Development and evaluation of optimized sucrose ester stabilized oleanolic acid nanosuspensions prepared by wet ball milling with design of experiments.

The aim of this study was to develop optimized sucrose ester (SE) stabilized oleanolic acid (OA) nanosuspensions (NS) for enhanced delivery via wet ball milling by design of experiments (DOE). In this study, SEOA NS batches were prepared by wet ball milling method. Mean particle sizes and polydispersity indices were determined using a nanosizer. The percent encapsulation efficiency, saturation solubility and in vitro dissolution rate were obtained with analyses using HPLC. Preparation methods were optimized by DOE using the Minitab software. The in vitro bioefficacy was obtained by methyl thiazolyl tetrazolium (MTT) measurements in A549 human non small cell lung cancer cell line. The in vivo pharmacokinetics profile was determined using LC-electrospray ionization (ESI)-MS/MS. The study produced spherical SEOA NS particles (ca. 100 nm in diameter) which were found to be able to increase OA saturation solubility considerably. Optimized SEOA-GBD NS (milled at 600 rpm for 3 h, sucrose monolaurate (SEL) : sucrose monopalmitate (SEP) at 9 : 1, w/w; SE : OA at 1 : 1, w/w) was found to be physically stable over 14 d at 4°C. The NS showed much higher dissolution rate, cytotoxicity and bioavailability when compared with the free drug. Thus, the prepared OA as SE stabilized NS particles by wet ball milling enhanced the saturation solubility, in vitro dissolution rate, bioefficacy and in vivo bioavailability of OA. The use of sugar esters may also be potentially applied to other hydrophobic drugs.

Energy-based analysis of cone milling process for the comminution of roller compacted flakes.

Cone mill is commonly used for the milling of wet and dry agglomerates in the pharmaceutical industry as it is capable of producing milled granules with desired size characteristics. The aim of this study was to evaluate the various cone mill process parameters in terms of milling rate and energy consumption for the comminution of roller compacted flakes. A placebo formulation containing microcrystalline cellulose, lactose and magnesium stearate was used to evaluate the milling performance. Results of this study showed that higher milling rate was obtained with the combination of higher impeller speed, teethed round sidearm impeller and grater screen surface profile. Either one of the later two parameters when present in any mill setting was found to be capable of shortening the residence time of flakes inside the milling chamber, thus resulting in a higher milling rate. On the other hand, selection of appropriate screen surface profile and impeller speed was very important at lowering the effective specific energy consumption during milling. Grater screen surface profile and impeller speed between 2000 and 2400 rpm were found to act synergistically as the best combination for an energy sparing process. Impeller sidearm shape was found to have no significant effect on energy consumption.

Antioxidant and Nrf2 inducing activities of luteolin, a flavonoid constituent in Ixeris sonchifolia Hance, provide neuroprotective effects against ischemia-induced cellular injury.

Ixeris sonchifolia Hance is an herb distributed in northeastern part of China and has been used by natives to invigorate circulation. In the present study, bioactivity-guided fractionation of I. sonchifolia Hance extract was performed with the aim to isolate and identify the compounds underlying the potential protective effects against ischemia brain injury. Among the four fractions isolated from the herb extract, the ethyl acetate fraction was found to scavenge DPPH radicals, induce ARE-dependent transcriptional activity and upregulate Nrf2 protein levels. The isolation work focused on this fraction revealed the presence of two categories of compounds: flavonoids and sesquiterpene lactones. Among the five isolated flavonoids, luteolin was evaluated to possess direct and indirect antioxidant activities by scavenging free radicals and inducing the upregulation of ARE-dependent phase II enzymes. Concomitant with the findings from the cell-based assays, in the middle cerebral artery occlusion-induced ischemia rat model, administration of luteolin at 4 mg/kg displayed neuroprotective effects by reducing infarct area and inhibiting neuronal cell death. In summary, the obtained results suggest that flavonoids in I. sonchifolia Hance, in particular luteolin, contribute at least partly to the neuroprotective effects against ischemia-induced cellular injury and can be potentially developed for treatment of ischemia-reperfusion induced diseases.

