Design and Development of Immunomodulatory Antigen Delivery Systems Based on Peptide/PEG-PLA Conjugate for Tuning Immunity.

Cancer vaccines are considered to be a promising tool for cancer immunotherapy. However, a well-designed cancer vaccine should combine a tumor-associated antigen (TAA) with the most effective immunomodulatory agents and/or delivery system to provoke intense immune responses against the TAA. In the present study, we introduced a new approach by conjugating the immunomodulatory molecule LD-indolicidin to the hydrophilic chain end of the polymeric emulsifier poly(ethylene glycol)-polylactide (PEG-PLA), allowing the molecule to be located close to the surface of the resulting emulsion.

Solubilization of water-insoluble drugs due to random amphiphilic and degradable poly(dimethylmalic acid) derivatives.

Amphotericin B (AmB) and clofazimine are potent drugs hindered by their low water solubilities and their toxicities. Carriers able to increase their apparent water solubilities are needed for these drugs and for other molecules with similar properties. Random amphiphilic copolymers derived from poly(dimethylmalic acid) were obtained using different hydrophobization ratios and side group sizes.

Nanoaggregates of biodegradable amphiphilic random polycations for delivering water-insoluble drugs.

Cationic amphiphilic random copolyesters were obtained by copolymerization of 5-Z-amino-δ-valerolactone and ε-caprolactone. The amino content of the final copolymers was controlled by the polymerization feed ratio and was in the range 10 to 100%. Copolymers solubility and aggregation behavior was assessed by conductometric and zeta potential analyses.

Nanoaggregates of a random amphiphilic polyanion to carry water-insoluble clofazimine in neutral aqueous media.

Clofazimine, an antibiotic drug active against mycobacteria and used for the treatment of leprosy, is a very weak base insoluble in neutral aqueous media. It may cause rather severe secondary effects. Basically, these two shortcomings can be minimized by combination with a drug carrier.

Bioresorbable polyelectrolyte amphiphiles as nanosized carriers for lipophilic drug solubilization and delivery.

Starting from drug carriers and drug-delivery systems described in the literature, this article examines more specifically those that are relevant to the field of nanocarriers composed of a degradable hydrophilic polyelectrolyte backbone with pendent hydrophobes arranged to form comb-like co-polymers. Advantage is taken of the nanosized, lipophilic pocket-bearing multimolecule aggregates formed in aqueous media by such amphiphilic polyelectrolytes to accommodate water-insoluble drug molecules according to a phenomenon named macromolecular microencapsulation. Comments are also made on the criteria to be fulfilled by nanosized polymeric drug carriers.

In vivo efficiency of targeted norfloxacin against persistent, isoniazid-insensitive, Mycobacterium bovis BCG present in the physiologically hypoxic mouse liver.

Persistence of Mycobacterium tuberculosis is a hypoxia-inducible state in which the bacteria are phenotypically insensitive to currently available antituberculous drugs. In humans, persistent M. tuberculosis is found in granulomatous lesions, either inside macrophages or in necrotic tissue, where the partial oxygen pressure (pO(2)) is very low.

Polymeric prodrugs of antibiotics with improved efficiency.

Macromolecular prodrugs of the antibiotic norfloxacin were prepared by coupling the drug via a peptide spacer onto a mannosylated dextran. The tetrapeptide gly-phe-gly-gly-gly-OMe was selected as substrate for lysosomal enzymes. The drug was coupled on the alpha-C of the terminal glycine.

Synthesis, degradation, and antimicrobial properties of targeted macromolecular prodrugs of norfloxacin.

Long-term antibiotic treatment is required to cure tuberculosis. Targeted antibiotics should improve the efficacy of treatment by concentrating the drugs close to the bacteria. The aim of the present study was to synthesize targeted conjugates.

Poly(ethylene glycol): protein-repulsive or albumin-compatible?

In the literature, many papers deal with the behavior of proteins in aqueous media in the presence of poly(ethylene glycol) (PEG) molecules or poly(ethylene oxide) (PEO) segments, physically adsorbed onto, or covalently attached to, macromolecules or to solid surfaces. In particular, it is well known that PEO segments make foreign materials stealthy, i.e.

Interactions between red blood cells and a lethal, partly quaternized tertiary polyamine.

Partially quaternized poly[thio-1-(N,N-diethyl-aminomethyl) ethylene]s, Q-P(TDAE)(x) with x indicating the percentage of quaternized subunits, have been proposed as potential carriers for drugs insoluble in water. However these cationic polyelectrolytes form emboli upon intravenous administration. In order to study the mechanism, Q-P(TDAE)(11) was incubated in vitro with red blood cells (RBCs) suspended in various aqueous media such as autologous plasma, autologous serum, albumin dissolved in phosphate buffer, plasma-serum mixtures and Tris buffer.

Monoacylation of ribonuclease A enables its transport across an in vitro model of the blood-brain barrier.

