The MYCN-HMGA2-CDKN2A pathway in non-small cell lung carcinoma--differences in histological subtypes.

Background: Extensive research has increased our understanding of the molecular alterations needed for non-small cell lung cancer (NSCLC) development. Deregulation of a pathway including MYCN, HMGA2 and CDKN2A, with the participation of DICER1, is of importance in several solid tumours, and may also be of significance in the pathogenesis of NSCLC.

Methods: Gene expression of MYCN, HMGA2, CDKN2A and DICER1 were investigated with RT-qPCR in surgically resected NSCLC tumour tissue from 175 patients.

Influence of PVP/VA copolymer composition on drug-polymer solubility.

In this study, the influence of copolymer composition on drug-polymer solubility was investigated. The solubility of the model drug celecoxib (CCX) in various polyvinylpyrrolidone/vinyl acetate (PVP/VA) copolymer compositions (70/30, 60/40, 50/50 and 30/70 w/w) and the pure homopolymers polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA) was predicted at 25 °C using a thermal analysis method based on the recrystallization of a supersaturated amorphous dispersion (recrystallization method). These solubilities were compared with a prediction based on the solubility of CCX in the liquid monomeric precursors of PVP/VA, N-vinylpyrrolidone (NVP) and vinyl acetate (VA), using the Flory-Huggins lattice theory (liquid monomer solubility approach).

Pharmacokinetic/Pharmacodynamic Relationship of Gabapentin in a CFA-induced Inflammatory Hyperalgesia Rat Model.

Purpose: Gabapentin displays non-linear drug disposition, which complicates dosing for optimal therapeutic effect. Thus, the current study was performed to elucidate the pharmacokinetic/pharmacodynamic (PKPD) relationship of gabapentin's effect on mechanical hypersensitivity in a rat model of CFA-induced inflammatory hyperalgesia.

Methods: A semi-mechanistic population-based PKPD model was developed using nonlinear mixed-effects modelling, based on gabapentin plasma and brain extracellular fluid (ECF) time-concentration data and measurements of CFA-evoked mechanical hyperalgesia following administration of a range of gabapentin doses (oral and intravenous).

Effect of cyclodextrin concentration on the oral bioavailability of danazol and cinnarizine in rats.

Cyclodextrins (CDs) are frequently used as an excipient to enhance the intestinal drug absorption of compounds with a low aqueous solubility. However, there exists an intricate interplay between opposing effects that determine the optimal dosing criterion. These opposing effects are the benefits of circumventing the dissolution time required to dissolve the non-absorbable drug particles in the intestine versus the disadvantage of decreasing the concentration of the drug available to permeate the intestinal membrane if excessive CD concentrations are used.

Effect of food intake and co-administration of placebo self-nanoemulsifying drug delivery systems on the absorption of cinnarizine in healthy human volunteers.

Positive food effects may be observed for low aqueous soluble compounds, these effects could potentially be circumvented using lipid based formulations. However, as all compounds are not chemically stable in lipid based systems, alternative dosage regimes could be investigated to evade the stability issue. The two aims for this present study were therefore; i) to investigate if a nutritional drink, Fresubin Energy®, could induce food effect in humans for the poorly soluble compound cinnarizine; and ii) to investigate if co-administration of a self-nano-emulsifying drug delivery systems (SNEDDS) with a conventional cinnarizine tablet could reduce the observed food-effect.

Influence of Copolymer Composition on In Vitro and In Vivo Performance of Celecoxib-PVP/VA Amorphous Solid Dispersions.

Previous studies suggested that an amorphous solid dispersion with a copolymer consisting of both hydrophobic and hydrophilic monomers could improve the dissolution profile of a poorly water-soluble drug compared to the crystalline form. Therefore, this study investigated the influence of the copolymer composition of polyvinylpyrrolidone/vinyl acetate (PVP/VA) on the non-sink in vitro dissolution behavior and in vivo performance of celecoxib (CCX) amorphous solid dispersions. The study showed that the hydrophilic monomer vinylpyrrolidone (VP) was responsible for the generation of CCX supersaturation whereas the hydrophobic monomer vinyl acetate (VA) was responsible for the stabilization of the supersaturated solution.