Application of near-infrared spectroscopy in real-time monitoring of product attributes of ribbed roller compacted flakes.

This study assessed the utility of near-infrared (NIR) spectroscopy for the real-time monitoring of content uniformity and critical quality attributes (tensile strength, Young's modulus, and relative density) of ribbed roller compacted flakes made by axially corrugated or ribbed rolls. A custom-built setup was used to capture off-line NIR spectra from the flakes containing micronized chlorpheniramine maleate, microcrystalline cellulose, lactose, and magnesium stearate. The partial least square regression method was employed to build calibration models from these off-line NIR spectra using experimental design and validated using test set validation. During calibration model development, various factors, such as spectral acquisition mode, probe positioning, spectral preprocessing method, and beam size, were investigated to improve the prediction ability of the models. The statistical results obtained for calibration models and their validation revealed that dynamic spectral acquisition and proper probe positioning were very crucial to minimize the incorporation of variability in NIR spectra resulting from the flake's undulation. Calibration and validation statistics also suggested the importance of selecting appropriate spectral preprocessing method and beam size. In this study, best calibration models resulted from standard normal variate followed by first derivative preprocessed dynamic spectra captured using beam size ~1.2 mm. Best calibration models constructed from off-line NIR spectra were used in real-time analysis of flake attributes. Finally, adequacy of best calibration models was established from real-time prediction results. Overall, with the proposed setup, it was possible to monitor the roller compaction process in real time for various properties associated with the ribbed flakes in a rapid, efficient, and nondestructive manner.

Formulation, biological and pharmacokinetic studies of sucrose ester-stabilized nanosuspensions of oleanolic Acid.

PURPOSE: The aim of this study was to develop sucrose ester (SE)-stabilized oleanolic acid (OA) nanosuspensions (NS) for enhanced delivery. METHODS: SEOA NS were prepared via O/W emulsion and organic solvent evaporation methods. The particles' size and polydispersity index were measured by nanosizer. Their percent encapsulation efficiency, saturation solubility and in vitro dissolution rate were obtained via HPLC. The in vitro bioefficacy was analyzed by MTT measurements in A549 human non-small-cell lung cancer cell line. The cellular uptake of OA and in vivo pharmacokinetics profile were determined using LC-ESI-MS/MS. RESULTS: Spherical SEOA NS particles (~100 nm in diameter) were produced and found to be physicochemically stable over a month at 4°C. In particular, SEOA 4121 NS (SEL: SEP at 4:1 w/w; SE: OA at 2:1 w/w) produced the greatest increase in saturation solubility (1.89 mg/mL vs. 3.43 µg/mL), dissolution rate, cytotoxicity and bioavailability. Preliminary studies indicated that cellular uptake of SEOA NS by A549 cells was temperature-, concentration- and time-dependent. CONCLUSION: Preparing OA as SE-stabilized NS particles provides a novel method to enhance saturation solubility, in vitro dissolution rate, bioefficacy and in vivo bioavailability of free OA and/or other potentially useful hydrophobic drugs.

Polyethyleneimine-modified pectin beads for colon-specific drug delivery: in vitro and in vivo implications.

Calcium-pectinate (Ca-pectinate) beads have shown immense potential as colon-specific drug carrier. However, Ca-pectinate itself is unable to prevent its swelling/degradation in the upper gastro-intestinal (GI) conditions. Hence, polyethyleneimine (PEI) was added in the cross-linking solution to strengthen the Ca-pectinate network. Resveratrol was used as a model drug due to its promising therapeutic activity towards several colonic diseases. Beads were prepared by varying cross-linking solution pH and other formulation variables. The effects of these formulation variables were investigated on the bead's characteristics. Furthermore, surface morphology, drug-polymer interaction, stability, and in vivo pharmacokinetic study of the optimized formulation were performed. The optimized PEI-modified beads prevented drug release in the upper GI conditions, while released the drug in simulated colonic fluid. Furthermore, in vivo pharmacokinetics studies in rats demonstrated delayed appearance of drug in blood after oral administration. The optimized Ca-pectinate beads demonstrated both in vitro and in vivo colon-specific drug release.

