Oral delivery of camptothecin using cyclodextrin/poly(anhydride) nanoparticles

Camptothecin (CPT), a molecule that shows powerful anticancer activity, is still not used in clinic due to its high hydrophobicity and poor active form's stability. In order to solve these drawbacks, the combination between poly(anhydride) nanoparticles and cyclodextrins was evaluated. CPT-loaded nanoparticles, prepared in the presence of 2-hydroxypropyl-β-cyclodextrin, (HPCD-NP) displayed a mean size close to 170nm and a payload of 50μg per mg (25 times higher than the one of the control nanoparticles). CPT was not released from nanoparticles under gastric conditions. However, under intestinal conditions, about 50% of the drug content was released as a burst, whereas the remained drug was released following a zero-order kinetic. Pharmacokinetic studies revealed that the CPT plasma levels, from orally administered nanoparticles, were high and sustained up to 48h. The CPT oral bioavailability was 7-fold higher than the value obtained with the control, whereas its clearance was significantly lower than for the aqueous suspension. These observations may be directly related to a prolonged residence time of nanoparticles in close contact with the intestinal epithelium, the presence of the cyclodextrin that decreases the CPT transformation into its inactive form and the generation of an acidic microenvironment during the degradation of the poly(anhydride) that would prevent the transformation of the active lactone into the inactive carboxylate conformation

In vitro reversion of amphotericin B resistance in Leishmania donovani by poloxamer 188

A micellar formulation of amphotericin B (AmB) solubilized with poloxamer 188 was evaluated against an AmB Leishmania donovani-resistant line. A concave isobologram showed a synergistic effect of this association against promastigotes. This result was confirmed with amastigotes since the 50% effective concentration of the new formulation was 100 times less than that of the control AmB formulation

Bioadhesive properties of Gantrez nanoparticles

Bioadhesive nanoparticles have been proposed as carriers for the oral delivery of poorly available drugs and facilitate the use of this route. This work summarises some experiments describing the bioadhesive potential of Gantrez nanoparticles fluorescently labeled with rhodamine B isothiocyanate. The adhesive potential of Gantrez was found to be stronger when folded as nanoparticles than in the solubilised form. Conventional nanoparticles displayed a tropism for the upper areas of the gastrointestinal tract, with a maximum of adhesion 30 min post-administration and a decrease in the adhered fraction along the time depending on the given dose. The cross-linkage of nanoparticles with increasing amounts of 1,3-diaminopropane stabilised the resulting carriers and prolonged their half-life in an aqueous environment; although, the adhesive capacity of nanoparticles, the intensity and the relative duration of the adhesive interactions within the gut as a function of the cross-linking degree. Finally, nanoparticles were coated with either gelatin or albumin. In the first case, the presence of gelatin dramatically decreased the initial capacity of these carriers to interact with the gut mucosa and the intensity of these phenomenons. In the latter, bovine serum albumin coated nanoparticles (BSA-NP) showed an important tropism for the stomach mucosa without further significant distribution to other parts of the gut mucosa

Co-encapsulation of an antigen and CpG oligonucleotides into PLGA microparticles by TROMS technology.

It seems well established that CpG oligonucleotides Th1 biased adjuvant activity can be improved when closely associated with a variety of antigens in, for example, microparticles. In this context, we prepared 1-μm near non-charged PLGA 502 or PLGA 756 microparticles that loaded with high efficiency an antigen (50% ovalbumin (OVA), approximately) into their matrix and CpG-chitosan complexes (near to 20%) onto their surface maintaining OVA and CpG integrity intact. In the intradermal immunization studies, whereas OVA microencapsulated into PLGA 756 alone induced a strong humoral immune response assisted by a very clear Th1 bias (IgG2a/IgG1=0.875) that was decreased by CpG co-delivery (IgG2a/IgG1=0.55), the co-encapsulation of CpG with OVA in PLGA 502 particles significantly improved the antibody response and isotype shifting (IgG2a/IgG1=0.73) in comparison with mice immunized with OVA loaded PLGA 502 (IgG2a/IgG1=0). This improvement was not correlated with the cellular immune response where the effect of co-encapsulated CpG was rather negative (2030.2 pg/mL and 335.3 pg/mL IFN-g for OVA PLGA 502 for OVA CpG PLGA 502, respectively). These results underscore the critical role of polymer nature and microparticle characteristics to show the benefits of coencapsulating CpG motifs in close proximity with an antigen

Nanoparticles from Gantrez® AN-poly(ethylene glycol) conjugates as carriers for oral delivery of docetaxel

