Distribution of Organohalogen and Synthetic Musk Compounds in Breast Adipose Tissue of Breast Cancer Patients in Ulster County, New York, USA.

We determined the concentrations of 98 halogenated organic compounds and synthetic musks in breast fat tissues of 50 breast cancer patients (age range: 34-77 years) collected during 1996-1998 in Ulster County, New York, USA. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl 153 (PBB-153), polybrominated diphenyl ethers (PBDEs), and synthetic musk compounds (SMCs) were analyzed in breast fat tissues, and 46 analytes were found at a detection frequency of ≥ 65% and at concentrations in the decreasing order of OCPs > PCBs > SMCs > PBDEs > PBB-153. PCBs (median: 323 ng/g wet wt) and dichlorodiphenyltrichloroethanes (DDTs, median: 293 ng/g wet wt) were the major compounds found in breast fat tissues. Among PCB congeners, hexa- and hepta-chlorobiphenyls (60% of total PCBs) were the abundant ones. p,p'-DDE accounted for more than 99% of the total DDT concentrations. The concentrations of SMCs and PBDEs were 1-2 orders of magnitude lower than those of PCBs and DDTs. 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-r-2-benzopyran (median: 33 ng/g wet wt) was the most abundant SMC, whereas BDE-47 (median: 4.5 ng/g wet wt) was the most dominant PBDE congener present in breast tissues. A significant correlation (p < 0.05) between women's age and concentrations of DDTs, chlordanes, hexachlorobenzene and PCBs in breast tissues was found. Concentrations of PCBs, PBDEs, OCPs, and SMCs were not significantly different between malignant and benign tumor cases. This study adds baseline information on target tissue burdens of persistent organic contaminants in breast cancer patients.

Cationic Nanoliposomes Are Efficiently Taken up by Alveolar Macrophages but Have Little Access to Dendritic Cells and Interstitial Macrophages in the Normal and CpG-Stimulated Lungs.

The purpose of this study was to assess whether cationic nanoliposomes could address tumor vaccines to dendritic cells in the lungs in vivo. Nanoliposomes were prepared using a cationic lipid, dimethylaminoethanecarbamoyl-cholesterol (DC-cholesterol) or dioleoyltrimethylammoniumpropane (DOTAP), and dipalmitoylphosphatidylcholine (DPPC), the most abundant phospholipid in lung surfactant. The liposomes presented a size below 175 nm and they effectively entrapped tumor antigens, an oligodeoxynucletotide containing CpG motifs (CpG) and the fluorescent dye calcein used as a tracer. Although the liposomes could permanently entrap a large fraction of the actives, they could not sustain their release in vitro. Liposomes made of DOTAP were safe to respiratory cells in vitro, while liposomes composed of DC-cholesterol were cytotoxic. DOTAP nanoliposomes were mainly taken up by alveolar macrophages following delivery to the lungs in mice. Few dendritic cells took up the liposomes, and interstitial macrophages did not take up liposomal calcein more than they took up soluble calcein. Stimulation of the innate immune system using liposomal CpG strongly enhanced uptake of calcein liposomes by all phagocytes in the lungs. Although a small percentage of dendritic cells took up the nanoliposomes, alveolar macrophages represented a major barrier to dendritic cell access in the lungs.

Drug-fortified liposomes as carriers for sustained release of NSAIDs: The concept and its validation in the animal model for the treatment of arthritis.

