GSH-targeted nanosponges increase doxorubicin-induced toxicity "in vitro" and "in vivo" in cancer cells with high antioxidant defenses

Several reports indicate that chemo-resistant cancer cells become highly adapted to intrinsic oxidative stress by up-regulating their antioxidant systems, which causes an increase of intracellular GSH content. Doxorubicin is one of the most widely used drugs for tumor treatment, able to kill cancer cells through several mechanisms. However, doxorubicin use is limited by its toxicity and cancer resistance. Therefore, new therapeutic strategies able to reduce doses and to overcome chemo-resistance are needed. A new class of glutathione-responsive cyclodextrin nanosponges (GSH-NS), is able to release anticancer drugs preferentially in cells having high GSH content. Doxorubicin-loaded GSH-NS, in the cancer cells with high GSH content, inhibited clonogenic growth, cell viability, topoisomerase II activity and induced DNA damage with higher effectiveness than free drug. Moreover, GSH-NS reduced the development of human tumor in xenograft models more than free drug. These characteristics indicate that GSH-NS can be a suitable drug delivery carrier for future applications in cancer therapy.

Solid lipid nanoparticles loaded with fluorescent-labelled Cyclosporine A: anti-inflammatory activity in vitro

FMOC-isocyclosporine A, a fluorescent labeled cyclosporine A, was encapsulated in solid lipid nanoparticles (SLN) prepared by the coacervation technique, and its anti-inflammatory activity was evaluated. The anti-inflammatory activity of the fluorescent labelled molecule, measured as inhibition of TNF-α secretion, is similar to the native one. SLN were compared to commercial formulations, through measurement of cytokine release and drug uptake in rat peripheral blood mononuclear cells. Drug-loaded SLN inhibit TNF-α secretion in a lower extent than commercial formulations, probably due to a lower uptake by the cells, but the increase of IL-10 secretion caused by the lipid matrix itself makes this formulation interesting for its anti-inflammatory activity.

Modulation of butyrate anticancer activity by solid lipid nanoparticle delivery: an in vitro investigation on human breast cancer and leukemia cell lines

PURPOSE

Histone modification has emerged as a promising approach to cancer therapy. The short-chain fatty acid, butyric acid, a histone deacetylase (HD) inhibitor, has shown anticancer activity. Butyrate transcriptional activation is indeed able to withdraw cancer cells from the cell cycle, leading to programmed cell death. Since butyrate's clinical use is hampered by unfavorable pharmacokinetic and pharmacodynamic properties, delivery systems, such as solid lipid nanoparticles (SLN), have been developed to overcome these constraints.

METHODS

In order to outline the influence of butyrate delivery on its anticancer activity, the effects of butyrate as a free (sodium butyrate, NB) or nanoparticle (cholesteryl butyrate solid lipid nanoparticles, CBSLN) formulation on the growth of different human cancer cell lines, such as the promyelocytic leukemia, HL-60, and the breast cancer, MCF-7 was investigated. A detailed investigation into the mechanism of the induced cytotoxicity was also carried out, with a special focus on the modulation of HD and cyclin-dependent kinase (CDK) mRNA gene expression by real time PCR analysis.

RESULTS

In HL-60 cells, CBSLN induced a higher and prolonged expression level of the butyrate target genes at lower concentrations than NB. This led to a significant decrease in cell proliferation, along with considerable apoptosis, cell cycle block in the G0/G1 phase, significant inhibition of total HD activity and overexpression of the p21 protein. Conversely, in MCF-7 cells, CBSLN did not enhance the level of expression of the butyrate target genes, leading to the same anticancer activity as that of NB.

CONCLUSIONS

Solid lipid nanoparticles were able to improve butyrate anticancer activity in HL-60, but not in MCF-7 cells. This is consistent with difference in properties of the cells under study, such as expression of the TP53 tumor suppressor, or the transporter for short-chain fatty acids, SLC5A8.

Solid lipid nanoparticles of cholesteryl butyrate inhibit the proliferation of cancer cells in vitro and in vivo models

BACKGROUND AND PURPOSE

Solid lipid nanoparticles containing cholesteryl butyrate (cholbut SLN) can be a delivery system for the anti-cancer drug butyrate. These nanoparticles inhibit adhesion of polymorphonuclear and tumour cells to endothelial cells and migration of tumour cells, suggesting that they may act as anti-inflammatory and anti-tumour agents. Here we have evaluated the effects of cholbut SLN on tumour cell growth using in vitro and in vivo models.

EXPERIMENTAL APPROACH

Cholbut SLNs were incubated with cultures of four tumour cell lines, and cell growth was analysed by assessing viability, clonogenic capacity and cell cycle. Effects on intracellular signalling was assessed by Western blot analysis of Akt expression. The in vivo anti-tumour activity was measured in two models of PC-3 cell xenografts in SCID/Beige mice.

KEY RESULTS

Cholbut SLN inhibited tumour cell line viability, clonogenic activity, Akt phosphorylation and cell cycle progression. In mice injected i.v. with PC3-Luc cells and treated with cholbut SLN, . in vivo optical imaging and histological analysis showed no metastases in the lungs of the treated mice. In another set of mice injected s.c. with PC-3 cells and treated with cholbut SLN when the tumour diameter reached 2 mm, analysis of the tumour dimensions showed that treatment with cholbut SLN substantially delayed tumour growth.

CONCLUSION AND IMPLICATIONS

Cholbut SLN were effective in inhibiting tumour growth in vitro and in vivo. These effects may involve, in part, inhibition of Akt phosphorylation, which adds another mechanism to the activity of this multipotent drug.

Solid lipid nanoparticles: could they help to improve the efficacy of pharmacologic treatments for brain tumors?

OBJECTIVES

Brain malignant neoplasms are still characterized by poor prognosis due to their peculiar hallmarks that severely limit aggressive multimodal therapeutic approaches. The optimization of the intratumoral drug delivery, directed to achieve effective concentrations and to reduce systemic undesired toxicity, is one of the primary goals of the brain tumors therapeutic strategies. Different passive and active delivery carriers allowing to a better control of drug distribution, metabolism, and elimination after parenteral administration have been developed. In the present review we will describe general characteristics and evaluate the efficacy of Solid Lipid Nanoparticles (SLN) as carriers of different drugs in experimental brain malignant tumor therapy.

METHODS

SLN vehiculating different illustrative types of antineoplastic agents (conventional cytotoxic drugs such as doxorubicin and paclitaxel, the prodrug Cholesteryl butyrate, and anti VEGF antisense oligonucleotides) have been tested in experimental animal models of cerebral gliomas.

RESULTS

SLN proved to successfully vehiculate into the brain different types of cytotoxic and gene therapeutical agents (otherwise unable to pass through the Blood-Brain Barrier) and to induce effective anti-tumoral therapeutical response.

DISCUSSION

Compared to other vehicules, SLN seem to offer more advantages (such as higher physical stability, greater protection from degradation and better release profile of incorporated drugs, good tolerability and possibility of site-specific targeting) and could be regarded as an effective carrier for chemotherapeutic drugs, gene therapeutical agents, and diagnostic tools in neuro-oncology.