Preparation and evaluation of zinc-pectin-chitosan composite particles for drug delivery to the colon: role of chitosan in modifying in vitro and in vivo drug release.

Zinc-pectin-chitosan composite microparticles were designed and developed as colon-specific carrier. Resveratrol was used as model drug due to its potential activity on colon diseases. Formulations were produced by varying different formulation parameters (cross-linking pH, chitosan concentration, cross-linking time, molecular weight of chitosan, and drug concentration). Single-step formulation technique was compared with multi-step technique. Effect of these parameters was investigated on shape, size, weight, weight loss (WL), moisture content (MC), encapsulation efficiency (EE), drug loading (L), and drug release pattern of the microparticles. The formulation conditions were optimized from the drug release study. In vivo pharmacokinetics of the zinc-pectinate particles was compared with the zinc-pectin-chitosan composite particles in rats. Formulations were spherical with 920.48-1107.56 µm size, 21.19-24.27 mg weight of 50 particles, 89.83-94.34% WL, 8.31-13.25% MC, 96.95-98.85% EE, and 17.82-48.31% L. Formulation parameters showed significant influence on drug release pattern from the formulations. Formulation prepared at pH 1.5, 1% chitosan, 120 min cross-linking time, and pectin:drug at 3:1 ratio demonstrated colon-specific drug release. Microparticles were stable at 4 °C and room temperature. Pharmacokinetic study indicated in vivo colon-specific drug release from the zinc-pectin-chitosan composite particles only.

Design of a pectin-based microparticle formulation using zinc ions as the cross-linking agent and glutaraldehyde as the hardening agent for colonic-specific delivery of resveratrol: in vitro and in vivo evaluations.

The aim of this study was to develop a colon-specific microparticle formulation based on pectin. Resveratrol was used as a model drug due to its potential therapeutic efficacy on colitis and colon cancer. Microparticles were produced by cross-linking pectin molecules with zinc ions and with glutaraldehyde as hardening agent for pectins. Different microparticles were prepared by varying the formulation variables. Effect of these formulation variables were investigated on particle shape and size, moisture content and weight-loss during drying, encapsulation efficiency, swelling-erosion ratio, and drug release pattern of the formulated microparticles. Formulation conditions were optimized based on the in vitro drug release study. Morphology, Fourier transform infrared spectroscopy, stability, and in vivo pharmacokinetic study of the microparticles prepared at the optimized formulation conditions were performed. Microparticles were spherical with <1 mm diameter and encapsulation efficiencies of >94%. The glutaraldehyde-modified microparticles prepared at optimized formulation conditions revealed colon specific in vitro and in vivo drug release. Plasma appearance of drug was delayed for 4-5 h after their administration directly into stomach, but displayed comparable area under the curve to other controls in the experiment, indicating the potential of the developed formulation as a colon-specific drug delivery system.

Pachymic acid impairs breast cancer cell invasion by suppressing nuclear factor-κB-dependent matrix metalloproteinase-9 expression.

Pachymic acid (PA), a lanostane-type triterpenoid derived from Poria cocos, possesses demonstrated anti-inflammatory and anti-cancer activities. Nonetheless, the biological properties and mechanism/s of action of PA remain largely undefined. In this study, the activity of PA against breast cancer cell invasion was evaluated. Invasiveness of human-derived MDA-MB-231 and MCF-7 breast carcinoma cells was suppressed by PA at non-lethal concentrations, which was associated with a decrease in matrix metalloproteinase-9 (MMP-9) secretion as a result of PA-mediated down-regulation of MMP-9 mRNA expression. In order to elucidate the underlying anti-invasive mechanism, the effect of PA on transcription factors activator protein-1 (AP-1) and nuclear factor kappaB (NF-κB) was examined using luciferase-based reporter gene assays. PA was found to bring about a reduction in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activity of NF-κB, but not that of AP-1. In accord with the luciferase activity data, western blot analysis showed that PA inhibited NF-κB signaling pathway, but did not alter the phosphorylation states of mitogen-activated protein kinases including ERK, JNK, and p38 kinase. The inhibition of PA on NF-κB signaling pathway was further attributed to PA-mediated diminution in PMA-induced degradation of inhibitor of kappaBα (IκBα) through preventing phosphorylation of the upstream signal IκB kinase (IKK). A decrease in p65 nuclear translocation was achieved, which led to attenuation of NF-κB transactivation. Taken together, it was concluded that by targeting NF-κB signaling, PA inhibited breast cancer cell invasion through decreasing MMP-9 expression. PA may thus be potentially exploited for use in tumor metastasis intervention.