Drug-fortified cationic liposomes of 6­methoxy­2­naphthylacetic acid (6­MNA) were prepared and characterized by various techniques. The residence time of drug-fortified liposomes in joint cavity was evaluated by intra-articular (IA) administration of the radio-labeled (99mTc) liposomal formulation in the inflamed joints in rats. The cationic liposomal formulation composed of 6­MNA (3) as an active agent, its double salt (4) with the lipid 1,2­distearoyl­sn­glycero­3­phosphoethanolamine (DSPE), and pharmaceutically acceptable excipients such as hydrogenated soyabean phospatidylcholine (HSPC) and 1,2­dioleyloxy­3­trimethylammoniumpropane chloride (DOTAP) were developed using thin film hydration technique. The cryo-TEM analysis confirmed that the prepared optimized liposomal formulation (DFL-2) was a mixture of small unilamellar vesicles (SUVs), large unilamellar vesicles (LUVs) and multilamellar vesicles (MLVs). In addition, the TEM analysis confirmed that the prepared liposomes were of spherical in shape having liposome size in the range of 500-900 nm and zeta potential of about +30 mV. The developed cationic liposomes exhibited sustained release profile of payload of 6­MNA for over >12 h and about five times higher retention in the inflamed animal joints after 24 h (by scintigraphy of the joints) as compared to the plain 6­MNA solution when administered by IA route. The anti-inflammatory activity of prepared liposomal composition is evaluated by Freund's adjuvant induced arthritic model in rats. The liposomal formulation was well tolerated by all animals indicating good biocompatibility. Further, the cationic liposomal formulation treated group showed decreased erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in comparison to the control and the standard groups in the in vivo study. The improved efficacy of the drug-fortified liposomal formulation was due to the coupled effect of longer retention and sustained release of the active drug 6­MNA in the joints. From the obtained results it could be concluded that the combined effect of the cationic charge on the drug-fortified liposomes and the inherent affinity of the active agent towards the synovial joint tissues, coupled with slow release of the active drug due to double salt approach at the site of administration could potentially decrease the frequency of IA drug administration. Hence such a formulation could prove to be a therapeutic boon for the management of late stage arthritis.

Size-controlled lipid nanoparticle production using turbulent mixing to enhance oral DNA delivery.

Lipid-based nanoparticles (LNPs) have been developed to address the transport and uptake barriers to enhance the delivery efficiency of plasmid DNA therapeutics. In these systems, plasmid DNA can be encapsulated through condensation by a cationic lipid to form lipo-complexes, or polycation following complexation into cationic liposomes to form lipo-polyplexes. Conventional methods for achieving these two DNA-delivering LNP vehicles suffer from significant batch-to-batch variation, poor scalability and complicated multi-step preparation procedures. Resultant nanoparticles often have uncontrollable size and surface charge with wide distribution, and poor stability when exposed to physiological media. Here we report a single-step flash nanocomplexation (FNC) process using turbulent mixing to prepare uniform lipo-complex or lipo-polyplex LNPs in a scalable manner, demonstrating excellent control over the nanoparticle size (from 40 to several hundred nm) and surface charge, with narrow size distribution. The FNC-produced LNPs could be purified and concentrated using a tangential flow filtration (TFF) process in a scalable manner. An optimized formulation of purified lipo-complex LNPs (DOTAP/Chol/DNA, 45 nm) showed significantly higher (5-fold in the lungs and 4-fold in the liver) transgene expression activity upon oral dosage than lipo-polyplex LNPs (DPPC/Chol/lPEI/DNA, 75 nm) or lPEI/DNA nanoparticles (43 nm). Repeated dosing (4 days, 150 µg/day) of the lipo-complex LNPs sustained the transgene activity over a period of one week without detectable toxicity in major organs, suggesting its potential for clinical translation. STATEMENT OF SIGNIFICANCE: We report a new method to prepare uniform size-controlled lipid-based DNA-loaded nanoparticles by turbulent mixing delivered by a multi-inlet vortex mixer. Two distinct compositions were successfully prepared: (1) lipo-complexes, through condensation of the plasmid DNA by cationic lipids; (2) lipo-polyplexes, by encapsulation of DNA/PEI together with neutral lipids. Comparing with conventional methods, which use multi-step processes with high batch-to-batch variations and poor control over nanoparticle characteristics, this method offers a single-step, continuous and reproducible assembly methodology that would promote the translation of such gene medicine products. Effective purification and concentration of nanoparticles were achieved by adopted tangential flow filtration method. Following oral gavage in mice, the lipo-complex nanoparticles showed the highest level of transgene expression in the lung and liver.

