Fasted and fed state human duodenal fluids: Characterization, drug solubility, and comparison to simulated fluids and with human bioavailability

Accurate in vivo predictions of intestinal absorption of low solubility drugs require knowing their solubility in physiologically relevant dissolution media. Aspirated human intestinal fluids (HIF) are the gold standard, followed by simulated intestinal HIF in the fasted and fed state (FaSSIF/FeSSIF). However, current HIF characterization data vary, and there is also some controversy regarding the accuracy of FaSSIF and FeSSIF for predicting drug solubility in HIF. This study aimed at characterizing fasted and fed state duodenal HIF from 16 human volunteers with respect to pH, buffer capacity, osmolarity, surface tension, as well as protein, phospholipid, and bile salt content. The fasted and fed state HIF samples were further used to investigate the equilibrium solubility of 17 representative low-solubility small-molecule drugs, six of which were confidential industry compounds and 11 were known and characterized regarding chemical diversity. These solubility values were then compared to reported solubility values in fasted and fed state HIF, FaSSIF and FeSSIF, as well as with their human bioavailability for both states. The HIF compositions corresponded well to previously reported values and current FaSSIF and FeSSIF compositions. The drug solubility values in HIF (both fasted and fed states) were also well in line with reported solubility data for HIF, as well as simulated FaSSIF and FeSSIF. This indicates that the in vivo conditions in the proximal small intestine are well represented by simulated intestinal fluids in both composition and drug equilibrium solubility. However, increased drug solubility in the fed vs. fasted states in HIF did not correlate with the human bioavailability changes of the same drugs following oral administration in either state.

Novel Biphasic Lipolysis Method To Predict in Vivo Performance of Lipid-Based Formulations

The absence of an intestinal absorption sink is a significant weakness of standard in vitro lipolysis methods, potentially leading to poor prediction of in vivo performance and an overestimation of drug precipitation. In addition, the majority of the described lipolysis methods only attempt to simulate intestinal conditions, thus overlooking any supersaturation or precipitation of ionizable drugs as they transition from the acidic gastric environment to the more neutral conditions of the intestine. The aim of this study was to develop a novel lipolysis method incorporating a two-stage gastric-to-intestinal transition and an absorptive compartment to reliably predict in vivo performance of lipid-based formulations (LBFs). Drug absorption was mimicked by in situ quantification of drug partitioning into a decanol layer. The method was used to characterize LBFs from four studies described in the literature, involving three model drugs (i.e., nilotinib, fenofibrate, and danazol) where in vivo bioavailability data have previously been reported. The results from the novel biphasic lipolysis method were compared to those of the standard pH-stat method in terms of reliability for predicting the in vivo performance. For three of the studies, the novel biphasic lipolysis method more reliably predicted the in vivo bioavailability compared to the standard pH-stat method. In contrast, the standard pH-stat method was found to produce more predictive results for one study involving a series of LBFs composed of the soybean oil, glyceryl monolinoleate (Maisine CC), Kolliphor EL, and ethanol. This result was surprising and could reflect that increasing concentrations of ethanol (as a cosolvent) in the formulations may have resulted in greater partitioning of the drug into the decanol absorptive compartment. In addition to the improved predictivity for most of the investigated systems, this biphasic lipolysis method also uses in situ analysis and avoids time- and resource-intensive sample analysis steps, thereby facilitating a higher throughput capacity and biorelevant approach for characterization of LBFs.

Combining biorelevant in vitro and in silico tools to investigate the in vivo performance of the amorphous solid dispersion formulation of etravirine in the fed state

INTRODUCTION

In the development of bio-enabling formulations, innovative in vivo predictive tools to understand and predict the in vivo performance of such formulations are needed. Etravirine, a non-nucleoside reverse transcriptase inhibitor, is currently marketed as an amorphous solid dispersion (Intelence® tablets). The aims of this study were 1) to investigate and discuss the advantages of using biorelevant in vitro setups to simulate the in vivo performance of Intelence® 100 mg and 200 mg tablets in the fed state, 2) to build a Physiologically Based Pharmacokinetic (PBPK) model by combining experimental data and literature information with the commercially available in silico software Simcyp® Simulator V17.1 (Certara UK Ltd.), and 3) to discuss the challenges of predicting the in vivo performance of an amorphous solid dispersion and identify the parameters which influence the pharmacokinetics of etravirine most.

METHODS

Solubility, dissolution and transfer experiments were performed in various biorelevant media simulating the fasted and fed state environment in the gastrointestinal tract. An in silico PBPK model for etravirine in healthy volunteers was developed in the Simcyp® Simulator, using in vitro results and data available from the literature as input. The impact of pre- and post-absorptive parameters on the pharmacokinetics of etravirine was investigated by simulating various scenarios.

RESULTS

In vitro experiments indicated a large effect of naturally occurring solubilizing agents on the solubility of etravirine. Interestingly, supersaturated concentrations of etravirine were observed over the entire duration of dissolution experiments on Intelence® tablets. Coupling the in vitro results with the PBPK model provided the opportunity to investigate two possible absorption scenarios, i.e. with or without implementation of precipitation. The results from the simulations suggested that a scenario in which etravirine does not precipitate is more representative of the in vivo data. On the post-absorptive side, it appears that the concentration dependency of the unbound fraction of etravirine in plasma has a significant effect on etravirine pharmacokinetics.

CONCLUSIONS

The present study underlines the importance of combining in vitro and in silico biopharmaceutical tools to advance our knowledge in the field of bio-enabling formulations. Future studies on other bio-enabling formulations can be used to further explore this approach to support rational formulation design as well as robust prediction of clinical outcomes.