The oral delivery of docetaxel (DTX) is challenging due to a low bioavailability, related to an important pre-systemic metabolism. With the aim of improving the bioavailability of this cytotoxic agent, nanoparticles from conjugates based on the copolymer of methyl vinyl ether and maleic anhydride (poly(anhydride)) and two different types of PEG, PEG2000 (PEG2) or methoxyPEG2000 (mPEG2), were evaluated. Nanoparticles, with a DTX loading close to 10%, were prepared by desolvation and stabilized with calcium, before purification and lyophilization. For the pharmacokinetic study, nanoparticles were orally administered to mice at a single dose of 30 mg/kg. The plasma levels of DTX were high, prolonged in time and, importantly, quantified within the therapeutic window. The relative oral bioavailability was calculated to be up to 56% when DTX was loaded in nanoparticles from poly(anhydride)-mPEG2000 conjugate (DTX-NP-mPEG2). Finally, a comparative toxicity study between equitoxic doses of free iv DTX and oral DTX-NP-mPEG2 was conducted in mice. Animals orally treated with DTX-loaded nanoparticles displayed less severe signs of hypersensitivity reactions, peripheral neurotoxicity, myelosuppression and hepatotoxicity than free iv docetaxel. In summary, poly(anhydride)-PEG conjugate nanoparticles appears to be adequate carries for the oral delivery of docetaxel

Co-encapsulated CpG oligodeoxynucleotides and ovalbumin in PLGA microparticles; an in vitro and in vivo study

Purpose: The objective of this work was to evaluate the effect in the immune response produced by CpG oligodeoxynucleotides (ODN) co-encapsulated with the antigen ovalbumin (OVA) within poly(lactic-co-glycolic) acid (PLGA) 502 and 752 microparticles (MP). Methods: MP were prepared by blending 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) with PLGA and Total Recirculation One Machine System (TROMS) technology and contained OVA along with CpG sequences associated to DOTAP. After confirming the integrity of both encapsulated molecules, BALB/c mice were immunized with the resulting MP and OVA-specific antibodies and cytokine production were assessed in order to determine the immunological profile induced in mice. Results: One m near non-charged MP co-encapsulated very efficiently both OVA and CpG ODN. The release of both OVA and CpG was slow and incomplete irrespective of polymer. The results of the immune response induced in BALB/c mice indicated that, depending on the PLGA polymer used, co-encapsulation did not improve the immunogenicity of the antigen, compared either with the simply co-administration of both antigen and CpG, or with the microencapsulated antigen. Thus, mice immunized with OVA associated to PLGA 756 displayed an IgG2a characterized response which was biased to an IgG1 profile in case of CpG co-encapsulation. On the contrary, the co-encapsulation of CpG with OVA into PLGA 502 significantly improved the isotype shifting in comparison with the one showed by mice immunized with OVA loaded PLGA 502. Conclusion: This study underlines the importance of MP characteristics to fully exploit simultaneous antigen and CpG ODN particulate delivery as effective vaccine construct

Nanoparticles from Gantrez-based conjugates for the oral delivery of camptothecin

Camptothecin (CPT) exhibits a number of challenges for its oral administration, including a low aqueous solu-bility, a lactone ring susceptible to hydrolysis, and an affinity to the intestinal P-gp. The aim of this work was to evaluate nanoparticles from Gantrez-based conjugates as carriers for the oral delivery of CPT. For this purpose two different conjugates (G-mPEG and G-HPCD), obtained by the covalent binding of either HP-beta-CD or methoxy-PEG (m-PEG) to the polymer backbone of GantrezTM AN, were synthetized and characterized. Both excipients (m -PEG and HPCD) were selected due to their reported abilities to stabilize the lactone ring of CPT and disturb the effect of intestinal P-gp. The resulting nanoparticles (G-mPEG-NP and G-HPCD-NP) presented a similar size (about 200 nm) and zeta potential (close to-35 mV); although, G-mPEG-NP presented a higher CPT payload than G-HPCD-NP. On the contrary, in rats, nanoparticles based on Gantrez conjugates appeared to be capable of crossing the protective mucus layer and reach the intestinal epithelium, whereas conventional Gantrez nano-particles displayed a mucoadhesive profile. Finally, the pharmacokinetic study revealed that both formulations were able to enhance the relative oral bioavailability of CPT; although this value was found to be 2.6-times higher for G-mPEG-NP than for G-HPCD-NP

Selenium Derivatives as Promising Therapy for Chagas Disease: In Vitro and In Vivo Studies