Palmitoleic Acid has Stronger Anti-Inflammatory Potential in Human Endothelial Cells Compared to Oleic and Palmitic Acids.

SCOPE: Fatty acids (FAs) may affect endothelial cell (EC) function, influencing atherogenesis and inflammatory processes. Palmitoleic acid (POA) has been described as an anti-inflammatory FA. However, its effects on ECs are underexplored. This study compares the effects of POA with those of palmitic acid (PA) and oleic acid (OA) on EC inflammatory responses. METHODS AND RESULTS: EAHy926 cells (EC lineage) are exposed to PA, OA, or POA, and stimulated with tumor necrosis factor (TNF)-α. Associated with the FA's own incorporation, PA induces a twofold increase in arachidonic acid, while POA increases the amount of cis-vaccenic acid. PA, but not OA, enhances the production of IL-6 and IL-8 in response to TNF-α. In contrast, POA decreases production of monocyte chemotactic protein (MCP)-1, IL-6, and IL-8 compared to PA. TNF-α increases surface intercellular adhesion molecule-1 expression previously decreased by POA. TNF-α stimulation increases the expression of NFκB, cyclooxygenase (COX)-2, MCP-1, and IL-6 genes and reduces the expression of peroxisome proliferator-activated receptor (PPAR)-α gene. PA enhances the expression of MCP-1, IL-6, and COX-2 genes, while POA downregulates these genes, decreases expression of NFκB, and upregulates PPAR-α gene expression. CONCLUSION: POA has anti-inflammatory effects on ECs stimulated with TNF-α and may counter endothelial dysfunction.

Lack of pharmacokinetic interaction between fluvastatin and green tea in healthy volunteers.

PURPOSE: The objective of this study is to assess the effects of green tea and its major catechin component, (-)-epigallocatechin gallate (EGCG), on CYP2C9-mediated substrate metabolism in vitro, and the pharmacokinetics of fluvastatin in healthy volunteers. METHODS: The metabolism of diclofenac and fluvastatin in human recombinant CYP2C9 was investigated in the presence of EGCG. In a randomized three-phase crossover study, 11 healthy volunteers ingested a single 20-mg dose of fluvastatin with green tea extract (GTE), containing 150 mg of EGCG, along with water (300 mL), brewed green tea (300 mL), or water (300 mL) after overnight fasting. Plasma concentrations of fluvastatin and EGCG were measured by ultra-performance liquid chromatography with fluorescence detection and a single mass spectrometer. RESULTS: EGCG inhibited diclofenac 4'-hydroxylation and fluvastatin degradation with IC50 of 2.23 and 48.04 µM, respectively. Brewed green tea used in the clinical study also dose-dependently inhibited the metabolism of diclofenac and fluvastatin in vitro. However, no significant effects of GTE and brewed green tea were observed in plasma concentrations of fluvastatin. The geometric mean ratios with 90% CI for area under the plasma concentration-time curve (AUC0-∞) of fluvastatin were 0.993 (0.963-1.024, vs. brewed green tea) and 0.977 (0.935-1.020, vs. GTE). CONCLUSIONS: Although in vitro studies indicated that EGCG and brewed green tea produce significant inhibitory effects on CYP2C9 activity, the concomitant administration of green tea and fluvastatin in healthy volunteers did not influence the pharmacokinetics of fluvastatin.

Co-administration of Fluvastatin and CYP3A4 and CYP2C8 Inhibitors May Increase the Exposure to Fluvastatin in Carriers of CYP2C9 Genetic Variants.

