Enhanced enteral bioavailability of vancomycin using water-in-oil-in-water multiple emulsion incorporating highly purified unsaturated fatty acid

Fish oil-based microemulsion can efficiently deliver oral peptide blocking PD-1/PD-L1 and simultaneously induce ferroptosis for cancer immunotherapy

Peptide immune checkpoint inhibitors in cancer immunotherapy have attracted great attention recently, but oral delivery of these peptides remains a huge challenge due to the harsh gastrointestinal environment, large molecular size, high hydrophilic, and poor transmembrane permeability. Here, for the first time, a fish oil-based microemulsion was developed for oral delivery of programmed death-1/programmed cell death-ligand 1 (PD-1/PD-L1) blocking model peptide, OPBP-1. The delivery system was characterized, in vitro and in vivo studies were conducted to evaluate its overall implication. As a result, this nutraceutical microemulsion was easily formed without the need of co-surfactants, and it appeared light yellow, transparent, good flowability with a particle size of 152 ± 0.73 nm, with a sustained drug release manner of 56.45 ± 0.36% over 24 h and a great stability within the harsh intestinal environment. It enhanced intestinal drug uptake and transportation over human intestinal epithelial Caco-2 cells, and drastically elevated the oral peptide bioavailability of 4.1-fold higher than that of OPBP-1 solution. Meanwhile, the mechanism of these dietary droplets permeated over the intestinal enterocytic membrane was found via clathrin and caveolae-mediated endocytic pathways. From the in vivo studies, the microemulsion facilitated the infiltration of CD8+ T lymphocytes in tumors, with increased interferon-γ (IFN-γ) secretion. Thus, it manifested a promising immune anti-tumor effect and significantly inhibited the growth of murine colonic carcinoma (CT26). Furthermore, it was found that the fish oil could induce ferroptosis in tumor cells and exhibited synergistic effect with OPBP-1 for cancer immunotherapy. In conclusion, this fish oil-based formulation demonstrated great potential for oral delivery of peptides with its natural property in reactive oxygen species (ROS)-related ferroptosis of tumor cells, which provides a great platform for functional green oral delivery system in cancer immunotherapy.

Drug Delivery Systems for the Oral Administration of Antimicrobial Peptides: Promising Tools to Treat Infectious Diseases

Antimicrobial peptides (AMPs) have a great potential to face the global expansion of antimicrobial resistance (AMR) associated to the development of multidrug-resistant (MDR) pathogens. AMPs are usually composed of 10–50 amino acids with a broad structural diversity and present a range of antimicrobial activities. Unfortunately, even if the oral route is the most convenient one, currently approved therapeutic AMPs are mostly administrated by the intravenous route. Thus, the development of novel drug delivery systems (DDSs) represents a promising opportunity to protect AMPs from chemical and enzymatic degradation through the gastrointestinal tract and to increase intestinal permeability leading to high bioavailability. In this review, the classification and properties as well as mechanisms of the AMPs used in infectiology are first described. Then, the different pharmaceutical forms existing in the market for oral administration are presented. Finally, the formulation technologies, including microparticle- and nanoparticle-based DDSs, used to improve the oral bioavailability of AMPs are reviewed.

Effects of vancomycin linoleic acid nanoparticles on male reproductive indices of Sprague-Dawley rats

The management of bacterial infections, especially trains of methicillin-resistant Staphylococcus aureus observe in health care settings, has markedly improved with the introduction of established drugs but using newer nano-based formulations. This study investigates the effects of vancomycin-linoleic acid nanoparticles on testicular tissue in an experimental animal model. Twenty-five adult male Sprague-Dawley rats maintained at the Animal House of the Biomedical Resources Unit were assigned to five groups namely E - solid lipid nanoparticles; F - vancomycin solid lipid nanoparticle; G - linoleic acid nanoparticle; H - vancomycin linoleic acid; and A - control. Perturbations in seminal fluid parameters showed a reduced sperm count in groups F & G which was statistically significant (p < .05) but motility and morphology were not significant when compared to controls (A). Reduced testosterone levels were found in groups E, F and H but were not statistically significant (p > .05). There was also increased luteinizing hormone (LH) and decreased in follicular stimulating hormone (FSH) levels was statistically significant (p < .05). Hypoplasia, tubular atrophy and shrinkage were observed in histologic sections of the treated groups with basement membrane thickening. Vancomycin solid lipid nanoparticle and its constituents SLN and LA disrupted testicular morphometry and the hormonal milieu sufficient to potentially induce altered reproductive function.

