Preparation, characterization of hydrophilic and hydrophobic drug in combine loaded chitosan/cyclodextrin nanoparticles and in vitro release study

Bromocriptine loaded chitosan nanoparticles intended for direct nose to brain delivery: pharmacodynamic, pharmacokinetic and scintigraphy study in mice model

The primary aim of this study was to investigate the potential use of chitosan nanoparticles as a delivery system to enhance the brain targeting efficiency of bromocriptine (BRC) following intranasal (i.n.) administration. The BRC loaded chitosan nanoparticles (CS NPs) were prepared by ionic gelation of CS with tripolyphosphate anions. These NPs had a mean size (161.3 ± 4. 7 nm), zeta potential (+40.3 ± 2.7 mV), loading capacity (37.8% ± 1.8%) and entrapment efficiency (84.2% ± 3.5%). The oral administration of haloperidol (2mg/kg) to mice produced typical Parkinson (PD) symptoms. Catalepsy and akinesia outcomes in animals receiving BRC either in solution or within CS NPs showed a reversal in catalepsy and akinesia behavior when compared to haloperidol treated mice, this reversal being specially pronounced in mice receiving BRC loaded CS NPs. Biodistribution of BRC formulations in the brain and blood of mice following i.n. and intravenous (i.v.) administration was performed using optimized technetium labeled (99mTc-labeled) BRC formulations. The brain/blood ratio of 0.47 ± 0.04, 0.69 ± 0.031, and 0.05 ± 0.01 for BRC solution (i.n.), BRC loaded CS NPs (i.n.) and (i.v.) respectively, at 0.5h are suggestive of direct nose to brain transport bypassing the blood-brain barrier. Gamma scintigraphy imaging of mice brain following i.v. and i.n. administrations were performed to determine the localization of drug in brain. The drug targeting index and direct transport percentage for BRC loaded CS NPs following i.n. route were 6.3 ± 0.8 and 84.2% ± 1.9%. These encouraging results confirmed the development of a novel non-invasive nose to brain delivery system of BRC for the treatment of PD.

Preparation and evaluation of warfarin-β-cyclodextrin loaded chitosan nanoparticles for transdermal delivery

The main objective of the present work was to prepare warfarin-β-cyclodextrin (WAF-β-CD) loaded chitosan (CS) nanoparticles for transdermal delivery. CS is a hydrophilic carrier therefore, to overcome the hydrophobic nature of WAF and allow its incorporation into CS nanoparticles, WAF was first complexed with β-cyclodextrin (β-CD). CS nanoparticles were prepared by ionotropic pre-gelation using tripolyphosphate (TPP). Morphology, size and structure characterization of nanoparticles were carried out using SEM, TEM and FTIR, respectively. Nanoparticles prepared with 3:1 CS:TPP weight ratio and 2mg/ml final CS concentration were found optimum. They possessed spherical particles (35±12nm diameter) with narrow size distribution (PDI=0.364) and 94% entrapment efficiency. The in vitro release as well as the ex vivo permeation profiles of WAF-β-CD from the selected nanoparticle formulation were studied at different time intervals up to 8h. In vitro release of WAF-β-CD from CS nanoparticles followed a Higuchi release profile whereas its ex vivo permeation (at pH 7.4) followed a zero order permeation profile. Results suggested that the developed WAF-β-CD loaded CS carrier could offer a controlled and constant delivery of WAF transdermally.

Is dialysis a reliable method for studying drug release from nanoparticulate systems?-A case study

The kinetics of in vitro drug release from nanoparticulate systems is extensive, though uncritically, being studied by dialysis. Evaluating the actual relevance of dialysis data to drug release was the purpose of this study. Diclofenac- or ofloxacin-loaded chitosan nanoparticles crosslinked with tripolyphosphate were prepared and characterized. With each drug, dynamic dialysis was applied to nanoparticle dispersion, solution containing dissolved chitosan·HCl, and solution of plain drug. Drug kinetics in receiving phase (KRP), nanoparticle matrix (KNM) and nanoparticle dispersion medium (KDM) were determined. Release of each drug from nanoparticles was also assessed by ultracentrifugation. Although KRP data may be interpreted in terms of sustained release from nanoparticles, KNM and KDM data show that, with both drugs, the process was in fact controlled by permeation across dialysis membrane. Analysis of KRP data reveals a reversible interaction of diclofenac with dispersed nanoparticle surface, similar to the interaction of this drug with dissolved chitosan·HCl. No such interactions are noticed with ofloxacin. The results from the ultracentrifugation method agree with the above interpretation of dialysis data. This case study shows that dialysis data from a nanoparticle dispersion is not necessarily descriptive of sustained-release from nanoparticles, hence, if interpreted uncritically, it may be misleading.

Delivering hydrophilic and hydrophobic chemotherapeutics simultaneously by magnetic mesoporous silica nanoparticles to inhibit cancer cells

Using nanoparticles to deliver chemotherapeutics offers new opportunities for cancer therapy, but challenges still remain when they are used for the delivery of multiple drugs, especially for the synchronous delivery of hydrophilic and hydrophobic drugs in combination therapies. In this paper, we developed an approach to deliver hydrophilic-hydrophobic anticancer drug pairs by employing magnetic mesoporous silica nanoparticles (MMSNs). We prepared 50 nm-sized MMSNs with uniform pore size and evaluated their capability for the loading of two combinations of chemotherapeutics, namely doxorubicin-paclitaxel and doxorubicin-rapamycin, by means of sequential adsorption from the aqueous solution of doxorubicin and nonaqueous solutions of paclitaxel or rapamycin. Experimental results showed that the present strategy successfully realized the co-loading of hydrophilic and hydrophobic drugs with high-loading content and widely tunable ratio range. We elaborate on the theory behind the molecular interaction between the silica hydroxyl groups and drug molecules, which underlie the controllable loading, and the subsequent release of the drug pairs. Then we demonstrate that the multidrug-loaded MMSNs could be easily internalized by A549 human pulmonary adenocarcinoma cells, and produce enhanced tumor cell apoptosis and growth inhibition as compared to single-drug loaded MMSNs. Our study thus realized simultaneous and dose-tunable delivery of hydrophilic and hydrophobic drugs, which were endowed with improved anticancer efficacy. This strategy could be readily extended to other chemotherapeutic combinations and might have clinically translatable significance.