Fluvastatin, which is one of the hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors (statins), is primarily metabolized by CYP2C9 and to a lesser extent by CYP3A4 and CYP2C8. Predictions of drug-drug interactions (DDI) are important for the safety of combination therapies with statins, in particular drugs that are metabolized by CYP3A4. Little information is available regarding drug interactions with fluvastatin. Since CYP2C9 is a polymorphic enzyme, we investigated the effect of DDI via CYP2C9, CYP3A4, and CYP2C8 on fluvastatin pharmacokinetics by using a validated prediction method in relation to CYP2C9 variants. The predicted increases in the area under the concentration-time curve (AUC) ratios of fluvastatin in carriers with CYP2C9*1/*2, CYP2C9*1/*3, CYP2C9*2/*2, CYP2C9*2/*3, and CYP2C9*3/*3 versus that found in carriers with CYP2C9*1/*1 were 1.16, 1.35, 1.37, 1.65, and 2.06, respectively. Our in silico model predicted that administration of fluvastatin in conjunction with the potent inhibitors that completely inhibited CYP3A4 and CYP2C8 in carriers with the CYP2C9*3/*3 variant would cause a 3.23- and 2.60-fold increase in the AUC ratios, respectively, when compared to that for the carriers with the CYP2C9*1/*1 taking fluvastatin alone. We also predicted the effect of telmisartan when coadministered with fluvastatin. Our prediction results showed that the interaction between telmisartan and fluvastatin via CYP enzymes were negligible in clinical situations.

Determination of the serine palmitoyl transferase inhibitor myriocin by electrospray and Q-trap mass spectrometry.

Myriocin is a potent inhibitor of serine-palmitoyl-transferase, the first and rate-determining enzyme in the sphingolipids biosynthetic pathway. This study developed, validated and applied a LC-MS/MS method to measure myriocin in minute specimens of animal tissue. The chemical analog 14-OH-myriocin was used as the internal standard. The two molecules were extracted from the tissue homogenate by solid-phase extraction, separated by gradient reversed-phase liquid chromatography and measured by negative ion electrospray mass spectrometry in the triple quadrupole. Detection was accomplished by multiple reaction monitoring, employing the most representative transitions, 400@104 and 402@104 for myriocin and 14-OH-myriocin, respectively. The typical limit of detection and lower limit of quantitation of the optimized method were 0.9 pmol/mL (~0.016 pmol injected) and 2.3 pmol/mL, respectively, and the method was linear up to 250 pmol/mL range (r2 = 0.9996). The intra- and between-day repeatability afforded a coefficient of variation ≤7.0%. Applications included quantification of myriocin in mouse lungs after 24 h from administration of ~4 nmol by intra-tracheal delivery. Measured levels ranged from 4.11 (median; 2.3-7.4 IQR, n = 4) to 11.7 (median; 7.6-22.7 interquartile range (IQR), n = 6) pmol/lung depending on the different formulations used. Myriocin was also measured in retinas of mice treated by intravitreal injection and ranged from 0.045 (less than the limit of detection) to 0.35 pmol/retina.

Effect of meal composition on postprandial lipid concentrations and lipoprotein particle numbers: A randomized cross-over study.