Impact of glutaraldehyde on in vivo colon-specific release of resveratrol from biodegradable pectin-based formulation.

Despite potential therapeutic efficacy of resveratrol on colitis and colorectal cancer, rapid absorption and metabolism at the upper gastro-intestinal (GI) tract prevent its clinical application. To overcome this, we attempted to develop colon-specific multi-particulate calcium-pectinate (Ca-pectinate) formulations of resveratrol. However, they were unable to prevent premature drug release at the upper GI tract. Thus, glutaraldehyde (Glu) was used for further cross-linking of the pectin chains. The formulation conditions and procedure were optimized from the in vitro drug release study. The optimized formulation was subjected to in vivo pharmacokinetic study in rats and compared with the unmodified Ca-pectinate and suspension formulation of resveratrol. Spherical particles (∼1 mm diameter) with high drug encapsulation were produced. Low cross-linking solution pH (1.5), minimum Glu concentration (2.5%) and cross-linking time (2 h) were crucial to exhibit colon-specific drug release. As Glu was added in the cross-linking solution, cross-linking between pectin chains and Glu occurred simultaneously during Ca-pectinate network formation, which appeared as a cost-effective formulation technique. Most importantly, the pharmacokinetic study demonstrated in vivo colon-specific drug release from the optimized formulation, while faster drug release was observed from the unmodified and suspension formulations. Hence, the developed formulation has potential to be used as colon-specific delivery system of resveratrol.

Formulation and optimization of zinc-pectinate beads for the controlled delivery of resveratrol.

Preventive and therapeutic efficacies of resveratrol on several lower gastrointestinal (GI) diseases (e.g., colorectal cancer, colitis) are well documented. To overcome the problems due to its rapid absorption and metabolism at the upper GI tract, a delayed release formulation of resveratrol was designed to treat these lower GI diseases. The current study aimed to develop a delayed release formulation of resveratrol as multiparticulate pectinate beads by varying different formulation parameters. Zinc-pectinate (Zn-pectinate) beads exhibited better delayed drug release pattern than calcium-pectinate (Ca-pectinate) beads. The effects of the formulation parameters were investigated on shape, size, Zn content, moisture content, drug encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of the formulated beads. Upon optimization of the formulation parameters in relative to the drug release profiles, the optimized beads were further subjected to morphological, chemical interaction, enzymatic degradation, and stability studies. Almost all prepared beads were spherical with approximately 1 mm diameter and efficiently encapsulated resveratrol. The formulation parameters revealed great influence on resveratrol retention and swelling-erosion behavior. In most of the cases, the drug release data more appropriately fitted with zero-order equation. This study demonstrates that the optimized Zn-pectinate beads can encapsulate very high amount of resveratrol and can be used as delayed release formulation of resveratrol.

Interaction of oxazaphosphorines with multidrug resistance-associated protein 4 (MRP4).