Cholesteryl butyrate solid lipid nanoparticles inhibit the adhesion and migration of colon cancer cells

BACKGROUND AND PURPOSE Cholesteryl butyrate solid lipid nanoparticles (cholbut SLN) provide a delivery system for the anti-cancer drug butyrate. These SLN inhibit the adhesion of polymorphonuclear cells to the endothelium and may act as anti-inflammatory agents. As cancer cell adhesion to endothelium is crucial for metastasis dissemination, here we have evaluated the effect of cholbut SLN on adhesion and migration of cancer cells. EXPERIMENTAL APPROACH Cholbut SLN was incubated with a number of cancer cell lines or human umbilical vein endothelial cells (HUVEC) and adhesion was quantified by a computerized micro-imaging system. Migration was detected by the scratch 'wound-healing' assay and the Boyden chamber invasion assay. Expression of ERK and p38 MAPK was analysed by Western blot. Expression of the mRNA for E-cadherin and claudin-1 was measured by RT-PCR. KEY RESULTS Cholbut SLN inhibited HUVEC adhesiveness to cancer cell lines derived from human colon-rectum, breast, prostate cancers and melanoma. The effect was concentration and time-dependent and exerted on both cancer cells and HUVEC. Moreover, these SLN inhibited migration of cancer cells and substantially down-modulated ERK and p38 phosphorylation. The anti-adhesive effect was additive to that induced by the triggering of B7h, which is another stimulus inhibiting both ERK and p38 phosphorylation, and cell adhesiveness. Furthermore, cholbut SLN induced E-cadherin and inhibited claudin-1 expression in HUVEC. CONCLUSION AND IMPLICATIONS These results suggest that cholbut SLN could act as an anti-metastastic agent and they add a new mechanism to the anti-tumour activity of this multifaceted preparation of butyrate.

High energy shock waves and 5-aminolevulinic for sonodynamic therapy: effects in a syngeneic model of colon cancer

The cytotoxic effect of the natural porphyrin precursor 5-aminolevulinic acid (ALA) exposed to high energy shock waves (HESW) was investigated in vitro on DHD/K12/TRb rat colon cancer cells and in vivo on a syngeneic colon cancer model. In vitro, viable cell growth was determined by trypan blue exclusion assay and cell death was investigated by flow cytometry. ALA (50 µg/ml) and HESW (E1, EFD = 0.22 mJ/mm², 1000 shots or E2, EFD = 0.88 mJ/mm², 500 shots) showed a significant reduction of cancer cell proliferation at day 3 compared to cells exposed to ALA (p < 0.01) or HESW (p < 0.001) alone. An enhancement of necrotic and apoptotic cells was observed after combined treatment at day 1 with ALA and HESW E1 (a 3.1 and 6.4 fold increase vs ALA alone) or E2 (a 3.4 and 5.3 fold increase vs ALA alone). In vivo, apoptosis detection was carried out by TUNEL assay, the pro-apoptotic gene Bad and Bcl-2 mRNA expression was evaluated by quantitative SYBR Green real time RT-PCR and cleavage of poly(ADP-ribose)-polymerase (PARP) was investigated by Western Blotting. An enhancement of apoptosis was observed in tumour tissues after the combined treatment at day 1 with ALA (375 mg/kg i.v.) and HESW (E2) compared to that of ALA exposure alone with improved apoptotic index (a 2.0 fold increase), Bad enhanced mRNA expression (p < 0.01), Bcl-2 decreased mRNA expression (p < 0.05) and increased PARP cleavage. The interaction between HESW and ALA is then effective in inducing apoptosis on a syngeneic colon cancer model.

Oral bioavailability of silymarin phytocomplex formulated as self-emulsifying pellets

The objective of this study was to develop new solid self-emulsifying pellets to deliver milk thistle extract (silymarin). These pellets were prepared via extrusion/spheronisation procedure, using a self-emulsifying system or SES (Akoline MCM®, Miglyol®, Tween 80®, soy lecithin and propylene glycol), microcrystalline cellulose and lactose monohydrate. To select the most suitable formulations for extrusion and spheronisation, an experimental design of experiences was adopted. The screening amongst formulations (13 different blends) was performed preparing pellets and evaluating extrusion profiles and quality of the spheronised extrudates. The pellets were characterised for size and shape, density, force required to crush them. Although more than one type of pellets demonstrated adequate morphological and technological characteristics, pellets prepared from formulation 7 revealed the best properties and were selected for further biopharmaceutical investigations, including in vitro dissolution and in vivo trials on rats to study serum and lymph levels after oral administration of the pellets. These preliminary technological and pharmacokinetic data demonstrated that extrusion/spheronisation is a viable technology to produce self-emulsifying pellets of good quality and able to improve in vivo oral bioavailability of main components of a phytotherapeutic extract of more than 100 times by enhancing the lymphatic route of absorption.

Solid lipid nanoparticles as anti-inflammatory drug delivery system in a human inflammatory bowel disease whole-blood model

Standard treatment for inflammatory bowel diseases (IBD) necessitates frequent intake of anti-inflammatory and/or immunosuppressive drugs, leading to significant adverse events. To evaluate the role solid lipid nanoparticles (SLN) play as drug delivery system in enhancing anti-inflammatory activity for drugs such as dexamethasone and butyrate in a human inflammatory bowel diseases whole-blood model. ELISA assay and the peripheral blood mononuclear cell (PBMC) cytokine mRNA expression levels were evaluated by quantitative SYBR Green real-time RT-PCR to determine the IL-1beta, TNF-alpha, IFN-gamma and IL-10 secretion in inflammatory bowel diseases patients' PBMC culture supernatants. There was a significant decrease in IL-1beta (p<0.01) and TNF-alpha (p<0.001) secretion, whilst IL-10 (p<0.05) secretion significantly increased after cholesteryl butyrate administration, compared to that of butyrate alone at the highest concentration tested (100 microM), at 24h exposure. There was a significant decrease in IL-1beta (p<0.01), TNF-alpha (p<0.001) and IL-10 (p<0.001) secretion after dexamethasone loaded SLN administration, compared to dexamethasone alone at the highest concentration tested (250 nM) at 24h exposure. No IFN-gamma was detected under any conditions and no cytotoxic effects observed even at the highest concentration tested. The incorporation of butyrate and dexamethasone into SLN has a significant positive anti-inflammatory effect in the human inflammatory bowel disease whole-blood model.

Thiopurine S-methyltransferase pharmacogenetics in a large-scale healthy Italian-Caucasian population: differences in enzyme activity

AIMS

To investigate the influence of genotype, age and gender on the thiopurine S-methyltransferase (TPMT) phenotype in healthy Italian-Caucasian subjects.

MATERIALS & METHODS

The study investigated the TPMT genotype and the TPMT phenotype of 943 healthy Italian-Caucasian subjects of different age and gender (age range: 0.08-68 years; 623 males 320 females). TPMT red blood cell activity was measured in all samples and genotype was determined for the TPMT alleles *2, *3A, *3B and *3C.

