 |
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Han Xiaoxiang |
1646 |
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Hen Jing C |
1651 |
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Hena Sufia |
1663 |
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Huang Zhangjie |
1651 |
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Kapashikar K V |
1626 |
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Kulkarni A R |
1667 |
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Li Jinsong |
1651 |
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Mehta J R |
1655 |
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Mishra C M |
1638 |
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Mohammad Ali |
1663 |
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Monfared Hassan Hosseini |
1643 |
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Parmar M L |
1631 |
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Pirouzmand Mahtab |
1643 |
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Prasad N B L |
1659 |
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Qunyan Wei |
1651 |
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Rajmane D S |
1626 |
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Rao M Sayaji |
1659 |
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Reddy Ch Sanjeeva |
1611 |
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Reddy K Hussain |
1659 |
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Safari Naser |
1643 |
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Singh Pravin Kumar |
1605 |
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Sugunan S |
1619 |
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Thakur R C |
1631 |
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Turković Nedžad |
1601 |
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Vijaya Kumar T |
1611 |
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Yang Guangyu |
1651 |
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Zhao Jishou |
1651 |
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Zheng Xiaoming |
1646 |
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Zhou Renxian |
1646 |
Vol. 45A, July 2006, pp.
1601-1604
On
distribution of π-electrons in rhombus-shaped benzenoid hydrocarbons
Ivan Gutman, Nedžad Turković & Boris Furtula
Received 20 April 2006;
accepted 12 May 2006
The distribution of π-electrons into rings of rhombus-shaped
benzenoid hydrocarbons is reported here. In this class of benzenoid systems,
the (unique) Clar formula represents only a minute fraction of the total number
of Kekulč structures, and therefore a breakdown of the Clar model could be
expected. It is found that the π-electron distribution follows a pattern
different from what is predicted by the Clar model: the greatest
π-electron content is in the two "full" peak hexagons (around
4.5 electrons). In the other boundary hexagons, the π-electrons are
distributed almost uniformly (around 3 electrons per hexagon). In the internal
hexagons, the π-electrons are also distributed in an almost uniform manner
(around 2 electrons per hexagon), the π-electron content of the
"full" hexagons insignificantly exceeding the π-electron
contents of the "empty" hexagons.
Vol. 45A, July 2006, pp. 1605-1610
NMR and thermal studies of
N-acryloylcarbazole/methacrylonitrile copolymers
A S Brar & Pravin Kumar Singh
Received 5 April 2006; revised 22 May 2006
Copolymers with different compositions of
N-acryloylcarbazole (A) and methacrylonitrile (M) are reported here.
Composition of the copolymer has been determined by 1H NMR spectrum.
The comonomer reactivity ratios, determined by both Kelen-Tudos (KT) and
non-linear error-in-variables (EVM) methods are rA= 1.27 ± 0.13, rM=
0.69 ± 0.06, and rA=
1.30, rM = 0.69,
respectively. Complete spectral assignments of the 1H and 13C{1H}
NMR spectra of the copolymers is done by Distortionless Enhancement by
Polarization Transfer (DEPT) and Heteronuclear Single Quantum Coherence (HSQC)
techniques. The methylene carbon signals of both (A and M) units have been
found to be sequence sensitive. The signals obtained are broad, pertaining to
the restricted rotation of bulky carbazole group and the quadrupolar effect of
nitrogen present in carbazole moiety. The thermal stability and glass
transition temperatures (Tg)
of the copolymers are dependant on polymer composition and characteristic of
rotational rigidity of the polymer chain. Variation in the values of Tg with the copolymer
composition has been found to be in good agreement with theoretical values
obtained from Johnston and Barton equations.
IPC Code: Int. Cl.8 C07C255/08; C07D209/82;
G03C1/04; G01N24/08
Vol. 45A, July 2006, pp. 1611-1618
Homogeneous catalysis of
aquachlororuthenium(III) complex and
evaluation of individual kinetic and thermodynamic parameters of
bromate-mandelic acid reaction
Ch Sanjeeva Reddy & T Vijaya Kumar
Received 24 September 2005; accepted 8 May 2006
Aquachlororuthenium(III) complex catalysed and
uncatalysed acid bromate oxidation of mandelic acid (MA) is reported here.
Uncatalysed oxidation exhibits first order each in [MA] and [bromate], and
second order in [acid]. Primary kinetic isotope effect (kH/kD
= 1) has been found to be absent. However, an inverse solvent isotope effect is
observed. The assumed mechanism includes slow formation of a mandelic ester of
bromic acid due to the nucleophilic attack by the alcoholic/hydroxyl group at
the bromine atom of HOBr+O(OH), which dissociates rapidly through
C-C bond cleavage to form benzaldehyde and CO2.
