Statistical optimization of bile salt deployed nanovesicles as a potential platform for oral delivery of piperine: accentuated antiviral and anti-inflammatory activity in MERS-CoV challenged mice.

The objective of this paper is to confine piperine, a poor oral bioavailable herbal drug into bile salt based nano vesicles for improving its aqueous solubility, hence, its therapeutic activity. Piperine-loaded bilosomes were fabricated adopting thin film hydration technique according to 32.21 full factorial design to investigate the impact of different formulation variables on the characters of bilosomes: entrapment efficiency (EE%), particle size, and % of drug released post 8 h (Q8hr). The selected optimum formula was F2 (enclosing 1% bile salt, brij72 as a surfactant, and ratio of surfactant:cholesterol was 9:1) with desirability value 0.801, exhibiting high EE% (97.2 ± 0.8%) nanosized spherical vesicles (220.2 ± 20.5 nm) and Q8hr (88.2%±5.6). The superiority of the optimized formula (F2) over the drug suspension was revealed via ex vivo permeation study, also pharmacokinetic study denoted to the boosted oral bioavailability of piperine-loaded bilosome compared to piperine suspension. Moreover, antiviral activity and safety margin of F2 was significantly higher than that of the drug suspension. The ability of piperine to interact with the key amino acids in the receptor binding domain 4L3N as indicated by its docking configuration, rationalized its observed activity. Furthermore, F2 significantly reduce oxidant markers, inflammatory cytokines in MERS-CoV-infected mice. Hence, bilosomes can be considered as a carrier of choice for piperine with potential antiviral and anti-inflammatory activities.

Pectin/lignocellulose nanofibers/chitin nanofibers bionanocomposite as an efficient biosorbent of cholesterol and bile salts.

A new biosorbent Ca-crosslinked pectin/lignocellulose nanofibers/chitin nanofibers (PLCN) was synthesized for cholesterol and bile salts adsorption from simulated intestinal fluid during gastric-intestinal passage. The physico-chemical properties of PLCN were studied using SEM, FTIR, XRD, DSC and BET. Before gastrointestinal passage, PLCN had an amorphous single-phase, compact structure formed via hydrogen and van der Waals bonds that revealed an irregular shape with the shriveled surface but watery condition and enzymatic digestion led to create a porous structure without destruction because of the water-insoluble nanofibers, therefore increasing the adsorption capacity. The maximum adsorption capacity reached 37.9 and 5578.4 mg/g for cholesterol and bile salts, respectively. Freundlich isotherm model indicated the reversible heterogeneous adsorption of both cholesterol and bile salts on PLCN. Further, their adsorption followed pseudo-second order kinetic model. These results suggest that PLCN has potential as a gastrointestinal-resistant biosorbent for cholesterol and bile salts adsorption applicable in medicine and food industry.

Quantitative estimation of the effects of bile salt surfactant systems on insulin stability and permeability in the rat intestine using a mass balance model.

The oral delivery of peptides and proteins is compromised by chemical and proteolytic instability as well as by permeability limitations. The aim of this study was to delineate the relative contributions of simple bile salt and bile salt:fatty acid mixed micellar systems to protein stability vs permeability enhancement in the rat intestine. Insulin disappearance from the rat intestine was evaluated when administered in simple micellar systems of sodium cholate (NaC), sodium taurocholate (NaTC) and sodium glycocholate (NaGC), and in mixed micellar systems of these bile salts and linoleic acid (LA). In-vitro stability studies were used to evaluate the extent of insulin degradation in the different micellar systems. After correction for insulin degradation in all systems a mass balance model was used to estimate the fractions of insulin absorbed for all systems. Mass balance estimates for the extent of insulin absorption in control perfusion systems were consistent with previously reported predictions of the model for ileal insulin absorption. Mass balance estimates for NaGC suggested no significant effects on the fraction of insulin absorbed relative to control. However, insulin absorption was estimated to occur to a significantly greater extent for NaTC simple micellar systems and was coincident with increased permeability of the hydrophilic marker molecule PEG 4000. The mass balance model estimated higher fractions of insulin absorbed for all mixed micellar systems in line with enhanced plasma insulin levels and higher PEG 4000 permeabilities for these systems.

Ocular toxicity of some corneal penetration enhancers evaluated by electrophysiology measurements on isolated rabbit corneas.

The influence on electrical resistance and membrane potential of rabbit corneas in vitro of some chemicals used as adjuvants in ophthalmic formulations was investigated, in the attempt to correlate changes in electrophysiological properties of the corneal tissue (possibly indicative of toxic/damaging effects to the corneal epithelium), with the promoting effect of the substances on transcorneal permeation in vitro of timolol maleate (TM). The chemicals, tested at different concentrations, were benzalkonium chloride (BAC), sodium ethylenediaminetetraacetate (EDTA), polyoxyethylene-20-stearyl ether (PSE), polyethoxylated castor oil (PCO), deoxycholic acid sodium salt (DC) and cetylpyridinium chloride (CPC). For these substances, definite correlations were found between promoting activity for permeation of TM and modification of electrophysiological parameters. These parameters were in all cases significantly altered by all agents at all concentrations after a 5-h contact. However, after a 1-h contact, 0.001% PSE and CPC did not significantly modify the corneal resistance, while PCO and PSE did not significantly modify the transcorneal potential at the tested concentrations. Only 0.001% PSE, a nonionic surfactant used as solubilizer and emulsifier, active as promoter for TM, did not modify both electrophysiological parameters to a significant extent after 1 h. The results of this study indicate correlations between ocular toxicity, promoting activity for transcorneal permeation of timolol and modification of the electrophysiological parameters.