RESULTS

TPMT activity levels in our whole population ranged from 1.6 up to 75.2 U/gHb. Significant TPMT activity differences between wild-type and heterozygous subjects were observed. We divided our TPMT activity into four categories according to our frequency distribution: low (0.1%), intermediate (32.9%), normal (60%) and high (7%), with arbitrary cut-off values of 8.0, 19.4 and 37.0 U/gHb, respectively. The whole population had a total of 94.5% of homozygous wild-type subjects, 5.4% heterozygous variants and one (0.1%) compound heterozygous variant TPMT*3B/*3C. The overall concordance rate between TPMT genotypes and phenotypes was 71.6%. The TPMT activity was significantly higher in wild-type children (0.08-17 years) than in wild-type adults (aged 18-68 years). Moreover, it was noted that wild-type infants from 0.08 to 5 years had a 9% higher average TPMT activity than the other wild-type groups, and only in children from 0.08 to 2 years was the TPMT activity higher in males than in females.

CONCLUSION

The data obtained in this study show that genetic factors seem to be the major aspect in TPMT phenotype variability in adults, whilst, in children, other physiological factors should be taken into consideration when assessing the TPMT phenotype, such as age and gender.

High energy shock waves (HESW) increase paclitaxel efficacy in a syngeneic model of breast cancer

The combined effect of high energy shock waves (HESW), generated by a piezoelectric device, and paclitaxel on Mat B-III rat breast cancer cells in vitro and in an in vivo animal model is presented. A significant reduction of in vitro Mat B-III cell proliferation versus cells treated with paclitaxel alone was observed with the combined exposure to paclitaxel (0.1, 1, or 10 nM) and HESW (0.22 mJ/mm2, 1000 shots). Moreover earlier induction and enhanced apoptosis occurred in cells subjected to the combined treatment with paclitaxel and HESW at 1 and 10 nM versus paclitaxel alone (p<0.01 and p<0.001, respectively). The percentage of apoptotic cells along with BAD mRNA expression, confirm a significant enhancement of apoptosis in tumor tissues subjected to the combined treatment with paclitaxel (2.5 mg/kg on days 7 and 11) and HESW (0.50 mJ/mm2, 500 shots on day 11) in comparison with paclitaxel alone. In conclusion, these data suggest that HESW enhance paclitaxel cytotoxicity in the Mat B-III syngeneic model of breast cancer.

Cholesterylbutyrate solid lipid nanoparticles as a butyric acid prodrug

Cholesterylbutyrate (Chol-but) was chosen as a prodrug of butyric acid. Butyrate is not often used in vivo because its half-life is very short and therefore too large amounts of the drug would be necessary for its efficacy. In the last few years butyric acid's anti-inflammatory properties and its inhibitory activity towards histone deacetylases have been widely studied, mainly in vitro. Solid Lipid Nanoparticles (SLNs), whose lipid matrix is Chol-but, were prepared to evaluate the delivery system of Chol-but as a prodrug and to test its efficacy in vitro and in vivo. Chol-but SLNs were prepared using the microemulsion method; their average diameter is on the order of 100-150 nm and their shape is spherical. The antineoplastic effects of Chol-but SLNs were assessed in vitro on different cancer cell lines and in vivo on a rat intracerebral glioma model. The anti-inflammatory activity was evaluated on adhesion of polymorphonuclear cells to vascular endothelial cells. In the review we will present data on Chol-but SLNs in vitro and in vivo experiments, discussing the possible utilisation of nanoparticles for the delivery of prodrugs for neoplastic and chronic inflammatory diseases.

Solid lipid nanoparticles formed by solvent-in-water emulsion-diffusion technique: development and influence on insulin stability

Insulin-loaded solid lipid nanoparticles (SLN), obtained by the solvent-in-water emulsion-diffusion technique, were produced using isovaleric acid (IVA) as organic phase, glyceryl mono-stearate (GMS) as lipid, soy lecithin and sodium taurodeoxycholate (TDC) as emulsifiers. IVA, a partially water-miscible solvent with low toxicity, was used to dissolve both insulin and lipids. SLN of spherical shape were obtained by simple water dilution of the O/W emulsion. Analysis of SLN content after processing showed interesting encapsulation efficiency with respect to therapeutic doses; moreover, insulin did not undergo any chemical modification within the nanoparticles and most of it remained stable after incubation of the SLN with trypsin solution. The biological activity of insulin, i.e. the ability to decrease glycemia in rats, was not negatively influenced by the SLN production process, as after subcutaneous administration of insulin extracted from SLN to animals, the blood glucose levels were quite similar to those obtained after administration of a conventional insulin suspension. Consequently, SLN seem to have interesting possibilities as delivery systems for oral administration of insulin.

Expression of CYP3A isoforms and P-glycoprotein in human stomach, jejunum and ileum

1. CYP3A isoforms metabolise a diverse array of clinically important drugs and P-glycoprotein (P-gp), a transmembrane efflux pump, can extrude a wide variety of drugs from the cell. It has been suggested that the function of CYP3A4 is complementary to that of P-gp along the gastrointestinal (GI) tract, together forming a coordinated intestinal barrier against xenobiotics. Therefore, the expression of CYP3A4, CYP3A5, CYP3A7 and ABCB1 (P-gp) genes were quantified in five normal samples from the human stomach, seven from the jejunum and eight from the ileum by real-time reverse transcription-polymerase chain reaction and western blot analysis. 2. In the tissues examined, measurable mRNA expression of CYP3A was found in almost all samples from the stomach, jejunum and ileum. The rank order for CYP3A mRNA expression was CYP3A4 > CYP3A5 > CYP3A7 in the GI tract studied, whereas median mRNA CYP3A4 expression was highest in the small intestine and lowest in the stomach. Expression of ABCB1 mRNA was found in almost all samples and the median mRNA expression level was comparable in the jejunum and ileum, but lower in the stomach. Our data also show a significant correlation between all mRNA transcripts studied and a wide interindividual variation. 3. At the protein level, CYP3A4 was detected in all stomach and small intestine samples, the levels being substantially higher in the small intestine than in the stomach. P-Glycoprotein was detected in all GI samples, but no statistically significant difference was found along the GI tract considered. 4. Collectively, these results demonstrate that CYP3A4 is the main CYP3A expressed in the GI tract investigated, an extensive interindividual variability in the expression of the different CYP3A isoforms in all tissues examined and P-gp apoprotein levels similar in the stomach, jejunum and ileum.

Prevailingly Cationic Agmatine-Based Amphoteric Polyamidoamine as a Nontoxic, Nonhemolytic, and “Stealthlike” DNA Complexing Agent and Transfection Promoter

AGMA1, a prevailingly cationic amphoteric polyamidoamine obtained by polyaddition of (4-aminobutyl)guanidine (agmatine) to 2,2-bis(acrylamido)acetic acid, was studied as a potential DNA carrier and transfection promoter. Fluorescein-labeled AGMA1 was prepared by conjugation with fluorescein isothiocyanate and its cell uptake, blood permanence, and body distribution studied. In spite of its cationic character, AGMA1 is neither toxic nor hemolytic in the pH range 4.0-7.4, circulates for a long time in the blood without preferentially localizing in the liver, easily enters HT-29 cells, gives stable complexes with DNA, and is endowed with good transfection efficiency, suggesting the ability to transport in the cytoplasm a DNA payload without any measurable membranolytic activity. If compared with other transfection promoters, including polyamidoamines of different structures, AGMA1 is apparently endowed with a unique combination of desirable requirements for a nonviral DNA polymer carrier and warrants potential as a transfection agent in vivo.