Dietary Carbohydrates and Lipids in the Pathogenesis of Leaky Gut Syndrome: An Overview

This review summarizes the recent knowledge on the effects of dietary carbohydrates and lipids on the pathophysiology of leaky gut syndrome (LGS). Alterations in intestinal barrier permeability may lead to serious gastrointestinal (GI) disorders. LGS is caused by intestinal hyperpermeability due to changes in the expression levels and functioning of tight junctions. The influence of dietary habits on intestinal physiology is clearly visible in incidence rates of intestinal diseases in industrial and developing countries. Diseases which are linked to intestinal hyperpermeability tend to localize to Westernized countries, where a diet rich in fats and refined carbohydrates predominates. Several studies suggest that fructose is one of the key carbohydrates involved in the regulation of the intestinal permeability and its overuse may cause harmful effects, such as tight junction protein dysfunction. On the other hand, short chain fatty acids (mainly butyrate) at appropriate concentrations may lead to the reduction of intestinal permeability, which is beneficial in LGS. However, long chain fatty acids, including n-3 and n-6 polyunsaturated fatty acids have unclear properties. Some of those behave as components untightening and tightening the intestinal membrane.

Formulation technologies and advances for oral delivery of novel nitroimidazoles and antimicrobial peptides

Antibiotic resistance has become a global crisis, driving the exploration for novel antibiotics and novel treatment approaches. Among these research efforts two classes of antibiotics, bicyclic nitroimidazoles and antimicrobial peptides, have recently shown promise as novel antimicrobial agents with the possibility to treat multi-drug resistant infections. However, they suffer from the issue of poor oral bioavailability due to disparate factors: low solubility in the case of nitroimidazoles (BCS class II drugs), and low permeability in the case of peptides (BCS class III drugs). Moreover, antimicrobial peptides present another challenge as they are susceptible to chemical and enzymatic degradation, which can present an additional pharmacokinetic hurdle for their oral bioavailability. Formulation technologies offer a potential means for improving the oral bioavailability of poorly permeable and poorly soluble drugs, but there are still drawbacks and limitations associated with this approach. This review discusses in depth the challenges associated with oral delivery of nitroimidazoles and antimicrobial peptides and the formulation technologies that have been used to overcome these problems, including an assessment of the drawbacks and limitations associated with the technologies that have been applied. Furthermore, the potential for supercritical fluid technology to overcome the shortcomings associated with conventional drug formulation methods is reviewed.

Polyunsaturated fatty acid-based targeted nanotherapeutics to enhance the therapeutic efficacy of docetaxel

Since breast cancer is one of the most lethal malignancies, targeted strategies are urgently needed. In this study, we report the enhanced therapeutic efficacy of docetaxel (DTX) when combined with polyunsaturated fatty acids (PUFA) for effective treatment of multi-resistant breast cancers. Folic acid (FA)-conjugated PUFA-based lipid nanoparticles (FA-PLN/DTX) was developed. The physicochemical properties, in vitro uptake, in vitro cytotoxicity, and in vivo anticancer activity of FA-PLN/DTX were evaluated. FA-PLN/DTX could efficiently target and treat human breast tumor xenografts in vivo. They showed high payload carrying capacity with controlled release characteristics and selective endocytic uptake in folate receptor-overexpressing MCF-7 and MDA-MB-231 cells. PUFA synergistically improved the anticancer efficacy of DTX in both tested cancer cell lines by inducing a G2/M phase arrest and cell apoptosis. Combination of PUFA and DTX remarkably downregulated the expression levels of pro-apoptotic and anti-apoptotic markers, and blocked the phosphorylation of AKT signaling pathways. Compared to DTX alone, FA-PLN/DTX showed superior antitumor efficacy, with no signs of toxic effects in cancer xenograft animal models. We propose that PUFA could improve the therapeutic efficacy of anticancer agents in cancer therapy. Further studies are necessary to fully understand these findings and achieve clinical translation.

