Coating study solvent response

Table 12B Regression Analysis Output for Coating Study Solvent Response Response Surface Regression—Solvent vs. AirPress, SprayRate, AirTemp...

Case study 3—Dissolution and Residual Solvent Control in Tablet Coating A Three-Factor Response Surface Methodology... 

Due to the relative ease of control, temperature is one of the most widely used external stimuli for the synthesis of stimulus-responsive bmshes. In this case, thermoresponsive polymer bmshes from poly(N-isopropylacrylamide) (PNIPAM) are the most intensively studied responsive bmshes that display a lower critical solution temperature (LOST) in a suitable solvent. Below the critical point, the polymer chains interact preferentially with the solvent and adopt a swollen, extended conformation. Above the critical point, the polymer chains collapse as they become more solvophobic. Jayachandran et reported the synthesis of PNIPAM homopolymer and block copolymer brushes on the surface of latex particles by aqueous ATRP. Urey demonstrated that PNIPAM brushes were sensitive to temperature and salt concentration. Zhu et synthesized Au-NPs stabilized with thiol-terminated PNIPAM via the grafting to approach. These thermosensitive Au-NPs exhibit a sharp, reversible, dear opaque transition in solution between 25 and 30 °C. Shan et al. prepared PNIPAM-coated Au-NPs using both grafting to and graft from approaches. Lv et al. prepared dual-sensitive polymer by reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide from trithiocarbonate groups linked to dextran and sucdnoylation of dextran after polymerization. Such dextran-based dual-sensitive polymer is employed to endow Au-NPs with stability and pH and temperature sensitivity. 

The selective extraction of catecholamines has been the subject of some studies [250,269]. Recently B. Claude et al developed a method for the selective SPE of catecholamines and metanephrines from bovine serum using MIPs, and reported the recovery, RSD and linearity range of the method to be in the orderof64-98%, less than 6% and 0.30-0.90 pM respectively [250]. In another study M. Bouri et al reported the selective extraction of catecholamines from urine using a dopamine MIP coated magnetic molecularly imprinted polymer and capillary electrophoresis. They used methacrylic acid as the monomer, ethylene glycol dimethacrylate as the cross-Unker and coated the MIP on FCjO particles and used 2,2 - azobisisbutyronitrile as the initiator in methanol/water or acetonitrile/water solvents, and reported LOD of 0.04-0.06 pM, RSD of 0.7%-1.4% and a response range of 2.9%-5.5% [269]. 

Obviously, in this form of IT-SMPE and for a given concentration of analyte, the responses depend on the sample volume passed through the capillaiy. On the other hand, according to previously described results the presence of small percentages of an organic solvent (such as acetonitrile) in the sample modifies the retention properties of the capillary coating [28]. Consequently, a systematic study was carried out in order evaluate the effect of the volume of sample to be processed, as well as the usefulness of adding acetonitrile to the... 

---