Lactose oleate as new biocompatible surfactant for pharmaceutical applications.

Sugar fatty acid esters are an interesting class of non-ionic, biocompatible and biodegradable sugar-based surfactants, recently emerged as a valid alternative to the traditional commonly employed (e.g. polysorbates and polyethylene glycol derivatives). By varying the polar head (carbohydrate moiety) and the hydrophobic tail (fatty acid), surfactants with different physico-chemical characteristics can be easily prepared. While many research papers have focused on sucrose derivatives, relatively few studies have been carried out on lactose-based surfactants. In this work, we present the synthesis and the physico-chemical characterization of lactose oleate. The new derivative was obtained by enzymatic mono-esterification of lactose with oleic acid. Thermal, surface, and aggregation properties of the surfactant were studied in detail and the cytotoxicity profile was investigated by MTS and LDH assays on intestinal Caco-2 monolayers. Transepithelial electrical resistance (TEER) measurements on Caco-2 cells showed a transient and reversible effect on the tight junctions opening, which correlates with the increased permeability of 4 kDa fluorescein-labelled dextran (as model for macromolecular drugs) in a concentration dependent manner. Moreover, lactose oleate displayed a satisfactory antimicrobial activity over a range of Gram-positive and Gram-negative bacteria. Overall, the obtained results are promising for a further development of lactose oleate as an intestinal absorption enhancer and/or an alternative biodegradable preservative for pharmaceutical and food applications.

Lipid excipients Peceol and Gelucire 44/14 decrease P-glycoprotein mediated efflux of rhodamine 123 partially due to modifying P-glycoprotein protein expression within Caco-2 cells.

PURPOSE: The objective of this study was to determine the influence of two lipid excipients, Peceol(c) and Gelucire(c) 44/14 on P-glycoprotein (Pgp) activity and protein expression in human colon adenocarcinoma cells (Caco-2). Lipid excipients are increasingly used as drug delivery systems for hydrophobic drugs to increase their bioavailability by overcoming the barrier of low absorption. This study will probe a novel mechanism by which lipid excipients reduce Pgp-mediated efflux and thereby increase bioavailability of orally administered therapeutics. METHODS: Non-cytotoxic concentrations of Peceol(c) and Gelucire(c) 44/14 were determined for 24-hour treatments of Caco-2 cells using integrity of the cell membranes and mitochondrial respiration as markers. Pgp activity after treatment with non-cytotoxic concentrations of Peceol(c) and Gelucire(c) 44/14 was measured with a fluorescent Pgp substrate, rhodamine 123 (Rh123). The activity of Pgp was ascertained by measuring accumulation and the directional flux of Rh123 using the Transwell(c) semi-permeable cell culture support system. To assess the effect of Peceol(c) and Gelucire(c) 44/14 on Pgp protein expression, Western blotting with a specific Pgp antibody was performed. RESULTS. The two assays for cytotoxicity were in agreement and showed that concentrations of less than 0.5% (v/v) Peceol(c) and less than 0.02% (w/v) Gelucire(c) 44/14 were not toxic to Caco-2 cells. Rh123 accumulation was increased up to 3-fold in cells treated with sub-toxic concentrations of the excipients. The flux of Rh123 across the cell monolayer was unaffected by treatment in the absorptive (apical to basolateral) direction but the efflux transport was reduced after treatment with Peceol(c), Gelucire(c) 44/14 or the positive control , 100microM verapamil. Some of the reduction in Pgp efflux activity can be explained by the reduction in protein expression after treatment with the lipid excipients; treatment with 0.25% (v/v) and 0.5% (v/v) Peceol(c) reduced Pgp protein levels to 62.4% and 68.4% of the control respectively while Gelucire(c) 44/14 treatments of 0.01% (w/v) and 0.02% (w/v) reduced Pgp to 64.5% and 51.8% respectively. CONCLUSION: In this study we utilized established methodologies to assess the inhibitory effect of the excipients on the Pgp-mediated efflux of the probe, Rh123 and tested the hypothesis that long-term treatment of Caco-2 cells with the lipid excipients, Peceol(c) and Gelucire(c) 44/14, decreased Pgp protein expression. The results suggest a new mechanism which may contribute to the improved bioavailability seen for drugs formulated with lipid-based excipients.

W/O microemulsions for ocular delivery: evaluation of ocular irritation and precorneal retention.