Intracellular accumulation and cytotoxicity of doxorubicin with different pharmaceutical formulations in human cancer cell lines

The structure of both carrier and anticancer drug affects the intracellular fate of a transported drug. The study investigated in vitro intracellular accumulation and cytotoxic activity of doxorubicin-loaded solid lipid nanoparticles (SLN), doxorubicin in pegylated liposomes (Caelyx) and free doxorubicin. Intracellular doxorubicin levels and cytotoxic activity were determined by high performance liquid chromatography with fluorescence detection, and by the trypan blue dye exclusion assay, respectively. Doxorubicin-loaded SLN inhibited cell growth more strongly than either free or liposomal doxorubicin, in human colorectal adenocarcinoma, HT-29, retinoblastoma Y79, and glioblastoma U373 cell lines. The IC50 values for doxorubicin-loaded SLN were significantly lower after 24 h exposure than those for free doxorubicin in all cell lines; after 48 h exposure they were lower than those for liposomal doxorubicin in HT-29 and Y79 cells. The enhanced cytotoxic activity of doxorubicin-loaded SLN was associated with increased drug incorporation in cells: intracellular doxorubicin levels were significantly enhanced after exposure to drug-loaded SLN versus either free or liposomal drug. Rate of intracellular accumulation and cytotoxic activity also differed among different cell lines; in particular, cells of epithelial origin were found to be more sensitive to doxorubicin-loaded SLN. In conclusion, the greater sensitivity of HT-29, Y79, and U373 cells to doxorubicin-loaded SLN than to the other drug formulations may be due to the capability of the delivery system to enhance drug action, through a marked uptake and accumulation of SLN within the cell.

High energy shock waves (HESW) for sonodynamic therapy: effects on HT-29 human colon cancer cells

BACKGROUND

Whether high energy shock waves (HESW), generated by a piezoelectric generator, were able to activate a sonosensitizer, 5-aminolevulinic acid (ALA) and induce inhibition of cell growth in HT-29 human colorectal cancer cells was investigated.

MATERIALS AND METHODS

Cell survival and cell death pathways were investigated by cell growth curves, flow cytometry analysis and ELISA nucleosome evaluation. HT-29 cells were exposed to ALA and different HESW treatments: E1 (energy flux density = 0.22 mJ/mm2; 500 and 1000 shots) and E2 (energy flux density = 0.88 mJ/mm2; 500 and 1000 shots).

RESULTS

A significant reduction of HT-29 cell growth with respect to untreated cells was observed only after treatment with ALA and HESW E2, 500 shots. In particular, HESWE2, 500 shots, was able to induce an arrest of HT-29 cells exposed to ALA in the G0/G1-phase of the cell cycle.

CONCLUSION

HESW is proposed for the sonodynamic treatment of cancer cells.

Pharmacokinetics of cyclosporine in recipients of marginal versus standard liver transplants

In the field of transplants, the practice of using marginal donor livers has become widely accepted, yielding good clinical results. This study investigated and compared the pharmacokinetics of cyclosporine in marginal and standard liver transplant recipients. Twenty-four de novo liver transplant patients, 12 with marginal and 12 with standard (normal) grafts, were treated with a microemulsion formulation of cyclosporine (capsules 100 mg) as immunosuppressive therapy. Blood concentration profiles were measured, and pharmacokinetic calculations performed at days 3 and 10 after transplantation. Different sampling strategies to predict drug exposure (AUC(0-12 h)) were compared, and the best limited-sampling strategies to monitor the desired blood levels were determined. Marginal and standard patients showed a significant difference in blood concentration and pharmacokinetic profiles of cyclosporine at the day 10 post-transplantation. Blood concentration at 4h (C(4 h)) was the single best timepoint to estimate AUC(0-12 h) in marginal liver transplant (r(2)=0.700), while C(2h) was confirmed to be the optimal choice with standard graft (r2=0.720). Two blood samples at 2 and 6 h significantly improved the prediction model in both groups (r2=0.920). Our data suggest that patients receiving a marginal liver transplant present a different pharmacokinetic profile of cyclosporine from those receiving standard graft, which should be taken into account in dosing the patient to avoid subtherapeutic blood concentrations or toxic effects.

Cholesteryl butyrate solid lipid nanoparticles inhibit adhesion of human neutrophils to endothelial cells

1. Adhesion of polymorphonuclear cells (PMNs) to vascular endothelial cells (EC) is a critical step in recruitment and infiltration of leukocytes into tissues during inflammation. High doses of butyric acid have been shown to ameliorate inflammation in inflammatory bowel diseases (IBD). Cholesteryl-butyrate solid lipid nanoparticles (chol-but SLN) as prodrug are a possible delivery system for butyric acid. 2. Sodium butyrate or chol-but SLN were coincubated with human PMNs and human umbilical vein EC (HUVEC); adhesion was quantified by computerized microimaging fluorescence analysis. Both chol-but SLN and sodium butyrate displayed antiadhesive effects on FMLP- and IL-1beta-stimulated cells in a concentration-response curve (10(-8)-10(-5) M), but chol-but SLN were in all cases more active. Moreover, chol-but SLN inhibited FMLP-induced adhesion of PMNs to FCS-coated plastic wells, thus showing a direct effect on PMNs, while sodium butyrate had little effect. Confocal microscopy showed that fluorescent SLN entered PMNs and HUVEC after 10 min incubation. Chol-but SLN acted either on activated PMN or HUVEC. 3. Chol-but SLN inhibited O2-* production and myeloperoxidase release by PMNs evoked by FMLP, in a dose-dependent, but not time-dependent, manner and were more active than sodium butyrate. 4. In conclusion, in all tests chol-but SLN were more active than sodium butyrate. Thus, chol-but SLN might be a valid alternative to sodium butyrate in the anti-inflammatory therapy of ulcerative colitis, avoiding complications related to the administration of sodium butyrate.

