Yet Another Doctor Blog On The Internet

Novel application of Eudragit RL and cholesteryl oleyl carbonate to thermo-sensitive drug delivery system.


To investigate the frequency of CYP2B6 polymorphisms and the influence of haplotype structure on plasma efavirenz concentrations in Thai adults with HIV-1 infection.

High BMI at treatment initiation did not always predict hyperlactatemia. All patients who died had a baseline CD4 count <10 cells/mm(3) at HAART initiation.

To determine the suitability of the ExaVir Load and ExaVir Drug assays for use in patient monitoring.

The availability of enfuvirtide enables assessment of whether human immunodeficiency virus (HIV) decay can be enhanced by targeting reverse transcriptase, protease, and fusion. We performed a 12-week study of 22 patients randomized to receive ritonavir-boosted saquinavir and efavirenz with (the 3-target arm) or without (the 2-target arm) enfuvirtide. We observed no difference in the mean+/-SD elimination-rate constant for overall decay (0.142+/-0.040 per day and 0.128 +/- 0.033 per day in the 2- and 3-target arms, respectively; P>.1) or for modeled first-phase decay rate (-0.62+/-0.34 per day and -0.51+/-0.16 per day; P>.1). Antiretroviral therapy that inhibits HIV reverse transcriptase and protease exerts potent antiviral effects that might not be augmented by the addition of an HIV fusion inhibitor.

New psychoactive substances (NPS) are not tested for their cytochrome P450 (CYP) inhibition potential before consumption. Therefore, this potential was explored for tryptamine-derived NPS (TDNPS) including alpha-methyl tryptamines (AMTs), dimethyl tryptamines (DMTs), diallyl tryptamines (DALTs), and diisopropyl tryptamines (DiPTs) using test substrates preferred by the Food and Drug Administration in a cocktail assay. All tested TDNPS with the exception of DMT inhibited CYP2D6 activity with IC50 values below 100μM. DALTs inhibited CYP2D6 activity similar to paroxetine and quinidine and CYP1A2 activity comparable to fluvoxamine. 5-Methoxy-N,N-diallyltryptamine reduced in vivo the caffeine metabolism in rats consistent with in vitro results. Five of the AMTs also inhibited CYP1A2 activity comparable to amiodarone. AMT and 6-F-AMT inhibited CYP2A6 activity in the range of the test inhibitor tranylcypromine. CYP2B6 activity was inhibited by 19 tryptamines, but weakly compared to efavirenz. CYP2C8 activity was inhibited by five of the tested TDNPS and three showed values comparable to trimethoprim and gemfibrozil. Six tryptamines inhibited CYP2C9 and seven CYP2C19 activities comparable to fluconazole and chloramphenicol, respectively. Nineteen compounds showed inhibition of CYP2E1 and 18 of CYP3A activity, respectively. These results showed that the CYP inhibition by TDNPS might be clinically relevant, but clinical studies are needed to explore this further.

Interactions between efavirenz (EFZ) with calf thymus DNA (CT-DNA) were investigated in vitro under stimulated physiological conditions using multispectroscopic techniques, cyclic voltammetry viscosity measurement, and gel electrophoresis. Methylene blue and acridine orange dyes were used as spectral probes by fluorescence spectroscopy. Hypochromicity was observed in ultra-violet (UV) absorption band of EFZ. Considerable fluorescence enhancement of EFZ was observed in the presence of increasing amounts of DNA solution and the binding constants (Kf ) and corresponding numbers of binding sites (n) were calculated at different temperatures. Thermodynamic parameters including enthalpy change (ΔH) and entropy change (ΔS) were calculated to be -304.78 kJ mol(-1) and -924.52 J mol(-1)  K(-1) according to the van 't Hoff equation, which indicated that reaction is predominantly enthalpically driven. In addition, UV/vis absorption titration of DNA bases confirmed that EFZ interacted with guanine and cytosine preferentially. Gel electrophoresis of DNA with EFZ demonstrated that EFZ also has the ability to cleave supercoiled plasmid DNA. Circular dichroism study showed stabilization of the right-handed B form of CT-DNA. All results suggest that EFZ interacts with CT-DNA via an intercalative mode of binding.

In drug-drug interaction studies, lopinavir/ritonavir significantly increased tenofovir Cmax, AUC and Cmin. Effects of each PI on tenofovir Cmin were greater than effects on Cmax or AUC. Using a 250 mg paediatric dose of tenofovir with lopinavir/ritonavir, tenofovir Cmin was predicted to remain higher than tenofovir 300 mg used with efavirenz (GMR=1.26, 95% CI 1.14-1.38). Similar results were observed for use of tenofovir 250 mg with atazanavir/ritonavir (GMR=1.07, 95% CI 1.01-1.13) and with darunavir/ritonavir (GMR=1.14, 95% CI 0.99-1.31). Predicted tenofovir AUC levels for the 250 mg dose with protease inhibitors were all within the bioequivalence range, relative to use with efavirenz. Using a 200 mg paediatric dose of tenofovir with lopinavir/ritonavir, the tenofovir Cmin was predicted to be bioequivalent to tenofovir 300 mg used with efavirenz (GMR=1.02, 95% CI 0.92-1.11). Similar results were observed for use of tenofovir 200 mg with atazanavir/ritonavir (GMR=0.86, 95% CI 0.82-0.91) and with darunavir/ritonavir (GMR=0.92, 95% CI 0.80-1.05). All three results were within the bioequivalence limits of 0.8-1.25.