Microdosed midazolam for the determination of cytochrome P450 3A activity: Development and clinical evaluation of a buccal film.

Cytochrome P450 3A (CYP3A) isozymes metabolize about 50% of all marketed drugs. Their activity can be modulated up to 400-fold, which has great impact on individual dose requirements for CYP3A substrates. The activity of CYP3A can be monitored using the CYP3A substrate midazolam. To avoid pharmacological midazolam effects during phenotyping, a microdosing approach is preferred. However, the preparation of microdosed dosage forms remains a challenge. Fast dissolving buccal films are therefore proposed to facilitate this task. It was the aim of the present study to clinically evaluate a novel buccal film containing microdoses of midazolam for assessment of CYP3A activity. In a randomized, open-label crossover design, the pharmacokinetics of midazolam and its active hydroxy-metabolite, 1'­OH­midazolam, was assessed in 12 healthy volunteers after administration of single microdoses of midazolam (30 µg) as buccal film or buccal solution. The buccal film did rapidly disintegrate, was well tolerated, and no adverse events occurred. The film and the solution showed very similar midazolam plasma concentration-time profiles but were not bioequivalent according to EMA and FDA guidelines. For Cmax, AUC0-12h, and AUC0-∞ the geometric mean ratios of film to solution, with their 90% confidence intervals in parentheses, were 1.15 (1.00-1.32), 1.16 (1.04-1.28), and 1.19 (1.08-1.31), respectively. As a proxy for CYP3A activity, molar metabolic ratios of midazolam and 1'­OH­midazolam were analyzed over time, which revealed good correlations already 1 h or 2 h after application of the film or the solution, respectively. The tested midazolam buccal film is a convenient dosage form that facilitates administration of a phenotyping probe considerably and may potentially be used in special patient populations such as pediatric patients. Clinical Trials.gov Identifier: NCT03204578.

Human mannose-binding lectin 2 is directly regulated by peroxisome proliferator-activated receptors via a peroxisome proliferator responsive element.

Human mannose-binding lectin (MBL) is encoded by the MBL2 gene and is a key player in innate immunity. However, the mechanism of the transcriptional regulation of MBL2 is largely unknown. The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that play an important role in a number of biological responses, including lipid homeostasis, immune function and adipogenesis. In this study, we showed that PPARα and PPARγ up-regulate the expression of human MBL2. Using a luciferase assay, electrophoretic mobility-shift assay and chromatin immunoprecipitation assay, we demonstrated that PPARs regulate the expression of human MBL2 via the peroxisome proliferator responsive element (PPRE). On the other hand, MBL2 mRNA expression was not affected by the PPARα ligand both in vivo in rat liver and in vitro in rat H4IIE hepatoma cells. Thus, there is a species difference in regulation of MBL2 gene expression by PPARs between humans and rodents. We also show that the species differences in response to PPAR could be due in part to sequence-specific differences in the PPRE in the promoter region of MBL2. These results indicate that human, but not rat, MBL2 expression is regulated by PPARs via a PPRE.

Regulation of the human SLC25A20 expression by peroxisome proliferator-activated receptor alpha in human hepatoblastoma cells.

Solute carrier family 25, member 20 (SLC25A20) is a key molecule that transfers acylcarnitine esters in exchange for free carnitine across the mitochondrial membrane in the mitochondrial beta-oxidation. The peroxisome proliferator-activated receptor alpha (PPARalpha) is a ligand-activated transcription factor that plays an important role in the regulation of beta-oxidation. We previously established tetracycline-regulated human cell line that can be induced to express PPARalpha and found that PPARalpha induces the SLC25A20 expression. In this study, we analyzed the promoter region of the human slc25a20 gene and showed that PPARalpha regulates the expression of human SLC25A20 via the peroxisome proliferator responsive element.

Prenylterphenyllin and its dehydroxyl analogs, new cytotoxic substances from a marine-derived Fungus Aspergillus candidus IF10.

Three novel cytotoxic substances named prenylterphenyllin (1), 4''-deoxyprenylterphenyllin (2), and 4''-deoxyisoterprenin (3) were isolated from a cultured marine-derived fungus of Aspergillus candidus IF10 together with 4''-deoxyterprenin (4). Their chemical structures were elucidated on the basis of 2D NMR analysis. These compounds 1 approximately 4 showed cytotoxic activity against human epidermoid carcinoma KB cells (KB3-1) with IC(50) of 8.5, 3.0, 2.5, and 4.5 microg/ml, respectively.