Plasma concentrations of 5-fluorouracil and its metabolites in colon cancer patients

5-Fluorouracil (5-FU) is a common anticancer agent used in the treatment of solid tumours, with a reported variability in the pharmacokinetic profile and inter-patient differences in efficacy and toxicity. Since 5-FU is intracellularly metabolised to active cytotoxic fluoronucleotides, some authors suggested it would be useful to determine the plasma levels of its main metabolites 5-fluoro-5,6-dihydrouracil (5-FUH2), 5-fluorouridine (5-FUrd) and 5-fluoro-2'-deoxyuridine (5-FdUrd), in order to better characterise population pharmacokinetics-pharmacodynamics (PK-PD) of this drug. We developed and validated an HPLC method to simultaneously determine plasma concentrations of 5-FU and the three main metabolites, and we analysed the plasma concentration-time curves of the first dose of 18 colon cancer patients treated with folinic acid and 5-FU 400 mg m(-2) by intra-venous bolus injection as adjuvant chemotherapy. Non-compartmental PK analysis has been applied to 5-FU and 5-FUH2 concentrations, estimating the following parameters (median values): Cmax 55.44 and 6.23 microg ml(-1), respectively, AUC(0-2 h) 11.59 and 5.94 hx microg ml(-1), CLTB 30.64 and 51.81 lh(-1) m(-2), 5-FUH2/5-FU AUC ratio 0.47 (range 0.29-1.12). We verified the patient covariables which could influence the inter-patient variability in the area under the time-concentration curves, and we observed that age, sex, weight, body surface area, cycle of therapy, toxicity development and 5-FUrd or 5-FdUrd detectability did not have statistical influence on 5-FUH2/5-FU AUC ratio. In eight subjects, we compared the PK data of the first and the fifth day of dose administration, and we found stable 5-FU values, but the 5-FUH2 disposition decreased with lower AUC(0-2 h) (7.90 hx microg ml(-1) versus 5.99 hx microg ml(-1)) and, particularly, Cmax (8.38 microg ml(-1) versus 5.50 microg ml(-1)) at day 5. This fact, evident in almost every patient, could suggest a possible reduction in the catabolic pathway of 5-FU leading to 5-FUH2, with a possible increase of the therapeutic pathway. For this reason, we tried to detect 5-FUrd and 5-FdUrd and, in fact, in our patients these metabolites were detected only in few samples, but most of them at day 5. In conclusion, our study confirms the relevance of pharmacokinetic analysis of 5-FU main metabolites and especially 5-FUH2, to better understand the metabolism and to improve the therapeutic efficacy.

Cytotoxicity of anticancer drugs incorporated in solid lipid nanoparticles on HT-29 colorectal cancer cell line

Solid lipid nanoparticles (SLN) carrying cholesteryl butyrate (chol-but), doxorubicin and paclitaxel had previously been developed, and the antiproliferative effect of SLN formulations versus conventional drug formulations was here evaluated on HT-29 cells. The 50% inhibitory concentration (IC(50) values were interpolated from growth curves obtained by trypan blue exclusion assay. In vitro cytotoxicity of SLN carrying chol-but (IC(50 72 h) 0.3 +/- 0.03 mM vs >0.6 mM) and doxorubicin (IC(50 72 h) 81.87 +/- 4.11 vs 126.57 +/- 0.72 nM) was higher than that of conventional drug formulations. Intracellular doxorubicin was double after 24 h exposure to loaded SLN versus the conventional drug formulation, at the highest concentration evaluated by flow cytometry. In vitro cytotoxicities of paclitaxel-loaded SLN and conventional drug formulation (IC(50 72 h) 37.36 +/- 6.41 vs 33.43 +/-1.17 nM) were similar. Moreover, the combination of low concentrations of chol-but SLN (0.1-0.2 mM) and doxorubicin (1.72 nM) or paclitaxel (1.17 nM) exerted a greater-than-additive antiproliferative effect at 24 h exposure, while the combination of Na-but and doxorubicin or paclitaxel did not. These preliminary in vitro results suggest that SLN could be proposed as alternative drug delivery system.

Cholesteryl butyrate solid lipid nanoparticles as a butyric acid pro-drug: effects on cell proliferation, cell-cycle distribution and c-myc expression in human leukemic cells

Cholesteryl butyrate solid lipid nanoparticles (chol-but SLN) have been proposed as a pro-drug to deliver butyric acid. We compared the effects on cell growth, cell-cycle distribution and c-myc expression of chol-but SLN and sodium butyrate (Na-but) in the human leukemic cell lines Jurkat, U937 and HL-60. In all the cell lines 0.5 and 1.0 mM chol-but SLN provoked a complete block of cell growth. Cell-cycle analysis demonstrated in Jurkat cells that 0.25 mM chol-but SLN caused a pronounced increase of G2/M cells and a decrease of G0/G1 cells, whereas in U937 and HL-60 cells chol-but SLN led to a dose-dependent increase of G0/G1 cells, with a decrease of G2/M cells. In Jurkat and HL-60 cells 0.5 mM chol-but SLN induced a significant increase of sub-G0/G1 apoptotic cells. Cell growth and cell-cycle distribution were unaffected by the same concentrations of Na-but. A concentration of 0.25 mM chol-but SLN was able to cause a rapid and transient down-regulation of c-myc expression in all the cell lines, whereas 1 mM Na-but caused a slight reduction of c-myc expression only in U937 cells. The results show how chol-but SLN affects the proliferation pattern of both myeloid and lymphoid cells to an extent greater than the natural butyrate.

Determination of disodium clodronate in human plasma and urine using gas-chromatography–nitrogen-phosphorous detections: validation and application in pharmacokinetic study

We present a specific method for the determination of disodium clodronate in human plasma and urine using a gas-chromatographic system with nitrogen phosphorus detector (NPD). The compound was extracted from plasma and urine samples by an anion-exchange resin and derivatizated with bistrimethylsilyltrifluoroacetamide (BSTFA). Sodium bromobisphosphonate was used as internal standard. The calibration curves were linear in both plasma and urine, with a regression coefficient r > 0.9975 in plasma and r > 0.9977 in urine. The limit of quantitation was 0.3 microg/ml in plasma and 0.5 microg/ml in urine. The method was validated by intra-day assays at three concentration levels. During the study we carried out inter-day assays to confirm the feasibility of the method. The precision in plasma at 0.5, 15, and 45 microg/ml was 12.4, 0.2, and 6.5% (n = 40), respectively; in urine at 0.8, 8, and 40 microg/ml it was 8.6, 6.4, and 9.3% (n = 40), respectively. The method was accurate and reproducible, and was successfully applied to determine the pharmacokinetic parameters of clodronate in healthy volunteers after intravenous infusion and intramuscular injection of 200 mg of the compound. The Cmax after intravenous infusion and intramuscular injection was 16.1 and 12.8 microg/ml, respectively. AUC(0-48 h) after infusion administration and intramuscular injection was 44.2 +/- 18.0 and 47.5 +/- 12.4 h microg/ml, respectively. The elimination half-life in both administrations was 6.31 +/- 2.7 h.

Long-term analgesic effect of clodronate in rodents

Several studies have shown that treatment with bisphosphonates can reduce the pain associated with different painful diseases. In a previous study we demonstrated that in mice two bisphosponates, clodronate and pamidronate, had an antinociceptive effect under acute conditions not related to bone processes, after in vein (iv) or intracerebroventricular (icv) injection. The present study tested the time-dependent antinociceptive action of clodronate and pamidronate in comparison with that of acetylsalicylic acid (ASA) and morphine after iv and icv injection using the tail-flick test in acute and chronic treatment. The effects of clodronate on other measures of animal behaviour were also evaluated. In the tail-flick test, administration of clodronate iv produced an antinociceptive effect that was greater than that of ASA and statistically significant up to 16 h; pamidronate iv showed a significant antinociceptive effect for only 6 h. Clodronate and pamidronate icv showed an increase in tail-flick latency time that was significant and lasted for 16 and 6 h, respectively, while morphine produced an antinociceptive effect for 24 h. In the test we found significant differences between male and female mice in the latency time values but not in the length of the analgesic effect. In the chronic treatment paradigm, clodronate produced a significant increase of the tail-flick latency after the first injection. The analgesic effect increased up to 50% after 5 days of treatment. Significant analgesic effects were still present after 3, 7, and 14 days from the end of treatment. Clodronate did not produce any significant behavioural effects in the Rota-rod test, pentobarbital-induced sleeping time, and locomotor activity cage. These data indicate that clodronate presents a central and peripheral prolonged antinociceptive effect, without any behavioural side effects.

