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The interaction of stearic acid with non-polar benzene along polar co-solvent (amyl alcohol) is revealed in the present study. The dielectric nature of complex mixture examined in the frequency regime of 10 MHz to 30 GHz over a various temperature and concentration using time domain reflectometry(TDR). Dielectric parameters (static dielectric constant, dielectric loss, relaxation time, dielectric permittivity) were estimated from the obtained complex spectra. The excess dielectric values validate the molecular interaction between the solute and solvents. The obtained dielectric and relaxation parameter reveals the fluctuating electrostatic type interaction among the complex mixture. Thermal parameters are determined from the obtained relaxation time, in which the negative Gibb's free energy indicates the formation of high ordered complex. The FT-IR spectrums and their assignments confirm the molecular interaction between the mixture. [ABSTRACT FROM AUTHOR]

Background: Long-acting antiretroviral implants may be an essential means of protecting high-risk individuals from HIV infection. Long acting formulations can overcome issue of compliance associated with current pill forms of PrEP. Here we describe the design and testing of a reservoir subcutaneous implant capable of releasing cabotegravir for a year. Methods: We compressed cabotegravir along with solubilizing excipients into cylindrical pellets and inserted them into a heat-sealed hydrophilic polyether urethane membrane. The membrane was selected so that it can conduct the drug into the subcutaneous space. The implants were manufactured with dimensions of 47 mm lumen length, 3.6 mm outer diameter, and 200 [micro]m wall thickness. Four cabotegravir pellets were loaded in the core, with a total drug loading of 274 [+ or -] 3 mg. Results: After implantation, the implant swelled and released an average of 0.35 mg/day of cabotegravir in rhesus macaques. Five implants achieved an average cabotegravir plasma concentration of 373 ng/m in macaques. Adjacent implants demonstrated a PK less than anticipated, revealing that implant placement is important because of potential implant interference. The nonhuman primates tolerated the implant without gross or microscopic signs of toxicity compared to placebo after 1 month and 3 months. Cabotegravir plasma levels in macaques dropped below detectable levels within two weeks after the removal of the implants. Extended PK studies in Rats revealed stable release of cabotegravir for 6 months. Conclusions: Long-acting formulations of antiretroviral compounds have the potential to increase the efficacy of PrEP by eliminating issues of compliance that can be associated with daily pill taking in high risk populations. We describe a cabotegravir reservoir implant designed to last 1 year before removal and replacement (as needed). The removal of the implant avoids the drug PK tail associated with long-acting injectable formulations. The release is stable for at least 6 months and shows no evidence of adverse host reactions to the implant after histological analysis. Although the function of this reservoir implant in humans and the plasma cabotegravir concentrations required for protection in humans remains to be conclusively determined, this reservoir implant has the potential to provide an additional option for individuals seeking efficient PrEP for HIV prevention., OA04.04 T.J. Hope (1); D. Karunakaran (2); S.M. Simpson (2); J.T. Su (3); E. Bryndza-Tfaily (4); R. Vezy (5); G. Dobek (6); J. Qiu (2); D. Watrous (2); S. Sung [...]

The dielectric dispersion spectra of morpholine with methanol and ethanol binary mixtures have been studied by using Time Domain Reflectometry. Frequency dependent variations of specified mole fraction for the temperature 288 K, 293 K, 298 K, 303 K were determined. The complex permittivity spectra fitted by Debye model. The dielectric parameters of the associating liquids analysed and the ordering of molecules favours two relaxation sites and discussed on the basis of dielectric properties. The swapping bond of H at N–H favours intermolecular interaction. The intra-molecular exists between O and N within the ring. The excess properties of the mixture solutions has effective Kirkwood correlation factor that predicts molecular interaction and orientation among solute and solvents. The thermodynamic parameters ΔG, ΔH and ΔS of the solutions and dielectric loss factor of the mixed solvents bearing alcohols were determined. FTIR spectral assignments of solutions validate the molecular interaction and their shifts. [ABSTRACT FROM AUTHOR]

The complex spectra of glycolic acid (GA) and water mixture have been measured by time domain reflectometry (TDR) in the frequency range 10 MHz to 30 GHz at various temperatures for entire concentration. Dielectric relaxation time (τ), static dielectric constant (ɛ0) and dielectric permittivity at low frequency (ɛʹ) and at optical frequency (ɛʺ) have been determined from measured complex spectra (ɛ*) using non-linear square fit method. Conductivity, Kirkwood and effective Kirkwood correlation factor of mixture calculated from the determined dielectric parameters have been used to find the alignment of dipoles between molecules. Thermodynamic parameters enthalpy, entropy and Gibb’s free energy have been determined which enable the direction of reaction. Excess permittivity of glycolic acid-water mixture has also been determined which confirms the molecular interaction. Macroscopic parameters such as density and viscosity of mixture have been determined at room temperature. FTIR spectral characterization concedes the solute-solvent interaction. [ABSTRACT FROM AUTHOR]

Evaluates the thickness dependence of the phase transition temperature in Ag[sub2]Se thin films. Experimental procedure; Results of the study; Conclusions.

Measures the thermoelectric power of annealed β-silver selenide thin films of different thicknesses while heating and cooling by integral method. Analysis of thickness effects during heating; Reciprocal thickness dependence of thermoelectric power of silver selenide films at different temperatures during cooling; Information on mean-free-path model.

Discusses the thermal hysteresis behavior observed during the first-order phase transitions of silver-tellurium thin films. Use of electrical resistance and thermoelectric power measurements; Lateral dimensions of the films and source-to-substrate distance; Overview of the scanning calorimetric analysis curves of reversible thermal transitions.