A major challenge in correcting disorders affecting the central nervous system is to induce blood-brain barrier (BBB) crossing of exogenous biological compounds such as proteins or specific nucleic acid sequences. Fatty acids, due to their high membrane affinity and low toxicity, are good potential candidates to promote this barrier crossing when covalently bound to proteins. In this paper, we report that regiospecific monoacylation of ribonuclease A (RNase A) enables its transport across an in vitro model of the BBB.

Effect of protein chemical hydrophobization on antiglucose oxidase immunoglobulin production in mouse.

One problem resulting from the therapeutic use of enzymes is the adverse immunological reactions. In order to study the immunoglobulin production elicited into mice by different derivatives of an enzyme, glucose oxidase was chosen as a model. The immunoglobulin productions induced by apoglucose oxidase, prepared by removing flavine adenine dinucleotide from the native enzyme through an acidic treatment and devoid of enzymatic activity, by metaperiodate-oxidized glucose oxidase that lost about 50% of its carbohydrate moiety, and by propyl aliphatic chains-coupled glucose oxidase were as intense as that induced by native glucose oxidase.

Immunoassay for native enzyme quantification in biological samples.

In order to detect low levels of enzyme activity, specifically glucose oxidase, in biological samples, an immunoenzymatic assay was developed since currently available methods could not be used because of either their lack of sensitivity or the conditions prevailing in our samples: turbidity of the medium, presence of redox systems other than glucose oxidase, and high concentration of proteins. The principle of the method is to coat a polystyrene surface with a fragment Fc-specific anti-IgG, then with an antibody directed against the looked-for enzyme, which is simultaneously the antigen and the enzyme activity required for immunoenzymatic detection. We applied this concept to biological samples after glucose oxidase administration to mice.

Fatty acid acylation of RNase A using reversed micelles as microreactors.

A water soluble protein, RNAse A, was fatty-acylated using AOT reversed micelles in 2,2,4-trimethyl pentane as microreactors and myristoyl chloride as reagent. Artificial attachment of lipid molecules to this protein was performed for different hydration degrees by changing Wo = [water]/ [AOT], the parameter which controls the microreactor size. The chemically modified protein was monitored using reverse phase HPLC and characterized by HPLC, free amino groups titration, and electrophoresis.

Influence of barrier-crossing limitations on the amount of macromolecular drug taken up by its target.

Macromolecules (substitutive enzymes, polymeric prodrugs, immunotoxins, radiolabeled antibodies, or peptide hormones) are of interest in the treatment of several diseases. To reach the tissues, these macromolecular drugs have to cross the capillary wall, which represents an important transfer limitation. While pharmacokinetics usually studies the changes in drug concentration in different body compartments, analyzing the amount of drug gaining access to its target may be more relevant for assessing the efficiency of macromolecules than for low molecular mass drugs.

Chemically processed bovine heterografts of the second generation as arterial substitutes: a comparative evaluation of three commercial prostheses.

The use of chemically processed bovine heterografts is primarily confined to the construction of arterio-venous blood accesses in those patients requiring hemodialysis, plasmapheresis or chemotherapy. The grafts of the first generation i.e.

In vivo evaluation of polyester arterial grafts coated with albumin: the role and importance of cross-linking agents.

Previous in vitro studies have predicted that the type of chemical used to cross-link albumin-coated polyester arterial prostheses may influence the rate of bioerosion of the albumin layer in vivo. This study has confirmed that the healing process of this type of compound prosthesis does indeed depend on the nature and concentration of the cross-linking agent used. Four series of implantations in the thoracic aorta of dogs for scheduled periods for 4 h up to 6 months were conducted using 1.

Elimination of artifacts due to glutaraldehyde fixation in the histochemical detection of glucose oxidase with tetrazolium salts.

High background staining due to glutaraldehyde fixation prevents phenazine methosulphate and a tetrazolium salt being used to visualize glucose oxidase activity in tissue slices prepared from mice injected with the enzyme. Experiments in solution showed that products formed during the reaction between amino groups and glutaraldehyde are, at least in part, responsible for the non-enzymatic reduction of tetrazolium salts. Experiments performed with artificial membranes chemically akin to glutaraldehyde-fixed sections and prepared by cross-linking albumin by glutaraldehyde, showed that double bonds in amino-glutaraldehyde products are mainly responsible for the background staining development, whereas thiol groups play only a minor role.

Blood hemolysis by PTFE and polyurethane vascular prostheses in an in vitro circuit.

In order to improve understanding of the appearance of bright yellow stains in vivo (consecutive to the absorption of bilirubin) on a novel microporous, hydrophilic polyetherurethaneurea vascular prosthesis, the in vitro hemolytic activity of the material was compared with expanded polytetrafluoroethylene and silicone rubber. The results show that the tendency of the polyetherurethaneurea to produce free hemoglobin is low, so that the yellow staining observed is likely to be a result of the contact between the polymer and thrombi: Bilirubin is produced because of hemoglobin degradation in the thrombi rather than an active hemolysis on the surface of the prosthesis itself.

Effect of prosthetic sugar groups on the pharmacokinetics of glucose-oxidase.

The administration of enzymes is of potential therapeutic value in many disease states, e.g. lysosomal storage diseases, provided problems in the metabolism and targeting of large proteins can be overcome.