Evaluation and Safety Validation of Dehydrating Methods for Goat Meat in Rural Malawi

ObjectivesThis study was conducted to evaluate the dehydration methods of goat meat based in Malawi and the effects on food safety.Materials and MethodsGoat meat was prepared as ground, minced, and whole muscle strips. Samples were treated with 6% lemon juice marinade, 6% vinegar marinade, or salt rub. During phase 1, dehydration of the meat was performed with a solar dehydrator (n = 108), electric oven (n = 108) or drum oven (n = 108). Qualitative data on the three drying methods was collected from a panel of students from Mzuzu University, Malawi, on the practicality of each method in a local rural setting. Additionally, visual observations were conducted 30 d prior to drying for the presence of mold and insects to give an indication of shelf life. Phase 2 was performed at Texas Tech University in Lubbock, Texas where whole muscle strips of lamb were submerged in a five-strain Escherichia coli surrogate cocktail of Escherichia coli for 5 min, allowed 30 min for cell attachment, then dried using an electric and drum oven, replicating the dehydration procedure in Malawi. For each replicate (n = 2), attachment samples (n = 10), samples dried in the electric oven (n = 10) and samples dried in drum oven samples (n = 10) were aseptically plated on MacConkey agar with a TSA overlay and enumerated for E. coli.ResultsIn phase 1, mold growth was observed on 15.7% (34/216) of samples dried in the solar dehydrator and drum oven. Of those positive for mold, 32.4% (n = 11) were minced, and 67.6% (n = 23) were whole muscle strips. No samples dried using the electric oven displayed mold (0/108). No samples displayed insects. Based on qualitative data that was gathered, top reasons to dry goat meat using the drum oven include “not requiring electricity” and “drum ovens are a common piece of equipment in villages”. Top reasons against using a drum oven include “unequal distribution of heat” and “high level of oversight required during drying”. Top reasons to dry goat meat using electric oven include “fast drying time”, “uniform distribution of heat”, and “limited oversight required”. Top reasons against using electric oven to dry goat meat include “requiring electricity” and “low knowledge of electric oven operation in a community setting”. Top reasons to use the solar dehydrator to dry goat meat include “not requiring electricity or firewood” and “limited oversight required”. Top reasons against using the solar dehydrator to dry goat meat include “slow drying time” and “uneven heat distribution due to time of day and shadows”. In phase 2, a 5-log reduction was observed for all electric oven treatment replicates (100%, 2/2) and half drum oven (50%, 1/2) replicates. However, variation in the reduction of E.coli is a direct result of weather and fuel provided to the drum oven.ConclusionElectric drying oven displayed the most consistent results for shelf life and safety. However, in rural Malawi, dehydrating methods should be chosen on a case by case basis.

Validation of Dissolution Testing with Biorelevant Media: An OrBiTo Study

Dissolution testing with biorelevant media has become widespread in the pharmaceutical industry as a means of better understanding how drugs and formulations behave in the gastrointestinal tract. Until now, however, there have been few attempts to gauge the reproducibility of results obtained with these methods. The aim of this study was to determine the interlaboratory reproducibility of biorelevant dissolution testing, using the paddle apparatus (USP 2). Thirteen industrial and three academic laboratories participated in this study. All laboratories were provided with standard protocols for running the tests: dissolution in FaSSGF to simulate release in the stomach, dissolution in a single intestinal medium, FaSSIF, to simulate release in the small intestine, and a "transfer" (two-stage) protocol to simulate the concentration profile when conditions are changed from the gastric to the intestinal environment. The test products chosen were commercially available ibuprofen tablets and zafirlukast tablets. The biorelevant dissolution tests showed a high degree of reproducibility among the participating laboratories, even though several different batches of the commercially available medium preparation powder were used. Likewise, results were almost identicalbetween the commercial biorelevant media and those produced in-house. Comparing results to previous ring studies, including those performed with USP calibrator tablets or commercially available pharmaceutical products in a single medium, the results for the biorelevant studies were highly reproducible on an interlaboratory basis. Interlaboratory reproducibility with the two-stage test was also acceptable, although the variability was somewhat greater than with the single medium tests. Biorelevant dissolution testing is highly reproducible among laboratories and can be relied upon for cross-laboratory comparisons.

Sertraline inhibits the transport of PAT1 substrates in vivo and in vitro

BACKGROUND AND PURPOSE

Intestinal nutrient transporters may mediate the uptake of drugs. The aim of this study was to investigate whether sertraline interacts with the intestinal proton-coupled amino acid transporter 1 PAT1 (SLC36A1).

EXPERIMENTAL APPROACH

In vitro investigations of interactions between sertraline and human (h)PAT1, hSGLT1 (sodium-glucose linked transporter 1) and hPepT1 (proton-coupled di-/tri-peptide transporter 1) were conducted in Caco-2 cells using radiolabelled substrates. In vivo pharmacokinetic investigations were conducted in male Sprague-Dawley rats using gaboxadol (10 mg·kg(-1), p.o.) as a PAT1 substrate and sertraline (0-30.6 mg·kg(-1)). Gaboxadol was quantified by hydrophilic interaction chromatography followed by MS/MS detection.

KEY RESULTS

Sertraline inhibited hPAT1-mediated L-[(3)H]-Pro uptake in Caco-2 cells. This interaction between sertraline and PAT1 appeared to be non-competitive. The uptake of the hSGLT1 substrate [(14)C]-α-methyl-D-glycopyranoside and the hPepT1 substrate [(14)C]-Gly-Sar in Caco-2 cells was also decreased in the presence of 0.3 mM sertraline. In rats, the administration of sertraline (0.1-10 mM, corresponding to 0.3-30.6 mg·kg(-1), p.o.) significantly reduced the maximal gaboxadol plasma concentration and AUC after its administration p.o.

CONCLUSIONS AND IMPLICATIONS

Sertraline is an apparent non-competitive inhibitor of hPAT1-mediated transport in vitro. This inhibitory effect of sertraline is not specific to hPAT1 as substrate transport via hPepT1 and hSGLT1 was also reduced in the presence of sertraline. In vivo, sertraline reduced the amount of gaboxadol absorbed, suggesting that the inhibitory effect of sertraline on PAT1 occurs both in vitro and in vivo. Hence, sertraline could alter the bioavailability of drugs absorbed via PAT1.