Multidrug resistance-associated protein 4 (MRP4) is an organic anion efflux pump capable of transporting nucleoside, nucleotide analogs, and cyclic nucleotide. MRP4 could have an influence on the resistance and transport of the two oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IF). V/HepG2 (HepG2, hepatoma cells stably transfected with an empty vehicle plasmid) and MRP4/HepG2 (HepG2 cells stably expressing MRP4) were exposed to CP and IF in the absence or presence of various MRP4 inhibitors. HepG2 and HEK293 human kidney cells were also used to investigate the inducing potency of oxazaphosphorines on the MRP4 expression. In this study, insertion of MRP4 gene in HepG2 cells was found to confer significant resistance to CP and IF in the 48-h drug-exposure assays. In the presence of various MRP4 inhibitors, the resistance to CP and IF was then partially reversed. These indicate that CP and IF are highly possible substrates of MRP4. In addition, CP and clofibrate (CFB), a reported MRP4 inducer, in vivo significantly increased the MRP4 expression at both protein level and mRNA level in HEK293 cells at higher concentrations, while IF significantly decreased the MRP4 expression at mRNA level at lower concentration and had no effect at higher concentrations. However, all tested compounds (CP, IF, and CFB) did not change the MRP4 protein expression in HepG2 cells. CP and CFB are cell-specific and concentration-dependent MRP4 inducers. The finding may have implications in the CP- or IF-based chemotherapy.

Pachymic acid inhibits cell growth and modulates arachidonic acid metabolism in nonsmall cell lung cancer A549 cells.

Aberrant arachidonic acid (AA) metabolism has been involved in inflammation and carcinogenesis. The key enzymes in AA metabolism such as cytosolic phospholipase A2 (cPLA(2)) and cyclooxygenase-2 (COX-2) have been implicated in the development and progression of many human cancers, including lung cancer. Hence, the blockade of these enzymes may suppress promotion and survival of human cancer cells. We and others have shown that a natural triterpenoid, pachymic acid (PA), can exhibit antiinflammatory and anticancer properties; however, its potential mechanism has not been fully clarified. In this study, we examined the effect of PA on the proliferation of human nonsmall cell lung cancer A549 cells. Furthermore, we investigated the influences of nontoxic levels of PA on AA metabolism. Additionally, the cellular events and signal transduction pathways influenced by PA were also examined. Our results showed that PA (1) inhibited anchorage-dependent and -independent A549 growth in a concentration-dependent manner, (2) induced apoptosis and disrupted mitochondrial membrane potential in A549 cells, and at nonlethal levels, (3) decreased IL-1 beta-induced activation of cPLA(2) and COX-2, (4) suppressed IL-1 beta-induced activation of mitogen-activated protein kinases (MAPKs), and (5) inhibited IL-1 beta-stimulated nuclear factor kappa B (NF-kappaB) signaling pathways. We speculate that inhibition of AA metabolism by PA is mediated in part by its inhibition of MAPKs and NF-kappaB signaling pathways. Our study reveals that, apart from its cytotoxic effect, PA has the chemopreventive potential by reducing production of eicosanoids from AA metabolism.

Colon-specific delivery of resveratrol: optimization of multi-particulate calcium-pectinate carrier.

This study aimed at devising multi-particulate calcium-pectinate (Ca-pectinate) bead formulations for colon-targeted delivery of resveratrol. As Ca-pectinate beads were not sufficient to endure the upper GI environment and premature release of resveratrol occurred before their arrival to the colon, the beads were hardened by adding polyethyleneimine (PEI) in the cross-linking solution. The effects of PEI concentration, cross-linking time, and pectin to resveratrol ratio were investigated on beads' characteristics, encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of formulated beads. Proper conditions were optimized from these studies and optimized beads were further subjected to morphological examination. Formulated beads were spherical with approximately 1 mm diameter. Addition of PEI to the cross-linking solution and a minimum cross-linking time were found to be crucial factors for colon-specific release of resveratrol. As PEI was added in the cross-linking solution, hardening of the bead surface occurred simultaneously with bead formation. Observations from the present study revealed that optimized Ca-pectinate beads hardened with PEI can efficiently encapsulate resveratrol and have potential for colon-specific delivery to the lower GI tract.

Resveratrol-loaded calcium-pectinate beads: effects of formulation parameters on drug release and bead characteristics.