BACKGROUND: It is unclear how high-protein (HP) and high-monounsaturated fat (HMF) meals affect postprandial blood lipids and lipoprotein particle numbers (LPN). PURPOSE: To compare a HP versus a HMF meal on postprandial lipid and LPN responses. METHODS: Twenty-four participants (age: 36.3±15.0 years; body mass index: 23.6±2.0 kg/m2; 45.8% female) were fed a HP (31.9% energy from protein) and a HMF (35.2% fat and 20.7% monounsaturated fat) meal in a randomized cross-over trial design. Energy and carbohydrate content were the same across meals. Blood samples were drawn in the fasting state and 3 hour postprandial state, and assessed for lipids and LPN. RESULTS: Repeated measures analysis showed a significant (p<0.05) treatment by time interaction effect for triglycerides (TG), the primary variable, total high-density lipoprotein particles (T-HDLP) and T-HDLP minus large-buoyant high-density lipoprotein 2b (T-HDLP-LB-HDL2b). HP versus HMF condition led to significantly lower TG at 120 (geometric mean: 90.1 (95% confidence interval (CI): 76.4-106.3) vs. 146.5 (124.2-172.9) mg/dL) and 180 (101.4 (83.1-123.8) vs. 148.7 (121.9-181.4) mg/dL) min and higher T-HDLP at 120 (mean difference: 297.3 (95% CI: 48.6-545.9) nmol/L) and 180 (291.6 (15.8-567.5) nmol/L) min. The difference in T-HDLP by condition was due to the significantly higher small-dense HDLP (T-HDLP-LB-HDL2b) during HP versus HMF condition at 120 (mean difference: 452.6 (95% CI: 177.4-727.9) nmol/L) and 180 (496.8 (263.1-730.6) nmol/L) min. Area under the curve analysis showed that HP versus HMF condition led to significantly lower TG, non-HDLP, and very-low-density lipoprotein particles (VLDLP) responses but significantly less favorable responses in LB-HDL2b particles, T-HDLP-LB-HDL2b, and LB-HDL2b/T-HDLP ratio. CONCLUSION: The HP meal led to lower TG, non-HDLP, and VLDLP but less favorable LB-HDL2b, small-dense HDLP, and LB-HDL2b/T-HDLP ratio responses versus a HMF meal. Further studies are needed to confirm these findings over multiple meals.

Quantitative Analyses of Hepatic OATP-Mediated Interactions Between Statins and Inhibitors Using PBPK Modeling With a Parameter Optimization Method.

This study aimed to construct a widely applicable method for quantitative analyses of drug-drug interactions (DDIs) caused by the inhibition of hepatic organic anion transporting polypeptides (OATPs) using physiologically based pharmacokinetic (PBPK) modeling. Models were constructed for pitavastatin, fluvastatin, and pravastatin as substrates and cyclosporin A (CsA) and rifampicin (RIF) as inhibitors, where enterohepatic circulations (EHC) of statins were incorporated. By fitting to clinical data, parameters that described absorption, hepatic elimination, and EHC processes were optimized, and the extent of these DDIs was explained satisfactorily. Similar in vivo inhibition constant (Ki ) values of each inhibitor against OATPs were obtained, regardless of the substrates. Estimated Ki values of CsA were comparable to reported in vitro values with the preincubation of CsA, while those of RIF were smaller than reported in vitro values (coincubation). In conclusion, this study proposes a method to optimize in vivo PBPK parameters in hepatic uptake transporter-mediated DDIs.

Gastrointestinal Motility Variation and Implications for Plasma Level Variation: Oral Drug Products.

The oral route of administration is still by far the most ubiquitous method of drug delivery. Development in this area still faces many challenges due to the complexity and inhomogeneity of the gastrointestinal environment. In particular, dosing unpredictably relative to motility phase means the gastrointestinal environment is a random variable within a defined range. Here, we present a mass balance analysis that captures this variation and highlights the effects of gastrointestinal motility, exploring what impacts it ultimately has on plasma levels and the relationship to bioequivalence for high solubility products with both high and low permeability (BCS I and III). Motility-dependent compartmental absorption and transit (MDCAT) mechanistic analysis is developed to describe the underlying fasted state cyclical motility and how the contents of the gastrointestinal tract are propelled.

Improvement of fluvastatin bioavailability by loading on nanostructured lipid carriers.