Fed and fasted state gastro-intestinal in vitro lipolysis: In vitro in vivo relations of a conventional tablet, a SNEDDS and a solidified SNEDDS

The present study aims at evaluating the ability of a gastro-intestinal in vitro lipolysis model to predict the performance of two lipid formulations and a conventional tablet containing a poorly soluble drug, cinnarizine, in dogs, both in the fasted and fed state. A self-nano-emulsifying drug delivery system (SNEDDS) was either dosed in a hard gelatin capsule (SNEDDS-C) or loaded onto a porous tablet core (SNEDDS-T) and compared to a marketed conventional tablet (Conv) in an in vitro lipolysis model. The model simulates the digestion in the stomach and intestine during either the fasted or the fed state. Whole fat milk (3.5%) was used in the fed state model to mimic the dynamic lipolysis events after ingestion of food. The results were compared to a dog study published in this issue. In the fasted state in vitro lipolysis model, the amount of solubilized cinnarizine decreased in the order SNEDDS-C>SNEDDS-T>Conv, which correlated well with the in vivo bioavailability. In the fed state in vitro lipolysis model, cinnarizine was solubilized to the same degree for all formulations. Compared to the fasted state model, only the performance of the conventional tablet was improved, indicating food effect. This correlated with the in vivo study, where the tablet was the only formulation with a significant food effect. The fasted state model correlated well with the in vivo results and although the fed state model did not accurately predict the fed state in vivo results, it could predict which formulation that would exhibit a food effect.

Function and expression of the proton-coupled amino acid transporter PAT1 along the rat gastrointestinal tract: implications for intestinal absorption of gaboxadol

BACKGROUND AND PURPOSE

Intestinal absorption via membrane transporters may determine the pharmacokinetics of drug compounds. The hypothesis is that oral absorption of gaboxadol (4,5,6,7-tetrahydroisoxazolo [5,4-c] pyridine-3-ol) in rats occurs via the proton-coupled amino acid transporter, rPAT1 (encoded by the gene rSlc36a1). Consequently, we aimed to elucidate the in vivo role of rPAT1 in the absorption of gaboxadol from various intestinal segments obtained from Sprague-Dawley rats.

EXPERIMENTAL APPROACH

The absorption of gaboxadol was investigated following its administration into four different intestinal segments. The intestinal expression of rSlc36a1 mRNA was measured by quantitative real-time PCR. Furthermore, the hPAT1-/rPAT1-mediated transport of gaboxadol or L-proline was studied in hPAT1-expressing Xenopus laevis oocytes, Caco-2 cell monolayers and excised segments of the rat intestine.

KEY RESULTS

The absorption fraction of gaboxadol was high (81.3-91.3%) following its administration into the stomach, duodenum and jejunum, but low (4.2%) after administration into the colon. The pharmacokinetics of gaboxadol were modified by the co-administration of L-tryptophan (an hPAT1 inhibitor) and L-proline (an hPAT1 substrate). The in vitro carrier-mediated uptake rate of L-proline in the excised intestinal segments was highest in the mid jejunum and lowest in the colon. The in vitro uptake and the in vivo absorption correlated with the expression of rSlc36a1 mRNA along the rat intestine.

CONCLUSIONS AND IMPLICATIONS

These results suggest that PAT1 mediates the intestinal absorption of gaboxadol and therefore determines its oral bioavailability. This has implications for the in vivo role of PAT1 and may have an influence on the design of pharmaceutical formulations of PAT1 substrates.

In vitro and in vivo performance of novel supersaturated self-nanoemulsifying drug delivery systems (super-SNEDDS)

Novel supersaturated self-nanoemulsifying drug delivery systems (super-SNEDDS) containing the poorly water-soluble drug halofantrine above equilibrium solubility (150% S(eq)) were compared in vitro and in vivo with conventional SNEDDS containing the drug below equilibrium solubility (75% S(eq)). Pre-concentrates comprising of either medium chain lipids (Captex 300/Capmul MCM) or long chain lipids (soybean oil/Maisine), Cremophor RH40 and ethanol were formulated maintaining the lipid-to-surfactant-to-cosolvent ratio constant (55:35:10, w/w %). The ability of super-SNEDDS to increase the absorption of halofantrine in dogs, as well as the predictivity of the dynamic in vitro lipolysis model was studied. In vitro lipolysis of SNEDDS and super-SNEDDS showed rapid drug precipitation from all formulations while the same drug concentrations in the digestion medium were found during digestion of equal amounts of SNEDDS and super-SNEDDS. Elevated halofantrine solubilisation during in vitro lipolysis was observed only when multiple capsules of conventional SNEDDS were subjected to in vitro digestion. After lipolysis the isolated super-SNEDDS pellets were characterised by XRPD revealing no crystalline halofantrine from any of the investigated formulations. Subsequent dissolution studies of the super-SNEDDS pellet in the lipolysis medium demonstrated enhanced dissolution of halofantrine suggesting that halofantrine in the pellet was amorphous. The enhanced dissolution of the amorphous halofantrine was also reflected in vivo since two capsules of conventional SNEDDS were needed to achieve similar AUC and C(max) as obtained after dosing of a single capsule of super-SNEDDS. The study demonstrated that the absorption of halofantrine was not hampered by drug precipitation. Super-SNEDDS lead to precipitation of halofantrine in an amorphous form, which can be the driving force for enhanced absorption. Since super-SNEDDS were also physically stable for at least 6 months they represent a potential novel oral lipid-based drug delivery system for low aqueous soluble compounds.

