Assessing the Utility of In Vitro Screening Tools for Predicting Bio-Performance of Oral Peptide Delivery.

Purpose: In this study we evaluated the utility of in-vitro screening tools for predicting the in-vivo behavior of six cyclic peptides with different solubility and permeability properties (BCS class II and III), intended for oral delivery in presence of permeation enhancer Labrasol.

Methods: An in vitro flux assay was used to assess peptide permeation across a biomimetic, lipid-based membrane and in vivo studies in rats were used to determine oral peptide bioavailability in the presence of Labrasol.

Results: The in vitro flux was significantly increased for BCS class III peptides, while it significantly decreased or remained unchanged for BCS class II peptides with increasing Labrasol concentrations.

Administration of Fenofibrate Markedly Elevates Fabp3 in Rat Liver and Plasma and Confounds Its Use as a Preclinical Biomarker of Cardiac and Muscle Toxicity.

Proteins involved in lipid homeostasis are often regulated through the nuclear peroxisome proliferator-activated receptors (PPAR). PPARα is the target for the fibrate-class of drugs. Fenofibrate has been approved for its lipid-lowering effects in patients with hypercholesterolemia and hypertriglyceridemia.

Automated DBS microsampling, microscale automation and microflow LC-MS for therapeutic protein PK.

Aim: Reduce animal usage for discovery-stage PK studies for biologics programs using microsampling-based approaches and microscale LC-MS.

Methods & Results: We report the development of an automated DBS-based serial microsampling approach for studying the PK of therapeutic proteins in mice. Automated sample preparation and microflow LC-MS were used to enable assay miniaturization and improve overall assay throughput.

Physicochemical properties, form, and formulation selection strategy for a biopharmaceutical classification system class II preclinical drug candidate.

This work summarizes the pharmaceutical evaluation of a preclinical drug candidate with poor physicochemical properties. Compound 1 is a weakly basic, GPR-119 agonist designated to Biopharmaceutics Classification System Class II because of good permeability in a Caco-2 cell line model and poor solubility. Compound 1 showed good oral bioavailability from a solution formulation at low doses and oral exposure sufficient for toxicological evaluation at high doses from a nanosuspension of Form A-the only known polymorph of 1 during drug discovery.

siRNA-mediated knockdown of P450 oxidoreductase in rats: a tool to reduce metabolism by CYPs and increase exposure of high clearance compounds.

Purpose: To develop a tool based on siRNA-mediated knockdown of hepatic P450 oxidoreductase (POR) to decrease the CYP-mediated metabolism of small molecule drugs that suffer from rapid metabolism in vivo, with the aim of improving plasma exposure of these drugs.

Methods: siRNA against the POR gene was delivered using lipid nanoparticles (LNPs) into rats. The time course of POR mRNA knockdown, POR protein knockdown, and loss of POR enzyme activity was monitored.

Combined use of crystalline sodium salt and polymeric precipitation inhibitors to improve pharmacokinetic profile of ibuprofen through supersaturation.

To maximize the pharmacological effect of a pain reliever such as ibuprofen, early onset of action is critical. Unfortunately, the acidic nature of ibuprofen minimizes the amount of drug that can be solubilized under gastric conditions and would be available for immediate absorption upon entry into the intestine. Although the sodium salt of ibuprofen has higher solubility, rapid conversion from the salt to the poorly soluble free acid phase occurs under gastric conditions.

Quantitation of physiological and biochemical barriers to siRNA liver delivery via lipid nanoparticle platform.

Effective delivery of small interfering RNA (siRNA) requires efficient cellular uptake and release into cytosol where it forms an active complex with RNAi induced silencing complex (RISC). Despite rapid developments in RNAi therapeutics, improvements in delivery efficiency of siRNA are needed to realize the full potential of this modality in broad therapeutic applications. We evaluated potential physiological and biochemical barrier(s) to the effective liver delivery of siRNA formulated in lipid nanoparticle (LNP) delivery vehicles.

The effect of the neonatal Fc receptor on human IgG biodistribution in mice.

The neonatal Fc receptor (FcRn) plays a pivotal role in IgG homeostasis, i.e., it salvages IgG antibodies from lysosomal degradation following fluid-phase pinocytosis, thus preventing rapid systemic elimination of IgG.

Lymphatic transport and catabolism of therapeutic proteins after subcutaneous administration to rats and dogs.

The mechanism underlying subcutaneous absorption of macromolecules and factors that can influence this process were studied in rats using PEGylated erythropoietins (EPOs) as model compounds. Using a thoracic lymph duct cannulation (LDC) model, we showed that PEGylated EPO was absorbed from the subcutaneous injection site mainly via the lymphatic system in rats, which is similar to previous reports in sheep. After subcutaneous administration, the serum exposure was reduced by ∼70% in LDC animals compared with that in the control animals, and most of the systemically available dose was recovered in the lymph.

Using real-time quantitative TaqMan RT-PCR to evaluate the role of dexamethasone in gene regulation of rat P-glycoproteins mdr1a/1b and cytochrome P450 3A1/2.

Cytochromes P450 (CYPs) and p-glycoproteins (Pgps) are believed to play important roles in drug absorption, metabolism, and elimination. Numerous drugs and environmental chemicals can modulate expression of these two classes of genes in different species. The present study investigated the effect of dexamethasone (Dex) on gene expression on both message and protein levels of mdr1a, mdr1b, CYP3A1, and CYP3A2 in small intestine, colon, liver, kidney, and brain microvessels of the rats treated orally with Dex at 1 or 20 mg/kg/day for 3 days.