Nanopesticide based on botanical insecticide pyrethrum and its potential effects on honeybees.

Nanotechnology has the potential to overcome the challenges of sustainable agriculture, and nanopesticides can control agricultural pests and increase farm productivity with little environmental impact. However, it is important to evaluate their toxicity on non-target organisms, such as honeybees (Apis mellifera) that forage on crops. The aims of this study were to develop a nanopesticide that was based on solid lipid nanoparticles (SLNs) loaded with pyrethrum extract (PYR) and evaluate its physicochemical properties and short-term toxicity on a non-target organism (honeybee). SLN + PYR was physicochemically stable after 120 days. SLN + PYR had a final diameter of 260.8 ± 3.7 nm and a polydispersion index of 0.15 ± 0.02 nm, in comparison with SLN alone that had a diameter of 406.7 ± 6.7 nm and a polydispersion index of 0.39 ± 0.12 nm. SLN + PYR had an encapsulation efficiency of 99%. The survival analysis of honeybees indicated that PYR10ng presented shorter longevity than those in the control group (P ≤ 0.01). Empty nanoparticles and PYR10ng caused morphological alterations in the bees' midguts, whereas pyrethrum-loaded nanoparticles had no significant effect on digestive cells, so are considered safer, at least in the short term, for honeybees. These results are important in understanding the effects of nanopesticides on beneficial insects and may decrease the environmental impacts of pesticides.

Effects of lidocaine and the inclusion complex with 2-hydroxypropyl-ß-cyclodextrin on cell viability and proliferation of oral squamous cell carcinoma.

OBJECTIVES: Squamous cell carcinoma (SCC) is a malignant disease that affects the oral cavity. Lidocaine has shown antiproliferative and cytotoxic activity on several cell types. The rapid dispersion is a limitation issue; however, the complexation in cyclodextrin improved pharmacological features and modified the drug release. This study investigated the effects of lidocaine (lido) complexed with 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD-lido) on cell viability and proliferation of human tongue squamous cell carcinoma SCC9 and SCC25. METHODS: The complex formation was confirmed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Cells SCC9 and SCC25 were exposed to lido and HP-ß-CD-lido (40-4000 µm), and the effects on cell viability (MTT) and antiproliferative activity (SRB) were tested. KEY FINDINGS: Differential scanning calorimetry and SEM results demonstrated the occurrence of host-guest interaction. Lido and HP-ß-CD-lido (4000 µm) significantly reduced the viability of SCC9 cells to 83% and 63%, respectively. The viability of SCC25 treated with lido, and HP-ß-CD-lido (4000 µm) was 71% and 44%, respectively. Lido (4000 µm) reduced the proliferation of SCC9 and SCC25 to 39.5% and 23.7%, respectively. HP-ß-CD-lido (4000 µm) was cytotoxic for both cell lines. CONCLUSIONS: HP-ß-CD was able to potentiate the in vitro cytotoxic effects of lidocaine on human squamous cell carcinoma.

Exogenous administration of 15d-PGJ2-loaded nanocapsules inhibits bone resorption in a mouse periodontitis model.

The 15-deoxy-(Δ12,14)-PG J(2) (15d-PGJ(2)) has demonstrated excellent anti-inflammatory results in different experimental models. It can be used with a polymeric nanostructure system for modified drug release, which can change the therapeutic properties of the active principle, leading to increased stability and slower/prolonged release. The aim of the current study was to test a nanotechnological formulation as a carrier for 15d-PGJ(2), and to investigate the immunomodulatory effects of this formulation in a mouse periodontitis model. Poly (D,L-lactide-coglycolide) nanocapsules (NC) were used to encapsulate 15d-PGJ(2). BALB/c mice were infected on days 0, 2, and 4 with Aggregatibacter actinomycetemcomitans and divided into groups (n = 5) that were treated daily during 15 d with 1, 3, or 10 µg/kg 15d-PGJ(2)-NC. The animals were sacrificed, the submandibular lymph nodes were removed for FACS analysis, and the jaws were analyzed for bone resorption by morphometry. Immunoinflammatory markers in the gingival tissue were analyzed by reverse transcriptase-quantitative PCR, Western blotting, or ELISA. Infected animals treated with the 15d-PGJ(2)-NC presented lower bone resorption than infected animals without treatment (p < 0.05). Furthermore, infected animals treated with 10 µg/kg 15d-PGJ(2)-NC had a reduction of CD4(+)CD25(+)FOXP3(+) cells and CD4/CD8 ratio in the submandibular lymph node (p < 0.05). Moreover, CD55 was upregulated, whereas RANKL was downregulated in the gingival tissue of the 10 µg/kg treated group (p < 0.05). Several proinflammatory cytokines were decreased in the group treated with 10 µg/kg 15d-PGJ(2)-NC, and high amounts of 15d-PGJ(2) were observed in the gingiva. In conclusion, the 15d-PGJ(2)-NC formulation presented immunomodulatory effects, decreasing bone resorption and inflammatory responses in a periodontitis mouse model.

15d-PGJ2-loaded in nanocapsules enhance the antinociceptive properties into rat temporomandibular hypernociception.