The proton-coupled amino acid transporter, SLC36A1 (hPAT1), transports Gly-Gly, Gly-Sar and other Gly-Gly mimetics

BACKGROUND AND PURPOSE The intestinal proton-coupled amino acid transporter, SLC36A1, transports zwitterionic α-amino acids and drugs such as vigabatrin, gaboxadol and δ-aminolevulinic acid. We hypothesize that SLC36A1 might also transport some dipeptides. The aim of the present study was to investigate SLC36A1-mediated transport of Gly-Gly and Gly-Gly mimetics, and to investigate Gly-Sar transport via SLC36A1 and the proton-coupled dipeptide/tripeptide transporter, SLC15A1 in Caco-2 cells. EXPERIMENTAL APPROACH Transport of a compound via SLC36A1 was determined by its ability to induce an increase in the inward current of two-electrode voltage clamped SLC36A1 cRNA-injected Xenopus laevis oocytes. SLC36A1-mediated L-[³H]Pro uptake in Caco-2 cells was measured in the absence and presence of Gly-Gly or Gly-Sar. In addition, apical [¹⁴C]Gly-Sar uptake was measured in the absence and presence of the SLC36A1 inhibitor 5-hydroxy-L-tryptophan (5-HTP) or the SLC15A1 inhibitor L-4,4'-biphenylalanyl-L-proline (Bip-Pro). KEY RESULTS In SLC36A1-expressing oocytes, an inward current was induced by Gly-Sar, Gly-Gly, δ-aminolevulinic acid, β-aminoethylglycine, δ-aminopentanoic acid, GABA, Gly and Pro, whereas Val, Leu, mannitol, 5-HTP and the dipeptides Gly-Ala, Gly-Pro and Gly-Phe did not evoke currents. In Caco-2 cell monolayers, the apical uptake of 30 mM Gly-Sar was inhibited by 20 and 22% in the presence of 5-HTP or Bip-Pro, respectively, and by 48% in the presence of both. CONCLUSION AND IMPLICATIONS Our results suggest that whereas Gly-Gly amid bond bioisosteres are widely accepted by the hPAT1 carrier, dipeptides in general are not; and therefore, Gly-Sar might structurally define the size limit of dipeptide transport via SLC36A1.

An updated and simplified method for bile duct cannulation of rats

The single bile duct cannulated rat model was used for short-term intestinal absorption studies. Rats were randomly assigned to three groups: (A) bile duct cannulated, (B) control laparotomy and (C) no treatment. The body weight and health of the rats were monitored before and until day 5 after surgery, while bile flow was measured in group A on day 2. On the fifth day, tail vein blood was harvested, and alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin were quantified. Analysis of variance showed no significant difference between the groups for these parameters. This study demonstrated the suitability of a surgical rat model feasible for evaluation of the impact of bile in pharmacokinetic studies.

A review of molecular pathological markers in vulvar carcinoma: lack of application in clinical practice

Vulvar carcinoma is a rare female genital neoplasia. Radical surgery, which has been the standard treatment approach, is often accompanied by considerable morbidity. To reduce the incidence of complications there has been a movement toward individualised therapy and less radical surgery. Associated with this, new tumour markers that could serve as prognostic indicators would be of considerable value to guide treatment decision. In this review, a brief update of molecular pathological markers of vulvar carcinomas is provided, and their impact as prognostic markers is addressed. p16, p21, p14, p27, cyclin A, cyclin D1, p53, vascular endothelial growth factor (VEGF), transforming growth factor alpha, HER-2 and epidermal growth factor receptor (EGFR) have been found to be important in the pathogenesis and/or progression of vulvar carcinomas. Furthermore, human papillomavirus, p16, p21, p14, p53, VEGF, CD44v3, CD44v6, CD44v4, CD44v9, CD44v10, HER-2, EGFR, matrix metalloproteinase-12, caspase 3, Bcl-2 and nm23-H1 have been correlated to clinical outcome of patients with vulvar carcinomas. However, due to the relative small number of studies reported for each molecular pathological marker, and the relative small number of vulvar carcinomas included and the lack of multivariate analysis in the majority of these studies, no conclusion regarding the prognostic value of these markers can be drawn. Therefore, the investigated markers have not yet earned a place in standard clinical diagnostics or treatment, and further studies are needed to clarify the clinical value of these markers.

Intestinal gaboxadol absorption via PAT1 (SLC36A1): modified absorption in vivo following co-administration of L-tryptophan

BACKGROUND AND PURPOSE

Gaboxadol has been in development for treatment of chronic pain and insomnia. The clinical use of gaboxadol has revealed that adverse effects seem related to peak serum concentrations. The aim of this study was to investigate the mechanism of intestinal absorption of gaboxadol in vitro and in vivo.

EXPERIMENTAL APPROACH

In vitro transport investigations were performed in Caco-2 cell monolayers. In vivo pharmacokinetic investigations were conducted in beagle dogs. Gaboxadol doses of 2.5 mg.kg(-1) were given either as an intravenous injection (1.0 mL.kg(-1)) or as an oral solution (5.0 mL.kg(-1)).

KEY RESULTS

Gaboxadol may be a substrate of the human proton-coupled amino acid transporter, hPAT1 and it inhibited the hPAT1-mediated L-[(3)H]proline uptake in Caco-2 cell monolayers with an inhibition constant K(i) of 6.6 mmol.L(-1). The transepithelial transport of gaboxadol was polarized in the apical to basolateral direction, and was dependent on gaboxadol concentration and pH of the apical buffer solution. In beagle dogs, the absorption of gaboxadol was almost complete (absolute bioavailability, F(a), of 85.3%) and T(max) was 0.46 h. Oral co-administration with 2.5-150 mg.kg(-1) of the PAT1 inhibitor, L-tryptophan, significantly decreased the absorption rate constant, k(a), and C(max), and increased T(max) of gaboxadol, whereas the area under the curve and clearance of gaboxadol were constant.

CONCLUSIONS AND IMPLICATIONS

The absorption of gaboxadol across the luminal membrane of the small intestinal enterocytes is probably mediated by PAT1. This knowledge is useful for reducing gaboxadol absorption rates in order to decrease peak plasma concentrations.

