Comparative biological study between quinazolinyl–triazinyl semicarbazide and thiosemicarbazide hybrid derivatives

Molecular Diversity - Practical synthesis and biological activities of quinazolinyl–triazinyl semicarbazides (10a–j) and quinazolinyl–triazinyl thiosemicarbazides (11a–j)...     

Exploring the Interplay between Drug Release and Targeting of Lipid-Like Polymer Nanoparticles Loaded with Doxorubicin

Targeted delivery of doxorubicin still poses a challenge with regards to the quantities reaching the target site as well as the specificity of the uptake. In the present approach, two colloidal nanocarrier systems, NanoCore-6.4 and NanoCore-7.4, loaded with doxorubicin and characterized by different drug release behaviors were evaluated in vitro and in vivo. The nanoparticles utilize a specific surface design to modulate the lipid corona by attracting blood-borne apolipoproteins involved in the endogenous transport of chylomicrons across the blood–brain barrier. When applying this strategy, the fine balance between drug release and carrier accumulation is responsible for targeted delivery. Drug release experiments in an aqueous medium resulted in a difference in drug release of approximately 20%, while a 10% difference was found in human serum. This difference affected the partitioning of doxorubicin in human blood and was reflected by the outcome of the pharmacokinetic study in rats. For the fast-releasing formulation NanoCore-6.4, the AUC_0→1h was significantly lower (2999.1 ng × h/mL) than the one of NanoCore-7.4 (3589.5 ng × h/mL). A compartmental analysis using the physiologically-based nanocarrier biopharmaceutics model indicated a significant difference in the release behavior and targeting capability. A fraction of approximately 7.310–7.615% of NanoCore-7.4 was available for drug targeting, while for NanoCore-6.4 only 5.740–6.057% of the injected doxorubicin was accumulated. Although the targeting capabilities indicate bioequivalent behavior, they provide evidence for the quality-by-design approach followed in formulation development.     

Effects of feedback from collimating, focusing, and spot-array generating outcoupler gratings in surface-emitting semiconductor lasers

We experimentally demonstrate that a grating outcoupler used for complex beam shaping (spot-array generation) can produce unintentional optical feedback that severely disturbs the integrated in-plane laser that illuminates the coupler. Simulations show that these outcouplers, in contrast to conventional collimating or focusing outcouplers, tend to produce high levels of feedback in spite of the detuning used to suppress feedback. Further, this feedback is focused to high intensity in the laser gain medium. This focused light acts as a seed for the nonlinear self-focusing that causes wave-front distortion and filamentation, which degrades the beam quality.     

A facile IL–DMSO assisted synthesis of 5-, 6-, and 7-membered benzo-annelated cyclic guanidines

A new and facile IL–DMSO assisted method has been developed for the synthesis of biologically important cyclic guanidines like 2-aminobenzimidazole, 2-imino-4-quinazolinone, and 2-imino-5-benzotriazepinones at ambient temperatures. The desired products could be obtained by microwave irradiation³² also, but at elevated temperatures. A plausible mechanism for catalysis has been proposed.     

Semiconductor laser with curved deep-etched distributed Bragg reflectors supporting a planar Gaussian mode

A compact integration-compatible semiconductor laser supporting a planar Gaussian mode is demonstrated. Curved deep-etched distributed Bragg reflectors (DBR's), contouring the phase front of the Gaussian wave, act as feedback elements. The DBR's are 0.5 microm deep and have two first-order air gaps separated by a third-order semiconductor spacer. Low-threshold current (10 mA) is achieved for a 90-microm-long laser with a waist of 2 microm. Lasing in a planar Gaussian mode is observed up to 1.7 times the threshold current, whereas at higher currents the mode behavior degrades because of spatial hole burning.