K.P. Safna Hussan

Experimental and density functional theory studies on benzalkonium ibuprofenate, a double active pharmaceutical ingredient

Molecular aspects of a double active pharmaceutical ingredient in ionic liquid form, benzalkonium ibuprofenate (BaIb), were studied using density functional theory (DFT/B3LYP/6-31+G (d, p)). A detailed discussion on optimized geometry, energy, heat and the enthalpy of BaIb was carried out. The computed vibrational results agree well with the experimental results. The stability and biological activity were compared to the parent drugs on the basis of global descriptive parameters. The electrophilic and nucleophilic sites were pointed out in the MESP structures well evidently. NBO analysis was also done to predict the relative aromaticity, delocalization effects and the contribution towards stabilization energy of the title compound. The information about non-covalent, non-ionic weak interaction between the cation and anion was obtained from the list of Mulliken charges and NBO analysis.

Molecular dynamics, physical and thermal stability of neat amorphous amlodipine besylate and in binary mixture

ABSTRACT In this paper, a stable amorphous solid dispersion of an antihypertensive drug, amlodipine besylate (AMB) was prepared by entrapping it in a polymer matrix, polyvinyl pyrrollidone, in different weight ratios (AMB/PVP 05:95, 10:90, 20:80, 30:70). The glass forming ability of all binary dispersions were studied by means of differential scanning calorimetry and found good correlation between experimental Tg and Fox Florys prediction. By considering the daily dosage limit of 5mg, a weight ratio of 05:95 was further considered for the study. The structures of neat and binary of AMB were characterized by density functional theory, Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy and UV–visible spectroscopy. Further, detailed molecular dynamics of both pure and binary were investigated using broadband dielectric spectroscopy to judge the physical stability of the amorphous dispersions. Translation‐rotation coupling of AMB possibly explains the dual conductivity and dipolar nature of the secondary relaxation in neat AMB. Thus, the binary dispersion of AMB with commercially acceptable weight ratio with strong glass forming behaviour and better shelf life was prepared and characterized for practical applications.

Photoluminescent behavior of propylene carbonate and poly (methylmethacrylate) blend for transparent optoelectronic devices

Polymer blend formed by propylene carbonate with poly (methylmethacrylate) bypassed the degradation of PMMA. The miscibility of the blend was studied by SEM and XRD. The transparency and also the absorbance of the film were measured victimization UV-Vis spectroscopy and showed that it is transparent above 90%. It was found from the emission spectroscopy that, it exhibits strong luminescence. Thus, the blend can be used as a matrix to entrap novel conducting materials (rare earth metals, complexes, ionic liquids, conducting materials etc.,) to get a stable miscible, transparent, conducting and luminescent glass film for optoelectronic devices.

Polyaniline modified lignocellulosic fibers from sago seed shell powder for electrochemical devices

We report the development of a novel electrode material from agrarian waste, sago (Cycas circinalis) seed shell powder (SSP). Lignocellulosic fibers obtained from sago seed shell powder were modified with polyaniline (PANI) by an in situ oxidative polymerization technique. Morphological changes, thermal stability and crystallinity of modified SSP were investigated using FTIR, XRD, SEM, TGA and DSC techniques. The structural organization of SSP with the monomer of PANI significantly influenced the thermal and electrical properties of resulting PANI-SSP composite material. The developed PANI-SSP composite showed enhanced thermal stability up to 308 °C with appreciable dc-conductivity in the range of 10−1 S cm−1 having very low activation energy of 0.0153 eV. The I–V characteristics of the composite exhibited nonohmic behaviour similar to a diode. Thus, the chemical modification of lignocelluloses fibers opens up a new avenue for fabricating cheap, eco-friendly substrates for energy storage devices, disposable electronic applications and diverse scopes for research and development.