Water-in-oil microemulsions (w/o ME) capable of undergoing a phase-transition to lamellar liquid crystals (LC) or bicontinuous ME upon aqueous dilution were formulated using Crodamol EO, Crill 1 and Crillet 4, an alkanol or alkanediol as cosurfactant and water. The hypothesis that phase-transition of ME to LC may be induced by tears and serve to prolong precorneal retention was tested. The ocular irritation potential of components and formulations was assessed using a modified hen's egg chorioallantoic membrane test (HET-CAM) and the preocular retention of selected formulations was investigated in rabbit eye using gamma scintigraphy. Results showed that Crill 1, Crillet 4 and Crodamol EO were non-irritant. However, all other cosurfactants investigated were irritant and their irritation was dependent on their carbon chain length. A w/o ME formulated without cosurfactant showed a protective effect when a strong irritant (0.1 M NaOH) was used as the aqueous phase. Precorneal clearance studies revealed that the retention of colloidal and coarse dispersed systems was significantly greater than an aqueous solution with no significant difference between ME systems (containing 5% and 10% water) as well as o/w emulsion containing 85% water. Conversely, a LC system formulated without cosurfactant displayed a significantly greater retention compared to other formulations.

Quantitative Structure-Cytotoxicity Relationship of Oleoylamides.

Eighteen oleoylamides were subjected to quantitative structure-activity relationship analysis based on their cytotoxicity, tumor selectivity and anti-HIV activity, in order to assess their biological activities. Cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines and five human oral normal cells (gingival fibroblast, periodontal ligament fibroblast, pulp cell, oral keratinocyte, primary gingival epithelial cells) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor-selectivity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC50) against normal human oral cells to that against OSCC cell lines. Potency-selectivity expression (PSE) was determined by the ratio of TS to CC50 against OSCC. Anti-HIV activity was evaluated by the ratio of CC50 to the concentration leading to 50% cytoprotection from HIV infection (EC50). Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method. Among 18 derivatives, compounds 8: with a catechol group) and 18: with a (2-pyridyl)amino group) had the highest TS. On the other hand, doxorubicin and 5-fluorouracil (5-FU) were more highly cytotoxic to normal epithelial cells, displaying unexpectedly lower TS and PSE values. None of the compounds had anti-HIV activity. Among 330 chemical descriptors, 75, 73 and 19 descriptors significantly correlated to the cytotoxicity to normal and tumor cells, and TS, respectively. Multivariate statistics with chemical descriptors for molecular polarization and hydrophobicity may be useful for the evaluation of cytotoxicity and TS of oleoylamides.

Toxicological evaluation of mixtures of nonionic surfactants, alone and in combination with oil.

The toxicity to human bronchial (16-HBE14o-) epithelium cells of nonionic surfactants, polyoxyethylene-10-oleyl ether (C(18:1)E(10)), polyoxyethylene-10-dodecyl ether (C(12)E(10)), and N,N-dimethyl-dodecylamine-N-oxide (C(12)AO) alone or in combination with a range of pharmaceutically acceptable oils (namely, ethyl esters and triglyceride oils), was determined with the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Regardless of the presence of oil, all C(12)E(10)- and C(12)AO-containing systems were toxic at concentrations around or below their critical aggregation concentrations (as determined by surface tension measurements), suggesting that surfactant toxicity was due to the disruption caused by the partitioning of monomeric surfactant into the cell membrane. Systems prepared from C(18:1)E(10) alone or in combination with a low-molecular-weight oil, such as ethyl butyrate or tributyrin, were toxic above their critical aggregation concentration. In contrast, systems prepared from C(18:1)E(10) in combination with a high-molecular-volume oil (e.g., ethyl oleate, Miglyol 812, or soybean oil) were toxic only at concentrations significantly greater than their critical aggregation concentration, suggesting that in these cases surfactant toxicity was mediated by the aggregated form of the surfactant solubilizing components of the cell membrane. In the C(18:1)E(10)-stabilized system, it is proposed that toxicity was significantly reduced on incorporation of high-molecular-volume oils because these oils cause formation of a distinct oil core in the aggregates that leads to a reduction in the ability of the system to solubilize components of the cell membrane.

Immune responses and side effects of five different oil-based adjuvants in mice.