Dexibuprofen (S+-isomer ibuprofen) reduces gastric damage and improves analgesic and antiinflammatory effects in rodents

We determined the analgesic and antiinflammatory actions and the related acute mucosal gastric damage from the active S(+)-isomer ibuprofen (dexibuprofen), in comparison with those of the standard racemic formulation of ibuprofen in rodents. The antinociception was evaluated by hot-plate and tail-flick methods after IV and oral (PO) administration in mice and after PO administration in rats. S(+)-Ibuprofen was at least twice more potent than the ibuprofen racemic formulation. The antiinflammatory action of the test compound, assessed with the abdominal constriction test in mice (IV and PO) and with hind paw edema in rats (IV and PO), was found to be significantly more potent than that of ibuprofen after IV treatment in mice and PO administration in rats. Moreover, the test compound caused significantly less mucosal gastric damage than the racemic formulation administered at identical doses (50 mg/kg PO in rats). In conclusion, the S(+)-ibuprofen isomer was found to be more potent than the racemic formulation in analgesic and antiinflammatory tests and presented fewer gastric toxic effects. On the basis of the results of this work, we suggest that the administration of chemical entities, such as R(-)-ibuprofen, should be avoided if they are not essential for the anticipated therapeutic activity.

IMPLICATIONS

Ibuprofen is a nonsteroidal antiinflammatory drug often prescribed as a racemic formulation. We studied the analgesic and antiinflammatory effects of the active S(+)-isomer. The S(+)-ibuprofen was found to be more potent than the racemic formulation and produced less acute gastric damage.

Duodenal administration of solid lipid nanoparticles loaded with different percentages of tobramycin

Three types of solid lipid nanoparticles (SLN) containing three different percentages of tobramycin (1.25, 2.50, 5.00%) were prepared (Tobra-SLN), and the in vitro tobramycin diffusion through a hydrophilic/lipophilic membrane was determined. A variable quantity of each of the three SLN types was placed in the donor compartment to achieve the same amount of tobramycin in each case. Tobramycin diffusion varied with the percentage of drug incorporated in SLN: the higher the percentage of tobramycin incorporated, the greater the amount of the drug diffused. In vivo uptake and transport were determined after administering a fixed dose of tobramycin (5 mg/kg) in each of the three types of SLN intraduodenally to rats. At fixed times, blood was sampled from the jugular vein and lymph from the thoracic duct. Lymph and blood were examined by transmission electron microscopy (TEM) analysis to detect the presence, sizes, and shape of SLN. The pharmacokinetic parameters varied considerably with the type of Tobra-SLN: the area under the curve of plasma concentration versus time (AUC) of 1.25% Tobra-SLN was more than five times higher than that of 5.00% Tobra-SLN; the longest residence time was obtained with 1.25% Tobra-SLN; and the clearance of 5.00% Tobra-SLN was fivefold than that of 1.25% Tobra-SLN. This behavior may be related to the differences among the three types of SLN; namely, the number of SLN administered and the mean diameter, the total surface area, and the drug content in each nanoparticle. TEM analysis showed that Tobra-SLNs were targeted to the lymph. Tobra-SLN may act as a reservoir of the drug in the lymphatic system, thereby favoring its sustained release.

Simultaneous HPLC determination of 5-fluorouracil and its metabolites in plasma of cancer patients

5-Fluorouracil (5-Fu) is a commonly used anticancer agent for treatment of solid tumours. Certain studies have reported conflicting results between individual plasma concentration levels and toxicity or therapeutic effects. For this reasons some authors proposed to evaluate the plasma levels of 5-Fu metabolites 5-fluorouridine, 5-fluoro-2'-deoxyuridine and 5-fluoro-5,6-dihydro-uracil. The aim of the present work is to develop and validate a new HPLC method simultaneously determining 5-fluorouracil and its three metabolites, to be used to study the plasma levels, therapeutic effects and toxicity in cancer patients. The analytes were separated on a 4.6 x 250 mm ODS1 (5 micro m) not end-capped column, operating at room temperature. Elution was performed under isocratic conditions, employing a 1.5 mM K(3)PO(4) mobile phase (pH 5). 5-Bromo-5,6-dihydro-uracil was used as internal standard. The limits of quantitation were 0.5 micro g/mL for 5-fluorouracil, 1 micro g/mL for 5-fluoro-5,6-dihydro-uracil, 3 micro g/mL for 5-fluoro-2'-deoxyuridine and 5-fluorouridine; the stability, recovery, linearity, accuracy and specificity of the compounds were evaluated according to the criteria widely accepted. Using this method we measured plasma samples of 18 cancer patients treated with folinic acid (100 mg/m(2)) by intravenous administration, followed by an i.v. bolus of 5-Fu (400 mg/m(2)). The concentration levels of 5-fluorouracil and for 5-fluoro-5,6-dihydro-uracil were detectable in all the subjects while 5-fluorouridine and 5-fluoro-2'-deoxyuridine were present only in eight patients.

Intravenous administration to rabbits of non-stealth and stealth doxorubicin-loaded solid lipid nanoparticles at increasing concentrations of stealth agent: pharmacokinetics and distribution of doxorubicin in brain and other tissues

The pharmacokinetics and tissue distribution of doxorubicin incorporated in non-stealth solid lipid nanoparticles (SLN) and in stealth solid lipid nanoparticles (SSLN) (three formulations at increasing concentrations of stearic acid-PEG 2000 as stealth agent) after intravenous administration to conscious rabbits have been studied. The control was the commercial doxorubicin solution. The experiments lasted 6 h and blood samples were collected at fixed times after the injections. In all samples, the concentration of doxorubicin and doxorubicinol were determined. Doxorubicin AUC increased as a function of the amount of stealth agent present in the SLN. Doxorubicin was still present in the blood 6 h after the injection of SLN or SSLN, while no doxorubicin was detectable after the i.v. injection of doxorubicin solution. Tissue distribution of doxorubicin was determined 30 min, 2 and 6 h after the administration of the five formulations. Doxorubicin was present in the brain only after the SLN administration. The increase in the stealth agent affected the doxorubicin transported into the brain; 6 h after injection, doxorubicin was detectable in the brain only with the SSLN at the highest amount of stealth agent. In the other rabbit tissues (liver, lungs, spleeen, heart and kidneys) the amount of doxorubicin present was always lower after the injection of any of the four types of SLN than after the commercial solution. In particular, all SLN formulations significantly decreased heart and liver concentrations of doxorubicin.

