3 research outputs found
Controlled Mineralization of Calcium Carbonate on the Surface of Nonpolar Organic Fibers
Isotactic polypropylene (iPP) fiber, the surface of which
is hydrophobic,
can modulate the crystallization polymorphs of calcium carbonate (CaCO<sub>3</sub>) at the air/solution interface under mild conditions. The
present results provide a novel perspective on controlling the crystallization
of biominerals by an insoluble matrix, and they can shed new light
on understanding the biomineralization process of CaCO<sub>3</sub> as it occurs in nature
Double Asynchronous Orthogonal Sample Design Scheme for Probing Intermolecular Interactions
This paper introduces a new approach called double asynchronous
orthogonal sample design (DAOSD) to probe intermolecular interactions.
A specifically designed concentration series is selected according
to the mathematical analysis to generate useful 2D correlated spectra.
As a result, the interfering portions are completely removed and a
pair of complementary sub-2D asynchronous spectra can be obtained.
A computer simulation is applied on a model system with two solutes
to study the spectral behavior of cross peaks in 2D asynchronous spectra
generated by using the DAOSD approach. Variations on different spectral
parameters, such as peak position, bandwidth, and absorptivity, caused
by intermolecular interactions can be estimated by the characteristic
spectral patterns of cross peaks in the pair of complementary sub-2D
asynchronous spectra. Intermolecular interactions between benzene
and iodine in CCl<sub>4</sub> solutions were investigated using the
DAOSD approach to prove the applicability of the DAOSD method in real
chemical system
Enteric Polymer Based on pH-Responsive Aliphatic Polycarbonate Functionalized with Vitamin E To Facilitate Oral Delivery of Tacrolimus
To improve the bioavailability of
orally administered drugs, we synthesized a pH-sensitive polymer (polyÂ(ethylene
glycol)–polyÂ(2-methyl-2-carboxyl-propylene carbonate)–vitamin
E, mPEG–PCC–VE) attempting to integrate the advantages of enteric coating and P-glycoprotein
(P-gp) inhibition. The aliphatic polycarbonate chain was functionalized
with carboxyl groups and vitamin E via postpolymerization modification.
Optimized by comparison and central composite design, mPEG<sub>113</sub>–PCC<sub>32</sub>–VE<sub>4</sub> exhibited low critical
micelle concentration of 1.7 × 10<sup>–6</sup> mg/mL and
high drug loading ability for tacrolimus (21.2% ± 2.7%, w/w).
The pH-responsive profile was demonstrated by pH-dependent swelling
and <i>in vitro</i> drug release. Less than 4.0% tacrolimus
was released under simulated gastric fluid after 2.5 h, whereas an
immediate release was observed under simulated intestinal fluid. The
mPEG<sub>113</sub>–PCC<sub>32</sub>–VE<sub>4</sub> micelles
significantly increased the absorption of P-gp substrate tacrolimus
in the whole intestine. The oral bioavailability of tacrolimus micelles
was 6-fold higher than that of tacrolimus solution in rats. This enteric
polymer therefore has the potential to become a useful nanoscale carrier
for oral delivery of drugs