In this study, five different oil based adjuvants were compared to assess efficacy and side effects. Mice were injected subcutaneously (s.c.) or intraperitoneally (i.p.) with a weak immunogen (synthetic peptide) emulsified in Freund's adjuvant (FA), Specol, RIBI, TiterMax or Montanide ISA50. Efficacy of adjuvants was evaluated based on their properties to induce peptide specific IgG1, IgG2a and total IgG antibodies, native protein cross-reactive antibodies and cytokine production. Side effects were evaluated based on clinical and behavioural abnormalities, and (histo)pathological changes. Although marked differences in isotype profile and height of titre are observed among the different adjuvants used, we found that FA, Montanide ISA50 and Specol worked equally well in the s.c. and i.p. route, TiterMax functioned only when given i.p. and RIBI also did not perform up to par. The number of cytokine (interferon-gamma and interleukin-4) producing spleen cells was significantly higher after injection of RIBI compared with other adjuvants. Injection of FA or TiterMax resulted in severe pathological changes while after RIBI injection minimal changes were observed. In conclusion, high peptide specific antibody levels with limited side effects can be obtained by s.c. injection of peptide combined with Montanide ISA50 or Specol as alternatives to FA.

Eradication of drug resistant Staphylococcus aureus by liposomal oleic acids.

Staphylococcus aureus (S. aureus) represents a major threat to a broad range of healthcare and community associated infections. This bacterium has rapidly evolved resistance to multiple drugs throughout its antibiotic history and thus it is imperative to develop novel antimicrobial strategies to enrich the currently shrinking therapeutic options against S. aureus. This study evaluated the antimicrobial activity and therapeutic efficacy of oleic acid (OA) in a liposomal formulation as an innate bactericide against methicillin-resistant S. aureus (MRSA). In vitro studies showed that these OA-loaded liposomes (LipoOA) could rapidly fuse into the bacterial membranes, thereby significantly improving the potency of OA to kill MRSA compared with the use of free OA. Further in vivo tests demonstrated that LipoOA were highly effective in curing skin infections caused by MRSA bacteria and preserving the integrity of the infected skin using a mouse skin model. Moreover, a preliminary skin toxicity study proved high biocompatibility of LipoOA to normal skin tissues. These findings suggest that LipoOA hold great potential to become a new, effective, and safe antimicrobial agent for the treatment of MRSA infections.

Preparation, characterization and evaluation of breviscapine lipid emulsions coated with monooleate-PEG-COOH.

Series of monooleate-modified PEG with active carboxylic terminus on the other end (MO-PEG-COOH) were used to modify the lipid emulsions surface to prepare a sterically stabilized lipid emulsions for carrying Traditional Chinese Medicine - breviscapine. Based on the research of relationship between polymer structure and prolonged circulation activity, we developed an optimized formulation and a technological method to prepare the sterile and stable MO-PEG(10,000)-COOH (Bre-LE-PEG(10,000)) coated breviscapine lipid emulsions (Bre-LE) for intravenous administration. Follow the optimum preparation, the average particle size, polydispersity index, zeta potential, Ke value and content of final product were determined to be (207.1±8.5)nm, 0.197±0.005, (-33.6±2.0)mV, (21.1±2.3)% and (95.0±1.8)% respectively (n=3). The characteristics, stability and safety of Bre-LE-PEG(10,000) were also studied with Bre-LE as a control. Increased plasma concentration by surface modification of the lipid emulsions may enhance the pharmacological activity of breviscapine to promote blood circulation.

Immunogenicity of fatty acid anilides in rabbits and the pathogenesis of the Spanish toxic oil syndrome.

Fatty acid anilides, the major xenobiotic found in the cooking oils responsible for the Spanish toxic oil syndrome, are immunogenic for rabbits as ascertained by a skin test reaction, the characterization of specific antibodies against anilides and the immunofluorescent detection of 'anilide dependent antigens' in tissue slices from treated animals.

[Data on the standardization of a lubricant F-11 in the air of the work area]. / Materialy k normirovaniiu zamaslivatelia F-11 v vozdukhe rabochei zony.

F-11 lubricant is used in synthetic fibers industry for the polyamide fibers processing. LD50 in intragastric administration is over 11,000 mg/kg. Acute action threshold (limac) is 180 mg/m3 (as evidenced by changes of the investigatory reflex). Chronic action threshold (limch) is 100 mg/m3. MAC in the air is 5 mg/m3, hazard class III. F-11 lubricant is a moderately hazardous chemical compound.