Pharmacokinetics and tissue distribution of idarubicin-loaded solid lipid nanoparticles after duodenal administration to rats

Idarubicin-loaded solid lipid nanoparticles (IDA-SLN) and idarubicin in solution were prepared and the two formulations were administered to rats, either by the duodenal route or intravenously (iv). The aim of this research was to study whether the bioavailability of idarubicin can be improved by administering IDA-SLN duodenally to rats. Idarubicin and its main metabolite idarubicinol were determined in plasma and tissues by reversed-phase high-performance liquid chromatography. The pharmacokinetic parameters of idarubicin found after duodenal administration of the two formulations were different: area under the curve of concentration versus time (AUC) and elimination half-life were approximately 21 times and 30 times, respectively, higher after IDA-SLN administration than after the solution administration. Tissue distribution also differed: idarubicin and idarubicinol concentrations were lower in heart, lung, spleen, and kidneys after IDA-SLN administration than after solution administration. The drug and its metabolite were detected in the brain only after IDA-SLN administration, indicating that SLN were able to pass the blood-brain barrier. After iv IDA-SLN administration, the AUC of idarubicin was lower than after duodenal administration of the same formulation. Duodenal administration of IDA-SLN modifies the pharmacokinetics and tissue distribution of idarubicin. The IDA-SLN act as a prolonged release system for the drug.

Transmucosal transport of tobramycin incorporated in solid lipid nanoparticles (SLN) after duodenal administration to rats. Part II--tissue distribution

Tobramycin-loaded solid lipid nanoparticles (SLN) were prepared and administered by duodenal and intravenous (i.v.) routes to rats and the tissue distributions were determined successively at fixed times (30 min, 4 h and 24 h) and compared to those of the tobramycin solution after i.v. administration. The tissue distribution between tobramycin-loaded SLN administered duodenally and i.v. was different. A marked difference between tobramycin-loaded SLN administered duodenally and tobramycin solution administered i.v. was also evidenced. In particular, the amounts of tobramycin in the kidneys after tobramycin-loaded SLN administration either duodenally or i.v. were lower than after administration of i.v. solution. Tobramycin-loaded SLN were able to pass across the blood-brain barrier in rats to a greater extent after i.v. injection than after duodenal administration.

Analgesic effect of bisphosphonates in mice

Bisphosphonates are analogues of inorganic pyrophosphate and are inhibitors of bone resorption. Many derivatives have been developed for the treatment of enhanced bone resorption; several reports reveal that treatment with bisphosphonates is able to reduce the pain associated with different painful diseases. This study tested the antinociceptive action of four bisphosphonates, clodronate, alendronate, pamidronate and etidronate, in comparison with that of morphine and acetylsalicylic acid using two algesimetric tests in mice, tail-flick and writhing tests. In the tail-flick test, after intravenous (i.v.) injection, a dose-dependent antinociception was present after pamidronate, clodronate and acetylsalicylic acid whereas etidronate and alendronate produced an analgesic effect only with the highest dose tested. We also studied the central effect of clodronate and pamidronate and, after intracerebroventricular injection, both bisphosphonates showed a dose-dependent antinociceptive effect. In the writhing test clodronate and pamidronate showed a statistically significant antinociceptive action after i.v. and intramuscular administration. To verify if clodronate and pamidronate could modulate the peripheral opioid receptors we evaluated the gastrointestinal transit time in mice, but we did not find any effect on the gastrointestinal motility. These data indicate that clodronate and pamidronate present a central and peripheral antinociceptive effect; however, the main mechanism cannot be determined from the present data. We discuss the possible pharmacological hypothesis to interpret the present results. The findings suggest a pharmacological role of the bisphosphonates in the modulation of antinociception even in acute conditions not related to accelerated osteolytic and inflammatory response, with a possible clinical application to control pain.

Transmucosal transport of tobramycin incorporated in SLN after duodenal administration to rats. Part I--a pharmacokinetic study

Tobramycin-loaded solid lipid nanospheres (SLN) were prepared and administered to rats into the duodenum; their behaviour was compared to that of tobramycin-loaded SLN administered intravenously (i.v.). A tobramycin control solution was also administered to rats. Tobramycin in solution is not absorbed by the gastrointestinal route, while tobramycin incorporated in the SLN is absorbed. A high concentration of tobramycin is still present in plasma 24 hours after the duodenal administration of tobramycin-loaded SLN. Tobramycin-loaded SLN administered i.v. showed a prolonged circulation time compared to the i.v. administered tobramycin solution. The AUC of tobramycin in SLN administered duodenally is higher than those of tobramycin in SLN and in solution administered i.v.

Non-stealth and stealth solid lipid nanoparticles (SLN) carrying doxorubicin: pharmacokinetics and tissue distribution after i.v. administration to rats

Non-stealth and stealth solid lipid nanoparticles (SLN) carrying doxorubicin were prepared as drug delivery systems. The pharmacokinetics and tissue distribution of doxorubicin in these SLN were studied after i.v. administration to conscious rats and were compared to the commercial solution of doxorubicin. The same dose of each formulation (6 mg kg(-1)of body weight) of doxorubicin was injected in the rat jugular vein. Blood samples were collected after 1, 15, 30, 45, 60 min and 2, 3, 6, 12, and 24 h after the injection. Rats were sacrificed after intervals of 30 min, 4 h, and 24 h and samples of liver, spleen, heart, lung, kidney, and brain were collected. In all samples, the concentration of doxorubicin and of the metabolite, doxorubicinol, were determined. Doxorubicin and doxorubicinol were still present in the blood 24 h after injection of stealth and non-stealth SLN, while they were not detectable after the injection of the commercial solution. The results confirmed the prolonged circulation time of the SLN compared to the doxorubicin solution. In all rat tissues, except the brain, the amount of doxorubicin was always lower after the injection of the two types of SLN than after the injection of the commercial solution. In particular, SLN significantly decreased the heart concentration of doxorubicin.

Biodistribution of stealth and non-stealth solid lipid nanospheres after intravenous administration to rats

Drug-free stealth and non-stealth solid lipid nanospheres (SLNs) were administered intravenously to rats to evaluate their tissue distribution and their transport across the blood-brain barrier. Two types of experiments were performed using unlabelled and labelled SLNs. Rats were administered labelled non-stealth or stealth nanospheres (NSSLNs and SSLNs) and their tissue distribution was monitored for 60 min. In another experiment, rats were injected with unlabelled NSSLNs or SSLNs and the cerebrospinal fluid (CSF) was analysed using transmission electron microscopy (TEM) to confirm the presence of the SLNs. Some differences were found in the biodistribution between labelled NSSLNs and SSLNs. In particular, the radioactivity in the liver and the lung was much lower for SSLNs than for NSSLNs, confirming a difference in their uptake. Both types of SLNs were detected in the brain. TEM analysis showed both types of SLNs in rat CSF.

Plasma erythropoietin concentrations in patients receiving intensive platinum or nonplatinum chemotherapy

AIMS

Platinum chemotherapy has been shown to have potent antineoplastic activity against various tumours, especially testicular, bladder, ovarian, head and neck cancers. This activity is accompanied by side-effects of nephrotoxicity and cumulative myelosuppression, the latter frequently presenting as severe anaemia. Cisplatin and carboplatin nephrotoxicity might lower erythropoietin (Epo) secretion and, by this mechanism, contribute to the anaemia that follows therapy with this chemotherapeutic agent. The aim of the present work is to study the plasma immunoerythropoietin and haemoglobin levels of cancer patients treated with platinum or 5-fluorouracil-based chemotherapy.