Characterization and physical stability of spray dried solid dispersions of probucol and PVP-K30

The main purpose of this study was to obtain stable, well-characterized solid dispersions (SDs) of amorphous probucol and polyvinylpyrrolidone K-30 (PVP-K30) with improved dissolution rates. A secondary aim was to investigate the flow-through dissolution method for in-vitro dissolution measurements of small-sized amorphous powders dispersed in a hydrophilic polymer. SDs were prepared by spray drying solutions of probucol and different amounts of PVP-K30. The obtained SDs were characterized by dissolution rate measurements in a flow-through apparatus, X-ray Powder Diffraction (XRPD), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), particle sizing (laser diffraction) and Brunauer-Emmett-Teller Method (BET) and results were compared with starting material and a physical mixture. The physical stability was monitored after storage at 25 degrees C and 60% RH for up to 12 weeks. The flow-through method was found suitable as dissolution method. All SDs showed improved in-vitro dissolution rates when compared to starting material and physical mixtures. The greatest improvement in the in-vitro dissolution rate was observed for the highest polymer to drug ratio. By means of the results from XRPD and DSC, it was argued that the presence of amorphous probucol improved the dissolution rate, but the amorphous state could not fully account for the difference in dissolution profiles between the SDs. It was suggested that the increase in surface area due to the reduction in particle size contributed to an increased dissolution rate as well as the presence of PVP-K30 by preventing aggregation and drug re-crystallization and by improving wettability during dissolution. The stabilizing effect of the polymer was verified in the solid state, as all the SDs retained probucol in the amorphous state throughout the entire length of the stability study.

Effects of acute and chronic aripiprazole treatment on choice between cocaine self-administration and food under a concurrent schedule of reinforcement in rats

RATIONALE

Dopamine D2-like partial agonists such as aripiprazole have received some attention as potential pharmacotherapies for the treatment of psychostimulant addiction. However, the preclinical evaluations so far have focused on acute effects of aripiprazole.

OBJECTIVES

We tested the hypothesis that aripiprazole, both as acute and as chronic treatment, would preferentially decrease cocaine self-administration while sparing behavior maintained by a natural reinforcer, resulting in a shift in the allocation of behavior from cocaine-taking towards the alternative reinforcer.

MATERIALS AND METHODS

Rats were trained to self-administer intravenous cocaine in a concurrent choice procedure, with a palatable food as the competing reinforcer, under a fixed ratio (FR) 1 FR 5 chain schedule. Aripiprazole was then administered as continuous infusion by osmotic minipumps for 5 days, during which performance in the choice procedure was assessed daily.

RESULTS

An intermediate dose of aripiprazole decreased cocaine self-administration and shifted the cocaine choice curve to the right as an acute treatment. However, as a chronic treatment, aripiprazole failed to decrease cocaine self-administration or cocaine choice, despite a dose-dependent decrease in overall response rates and food-maintained behavior.

CONCLUSIONS

Our results confirm and extend earlier findings and indicate that acute administration of aripiprazole can decrease cocaine self-administration. However, based on the present data, chronic treatment with aripiprazole does not show much promise as a potential pharmacotherapy for cocaine addiction. Both acute and chronic treatment data are in agreement with published clinical findings, suggesting that the concurrent choice procedure in rats has predictive validity of efficacy in humans.

Optimization of Self-Microemulsifying Drug Delivery Systems (SMEDDS) Using a D-Optimal Design and the Desirability Function

D-optimal design and the desirability function were applied to optimize a self-microemulsifying drug delivery system (SMEDDS). The optimized key parameters were the following: 1) particle size of the dispersed emulsion, 2) solubility of the drug in the vehicle, and 3) the vehicle compatibility with the hard gelatin capsule. Three formulation variables, PEG200, a surfactant mixture, and an oil mixture, were included in the experimental design. The results of the mathematical analysis of the data demonstrated significant interactions among the formulation variables, and the desirability function was demonstrated to be a powerful tool to predict the optimal formulation for the explored system.

Expression of ZNF652, a novel zinc finger protein, in vulvar carcinomas and its relation to prognosis

AIMS

To determine the levels of expression of ZNF652 and its relevance to prognosis in vulvar squamous cell carcinomas.

METHODS

22 cases of vulvar intraepithelial neoplasia (VIN) and tumours from 217 patients with vulvar squamous cell carcinomas were investigated for expression of ZNF652 using immunostaining methods. The effect of ZNF652 ectopic expression was determined in the vulvar carcinoma cell line SW954 by western and cell-based assays.

RESULTS

High levels of ZNF652 nuclear expression were observed in 5 (100%) of VIN I, 6 (75%) of VIN II and 109 (50.2%) of the vulvar carcinomas, whereas low levels were seen in 2 (25%) VIN II, 9 (100%) of VIN III and 108 (49.8%) of the vulvar carcinomas. High levels of ZNF652 expression in the vulvar carcinomas were significantly correlated to high expression of EphA2. However, when correcting for multiple testing this correlation was lost. No association was identified between ZNF652 expression and p16, p21, p27, p53, cyclin A, D1, D3, E, EphrinA-1 and human papillomavirus. Variations in levels of ZNF652 were not related to prognosis. Low levels of ZNF652 protein were identified in the vulvar carcinoma cell line SW954. Furthermore, SW954 cells ectopically expressing ZNF652 showed reduced cell proliferation and the ability to form colonies on plastic.

CONCLUSIONS

ZNF652 protein expression is reduced in 25% of VIN II, 100% of VIN III and approximately 50% of the cases of vulvar squamous cell carcinoma, and may be an early event in the pathogenesis of vulvar squamous cell carcinoma. Variations in the levels of ZNF652 were not related to patient's prognosis.

Expression of EphA2 and EphrinA-1 in vulvar carcinomas and its relation to prognosis

AIMS

To examine the expression of EphA2 and EphrinA-1 in vulvar squamous cell carcinomas and investigate their prognostic relevance.

METHODS

Tumours from 224 patients with vulvar squamous cell carcinomas were investigated for expression of EphA2 and EphrinA-1 using single and double immunostaining methods.