The aim of this study is to prepare fluvastatin nanostructured lipid carriers (FLV-NLCs) in order to find an innovative way to alleviate FLV-associated disadvantages. The limitations include poor solubility and extensive first-pass metabolism, resulting in low (30%) bioavailability and short elimination half-life (1-3 hours). FLV-NLCs were prepared by hot emulsification-ultrasonication method. Ten runs were created by three-level factorial design (32) to optimize FLV-NLCs formulation process. In this study, two factors, four responses, and three-level factorial design were endorsed. The studied variables were lipid:oil ratio (X1) and sonication time (X2). However, the responses parameter determined the particle size (Y1, nm), entrapment efficiency percent (EE%, Y2), particles zeta potential (Y3), and 80% of the drug release after 24 hours (X4). Furthermore, stability and in vivo pharmacokinetics were studied in rats. The optimized consisted formula had an average particle size of 165 nm with 75.32% entrapment efficiency and 85.32% of drug released after 24 hours, demonstrating a sustaining drug release over 24 hours. An in vivo pharmacokinetic study revealed enhanced bioavailability by >2.64-fold, and the mean residence time was longer than that of FLV. We concluded that NLCs could be promising carriers for sustained/prolonged FLV release with enhanced oral bioavailability.

[A Woman Experienced Severe Thrombocytopenia When Treated With Fluvastatin]. / Thrombopénie sévère chez une patiente traitée par fluvastatine.

A 62-year-old woman treated with fluvastatin experienced three separate thrombocytopenic illnesses, severe on two occasions associated with nadir platelet count of 57 000/µL and 75 000/µL. The hospital pharmacist replaced fluvastatin by pravastatin during three stays. Platelet count has increased some days after this substitution. These results suggest that fluvastatin could be involved in these thrombocytopenic episodes.

Macrocyclic-, polycyclic-, and nitro musks in cosmetics, household commodities and indoor dusts collected from Japan: implications for their human exposure.

This paper reported the occurrence and concentrations of macrocyclic-, polycyclic- and nitro musks in cosmetics and household commodities collected from Japan. The high concentrations and detection frequencies of Musk T, habanolide, and exaltolides were found in commercial products, suggesting their large amounts of production and usage in Japan. Polycyclic musks, HHCB and OTNE, also showed high concentrations in cosmetics and products. The estimated dairy intakes of Musk T and HHCB by the dermal exposure to commercial products were 7.8 and 7.9 µg/kg/day in human, respectively, and perfume and body lotion are dominant exposure sources. We also analyzed synthetic musks in house dusts. Polycyclic musks, HHCB and OTNE, showed high concentrations in samples, but macrocyclic musks were detected only in a few samples, although these types of musks were highly detected in commercial products. This is probably due to easy-degradation of macrocyclic musks in indoor environment. The dairy intakes of HHCB by dust ingestions were 0.22 ng/kg/day in human, which were approximately five orders of magnitudes lower than those of dermal absorption from commercial household commodities.

Risk of adverse events among older adults following co-prescription of clarithromycin and statins not metabolized by cytochrome P450 3A4.

BACKGROUND: The cytochrome P450 3A4 (CYP3A4) inhibitor clarithromycin may also inhibit liver-specific organic anion-transporting polypeptides (OATP1B1 and OATP1B3). We studied whether concurrent use of clarithromycin and a statin not metabolized by CYP3A4 was associated with an increased frequency of serious adverse events. METHODS: Using large health care databases, we studied a population-based cohort of older adults (mean age 74 years) who were taking a statin not metabolized by CYP3A4 (rosuvastatin [76% of prescriptions], pravastatin [21%] or fluvastatin [3%]) between 2002 and 2013 and were newly prescribed clarithromycin (n=51,523) or azithromycin (n=52,518), the latter an antibiotic that inhibits neither CYP3A4 nor OATP1B1 and OATP1B3. Outcomes were hospital admission with a diagnostic code for rhabdomyolysis, acute kidney injury or hyperkalemia, and all-cause mortality. All outcomes were assessed within 30 days after co-prescription. RESULTS: Compared with the control group, patients co-prescribed clarithromycin and a statin not metabolized by CYP3A4 were at increased risk of hospital admission with acute kidney injury (adjusted relative risk [RR] 1.65, 95% confidence interval [CI] 1.31 to 2.09), admission with hyperkalemia (adjusted RR 2.17, 95% CI 1.22 to 3.86) and all-cause mortality (adjusted RR 1.43, 95% CI 1.15 to 1.76). The adjusted RR for admission with rhabdomyolysis was 2.27 (95% CI 0.86 to 5.96). The absolute increase in risk for each outcome was small and likely below 1%, even after we considered the insensitivity of some hospital database codes. INTERPRETATION: Among older adults taking a statin not metabolized by CYP3A4, co-prescription of clarithromycin versus azithromycin was associated with a modest but statistically significant increase in the 30-day absolute risk of adverse outcomes.