METHODS

Plasma was obtained from 25 patients who were about to receive chemotherapy for advanced malignancy: 15 treated with cisplatin or carboplatin and 10 with nonplatinum drugs. Blood was collected on the first day (before drug administration) and around day 15 of every chemotherapy course. Complete blood count, creatinine and immunoreactive Epo levels were also measured in 22 healthy volunteers.

RESULTS

An increase in Epo levels occurred following every course of 5-FU or platinum based chemotherapy in patients with steady concentrations of creatinine and decreased levels of haemoglobin (Hb). In particular, we observed an increase after about 15 days of the chemotherapy treatment and the Epo levels declined toward normal just before the following course. This phenomenon was evident in every course.

CONCLUSIONS

Our results suggest that chemotherapy administration, using the current standards of hydration and forced diuresis, slightly lowered Hb levels but did not depress Epo production, both in 5-FU and in platinum treated subjects.

Determination of Ibuprofen in human plasma by high-performance liquid chromatography: validation and application in pharmacokinetic study

A specific method for the simultaneous determination of S-(+)Ibuprofen and R-(-)Ibuprofen enantiomers in human plasma is described. Adopting a high-performance liquid chromatographic (HPLC) system with spectrofluorometer detector, the compounds were extracted from plasma in alcohol medium and were separated on C18 column, using a solution of acetonitrile-water-acetic acid-triethylamine as mobile phase. The limit of quantitation was 0.1 microg/mL for both compounds. The method was validated by intra-day assays at three concentration levels and was used in a kinetic study in healthy volunteers. During the study we carried out inter-day assays to confirm the feasibility of the method.

Pharmacokinetics of doxorubicin incorporated in solid lipid nanospheres (SLN)

The pharmacokinetics of doxorubicin incorporated as ion-pair into solid lipid nanospheres (SLN) was compared with that of the commercial solution of the drug. Male albino rats (Wistar-derived strain) were treated i.v. with equivalent doses (6 mg kg(-1)) of two different doxorubicin formulations: an aqueous dispersion of SLN carrying doxorubicin and a commercial doxorubicin solution (Adriablastina). These formulations were injected, under general anaesthesia, through a cannula into the jugular vein and blood samples were collected at 1, 15, 30, 45, 60, 120 and 180 min after administration. After 180 min rats were killed and samples of liver, heart, lung, kidney, spleen and brain were collected. Blood and tissue samples were analysed by a spectrofluorimetric method. The anthracycline concentration in the blood was markedly higher at each point times with the SLN than with the commercial solution. The drug concentration was also higher in the lung, spleen and brain. SLN-treated rats showed a lower doxorubicin concentration in liver, heart and kidney. The results showed that SLN increased the area under the curve (0-180 min) of doxorubicin compared to conventional doxorubicin solution and led to a different body distribution profile.

Economic impact of resistance in the community

Antimicrobial resistance is assumed to be an important health problem and an economic burden to society. However, the relationship between the emergence of in vitro microbiological resistance and its clinical and socioeconomic consequences has not yet been satisfactorily determined for either nosocomial or community-acquired infection. In the case of both nosocomial and community-acquired infection, previous exhaustive reviews of published and unpublished reports concluded that mortality, likelihood of hospitalization, and length of hospital stay were usually at least twice as great for patients infected with drug-resistant strains as for those infected with drug-susceptible strains of the same bacteria. However, evaluation of the economic impact of resistance is still problematic and the adverse economic and health effects of drug-resistant bacterial infections can only be roughly quantified. Decision analysis models, such as decision trees, can aid evaluation of the impact of resistance on health and economic outcomes from the perspective of a given decision maker. A model of cost analysis should be based on a knowledge of the incremental consumption of resources specifically dependent on the dynamics of antimicrobial resistance in a given clinical setting (e.g. home care or hospital care). In general, we can assume that the increased rate of isolation of resistant strains from community-acquired infections correlates positively with an increase in morbidity, mortality, risk of hospitalization and the need for additional days in hospital and for more expensive and powerful antibiotics. We implemented and simulated a general decision-tree model to analyse the influence of antibiotic resistance on the economic outcomes of community-acquired lower respiratory tract infections, from the perspective of both society and the health-care local organization (HCLO). This model allows simulation of the impact of different degrees of resistance on the direct costs of an antibiotic therapy as well as on the cost-effectiveness of antibiotics with different degrees of resistance.

Solid lipid nanoparticles in lymph and plasma after duodenal administration to rats

PURPOSE

To evaluate the uptake and transport of solid lipid nanoparticles (SLN), which have been proposed as alternative drug carriers, into the lymph and blood after duodenal administration in rats.

METHODS

Single doses of two different concentrations of aqueous dispersions of unlabelled and labelled SLN (average diameter 80 nm) were administered intraduodenally to rats. At different times, samples of lymph were withdrawn by cannulating the thoracic duct and blood was sampled from the jugular vein. Monitoring continued for 45 and 180 minutes, for unlabelled and labelled SLN respectively. The biological samples were analysed by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM) and gamma-counting.

RESULTS

TEM analysis evidenced SLN in lymph and blood after duodenal administration to rats: the size of SLN in lymph did not change markedly compared to that before administration. The labelled SLN confirmed the presence of SLN in lymph and blood.

CONCLUSIONS

The uptake and transport of SLN in the lymph, and to a lesser extent in the blood, were evidenced. The in vivo physical stability of SLN may have important implications in designing drug-carrying SLN.

Pudendal neuropathy in diabetic patients with faecal incontinence

To investigate the pathophysiology of faecal incontinence in diabetes mellitus, two groups of diabetic patients were studied: 14 subjects (7 females and 7 males, mean age 57 +/- 9 years) with faecal incontinence (Group A) and 15 subjects (6 females and 9 males, mean age 54.7 +/- 8 years) without faecal incontinence but affected by somatic peripheral neuropathy. A third group (C) of 10 healthy volunteers was used as controls. All subjects underwent electroneurographic evaluation of peripheral neuropathy, pudendal nerve terminal motor latency, anorectal manometry and rectal sensitivity tests. All the patients of group A had somatic peripheral neuropathy. Maximum squeeze pressure was lower in A compared to C (P < 0.025) and sustained for a shorter period in A compared with B (P < 0.0005) and C (P < 0.0005). All rectal sensitivity thresholds were higher in A compared with B and C. Pudendal Nerve Terminal Motor Latency was prolonged in 93% of patients studied in group A and in 73% of patients in group B (A vs B P < 0.005), with a significant difference in comparison with C: A vs C P < 0.0005, B vs C P < 0.005. Our findings suggest that somatic neuropathy plays an important role in faecal incontinence in diabetic patients, combined with sensation threshold impairment as a feature of an autonomic involvement.

Tachyphylactic action of high doses of pentagastrin

The study of the human LES was performed with manometrical methods for atropine action on gastrine tachyphylaxis. Our study points out that there is a complex self regulating neuronal circuit in the LES contraction. We discuss some hypothesis for the LES control. In particular ACh could activate an inhibitory adrenergic muscarinic receptor.