Natural lipids enriched self-nano-emulsifying systems for effective co-delivery of tamoxifen and naringenin: Systematic approach for improved breast cancer therapeutics

The nano-miceller drug delivery carriers of tamoxifen (TMX) having natural ingredients like polyunsaturated fatty acid (PUFA) with self-nano-emulsifying properties was developed with naringenin (NG) in a synergistic manner i.e. TMX-NG-SNEDDS. The optimized nano-formulation revealed complete drug release in 30 min and >80% permeation in 45 min. Superior cellular uptake potential (4.6-6.5-fold) of the TMX-NG-SNEDDS using Caco-2 cells while cytotoxicity study on MCF-7 cells indicated significant results (P<0.05) of TMX-NG-SNEDDS. The in vivo pharmacokinetic study also construed remarkable improvement (7.3 and 11.4-fold increase in C_max and AUC) in rate of drug absorption and 2-fold reduction in T_max by optimized TMX-NG-SNEDDS. In vivo DMBA model construed superior efficacy of the formulation by reducing tumor size, and improved survival rate of the animals justifies its safety aspect as well.

Novel dietary lipid-based self-nanoemulsifying drug delivery systems of paclitaxel with p-gp inhibitor: implications on cytotoxicity and biopharmaceutical performance

OBJECTIVES

This work describes the development and characterization of novel self-nanoemulsifying drug delivery systems (SNEDDS) employing polyunsaturated fatty acids for enhancing the oral bioavailability and anticancer activity of paclitaxel (PTX) by coadministration with curcumin (Cu).

METHODS

Preformulation studies endorsed sesame oil, labrasol, and sodium deoxycholate as lipid surfactants and cosurfactants based on their solubility for the drugs and spontaneity of emulsification to produce nanoemulsions. Further, phase titration studies were performed to identify a suitable nanoemulsion region for preparing the SNEDDS formulation.

RESULTS

The prepared formulations were characterized through in vitro, in situ, and in vivo studies to evaluate the biopharmaceutical performance. In vitro drug release studies showed 2.8- to 3.4-fold enhancement in the dissolution rate of both drugs from SNEDDS as compared with the pure drug suspension. Cell line studies revealed 1.5- to 2.7-fold reduction in the cytotoxicity on MCF-7 cells by plain PTX-SNEDDS and PTX-Cu-SNEDDS vis-à-vis the PTX-suspension. In situ intestinal perfusion studies revealed significant augmentation in permeability and absorption parameters of drug from PTX-Cu-SNEDDS over the plain PTX-SNEDDS and PTX-suspension (p < 0.001). In vivo pharmacokinetic studies also showed a remarkable improvement (i.e., 5.8- to 6.3-fold) in the oral bioavailability (Cmax and AUC) of the drug from PTX-SNEDDS and PTX-Cu-SNEDDS vis-à-vis the PTX-suspension.

CONCLUSIONS

Overall, the studies corroborated superior biopharmaceutical performance of PTX-Cu-SNEDDS.

Oleic acid and docosahexaenoic acid cause an increase in the paracellular absorption of hydrophilic compounds in an experimental model of human absorptive enterocytes