Evaluation of the usefulness of breast cancer resistance protein (BCRP) knockout mice and BCRP inhibitor-treated monkeys to estimate the clinical impact of BCRP modulation on the pharmacokinetics of BCRP substrates.

PURPOSE: To evaluate whether the impact of functional modulation of the breast cancer resistance protein (BCRP, ABCG2 421C>A) on human pharmacokinetics after oral administration is predictable using Bcrp knockout mice and cynomolgus monkeys pretreated with a BCRP inhibitor, elacridar. METHODS: The correlation of the changes of the area under the plasma concentration-time curve (AUC) caused by ABCG2 421C>A with those caused by the Bcrp knockout in mice, or BCRP inhibition in monkeys, was investigated using well-known BCRP substrates (rosuvastatin, pitavastatin, fluvastatin, and sulfasalazine). RESULTS: In mice, the bioavailability changes, which corrected the effect of systemic clearance by Bcrp knockout, correlated well with the AUC changes in humans, whereas the correlation was weak when AUC changes were directly compared. In monkeys, the AUC changes pretreated with elacridar resulted in a good estimation of those in humans within approximately 2-fold ranges. CONCLUSIONS: This study suggests that pharmacokinetics studies that use the correction of the bioavailability changes in Bcrp knockout mice are effective for estimating clinical AUC changes in ABCG2 421C>A variants for BCRP substrate drugs and those studies in monkeys that use a BCRP inhibitor serve for the assessment of BCRP impact on the gastrointestinal absorption in a non-rodent model.

Interaction of clopidogrel and statins in secondary prevention after cerebral ischaemia - a randomized, double-blind, double-dummy crossover study.

AIMS: Variability in responsiveness to clopidogrel is a clinical problem in secondary prevention after cerebral ischaemia which has been suggested to be linked to competitive metabolization of clopidogrel and cytochrome P450 (CYP) 3A4-oxidated statins such as simvastatin. We assessed the hypothesis that simvastatin, in contrast to CYP 2C9-metabolized fluvastatin, reduces clopidogrel-mediated platelet inhibition. METHODS: We performed a randomized, double-blind, double-dummy, two period crossover study in 13 patients with cerebral ischaemia (8F, 5 M), aged 64.1 ± 8.0 years (mean ± SD). After a 14 day period in which all patients received 75 mg clopidogrel day(-1) , patients additionally received either 20 mg simvastatin day(-1) or 80 mg fluvastatin day(-1) for 14 days. Regimens were crossed over after a 14 day wash-out period and switched regimens were continued for another 14 days. Platelet aggregation, clopidogrel active metabolite (CAM) plasma concentrations and routine laboratory parameters including prothrombin time (PT) Quick percent value were assessed at baseline and following each treatment phase. RESULTS: Clopidogrel reduced platelet aggregation in all patients as expected. Platelet aggregation and CAM plasma concentrations were unaltered when simvastatin or fluvastatin was added to clopidogrel. Simvastatin decreased PT Quick percent value (decrease from 109 ± 10.5% to 103 ± 11%, P < 0.05) when combined with clopidogrel but there was no such change following treatment with fluvastatin and clopidogrel. CONCLUSIONS: Our data indicate that treatment with CYP 3A4-metabolized simvastatin does not jeopardize clopidogrel-mediated inhibition of platelet aggregation. After co-administration of simvastatin and clopidogrel we observed a decrease in the PT Quick percent value which could be due to simvastatin-induced reduction of activity of prothrombin fragment 1 + 2.