Aquachlororuthenium(III) complex catalysed MA-bromate reaction exhibits second
order in [bromate], first order in [catalyst], fractional order in [MA] and a
dualistic effect in [acid]. The envisaged mechanism involves complex formation
between the substrate and the catalyst, which in turn forms a ternary complex
with two moles of the oxidant. The slow decomposition of the ternary complex to
form products constitutes the rate-determining step. The rate constants
involved in each step of the reaction have been evaluated along with their
thermodynamic parameters.
Vol. 45A, July 2006, pp. 1619-1625
Surface
properties and oxydehydrogenation of ethylbenzene over molybdenum doped ceria
systems
P Fincy Jose & S Sugunan
Received
29 April 2005; revised 12 April 2006
Pure cerium hydroxide has been prepared by
pseudo-template method and sulphate modification has been carried out by wet
impregnation method using H2SO4. Modified catalysts have
been prepared by incorporating varying amounts of molybdenum (5, 10 and 15%)
into pure as well as sulphated cerium hydroxide and characterized by XRD,
FT-IR, BET surface area and DRS techniques. The acid structural properties have
been determined by temperature programmed desorption of ammonia and
thermodesorption studies using 2, 6-dimethylpyridine. Study on catalytic
activity of the systems towards oxydehydrogenation of ethylbenzene shows the
formation of styrene as the major product. Reaction conditions such as air
flow, temperature of the reaction and flow rate of ethylbenzene have been
optimised.
IPC Code: Int. Cl.8
B01J21/00; B01J37/00
Vol. 45A, July 2006, pp. 1626-1630
Kinetics and mechanism of oxidation of aliphatic
alcohols by oxone catalyzed by Keggin type 12-tungstocobaltate(II)
D S Rajmane, K V Kapashikar & G S Gokavi
Received 30 November 2005; revised 26 April 2006
The
oxidation of various aliphatic alcohols by oxone catalyzed by Kegin type [CoIIW12O40]6-
has been studied in a buffer medium of pH=
4. The reaction proceeds by the
oxidation of [CoIIW12O40]6- to [CoIIIW12O40]5-
by oxone which then oxidizes the alcohol in a rate determining step generating
alcohol free radical. The reaction is accelerated by increase in the pH of the solution due to the
protonation equilibria of the oxidant. The reaction between oxone and [CoIIW12O40]6-
has also been studied and is found to proceed in two one-electron steps,
involving formation HSO52- free radical in a slow first step followed
by its reaction with reductant in a
fast step. The reaction rate is inhibited by the [ H+ ] due to
protonation equilibria of HSO5- which is the active species. Decreasing the
relative permittivity of the medium increases the rate of the reaction which is
attributed to the formation of an outer-sphere complex between the reactants.
The activation parameters determined for both the reactions support the
proposed mechanisms.
Vol. 45A, July 2006, pp.
1631-1637
Effect of
temperature on the viscosities of some divalent transition
metal sulphates and magnesium sulphate in water and
water+ethylene glycol mixtures
M L Parmar & R C Thakur
Received 6 January 2006; revised
15 April 2006
Relative viscosities for the solutions of some divalent transition
metal sulphates, viz. manganese sulphate, cobalt sulphate, nickel sulphate,
copper sulphate and zinc sulphate; and magnesium sulphate at different
concentrations have been determined in water and in water + ethylene glycol
(EG) [5, 10, 15, 20 and 25% by weight of EG] mixtures at 303.15 K, and in water
and in 5% (w/w) EG + water at five
different temperatures. The data have been analysed using the Jones-Dole
equation and the obtained parameters have been interpreted in terms of ion-ion
and ion-solvent interactions. The activation parameters of viscous flow have
been obtained which depicts the mechanism of viscous flow. The transition metal
sulphates and magnesium sulphate act as structure makers/promoters in water and
in EG + water mixtures.
Vol. 45A, July 2006, pp.
1638-1642
Synthesis,
spectroscopic (IR, electronic and FAB-mass) and magnetic
studies of some mixed ligand complexes of chromium (III)
R K Dubey, U K Dubey & C M Mishra
Received 31 October 2005; revised
18 May 2006
Some new mixed ligand complexes of chromium (III) of the type [Cr(L)2(L1)Cl].2H2O
[where LH = Schiff bases (derived from the condensation of 2-aminopyridine,
2-aminophenol, o-toludine, p-toludine, aniline, 3-nitroaniline and
anthranilic acid with salicylaldehyde/vanillin and substituted
benzimidazole/benzoxazole, or mercaptobenzimidazole; L=pyridine] have been
synthesized by the interactions of chromium (III) chloride with corresponding
ligand in 1:2 molar ratio in refluxing pyridine solution. The resulting
products have been characterized by elemental analysis and spectral as well as
magnetic susceptibility measurements. Structures of the chromium (III)
complexes are also proposed.