Surface active compounds present in food possibly have the ability to enhance the absorption of water soluble toxic agents. Therefore, we investigated whether fatty acids such as oleic acid and docosahexaenoic acid (DHA), both commonly present in food, negatively affect the integrity of tight junctions (TJ) in the intestinal epithelium and thereby increase the absorption of poorly absorbed hydrophilic substances. Caco-2 cells, which are derived from human absorptive enterocytes, were grown on permeable filters for 20-25 days. Differentiated cell monolayers were apically exposed for 90min to mannitol in emulsions of oleic acid (5, 15 or 30mM) or DHA (5, 15 or 30mM) in an experimental medium with or without Ca(2+) and Mg(2+). Absorption of (14)C-mannitol increased and trans-epithelial electrical resistance (TEER) decreased in cell monolayers exposed to oleic acid and DHA, compared to controls. Cytotoxicity, measured as leakage of LDH, was higher in groups exposed to 30mM oleic acid and all concentrations of DHA. Morphology of the cell monolayers was studied by using fluorescence microscopy. Exposure of cell monolayers to 5mM DHA for 90min resulted in a profound alteration of the cell-cell contacts as detected by staining the cells for beta-catenin. Oleic acid (30mM) treatment also induced dissolution of the cell-cell contacts but the effect was not as pronounced as with DHA. Cell monolayers were also exposed for 180min to 250nM cadmium (Cd) in emulsions of oleic acid (5 or 30mM) or DHA (1 or 5mM), in an experimental medium with Ca(2+) and Mg(2+). Retention of Cd in Caco-2 cells was higher after exposure to 5mM oleic acid but lower after exposure to 30mM oleic acid and DHA. Absorption of Cd through the monolayers increased after DHA exposure but not after exposure to oleic acid. Our results indicate that fatty acids may compromise the integrity of the intestinal epithelium and that certain lipids in food may enhance the paracellular absorption of poorly absorbed hydrophilic substances.

Docosahexaenoic Acid and Eicosapentaenoic Acid Induce Changes in the Physical Properties of a Lipid Bilayer Model Membrane

We investigated the effect of fatty acids such as stearic acid (SA, 18:0), oleic acid (OA, 18:1), eicosapentaenoic acid (EPA, 20:5), and docosahexaenoic acid (DHA, 22:6) on a dipalmitoylphosphatidylcholine (DPPC) bilayer by determining the phase transition temperature, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH), and detergent insolubility. Treatment with unsaturated fatty acid broadened and shifted the phase transitions of the DPPC bilayer to a lower temperature. The phase transition temperature and the value of fluorescence anisotropy of DPH at 37 degrees C decreased progressively with increasing treatment amounts of unsaturated fatty acid. A large amount of the DPPC bilayer treated with unsaturated fatty acid was dissolved in Triton X-100, obtaining a low level of detergent insolubility. These modifications of the bilayer physical properties were most pronounced with DHA and EPA treatment. These data show that unsaturated fatty acids, particularly DHA and EPA, induce a marked change in the lipid bilayer structure. The composition of fatty acids in the DPPC bilayer was similar after treatment with various unsaturated fatty acids, suggesting that the different actions of unsaturated fatty acids are attributed to change in the molecular structure (e.g., kinked conformation by double bonds). We further explored the change in physical properties induced by fatty acids dispersed in a water-in-oil-in-water multiple emulsion and found that unsaturated fatty acids acted efficiently on the DPPC bilayer, even when incorporated in emulsion form.

Drug targeting to the colon with lectins and neoglycoconjugates

Targeting of drugs to specific sites of action provides several advantages over non-targeted drugs. These include the prevention of side effects of drugs on healthy tissues and enhancement of drug uptake by targeted cells. This review will cover traditional approaches of colon drug targeting as well as the use of lectins and neoglycoconjugates for the targeted delivery. Direct and reverse targeting strategies, potential molecular targets and targeting moieties for colon drug delivery, targeted drug delivery systems (DDS) for colon delivery, anticancer DDS targeted to colon cancer are examined. Directions of future development are discussed.

Highly sensitive quantification of vancomycin in plasma samples using liquid chromatography-tandem mass spectrometry and oral bioavailability in rats

We developed a highly sensitive liquid chromatography-tandem mass spectrometry assay (LC-MS-MS) for a glycopeptide antibacterial drug, vancomycin (VCM), in rat plasma. After precipitating 100 micro l of plasma with 300 micro l of 10% trifluoroacetic acid-methanol (2:1, v/v), the supernatant was diluted with 300 micro l of distilled water and was passed through a filter. LC-MS-MS equipped with electrospray ionization in the positive ion mode used a pair of ions at 725/144 m/z for VCM in the multiple reaction-monitoring mode with a sample injection volume of 20 micro l. The calibration curve had a linear range from 0.01 to 20 micro g/ml when linear least square regression was applied to the concentration versus peak area plot. The drug in the sample was detected within 5 min. Precision, accuracy and limit of quantitation indicated that this method was suitable for the quantitative determination of VCM in rat plasma. Using this method, we defined for the first time that the oral bioavailability of VCM in rats was 0.069%. This method can be applied to basic pharmacokinetic and pharmaceutical studies in rats.