Transient cerebral hypoperfusion assisted intraarterial cationic liposome delivery to brain tissue.

Transient cerebral hypoperfusion (TCH) has empirically been used to assist intraarterial (IA) drug delivery to brain tumors. Transient (<3 min) reduction of cerebral blood flow (CBF) occurs during many neuro- and cardiovascular interventions and has recently been used to better target IA drugs to brain tumors. In the present experiments, we assessed whether the effectiveness of IA delivery of cationic liposomes could be improved by TCH. Cationic liposomes composed of 1:1 DOTAP:PC (dioleoyl-trimethylammonium-propane:phosphatidylcholine) were administered to three groups of Sprague-Dawley rats. In the first group, we tested the effect of blood flow reduction on IA delivery of cationic liposomes. In the second group, we compared TCH-assisted IA liposomal delivery versus intravenous (IV) administration of the same dose. In the third group, we assessed retention of cationic liposomes in brain 4 h after TCH assisted delivery. The liposomes contained a near infrared dye, DilC18(7), whose concentration could be measured in vivo by diffuse reflectance spectroscopy. IA injections of cationic liposomes during TCH increased their delivery approximately fourfold compared to injections during normal blood flow. Optical pharmacokinetic measurements revealed that relative to IV injections, IA injection of cationic liposomes during TCH produced tissue concentrations that were 100-fold greater. The cationic liposomes were retained in the brain tissue 4 h after a single IA injection. There was no gross impairment of neurological functions in surviving animals. Transient reduction in CBF significantly increased IA delivery of cationic liposomes in the brain. High concentrations of liposomes could be delivered to brain tissue after IA injections with concurrent TCH while none could be detected after IV injection. IA-TCH injections were well tolerated and cationic liposomes were retained for at least 4 h after IA administration. These results should encourage development of cationic liposomal formulations of chemotherapeutic drugs and their IA delivery during TCH.

More potent lipid-lowering effect by rosuvastatin compared with fluvastatin in everolimus-treated renal transplant recipients.

BACKGROUND: Dyslipidemia is a risk factor for premature cardiovascular morbidity and mortality in renal transplant recipients (RTRs). Pharmacotherapy with mTOR inhibitors aggravates dyslipidemia, thus necessitating lipid-lowering therapy with fluvastatin, pravastatin, or atorvastatin. These agents may not sufficiently lower lipid levels, and therefore, a more potent agent like rosuvastatin maybe needed. METHODS: We have aimed to assess the lipid-lowering effect of rosuvastatin as compared with fluvastatin in RTR receiving everolimus. Safety was assessed as the pharmacokinetic (PK) interaction potential of a rosuvastatin/everolimus combination in RTR. A 12-hour everolimus PK investigation was performed in 12 stable RTR receiving everolimus and fluvastatin (80 mg/d). Patients were then switched to rosuvastatin (20 mg/d), and a follow-up 12/24-hour PK investigation of everolimus/rosuvastatin was performed after 1 month. All other drugs were kept unchanged. RESULTS: In RTR already receiving fluvastatin, switching to rosuvastatin further decreased LDL cholesterol and total cholesterol by 30.2±12.2% (P<0.01) and 18.2±9.6% (P<0.01), respectively. Everolimus AUC0-12 was not affected by concomitant rosuvastatin treatment, 80.3±21.3 µg*h/L before and 78.5±21.9 µg*h/L after, respectively (P=0.61). Mean rosuvastatin AUC0-24 was 157±61.7 ng*h/mL, approximately threefold higher than reported in the literature for nontransplants. There were no adverse events, and none of the patients had or developed proteinuria. CONCLUSION: Rosuvastatin showed a superior lipid-lowering effect compared to fluvastatin in stable RTR receiving everolimus. The combination of everolimus/rosuvastatin seems to be as safe as the everolimus/fluvastatin combination.