Lipid-Based Gliclazide Nanoparticles for Treatment of Diabetes: Formulation, Pharmacokinetics, Pharmacodynamics and Subacute Toxicity Study.

INTRODUCTION: Solid lipid nanoparticles (SLNs) are considered a promising system in enhancing the oral bioavailability of poorly water-soluble drugs; owing to their intrinsic ability to increase the solubility together with protecting the incorporated drugs from extensive metabolism. OBJECTIVE: Exploiting such properties, SLNs loaded with gliclazide (GLZ) were developed in an attempt to improve the oral bioavailability and the anti-diabetic action of GLZ, together with prolonging its duration of action for better glycemic control. METHODS: SLNs were prepared by ultra-sonication technique using glyceryl behenate (Compritol®888 ATO) as a lipid matrix and poloxamer 188 (PLX) as a stabilizer. A 2*3 asymmetrical factorial design was adopted to study the effect of different stabilizer concentrations at different sonication times on the shape, and size of the particles, PDI and drug loading. The selected optimum formulation was then freeze dried using trehalose di-hydrate as a cryo-protectant in different ratios with respect to glyceryl behenate concentration. After freeze drying, the formulation was tested for in-vitro drug release, pharmacokinetics, and pharmacodynamics. Safety of the selected formula was established after carrying out a subacute toxicity study. RESULTS: The factorial design experiment resulted in an optimum formulation coded 10F2 (150 mg PLX/10 min sonication). Scanning electron micrographs showed spherical particles with smooth surface, whereas a ratio of 2:1 cryo-protectant:lipid was found to be optimum with particle size of 245.9 ± 26.2 nm, polydispersity index of 0.482 ± 0.026, and biphasic in-vitro release with an initial burst effect, followed by a prolonged release phase. On the other hand, the selected SLNs exhibited prolonged drug release when compared with the GLZ commercial immediate release (IR) tablets (Diamicron®). Pharmacokinetics study showed about 5-fold increase in GLZ oral bioavailability loaded in SLNs when compared with raw GLZ powder. Pharmacodynamics study on a diabetic rat model confirmed the better anti-diabetic action of GLZ loaded SLNs when compared to raw GLZ powder. Subacute toxicity study indicated the safety of SLNs upon repetitive oral administration.

Mucopenetrating nanoparticles for enhancement of oral bioavailability of furosemide: In vitro and in vivo evaluation/sub-acute toxicity study.

The aim of this study was to formulate and evaluate chitosan (CS)/alginate (ALG) nanoparticles (NPs) loaded with furosemide (FSM) in an attempt to enhance its release, permeability and bioavailability. Non-everted gut sac method was used to evaluate the ex vivo permeation of FSM from its suspension and the selected CS/ALG NPs formulation. The pharmacokinetic parameters of FSM subsequent to oral administration of the selected formulation were assessed in rats. In vivo subacute toxicity study of the prepared blank and FSM loaded formulations was evaluated in rats. The selected optimized formulation (F3) showed optimum particle size (PS), polydispersity index (PDI), zeta potential (ZP) and acceptable percentage entrapment efficiency (%EE) of 253.8nm±4.6, 0.25±0.03, -35mV±1 and 96%±1, respectively. The release profile of FSM from the selected formulation was characterized by initial burst effect in 0.1N HCl. Scanning electron microscope (SEM) demonstrated a smooth surface and spherical shape for the lyophilized optimized NPs. Selected CS/ALG NPs (F3) presented a significant enhancement (p≤0.01) in permeation parameters of FSM as well as in Tmax, Cmax, AUC0-24 and AUC0-∞. Subacute toxicity study results revealed that the selected formulation was safe and nontoxic. The histopathological inspection of the stomach and small intestine tissues of the loaded NPs (F3) and blank groups reflected no obvious signs of cellular toxicity or inflammatory reaction. CS/ALG NPs loaded with FSM enhanced both drug release and mucus-penetrating ability leading to an overall increase in FSM bioavailability. In addition, the in vivo subacute toxicity study results indicated the safety of the prepared NPs for oral drug delivery.