AIMS: To verify whether the nanoencapsulation of 15d-PGJ(2) in poly(D,L-lactide-co-glycolide) (PLGA) nanocapsules (15d-PGJ(2)-NC) might potentialize its antinociceptive activity into rats' temporomandibular joint (TMJ). MAIN METHODS: Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to evaluate the morphology and suspension of the PLGA nanocapsules. Rats were pretreated (15 min) with an intra-TMJ injection of unloaded 15d-PGJ(2) or 15d-PGJ(2)-NC at concentrations of 10, 100 or 1000 pg followed by an ipsilateral intra-TMJ injection of 1.5% formalin. The nociceptive behavioral response was observed during 45 min; animals were then sacrificed and the periarticular tissue was removed for IL-1ß measurements. KEY FINDING: TEM and AFM analyses showed that 15d-PGJ(2)-NC is spherical without any aggregates or adhesion confirming that this formulation is a good drug carrier system for 15d-PGJ(2). Pretreatment with 15d-PGJ(2)-NC (100 and 1000 pg/TMJ), but not unloaded 15d-PGJ(2), was found to significantly decrease the release of IL-1ß cytokine and the animals' nociceptive behavioral response induced by intra-TMJ injection of formalin. SIGNIFICANCE: The compound 15d-PGJ(2)-NC might be used as a potential antinociceptive and anti-inflammatory agent to treat temporomandibular disorders in clinical practice.

Screening of formulation variables for the preparation of poly(epsilon-caprolactone) nanocapsules containing the local anesthetic benzocaine.

In this work we describe the screening of four parameters in the preparation, by nanoprecipitation, of poly(epsilon-caprolactone) nanocapsules, used as a drug carrier system for the local anesthetic, benzocaine. A 2(4-1) factorial experimental design was used to study the influence of four different independent variables (polymer, oily phase, Span 60 and Tween 80) on nanocapsule characteristics (size, polydispersion index, zeta potential) and drug loading capability. Best results were obtained using an aqueous formulation comprising 100 mg of polymer, 200 mg of oily phase, 40 mg of Span 60 and 60 mg of Tween 80 in a final volume of 10 mL which produced a colloidal system with particle size of 188 nm, zeta potential -32 mV, polydispersion index 0.07, and benzocaine association efficiency > 87%. These findings open the way for future clinical studies using such formulations.

Polymeric alginate nanoparticles containing the local anesthetic bupivacaine.

Bupivacaine (BVC; S75­R25, NovaBupi® is an amide-type local anesthetic. Sodium alginate is a water-soluble linear polysaccharide. The present study reports the development of alginate/bis(2-ethylhexyl) sulfosuccinate (AOT) and alginate/chitosan nanoparticle formulations containing BVC (0.5%). The amounts of BVC associated in the alginate/AOT and alginate/chitosan nanoparticles were 87 ± 1.5 and 76 ± 0.9%, respectively. The average diameters and zeta potentials of the nanoparticles were measured for 30 days, and the results demonstrated the good stability of these particles in solution. The in vitro release kinetics showed a different behavior for the release profile of BVC in solution, compared with BVC-loaded alginate nanoparticles. In vitro and in vivo assays showed that alginate­chitosan BVC (BVC(ALG­CHIT)) and alginate­AOT BVC (BVC(ALG­AOT)) presented low cytotoxicity in 3T3-fibroblasts, enhanced the intensity, and prolonged the duration of motor and sensory blockades in a sciatic nerve blockade model.

Interaction between nitroheterocyclic compounds with beta-cyclodextrins: phase solubility and HPLC studies.

Chagas disease is a serious health problem for Latin America. Nitrofurazone (NF) and Hidroxymethylnitrofurazone (NFOH) are active against Trypanosoma cruzi. The effect of beta-cyclodextrin (beta-CD) and dimethyl-beta-cyclodextrin (DM-beta-CD) complexation on the UV absorption and retention time of nitrofurazone (NF) and its hydroxymethylated analog (NFOH) were studied in solution. The retention behavior was analyzed on a reversed phase C18 column and the mobile phase used was acetonitrile-water (20/80 v/v), in which cyclodextrins (beta-CD or DM-beta-CD) were incorporated as a mobile phase additive. The decrease in the retention times of NF (or NFOH) with increasing concentration of HP-beta-CD enables the determination of the complex stability constants by HPLC. A phase-solubility study was performed, according to the method reported by Higuchi and Connors, to evaluate the changes of NF/NFOH in the complexation state, and the diagrams obtained suggested that it forms complexes with a stoichiometry of 1:1. This is an important study for the characterization of potential formulations to be used as therapeutic options for the treatment of Chagas disease.

Study of the interaction between hydroxymethylnitrofurazone and 2-hydroxypropyl-beta-cyclodextrin.

Chagas disease is a serious health problem in Latin America. Hidroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug more active than nitrofurazone against Trypanosoma cruzi. However, NFOH presents low aqueous solubility, high photodecomposition and high toxicity. The present work is focused on the characterization of an inclusion complex of NFOH in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The complexation with HP-beta-CD was investigated using reversed-phase liquid chromatography, solubility isotherms and nuclear magnetic resonance. The retention behavior was analyzed on a reversed-phase C(18) column, using acetonitrile-water (20/80, v/v) as the mobile phase, in which HP-beta-CD was incorporated as a mobile phase additive. The decrease in the retention times with increasing concentrations of HP-beta-CD enables the determination of the apparent stability constant of the complex (K=6.2+/-0.3M(-1)) by HPLC. The solubility isotherm was studied and the value for the apparent stability constant (K=7.9+/-0.2M(-1)) was calculated. The application of continuous variation method indicated the presence of a complex with 1:1 NFOH:HP-beta-CD stoichiometry. The photostability study showed that the formation of an inclusion complex had a destabilizing effect on the photodecomposition of NFOH when compared to that of the "free" molecule in solution. The mobility investigation (by NMR longitudinal relaxation time) gives information about the complexation of NFOH with HP-beta-CD. In preliminary toxicity studies, cell viability tests revealed that inclusion complexes were able to decrease the toxic effect (p<0.01) caused by NFOH.