IPC
Code: Int. Cl.8
C07F11/00
Vol. 45A, July 2006, pp. 1643-1645
Substituent
effects on catalytic activity of transition metal phthalocyanine complexes
Hassan Hosseini Monfared, Saeid Dini, Naser
Safari & Mahtab Pirouzmand
Received 13 December 2004; revsied 19 April 2006
This study investigates the effects of 16- and
8-chloro substituents on catalytic activity of Fe(II), Co(II), and Cu(II)
phthalocyanine (MCl16Pc and MCl8Pc) complexes in olefin
epoxidation. The catalytic performance of these substituted catalysts has been
tested for the oxidation of cyclohexene, cyclooctene, and styrene with
iodosylbenzene and results have been compared with those of unsubstituted
catalysts. In cyclohexene oxidation, epoxide selectivity (22-56% for MCl8Pc
and 32-55% for MCl16Pc) is in order Fe(II) > Co(II) > Cu(II)
complexes. In the catalytic oxidation of cyclooctene and styrene, only the
corresponding epoxides have been obtained.
IPC Code: Int. Cl.8 B01J8/00
Vol. 45A, July 2006, pp.
1646-1650
Hydrogenation
of cinnamaldehyde over Pt/ZrO2 catalyst modified by Cr, Mn,Fe, Co,
Ni and Sn
Xiaoxiang Han, Renxian Zhou & Xiaoming Zheng
Received 30 December 2005;
revised 11 May 2006
Hydrogenation
of cinnamaldehyde (CMA) has been studied over Pt/ZrO2 and PtM/ZrO2
catalysts (M= Cr, Mn, Fe, Co, Ni, Sn) in ethanol at 343 K and 2.0 MPa. The
catalytic properties are shown to increase upon introduction of metals to
Pt/ZrO2 catalyst. Catalytic activities of the catalysts are enhanced
except PtCr/ZrO2 catalyst. PtMn/ZrO2, PtCo/ZrO2
and PtFe/ZrO2 catalysts show good yield of
cinnamyl alcohol (CMO), and PtNi/ZrO2 PtSn/ZrO2
catalysts show good yield of hydrocinnamaldehyde (HCMA). In the presence of
NaOH and H2O, rate of the hydrogenation of CMA increases
significantly and side reaction is remarkably inhibited. PtCo/ZrO2
catalyst shows best catalytic activity (TOF 7.4´10-2 s-1) and yield of CMO (84.1
mol%). PtNi/ZrO2 catalyst shows best yield of HCMA (62.8 mol%). More
active sites for the hydrogenation of C=O group on PtCo/ZrO2
catalyst surface are the
main reason of good selectivity of CMO.
IPC Code: Int. Cl.8
B01J23/42; B01J27/135
Vol. 45A, July 2006, pp. 1651-1654
Solid phase extraction and spectrophotometric determination
of gold
Jishou Zhao,
Jinsong Li, Zhangjie Huang, Qunyan Wei, Jing Chen & Guangyu Yang
Received 10 August 2005; revised 8 May 2006.
A sensitive, selective and rapid method for the determination of gold based on
the rapid reaction of gold with 5-(p-aminobenzylidene)-thiorhodanine
(ABTR) and the solid phase extraction of the colored chelate has been
developed. In 0.05-0.5 mol L-1 hydrochloric acid and emulsifier-OP
medium, ABTR reacts with gold to form a red chelate of molar ratio 1:3 (gold to
ABTR). This chelate has been preconcentrated by solid phase extraction with
polymer-based C18 cartridge and eluted from cartridge with dimethyl
formamide to attain an enrichment factor of 100. In DMF medium, the molar
absorptivity of the chelate is 1.23 ´ 105 L. mol-1. cm-1
at 550 nm. Beer’s law is obeyed in the range of 0.01-3 mg mL-1
of gold. The relative standard deviation for eleven replicate samples of 0.5 mg L-1
gold is 2.18%. The detection limit, based on three times of standard deviation,
is 0.02 mg L-1 in the original sample. This method has
been applied to the determination of gold in water and ore with good results.