Effect of gamma-linolenic acid or docosahexaenoic acid on tight junction permeability in intestinal monolayer cells and their mechanism by protein kinase C activation and/or eicosanoid formation

OBJECTIVE

Polyunsaturated fatty acids have been characterized as immunonutrients, but the effect of gamma-linolenic acid (GLA) or docosahexaenoic acid (DHA) on intestinal permeability has rarely been reported.

METHODS

Confluent Caco-2 cells on porous filter were used to measure tight junction function by fluorescein sulfonic acid permeability and transepithelial electrical resistance. Treatments with 0, 10, 50, and 100 microM of GLA or DHA during 24 h were compared. Then the effects of butylated hydroxytoluene (antioxidant), 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (protein kinase C antagonist), and inhibitors of enzymatic degradation to the eicosanoids, indomethacin (cyclooxygenase inhibitor) and 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-p-benzoquinone (lipoxygenase inhibitor), on GLA or DHA were examined.

RESULTS

GLA and DHA enhanced fluorescein sulfonic acid permeability to 8.7- and 1.4-fold, respectively, and lowered transepithelial electrical resistance to 0.52- and 0.73-fold, respectively, versus the control in a concentration-dependent manner without cell injury (P < 0.001 to 0.05). Indomethacin and 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-p-benzoquinone enhanced the changes mediated by GLA but did not alter the DHA effect. Butylated hydroxytoluene was ineffective. 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine facilitated the changes mediated by GLA, DHA, and eicosapentaenoic acid. The results indicated that the mechanism to change tight junction permeability via protein kinase C regulation is common but that via eicosanoid formation differs among GLA, DHA, and eicosapentaenoic acid.

CONCLUSIONS

GLA and DHA affect tight junction permeability in intestinal monolayer cells specifically and in a concentration-dependent manner.

Enhanced intestinal absorption of vancomycin with Labrasol and D-alpha-tocopheryl PEG 1000 succinate in rats

Vancomycin hydrochloride (VCM) is a glycopeptide antibiotic used for the treatment of infections caused by methicillin-resistant staphylococci. It is water soluble, having a high molecular weight, and poorly absorbed from the gastrointestinal tract. Mixtures of VCM with Labrasol and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) were prepared to improve oral absorption of VCM. Administration of VCM solution to rat ileum at a dose of 20 mg/kg did not result in detectable plasma VCM concentration. Formulation containing 50% of Labrasol resulted in a Cmax value of 5.86+/-0.97 microg/ml and an AUC(0-6h) value of 16.06+/-1.78 microgh/ml. Addition of TPGS to VCM solution at 12.5% concentration also increased the plasma VCM concentration with a Cmax value of 4.98+/-0.45 microg/ml. But the AUC(0-6 h) (9.87+/-1.90 microgh/ml) was significantly lower than that obtained with Labrasol. The addition of 5.0 and 25.0% TPGS to solutions of VCM containing 50% of Labrasol did not result in any significant increase either in Cmax or AUC(0-6 h) of VCM. Whereas the addition of 12.5% of TPGS has resulted in an increase in Cmax and AUC(0-6 h) by 2.2 and 2.4 times, respectively, suggesting that this concentration of 50% Labrasol and 12.5% TPGS (1:0.25) was optimum for improving intestinal absorption of VCM. A dose dependent decrease in the Cmax and AUC(0-6 h) values was observed when the dose of absorption enhancers was decreased by 50% with formulation containing Labrasol and TPGS in 1:0.25 ratio. The results of the study indicate that formulations containing Labrasol and TPGS improve intestinal absorption of hydrophilic macromolecular drug, VCM.