Resveratrol has potential therapeutic efficacy on several lower gastro-intestinal (GI) diseases such as colitis and colorectal cancer. But resveratrol is quickly absorbed and metabolized at the upper GI tract, which renders it unsuitable for this purpose. This study aimed at devising a delayed release formulation of resveratrol as calcium-pectinate (Ca-pectinate) beads and investigated the impact of various formulation parameters on bead characteristics. Ca-pectinate beads were prepared by varying six formulation parameters (cross-linking pH, cross-linker concentration, cross-linking time, drying condition, pectin concentration, and resveratrol concentration). Their effects were investigated on calcium entrapment, moisture content and weight loss during drying, particle shape and size, resveratrol entrapment and loading efficiency, swelling-erosion, and resveratrol retention pattern of formulated beads. Preparative conditions were optimized from these studies and optimized beads were further subjected to morphological examination, drug-polymer interaction, and enzymatic degradation study. Almost all prepared beads were spherical with approximately 1 mm diameter. Swelling-erosion and drug retention pattern were changed with formulation variables. Release data of almost all beads showed linearity of the plots for the cumulative percent resveratrol released versus square root of time often after an initial lag period. Observations from the present study revealed that optimized Ca-pectinate beads can encapsulate a very high amount of resveratrol (>97.5%) and can be used for delayed release and site-specific delivery to the lower GI tract. Depending on the formulation parameters, release of resveratrol after 10 h incubation in the intestinal media was 80-100%.

Sesquiterpene lactones from Ixeris sonchifolia Hance and their cytotoxicities on A549 human non-small cell lung cancer cells.

A new sesquiterpene lactone glucoside, 11,13-dihydroixerinoside (1), together with the five known sesquiterpene lactones, ixerinoside (2), ixerin Z (3), 11,13alpha-dihydroixerin Z (4), ixerin Z1 (5), and 3-hydroxydehydroleucodin (6), respectively, were isolated from the whole plants of Ixeris sonchifolia Hance. The compounds were identified by spectral analysis and comparison with spectroscopic data reported in the literatures. When the in vitro cytotoxic activities of compounds 1-6 were evaluated against A549 human non-small cell lung cancer cells, all six compounds exhibited cytotoxic activity against A549 cells, with compounds 2, 3, and 6 showing good activities (inhibitory concentration (IC(50) values < 30 microg/ml) that are comparable with well-established chemotherapeutic drug, 5-fluorouracil.

Polyporenic acid C induces caspase-8-mediated apoptosis in human lung cancer A549 cells.

Lung cancer continues to be the leading cause of cancer-related mortality worldwide. This warrants the search for new and effective agents against lung cancer. We and others have recently shown that lanostane-type triterpenoids isolated from the fungal species Poria cocos (P. cocos) can inhibit cancer growth. However, the mechanisms responsible for the anticancer effects of these triterpenoids remain unclear. In this study, we investigated the effect of polyporenic acid C (PPAC), a lanostane-type triterpenoid from P. cocos, on the growth of A549 nonsmall cell lung cancer cells (NSCLC). The results demonstrate that PPAC significantly reduced cell proliferation via induction of apoptosis as evidenced by sub-G1 analysis, annexin V-FITC staining, and increase in cleavage of procaspase-8, -3, and poly(ADP-ribose)-polymerase (PARP). However, unlike our previously reported lanostane-type triterpenoid, pachymic acid, treatment of cells with PPAC was not accompanied by disruption of mitochondrial membrane potential and increase in cleavage of procaspase-9. Further, PPC-induced apoptosis was inhibited by caspase-8 and pan caspase inhibitors but not by a caspase-9 inhibitor. Taken together, the results suggest that PPAC induces apoptosis through the death receptor-mediated apoptotic pathway where the activation of caspase-8 leads to the direct cleavage of execution caspases without the involvement of the mitochondria. Furthermore, suppressed PI3-kinase/Akt signal pathway and enhanced p53 activation after PPAC treatment suggests this to be an additional mechanism for apoptosis induction. Together, these results encourage further studies of PPAC as a promising candidate for lung cancer therapy.

Competitive substrates for P-glycoprotein and organic anion protein transporters differentially reduce blood organ transport of fentanyl and loperamide: pharmacokinetics and pharmacodynamics in Sprague-Dawley rats.