Hydration Differences Explain the Large Variations in the Complexation Thermodynamics of Modified γ-Cyclodextrins with Bile Salts.

The structure and thermodynamics of inclusion complexes of seven different γ-cyclodextrins (γCDs) and three biologically relevant bile salts (BS) were investigated in the present study. Natural γCD and six modified γCDs [two methyl-γCDs, one sulfobutyl ether-γCD (SBEγCD), and three 2-hydroxypropyl-γCDs (HPγCD)] and their complexes with BS were investigated by isothermal titration calorimetry, NMR, and molecular dynamics simulations. With the exception of the fully methylated γCD, which did not bind the BSs investigated, all of the γCDs formed 1:1 complexes with the BS, and the structures were similar to those with natural γCD; i.

Recent advances and potential applications of modulated differential scanning calorimetry (mDSC) in drug development.

Differential scanning calorimetry (DSC) is frequently the thermal analysis technique of choice within preformulation and formulation sciences because of its ability to provide detailed information about both the physical and energetic properties of a substance and/or formulation. However, conventional DSC has shortcomings with respect to weak transitions and overlapping events, which could be solved by the use of the more sophisticated modulated DSC (mDSC). mDSC has multiple potential applications within the pharmaceutical field and the present review provides an up-to-date overview of these applications.

Pharmaceutical excipients - quality, regulatory and biopharmaceutical considerations.

Practically all medications contain excipients, which are added for the purpose of production enhancement, patient acceptability, improving stability, controlling release etc. Typically excipients are the major components of a drug product, with the active molecule only present in relatively small amounts. Historically, excipients were termed inactive components.

Analytical advances in pharmaceutical impurity profiling.

Impurities will be present in all drug substances and drug products, i.e. nothing is 100% pure if one looks in enough depth.

Investigation of surface porosity measurements and compaction pressure as means to ensure consistent contact angle determinations.

Compounds wettability is critical for a number of central processes including disintegration, dispersion, solubilisation and dissolution. It is therefore an important optimisation parameter both in drug discovery but also as guidance for formulation selection and optimisation. Wettability for a compound is determined by its contact angle to a liquid, which in the present study was measured using the sessile drop method applied to a disc compact of the compound.

Methodology of oral formulation selection in the pharmaceutical industry.

Pharmaceutical formulations have to fulfil various requirements with respect to their intended use, either in the development phase or as a commercial product. New drug candidates with their specific properties confront the formulation scientist with industrial challenges for which a strategy is needed to cope with limited resources, stretched timelines as well as regulatory requirements. This paper aims at reviewing different methodologies to select a suitable formulation approach for oral delivery.

Tween 20 increases intestinal transport of doxorubicin in vitro but not in vivo.

The chemotherapeutic drug substance doxorubicin has been reported to be a substrate of P-gp, which induces a barrier for oral administration and leads to a bioavailability of 3% in male Sprague Dawley rats. Literature studies have reported increased transport of P-pg substrates, like digoxin, when co-administered with P-gp inhibitors (non-ionic surfactants) in vitro and in vivo . The aim of the present study was thus to investigate if different non-ionic surfactants would have a similar effect on the in vitro and in vivo absorption of doxorubicin.

Interaction of GABA-mimetics with the taurine transporter (TauT, Slc6a6) in hyperosmotic treated Caco-2, LLC-PK1 and rat renal SKPT cells.