This work was financially supported by the Ministerio de Economia, Industria y Competitividad (CONSOLIDER CSD2010-00065 and CTQ2017-90852-REDC). R.M.-E. is grateful for the fellowship from the Alfonso Martin Escudero Foundation.Chagas disease is a tropical infection caused by the protozoan parasite Trypanosoma cruzi and a global public health concern. It is a paradigmatic example of a chronic disease without an effective treatment. Current treatments targeting T. cruzi are limited to two obsolete nitroheterocyclic drugs, benznidazole and nifurtimox, which lead to serious drawbacks. Hence, new, more effective, safer, and affordable drugs are urgently needed. Selenium and their derivatives have emerged as an interesting strategy for the treatment of different prozotoan diseases, such as African trypanosomiasis, leishmaniasis, and malaria. In the case of Chagas disease, diverse selenium scaffolds have been reported with antichagasic activity in vitro and in vivo. On the basis of these premises, we describe the in vitro and in vivo trypanocidal activity of 41 selenocompounds against the three morphological forms of different T. cruzi strains. For the most active selenocompounds, their effect on the metabolic and mitochondrial levels and superoxide dismutase enzyme inhibition capacity were measured in order to determine the possible mechanism of action. Derivative 26, with a selenocyanate motif, fulfills the most stringent in vitro requirements for potential antichagasic agents and exhibits a better profile than benznidazole in vivo. This finding provides a step forward for the development of a new antichagasic agent.Spanish Government CONSOLIDER CSD2010-00065 CTQ2017-90852-REDCAlfonso Martin Escudero Foundatio

Polymeric carriers for amphotericin B: in vitro activity, toxicity and therapeutic efficacy against systemic candidiasis in neutropenic mice

Objective: To study the toxicity and activity of two new amphotericin B formulations: poly(ε-caprolactone) nanospheres coated with poloxamer 188 (AmB-NP) and mixed micelles with the same surfactant (AmB-MM). Materials and methods: The toxicity of these formulations was evaluated in erythrocytes, J774.2 macrophages and LLCPK1 renal cells, as well as in mice. Activity was determined in clinical isolates and in neutropenic mice. Mice were made neutropenic with 5-fluorouracil, infected with Candida albicans and treated with the antifungal formulations for three consecutive days. AmB association in cells and accumulation in kidneys and liver of animals was quantified by HPLC. Results: Both formulations decreased between 8- and 10-fold the MIC of the polyene against clinical isolates of C. albicans. However, their activity was lower than or equal to that of AmB-deoxycholate when it was assessed against C. albicans-infected macrophages. When given as a single intravenous dose in mice, AmB-MM and AmB-NP had an LD50 of 9.8 and 18.6 mg/kg, respectively, compared with 4 mg/kg for AmBdeoxycholate. Comparison of residual infection burdens in the liver and kidneys showed that AmB-deoxycholate (0.5 mg/kg) was more effective and faster in eradicating yeast cells than polymeric formulations. This fact can be related to a lower AmB accumulation inside macrophages and in liver and kidneys (about 1.5 mg drug/g tissue) of mice, compared with those detected for AmB-deoxycholate (4 mg drug/g). Overall, the efficacy of these formulations at 2 mg/kg was equal to that of AmB-deoxycholate at 0.5 mg/kg. Conclusions: AmB-MM and AmB-NP decreased the in vivo antifungal activity of AmB, and higher concentrations were therefore necessary to obtain a similar therapeutic effect. However, these higher concentrations were achievable owing to the reduced toxicity of these formulations

Pharmacokinetics and antitumor efficacy of paclitaxel-cyclodextrin complexes loaded in mucus-penetrating nanoparticles for oral administration

The authors report a novel approach for enhancing the oral absorption of paclitaxel (PTX) by encapsulation in poly(anhydride) nanoparticles (NPs) containing cyclodextrins and poly(ethylene glycol). Materials & methods: Formulations were prepared using the solvent displacement method. Subsequently, pharmacokinetics and organ distribution assays were evaluated after oral administration into C57BL/6J mice. In addition, antitumor efficacy studies were performed in a subcutaneous tumor model of Lewis lung carcinoma. Results: PTX-loaded NPs displayed sizes between 190–300 nm. Oral NPs achieved drug plasma levels for at least 24 h, with an oral bioavailability of 55–80%. Organ distribution studies revealed that PTX, orally administered in NPs, underwent a similar distribution to intravenous Taxol® (Bristol-Myers-Squibb, NJ, USA). For in vivo antitumor assays, oral strategy maintained a slower tumor growth than intravenous Taxol. Conclusion: PTX orally administered in poly(anhydride) NPs, combined with cyclodextrins and poly(ethylene glycol), displayed sustained plasma levels and significant antitumor effect in a syngenic tumor model of carcinoma in mice