RESULTS

High expression (strong/moderate staining intensity) of EphA2 and EphrinA-1 was observed in 114 (51%) and 126 (56%) vulvar carcinomas, respectively. In the three cases tested using the double immunostaining method, colocalisation of EphA2 and EphrinA-1 proteins was identified in the same neoplastic cells. High EphA2 expression was significantly correlated to high expression of EphrinA-1 (p<0.01) and cyclin A (p<0.01), large tumour size (p = 0.03), deep invasion (p<0.01) and higher FIGO stage (p = 0.05). A correlation between high EphrinA-1 expression and high levels of cyclin A (p<0.01) and p21 (p<0.01), deep invasion (p<0.01) and higher FIGO stage (p = 0.01) was also seen. In univariate analysis, high expression of EphrinA-1 was associated with poor survival (p = 0.03). However, in the multivariate analysis neither EphrinA-1 nor EphA2 were significantly correlated to survival.

CONCLUSIONS

EphA2 and EphrinA-1 were overexpressed in 51% and 56% of the vulvar squamous cell carcinomas, respectively, and high levels of EphA2 and EphrinA-1 proteins were associated with deep tumour invasion and high FIGO stage. However, EphA2 and EphrinA-1 were not independently associated with clinical outcome in vulvar carcinomas.

Molecular markers for lymph node involvement in locally advanced cervical carcinomas

5049

Background: Lymph node involvement is the first indication of cervical cancer spread and a strong prognostic factor. The aims of the present study were to identify genes associated with lymph node involvement. Methods: The nodal status and tumor volume were determined from MR images in 48 patients with FIGO stage 2a to 4a at the time of diagnosis. cDNA microarray technique was used to identify genes that differed in expression between node positive and negative tumors. Biopsies enriched for carcinoma tissue were co-hybridized with a common reference sample in a dye-swap design. Quantitative real time PCR (qRT PCR) and immunohistochemistry were used to validate microarray results and determine protein expression of selected genes. Results: Pathologic lymph nodes were seen in 29 patients and normal nodes in 19. We identified 16 genes with higher and 15 with lower expression in node positive tumors as compared to the negative ones. QRT PCR data of 4 genes were consistent with these findings. CKS2, MRPS23, MRPL11, LSM3 and PDK2 were upregulated in node positive tumors suggesting high proliferation activity and oxygen consumption. MSN, KLF3 and TBX3 were downregulated. CKS2, MRPS23, MRPL11, PDK2, LSM3, TBX3, KLF3 and MSN were significantly related to progression free survival in univariate analysis. Protein expression, determined for CKS2 and MSN, was significantly correlated to survival, consistent with these results. In multivariate analysis including only gene variables, MRPL11, PDK2 and TBX3 were significant. Including also clinical and MRI variables, tumor volume, KLF3 and TBX3 were significant. NEK1, CSTA, ANX4 and DDOST were upregulated indicating activated DNA damage repair (NEK1) and resistance to apoptosis (CSTA, ANX4, DDOST). NTN4 and HYAL1, which are involved in cell-matrix interactions, were downregulated, suggesting mechanisms for increased cell migration and invasive growth. Conclusions: Our findings are consistent with known phenotypic characteristics of node positive cervical tumors, such as hypoxia and high lactate content. They point to molecular mechanisms for development of hypoxia, deregulation of glucose metabolism, activation of survival strategies and interactions between carcinoma cells and tumor stroma that may promote metastasis formation.

No significant financial relationships to disclose.

Markers of apoptosis in stage IB squamous cervical carcinoma

AIMS

To examine the prognostic relevance of the expression of the Bcl-2, Bcl-xL, and Bax proteins in stage IB squamous cervical carcinoma (SCC).

METHODS

In total, 220 patients who underwent radical hysterectomy and bilateral lymphadenectomy at the Norwegian Radium Hospital for stage IB SCC between 1987 and 1993 were studied. Immunohistochemistry using monoclonal antibodies against Bcl-2, Bcl-xL, and Bax was used to examine protein expression. Ten patients who underwent hysterectomy for uterine prolapse served as controls.

RESULTS

Cytoplasmic expression of Bcl-2, Bcl-xL, and Bax was low (< 5% positive cells) in 159 of 220 (73%), 193 of 220 (87%), and 39 of 220 (18%) tumours, respectively, and high (> or = 5% positive cells) in 61 of 220 (27%), 27 of 220 (13%), and 181 of 220 (82%) tumours, respectively. In univariate analysis, all classic clinicopathological parameters but none of the investigated proteins were associated with prognosis. In multivariate analysis, only deep stromal invasion was independently related to survival.

CONCLUSION

Bcl-2, Bcl-xL, and Bax were not independently associated with prognosis in stage IB SCC.

TP53 mutations in early-stage ovarian carcinoma, relation to long-term survival

We conducted the present study to evaluate the frequency and prognostic importance on long-term survival of TP53 mutations and TP53 protein accumulation in a cohort of 178 patients with early-stage ovarian carcinomas. TP53 mutations scored as aberrant temporal temperature gradient gel electrophoresis pattern from all exons were observed in 39.9% of the tumours. Full screening of exons 5–8, followed by sequencing, was successful in 135 cases, and 48 mutations altering the protein were detected in 39 cases (28.9%). TP53 mutations were slightly less common in the Federation of Gynecologists and Obstetricians stage IA than in IB/IC (P=0.05). No significant correlations with histological type, grade of differentiation, DNA ploidy status or age at diagnosis were found. TP53 protein accumulation analysed by immunohistochemistry was found in 32.6% of all tumours, and was a poor predictor of TP53 mutations with 56.4% sensitivity, 77.1% specificity, 50% positive predictive value and 81.3% negative predictive value. Neither TP53 mutations nor TP53 protein accumulation influenced the prognosis significantly in this group of patients.

Comparison of two intervention programmes in young female players in European handball - with and without ankle disc

INTRODUCTION

The prevention of injuries in all sports calls for a structured plan. The plan consists, as earlier described, of four steps. We have previously presented studies incorporating all four steps. The studies have shown that it is possible to prevent most injuries in young female players in European handball by applying a training programme combining the use of an ankle disc with functional strength training. In the previous studies we were not able to discriminate whether the preventive effect was due to the functional strength training or the training with the ankle disc. The aim of this study was to compare a programme with ankle disc and functional strength training with a programme with functional strength training only.