BACKGROUND: Drug transport proteins may be instrumental in controlling the concentration of fentanyl at mu receptors in the brain and may provide potential therapeutic targets for controlling an individual response to opioid administration. P-glycoprotein (P-gp) efflux transporter and organic anion transport protein inward transporters (OATP, human; Oatp, rat) have been implicated in fentanyl and verapamil (only P-gp) transport across the blood-brain barrier. We hypothesized that transport proteins P-gp and Oatp mediate opioid uptake in a drug and organ-specific manner, making them excellent potential targets for therapeutic intervention. METHODS: Opioid (fentanyl or loperamide) was administered by IV infusion to Sprague-Dawley rats alone or in combination with competitive substrates of P-gp (verapamil) or Oatp (pravastatin, naloxone). Plasma, lung, and brain were collected over 10 min and at 60 min after opioid infusion and opioid concentration determined using liquid chromatography/mass spectrometry (LC/LC-MS/MS). Continuous electroencephalogram was used to determine the in vivo response to fentanyl and loperamide in the presence and absence of verapamil. RESULTS: Loperamide brain:plasma (P(B)) and lung:plasma (P(L)) partitioning was increased two and fivefold, respectively in the presence of verapamil. Verapamil administration was lethal unless the loperamide dose was reduced by half (0.95-0.475 mg/kg). Fentanyl brain:plasma and lung:plasma were reduced four and sixfold, respectively, by pravastatin and naloxone, whereas verapamil had much less effect. Electroencephalogram results indicated that verapamil reduced the fentanyl-induced central nervous system (CNS) effect and increased the loperamide CNS effect. CONCLUSION: Protein transporters appear to be organ and drug-specific in vivo, affecting first-pass pulmonary uptake and CNS response to opioid administration. Further, data suggest that transport protein inhibition may prove useful for normalizing an individual response to opioids.

Cytotoxic and anti-oxidant activities of lanostane-type triterpenes isolated from Poria cocos.

A new lanostane-type triterpene, 29-hydroxypolyporenic acid C (8), was isolated from the dried sclerotia of Poria cocos together with eight other known compounds pachymic acid (1), dehydropachymic acid (2), 3-acetyloxy-16alpha-hydroxytrametenolic acid (3), polyporenic acid C (4), 3-epi-dehydropachymic acid (5), 3-epi-dehydrotumulosic acid (6), tumulosic acid (7), and dehydrotumulosic acid (9). The compounds were identified by spectral analysis and comparison with spectroscopic data reported in the literatures. Although none of the nine (1 to 9) compounds showed promising antioxidant activity, 1 through 6 and 8 showed good cytotoxicity against human lung cancer cell line A549 and human prostate cancer cell line DU145. Interestingly, all these compounds exhibited better cytotoxicity towards A549 than DU145 cells.

The impact of aqueous solubility and dose on the pharmacokinetic profiles of resveratrol.

PURPOSE: This study aimed at the investigation of the impact of aqueous solubility and dose manipulation on the pharmacokinetics of resveratrol. METHODS: Water soluble intravenous and oral formulations of resveratrol were prepared with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and randomly methylated-beta-cyclodextrin (RM-beta-CD), respectively. Sodium salt and suspension of resveratrol in carboxymethyl cellulose (CMC) were used as the reference intravenous and oral formulations, respectively. The pharmacokinetics of resveratrol was assessed in Sprague-Dawley rats. Plasma resveratrol concentrations were measured by high performance liquid chromatography (HPLC). RESULTS: Both HP-beta-CD and RM-beta-CD enhanced the aqueous solubility of resveratrol. After intravenous administration, rapid elimination of resveratrol was observed at all tested doses (5, 10, and 25 mg kg(-1)) regardless of formulation types; with non-linear elimination occurring at the dose of 25 mg kg(-1). RM-beta-CD significantly increased the maximal plasma concentration of orally administered resveratrol, but, it did not increase the oral bioavailability in comparison with the CMC suspension. Furthermore, the oral bioavailability remained unchanged among all tested doses (15, 25, and 50 mg kg(-1)). CONCLUSIONS: Aqueous solubility barrier might affect the speed but not the extent of resveratrol absorption. Further, dose manipulation (up to 50 mg kg(-1)) did not have a significant impact on the oral bioavailability of resveratrol.