IPC Code: Int. Cl.8 G01N21/00; G01N30/00
Indian Journal
of Chemistry
Vol. 45A, July 2006, pp. 1655-1658
-Chloro-3-hydroxy-2-[2'-(5'-methylfuryl)]-4H-chromen-4-one as an analytical reagent
for the spectrophotometric determination of tungsten(VI)
R Agnihotri, N Agnihotri & J R Mehta
Received 14 November 2005; revised 16 May 2006
A 1:2 light
yellow complex of tungsten(VI) is formed with
6-chloro-3-hydroxy-2-[2'-(5'-methylfuryl)]-4H-chromen-4-one
(CHMFC) in 0.18-0.32 M HClO4
medium. The complex is extractable into chloroform and absorbs maximally at 435
nm. The absorbance remains constant for more than 1 h with molar absorptivity,
detection limit and Sandell’s sensitivity as 2.16 ´ 104 L
mol-1 cm-1, 0.131 mg mL-1 and 0.0085 mg W cm-2, respectively. Beer’s law is
obeyed in the concentration range of 0-2.6 mg W mL-1; the correlation coefficient is, r =1.001. Oxalate interferes in the
tungsten determination. The method has been satisfactorily applied to the
analysis of tungsten in various synthetic and technical samples.
IPC Code: Int. Cl.8 G01N21/00; G01N33/20
Indian Journal of Chemistry
Vol. 45A, July 2006, pp. 1659-1662
Spectrophotometric determination of copper(II) in alloys and
edible oils using 2-acetylthiophene thiosemicarbazone
M Sayaji Rao, N B L Prasad & K Hussain Reddy
Received 27 July 2005;
revised 5 April 2006
The reagent,
2-acetylthiophene thiosemicarbazone (ATT) has been synthesized and
characterized based on spectral data. The reagent gives intense yellowish green
coloured complex (λ max = 370 nm) with copper(II) in sodium acetate-acetic
acid buffer (pH 5-7) medium. The colour reaction has been investigated
in detail. The molar absorptivity and Sandell’s sensitivity of the copper(II)
complex of ATT are 1.83 ´ 104 L. mol-1 cm-1 and
0.0034 μg of Cu(II) cm-2 respectively. The method has been used
for the determination of copper(II) in alloys, edible oils and seeds.
IPC Code: Int.Cl.8
Vol. 45A, July 2006, pp. 1663-1666
TLC
separation of l-tryptophan using
microemulsion mobile phase and its spectrophotometric determination
Ali Mohammad, Sufia Hena & Showkat Ahmad Bhawani
Received 6 December 2005; revised
11 May 2006
The TLC system
comprising silica gel as the stationary phase, and water-in-oil microemulsion
(SDS+water+heptane+n-pentanol; (160 g + 8 mL + 16 mL + 25 mL) as the mobile
phase, has been identified as the most favourable system for selective
separation of l-tryptophan from
other amino acids in the presence of metal cation impurities. The proposed
method is applicable to the identification and separation of l-tryptophan from drug samples such as
Astymin-m (Forte), Astymin (liquid) and Alamin (Forte). The separation up to
10 mg of l-tryptophan
from milligram quantities (up to 0.77 mg) of other amino acids has also been
realized. The quantitative estimation of l-tryptophan
by spectrophotometry (lmax 570 nm) after separation from other amino
acids has been done. The recovery of tryptophan is around 98% and its limit of
detection on silica gel layer is 0.13 mg.
IPC Code: Int. Cl.8
G01N21/00
Indian Journal of Chemistry
Vol. 45A, July 2006, pp. 1667-1669
Solubility enhancement of rofecoxib in water in the presence of
hydrophilic polymers, surfactants, co-solvents, and small molecules at 310.15 K†
K H Desai, A R Kulkarni, S A Agnihotri, K B
Gudasi &
T M Aminabhavi
Received 6 January 2006; revised 16 March 2006
Solubility enhancement of rofecoxib in water has been studied in
presence of different concentrations of hydrophilic polymers like polyethylene
glycol-4000 polyethylene glycol-6000 and polyvinylpyrrolidone (PVP- K30);
surfactants like Span-20, Tween-80 and sodium lauryl sulfate (SLS); co-solvents
like ethanol, propylene glycol and glycerol and small molecules like urea,
mannitol and b-cyclodextrin at 310.15 K. Drug analysis has been carried
out by HPLC method using UV detector at 254 nm. Drug solubility is greatly
enhanced in the presence of PVP-K30, SLS, and ethanol. In the presence of small
molecules, urea enhances the solubility much higher than mannitol or b-cyclodextrin.
IPC Code: Int. Cl.8 A61K