METHODS

Twenty handball teams were asked to participate, and 16 of 20 handball teams agreed to participate. The teams were cluster randomised to either the programme with or without an ankle disc.

RESULTS

The group using the programme without the ankle disc had a significantly higher number of traumatic injuries (16 vs. 6). The incidences of traumatic injuries in the ankle disc group were 2.4 (95% CI 0.7; 6.2) injuries per 1000 h of match and 0.2 (95% CI 0.02; 0.7) injuries per 1000 h of practice. In the group without ankle disc the incidences were 6.9 (95% CI 3.3; 12.7) injuries per 1000 h of match and 0.6 (95% CI 0.2; 1.3) injuries per 1000 h of practice. A significantly higher multivariate odds ratio (4.8) was found in the group not using the ankle disc. In addition the group using the ankle disc had significantly fewer moderate and major injuries.

CONCLUSION

By adding ankle disc training to a training programme with functional strength training, it is possible to reduce the number of injuries significantly, especially the number of moderate and major injuries.

Deregulation of D-type cyclins in uterine cancers. Cyclin D1/D3 is differentially expressed in cervical cancer

BACKGROUND

We have previously found cyclin D1 to be overexpressed in 45% of corpus cancers, but in only 3% of cervical cancers. To see whether and how D-type cyclins contribute to the neoplastic phenotype in uterine cancers, aberrant expression and association between cyclins D1 and D3 proteins were studied.

MATERIALS AND METHODS

Expression of cyclin D3 was investigated by immunohistochemistry in 51 patients with primary cancer of the corpus and 73 cases of primary cervical carcinomas. Amplification of the cyclin D1 and D3 genes was investigated by fluorescence in situ hybridisation (FISH).

RESULTS

We found high/moderate levels of cyclin D3 in 53.5% of cervical cancers and 55% of corpus cancers. High/moderate expression of cyclin D1 and D3 was associated in the corpus cancers, but not in cervical cancers. The accumulation of cyclin D3 but not D1 protein could, in some cases, be explained by increased gene dosage since extra copies of chromosome 6 were found.

CONCLUSION

This study demonstrates that in cervical cancers cyclin D3 may compensate for low levels of cyclin D1, whereas in corpus cancers both isoforms may contribute to the neoplastic phenotype.

Association between histology grade, expression of HsMCM2, and cyclin A in human invasive breast carcinomas

AIM

Increased proliferation of tumour cells has prognostic value in human invasive breast carcinomas (IBCs), and high histology grade and cyclin A expression, which may reflect high proliferation rate, are associated with poor prognosis. Expression of HsMCM2 is related to cell proliferation. This study evaluates the correlation between the expression of cyclins A, D1, D3, and E, Ki-67, proliferating cell nuclear antigen (PCNA), histology grade, and HsMCM2 expression, in addition to the independent prognostic value of HsMCM2 expression in human IBCs.

METHODS

Immunohistochemistry to evaluate HsMCM2, Ki-67, and PCNA expression in tumours from 147 patients with IBC.

RESULTS

Nuclear staining for HsMCM2 was seen in 10-30% of the tumour cells in 30 samples, in 30-70% in 40 samples, in > 70% in 44 samples, and in < 10% in 33 samples. One way ANOVA showed a significant association between expression of HsMCM2 and cyclin A, D3, E, histology grade, and Ki-67. A borderline correlation was seen between HsMCM2 and PCNA. In multivariate analysis, the only association was with cyclin A, in addition to a borderline association with histology grade. In a Cox regression hazards model, expression of HsMCM2 was associated with poor patient survival, although it lost its independent prognostic value when cyclin A expression was included. Ki-67 and PCNA expression were not associated with patient survival.

CONCLUSION

Cyclin A expression is independently associated with HsMCM2 expression, histology grade, and Ki-67. HsMCM2 expression is associated with poor patient survival, although it loses prognostic value when adjusted for cyclin A.

Differential Ki67 and bcl-2 immunoexpression in solid-glandular and spindle cell components of biphasic synovial sarcoma: a double immunostaining assessment with cytokeratin and vimentin

AIMS

Synovial sarcoma is a malignant soft tissue of uncertain histogenesis that may show a biphasic (spindle and solid/glandular components) or a monophasic histological appearance. In previous studies, we demonstrated that the solid/glandular component possesses higher proliferation rates than the spindle cell component of biphasic synovial sarcomas and that the spindle cell component may exhibit a progressive transition from or to the solid-glandular component in biphasic synovial sarcoma. To evaluate this hypothesis further, we designed a novel approach to correlate immunoexpression of Ki67, bcl-2 and bax in the spindle cell and in the solid-glandular component of biphasic synovial sarcomas. We also performed a double-immunohistochemical assessment of the Ki67 proliferative indices and the immunoexpression of anti-apoptotic protein bcl-2 in neoplastic cells expressing either vimentin or cytokeratin.

METHODS AND RESULTS

Immunohistochemistry for vimentin (10 cases), bcl-2 (10 cases), Ki67(10 cases), cytokeratin (10 cases), and bax (eight cases), and double-immunostaining for vimentin/Ki67 (10 cases), vimentin/bcl-2 (nine cases), cytokeratin/Ki67 (10 cases), and cytokeratin/bcl-2 (10 cases) assays were performed in 10 cases of primary biphasic synovial sarcoma. Semiquantitative assessment was adopted for each case in both components. Statistical analysis was performed using Fisher's exact test or chi2 test. On conventional immunohistochemistry, the solid/glandular component revealed more expression of Ki67, bax and cytokeratin than the spindle cell component (P=0.0004, P=0.082, and P < 0.0001, respectively); on the other hand, the latter showed higher expression of bcl-2 and vimentin than the former (P=0.0281 and P=0.059, respectively). Double immunohistochemistry analysis revealed higher co-expression levels of cytokeratin/Ki67 and cytokeratin/bcl-2 than the spindle cell component (P=0.015 and P < 0.0001, respectively); conversely, the latter presented higher co-expression of vimentin/bcl-2 than the former (P=0.0007). All cases showed no more than 10% of cells coexpressing cytokeratin/bcl-2, cytokeratin/Ki67, and no case revealed cells coexpressing vimentin/Ki67.