The aim of the present study was to investigate if basic GABA-mimetics interact with the taurine transporter (TauT, Slc6a6), and to find a suitable cell based model that is robust towards extracellular changes in osmolality during uptake studies. Taurine uptake was measured in human Caco-2 cells, porcine LLC-PK1 cells, and rat SKPT cells using radiolabelled taurine. Hyperosmotic conditions were obtained by incubation with raffinose (final osmolality of 500mOsm) for 24h prior to the uptake experiments.

Roller compaction scale-up using roll width as scale factor and laser-based determined ribbon porosity as critical material attribute.

Due to the complexity and difficulties associated with the mechanistic modeling of roller compaction process for scale-up, an innovative equipment approach is to keep roll diameter fixed between scales and instead vary the roll width. Assuming a fixed gap and roll force, this approach should create similar conditions for the nip regions of the two compactor scales, and thus result in a scale-reproducible ribbon porosity. In the present work a non-destructive laser-based technique was used to measure the ribbon porosity at-line with high precision and high accuracy as confirmed by an initial comparison to a well-established volume displacement oil intrusion method.

Quantitative surface topography assessment of directly compressed and roller compacted tablet cores using photometric stereo image analysis.

Surface topography, in the context of surface smoothness/roughness, was investigated by the use of an image analysis technique, MultiRay™, related to photometric stereo, on different tablet batches manufactured either by direct compression or roller compaction. In the present study, oblique illumination of the tablet (darkfield) was considered and the area of cracks and pores in the surface was used as a measure of tablet surface topography; the higher a value, the rougher the surface. The investigations demonstrated a high precision of the proposed technique, which was able to rapidly (within milliseconds) and quantitatively measure the obtained surface topography of the produced tablets.

Statistical Analysis of a Method to Predict Drug-Polymer Miscibility.

In this study, a method proposed to predict drug-polymer miscibility from differential scanning calorimetry measurements was subjected to statistical analysis. The method is relatively fast and inexpensive and has gained popularity as a result of the increasing interest in the formulation of drugs as amorphous solid dispersions. However, it does not include a standard statistical assessment of the experimental uncertainty by means of a confidence interval.

Displacement of Drugs From Cyclodextrin Complexes by Bile Salts: A Suggestion of an Intestinal Drug-Solubilizing Capacity From an In Vitro Model.

The dosing of drugs in an aqueous cyclodextrin formulation requires sufficient amount of cyclodextrins to fully solubilize the drug, as described by Stella's cyclodextrin utility number (UCD). However, this framework does not take biopharmaceutical elements into account, such as the displacement of drug from the cyclodextrin cavity by bile salts present in the small intestine. As bile salts in the intestine are present at concentrations above the critical micelle concentration, an understanding of the interaction between cyclodextrins and bile salts at such supramicellar concentrations (SMC) is required for a better biopharmaceutical understanding of the release mechanism from orally dosed cyclodextrin complexes.

Investigation of enzyme-sensitive lipid nanoparticles for delivery of siRNA to blood-brain barrier and glioma cells.

Clinical applications of siRNA for treating disorders in the central nervous system require development of systemic stable, safe, and effective delivery vehicles that are able to cross the impermeable blood-brain barrier (BBB). Engineering nanocarriers with low cellular interaction during systemic circulation, but with high uptake in targeted cells, is a great challenge and is further complicated by the BBB. As a first step in obtaining such a delivery system, this study aims at designing a lipid nanoparticle (LNP) able to efficiently encapsulate siRNA by a combination of titratable cationic lipids.

Thermodynamic investigation of the interaction between cyclodextrins and preservatives - Application and verification in a mathematical model to determine the needed preservative surplus in aqueous cyclodextrin formulations.

Preservatives are inactivated when added to conserve aqueous cyclodextrin (CD) formulations due to complex formation between CDs and the preservative. To maintain the desired conservation effect the preservative needs to be added in apparent surplus to account for this inactivation. The purpose of the present work was to establish a mathematical model, which defines this surplus based upon knowledge of stability constants and the minimal concentration of preservation to inhibit bacterial growth.