Poly Isobutylcyanoacrylate Nanoparticles Research Articles

Applicability of dielectric measurements to the adsorption of drugs onto nanoparticles

Measurement of both the dielectric constant and permittivity of a suspension of polyisobutylcyanoacrylate nanoparticles prepared with increasing concentrations of betaxolol chlorhydrate, demonstrates that both methods allow the rapid determination of the adsorption isotherm plateau. These measurements could also provide interesting information about the effect of ageing on such suspensions.

Adsorption of hematoporphyrin onto polyalkylcyanoacrylate nanoparticles: carrier capacity and drug release

Experimental conditions for the formulation of hematoporphyrin loaded nanoparticles are presented. The adsorption was performed by incubation of unloaded nanoparticles with hematoporphyrin and was found to be dependent on the pH of the incubation medium. The maximum loading was achieved at pH 5.9 with a carrier capacity of about 30 μg HP/mg polyisobutylcyanoacrylate nanoparticles. The pH effect was correlated to the degree of ionization of hematoporphyrin. A rapid drug release from nanoparticles was, however, observed following dilution in phosphate buffer at pH 5.9 and was more important at pH 7.4. This fast release reflected an equilibrium shift between adsorbed drug and free drug. The addition of esterases to nanoparticles suspension modified this equilibrium by solubilization of the polymeric sites of drug adsorption and led to an increase in drug release. The potential of photosensitizer loaded nanoparticles in photodynamic therapy is briefly discussed.

Trypanocidal activity of free and carrier bound daunorubicin

Activities of a range of macromolecular conjugates of daunorubicin against Trypanosoma brucei rhodesiense in vitro and in vivo are described and compared to those of free daunorubicin. Conjugates tested were daunorubicin attached to bovine serum albumin by (i) a labile ‘glutaraldehyde’ linkage (D-BSAG), and (ii) a stable succinyl linkage (D-BSAS), daunorubicin covalently linked to agarose beads (D-AG), and daunorubicin adsorbed onto polyisobutyl-cyanoacrylate nanoparticles (D-PICA). Trypanocidal activity in vivo was retained in all except D-BSAS, whereas in vivo only D-BSAG had any activity. The results indicate that daunorubicin must be released from the conjugate before it can exert its activity.

Attachment of antibiotics to nanoparticles: preparation, drug-release and antimicrobial activity in vitro

Conditions for attachment of ampicillin and gentamicin to nanoparticles were studied. A freeze-dried formulation was also developed. The release rate of ampicillin from nanoparticles was studied both with and without esterases. For polyisobutyl-cyanoacrylate nanoparticles, the liberation of the drug was enhanced in esterase-rich medium. By contrast, drug release as a consequence of enzymatic degradation of the polymer was not observed with polyisohexylcyanoacrylate nanoparticles. Finally, the antimicrobial activities of both ampicillin and gentamicin remained unaltered upon linkage of these molecules to the nanoparticles.

The effect of macromolecular conjugates of daunorubicin on nuclear ultrastructure in [formula omitted

The effects of free and conjugated daunorubicin on T.b. rhodesiense in vitro are described. Free drug caused nucleolar lesions ranging from segregation to complete fragmentation. At equimolar concentrations a soluble bovine serum albumin conjugate with a stable succinyl linkage (D-BSAS) produced no ultrastructural lesions whereas a conjugate with a labile glutaraldehyde linkage (D-BSAG) and a conjugate linked to large agarose beads (D-ag) produced similar though less severe lesions than free drug. Polyisobutylcyanoacrylate nanoparticles caused trypanosomal lysis both with (D-PICA) and without adsorbed daunorubicin.

In Vivo Uptake of Polyisobutyl Cyanoacrylate Nanoparticles by Rat Liver Kupffer, Endothelial, andParenchymal Cells

Polyalkyl cyanoacrylate nanoparticles were previously developed as a biodegradable, ultrafine, solid drug carrier. Distribution studies in the rat showed an intense and rapid hepatic uptake. This liver accumulation appears to represent, to a certain extent, extracellularly bound nanoparticles. During liver perfusion, 15–20% of the liver-associated nanoparticles were washed out. The cellular distribution of strongly cell-associated nanoparticles was determined. At different intervals after injection of radioactive nanoparticles to rats, the cells were isolated according to a recently developed, low-temperature procedure during which processing of the carrier was inhibited. At all tested times, a relatively intense capture by Kupffer cells in comparison with endothelial and especially parenchymal cells was observed. This distribution pattern was not influenced by the size of the nanoparticles (0.08–0.215-μm diameter). This specific-interaction of nanoparticles with Kupffer cells opens possibilities for the treatment of some parasitic diseases involving this cell type.

Toxicity of Polyalkylcyanoacrylate Nanoparticles I: Free Nanoparticles

The present report describes preliminary results concerning the acute toxicity of placebo polyalkylcyanoacrylate nanoparticles used as drug carrier. It was demonstrated that nanoparticles induced cellular damage only at relatively high concentrations in the cell culture medium. The absence of mutagenicity was shown for both nanoparticles and their degradation products, and the LD50 for polybutyl- and polyisobutylcy-anoacrylate nanoparticles was also determined.

Toxicity of Polyalkylcyanoacrylate Nanoparticles II: Doxorubicin-Loaded Nanoparticles

The possibility of significantly reducing toxicity of an anticancer drug such as doxorubicin by fixing it on polyisobutylcyanoac-rylate nanoparticles was studied. It was shown that, when the drug was adsorbed on nanoparticles, significant reduction of both mortality and ' weight loss of mice were recorded under various administration schedules. Furthermore, cardiotoxicity was decreased due to the poor uptake by the myocardium.