CONCLUSION

Our findings indicate that in biphasic synovial sarcoma the acquisition of epithelial phenotype (solid/glandular component) is associated with a high expression of pro-apoptotic proteins and a high proliferative differentiation status, and conversely, mesenchymal phenotype (spindle cell component) is associated with a high expression of apoptosis-inhibitor bcl-2 and a low proliferative terminal-type differentiation status.

Cyclin A expression in superficial spreading malignant melanomas correlates with clinical outcome

The present study analysed by immunohistochemistry the protein level of cyclin A and Ki-67 in a panel of paraffin-embedded tissue obtained from 172 primary (110 superficial and 62 nodular) and 73 metastatic melanomas, and ten benign naevi. Since cyclin A exists in the same quaternary complex in the S-phase of the cell cycle as the cdk inhibitor p21WAF1/CIP1, the levels of the two proteins were compared. Cyclin A and Ki-67 were heterogeneously expressed in the malignant tumours, whereas in benign naevi, only rare positive cells were detected. In superficial spreading melanomas, the cyclin A level was related to tumour thickness, with less expression in thinner lesions (p<0.00001), and to Ki-67 (p<0.00001) and p21WAF1/CIP1 (p=0.01) scores. Multivariate analysis showed that in addition to the depth of the primary tumour, the protein level of cyclin A was an independent indicator of relapse-free period (thickness, p<0.00001; cyclin A, p=0.0003). In contrast, in nodular melanoma, the cyclin A level was associated with Ki-67 expression, but neither cyclin A nor Ki-67 was related to tumour thickness (cyclin A, p=0.06; Ki-67, p=0.61) and neither had any impact on relapse-free (cyclin A, p=0.64; Ki-67, p=0.32) or overall (cyclinA, p=0.94; Ki-67, p=0.45) survival. In conclusion, the results indicate that cyclin A is a strong prognostic factor for patients with superficial spreading melanomas. In nodular melanomas, the proliferation rate seems to have little impact on disease progression.

Comparison of total oral bioavailability and the lymphatic transport of halofantrine from three different unsaturated triglycerides in lymph-cannulated conscious rats

The lymphatic transport and the portal absorption of the lipophilic drug halofantrine were investigated in a conscious rat model. The rats were dosed with 0.1 g with triolein, trilinolein or trilinolenin containing 2 mg halofantrine. Following oral administration of the triglycerides, the mesenteric lymph and plasma samples were collected. The lymphatic transport for halofantrine was 11.1+/-1.2 after administration of trilinolein, 9.0+/-3.5 for trilinolenin and 8.6+/-2.2 for triolein and the total amount of halofantrine transported in the lymph was linear proportional with the amount of triglyceride in the lymph. The absorption of halofantrine directly into the blood showed a trend towards a higher AUC for trilinolien and trilinolenin compared to triolein, but no statistical difference could be found. The statistically analysis of the mean total bioavailability therefore shows that the absorption of halofantrine was largely independent on triglyceride unsaturation.

Comparison of the lymphatic transport of halofantrine administered in disperse systems containing three different unsaturated fatty acids

PURPOSE

To compare the influence of the degree of fatty acid unsaturation (oleic [C18:], linoleic [C18:2], or linolenic acid [C18:3]), with the intestinal lymphatic transport of halofantrine free base from disperse systems in anesthetized rats.

METHODS

The mesenteric lymph duct was cannulated in anesthetized rats. Lipid vehicle containing halofantrine was administered by intraduodenal infusion. The concentration of halofantrine in blood and lymph samples was analyzed.

RESULTS

The rank order of the lymphatic transport of halofantrine was C18:2 > C18:1 > C18:3. Comparison of the area under the curve (AUC) from the three fatty acids showed no statistically significant differences between the AUCs from the lymph cannulated rats. In terms of rank order effects, the plasma concentrations of halofantrine were highest for the rats dosed C18:2 followed by C18:3 and C18:1.

CONCLUSIONS

Using C18:2 as a vehicle increased the lymphatic transport of halofantrine 16.6-fold over that observed for the system containing C18:3. The extent of lymphatic transport for the C18:1 system did not differ from the other two formulations, but the combined lymph and plasma data indicated that the C18:2 was the most suitable lipid vehicle for the oral delivery of halofantrine.

p53, p21 and mdm2 expression vs the response to radiotherapy in transitional cell carcinoma of the bladder

OBJECTIVE

To identify, in a retrospective study, possible molecular markers predictive of radioresponsiveness in patients with transitional cell carcinoma (TCC) of the bladder.

PATIENTS AND METHODS

Patients with T2-T4a TCC treated with preoperative radiotherapy and cystectomy were included in the study if their cystectomy specimen was pT3b (in 42) or pT0 (in 17). Because treatment schedules changed over time, radiotherapy was given either as 2 Gy x 23 over 4-5 weeks with cystectomy 4-5 weeks later (in 23), or as 4 Gy x 5 during 1 week with cystectomy in the following week (in 36 patients). Protein expression of p53, mdm2 and p21 (CDKN1 A/WAF1/CIP1/SDI1) was assessed immunohistochemically in biopsies taken before radiotherapy.

RESULTS

There was no difference in protein expression when comparing all patients with pT0 and pT3b. However, for patients receiving 46 Gy, increased p53 expression (but not p21 or mdm2) predicted the absence of residual tumour (P = 0.005): six of seven patients with > 50% p53 expression had pT0 in the cystectomy specimen, whereas 10 of 12 patients with < or = 5% expression had pT3b. Over-expression of p53 correlated with longer overall (P = 0.045) and cancer-specific survival (P = 0.020).

CONCLUSION

The expression of mdm2 or p21 did not predict radioresponsiveness in patients with TCC of the bladder. The role of p53 remains unclear; the view that p53 over-expression confers radioresistance in bladder cancer is not supported.