A dynamic in vitro lipolysis model. I. Controlling the rate of lipolysis by continuous addition of calcium.

Lipolysis by pancreatic lipase was investigated with the aim to establish an in vitro lipolysis model, which can be used to investigate the dissolution of poorly soluble lipophilic drug substances at controlled hydrolysis rates. The effects of three experimental parameters -- the concentrations of bile salts and Ca(2+) and the lipase activity -- were investigated. The effect on the rate of hydrolysis of emulsified soybean oil was investigated in experiments in a pH-stat at pH 6.5 and 37 degrees C. The free fatty acids produced by the hydrolysis were titrated at pH 6.5. It was shown that all three investigated parameters influence the initial rate of hydrolysis, whereas only the lipase activity and the concentration of Ca(2+) affect the subsequent stages. It was also shown that the rate of lipolysis can be controlled by the rate of adding Ca(2+). Thus, it is possible to design an in vitro model using readily available and inexpensive materials in which the hydrolysis rate can be controlled by the continuous addition of Ca(2+).

Cytostar-T scintillating microplate assay for measurement of sodium-dependent bile acid uptake in transfected HEK-293 cells.

Real-time measurements of bile acid uptake into HEK-293 cell monolayers expressing the human sodium/bile acid cotransporters have been demonstrated using Cytostar-T microplates with an integral scintillating base. In these 96-well microplates, which permits culturing and observation of adherent cell monolayers, uptake of (14)C-labeled glycocholate and taurocholate into transfected HEK-293 cells was time-dependent, sodium-stimulated, and saturable. The sodium-activated uptake of 30 microM [(14)C]glycocholate (GC) via the ileal (IBAT) and liver (LBAT) transporters was 30-40 times higher than GC uptake in a sodium-free background. In addition, ouabain inhibition of the plasma membrane Na(+), K(+)-ATPase, causing the sodium gradient to collapse, resulted in total loss of glycocholate transport. Induction of gene expression by sodium butyrate showed that the amount of labeled bile acid accumulated in the cell monolayers at steady state was a function of the total amount of transporter expressed. Uptake of labeled bile acids was inhibited both by the specific IBAT inhibitor, 2164U90, and by various bile acids. No major difference was observed between IBAT and LBAT in their specificity for the bile acids tested while the dihydroxy bile acids had the highest affinity for both the transporters studied. The Cytostar-T proximity assay has been demonstrated to be an accurate and reproducible method for monitoring specific bile acid transport in transfected mammalian cells and the results are similar to those obtained by traditional methods. We conclude that the technique is an attractive approach to the cellular study of membrane transport of radiolabeled solutes in general and suggest a role in screening and characterization of novel transport inhibitors.

Dietary fibre, physicochemical properties and their relationship to health.

Dietary carbohydrates that escape digestion and absorption in the small intestine include non-digestible oligosaccharides (carbohydrates with a degree of polymerisation between three and ten), resistant starch and non-starch polysaccharides. The physiological effects of this heterogeneous mixture of substrates are partly predictable on the basis of their physicochemical properties. Monosaccharide composition and chain conformation influence the rate and extent of fermentation. Water-holding capacity affects stool weight and intestinal transit time. Viscous polysaccharides can cause delayed gastric emptying and slower transit through the small bowel, resulting in the reduced rate of nutrient absorption. Polysaccharides with large hydrophobic surface areas have potentially important roles in the binding of bile acids, carcinogens and mutagens. Ispaghula is capable of binding bile acids through a large number of weak binding sites on the polysaccharide structure, and having greatest effect on the potentially more harmful secondary bile acids deoxycholic acid and lithocholic acid.

[Influence of oral taurine supplementation on the intraduodenal concentration and conjugation of bile acids in full-term newborn infants]. / Influence d'une supplémentation orale en taurine sur la concentration intraduodénale et la conjugaison des acides biliaires chez le nourrisson né à terme.

We studied the effects of oral taurine supplementation on bile acids conjugation and duodenal bile salt concentrations in infants. Seventeen infants receiving enteral artificial nutrition were investigated. At the beginning of the study they were 6 to 14 weeks old, in good nutritional state, without malabsorption, protein-losing enteropathy and liver or infectious diseases. After at least 8 days of a stable, taurine-free regimen the infants received oral taurine supplementation (36-45 micromol/kg.24 h) for 8 days. Bile acids were measured before and after each supplementation period in bile samples obtained by duodenal tubing, using enzymatic methods and colorimetry. According to the initial plasma taurine levels before supplementation, the infants were divided into two groups: I) plasma taurine levels less than 60 mumol/l (mean 47 +/-5 mumol/l, n = 8); II) plasma taurine levels greater than 70 mumol/l (mean 77 +/- 2 mumol/l, = 9). After 8 days of taurine supplementation a significant increase of plasma and urinary taurine (P less than 0.01),total duodenal bile salt concentrations (P less than 0.05), total duodenal tauroconjugates (P less than 0.05),taurocholate (P less than 0.01), taurochenodeoxycholate (P less than 0.05), and glycocholate (P less than 0.01), duodenal concentrations, and a significant decrease of the glycoconjugate/tauroconjugate ratio (P less than 0.05), were observed, but only in group I. in group II infants we only noted a significant increase of urinary taurine (P less than 0.01), and of duodenal total tauroconjugates (P less than 0.05). This study shows that the biliary effects of an oral taurine supplementation depends on taurine status and that in taurine-depleted infants intakes of exogenous taurine higher than 45 mumol/kg. 24 h are perhaps necessary for optimal bile salt effects.