In vivo biodistribution, anti-inflammatory, and hepatoprotective effects of liver targeting dexamethasone acetate loaded nanostructured lipid carrier system.

We aimed to evaluate whether the enhancement of the liver accumulation and anti-inflammatory activity of dexamethasone acetate (DXMA) could be achieved by incorporating it into nanostructured lipid carrier (NLCs). DXMA-NLCs were prepared using a film dispersion-ultrasonication method and characterized in terms of particle size, PDI, zeta potential, differential scanning calorimetry, drug loading capacity, encapsulation efficiency, and in vitro release. The biodistribution and pharmacokinetics of DXMA-NLCs in mice were significantly different from those of the DXMA solution (DXMA-sol). The peak concentration of DXMA-NLCs was obtained half an hour after intravenous administration. More than 55.62% of the total administrated dose was present in the liver. An increase of 2.57 fold in the area under the curve was achieved when compared with that of DXMA-sol. DXMA-NLCs exhibited a significant anti-inflammatory and hepatoprotective effect on carrageenan-induced rats and carbon tetrachloride-induced mice compared with DXMA-sol. However, the effect was not in proportion to the dosage. The intermediate and low dosages presented better effects than DXMA-sol. All results indicate that NLCs, as a novel carrier for DXMA, has potential for the treatment of liver diseases, increasing the cure efficiency and decreasing the side effects on other tissues.

In vitro cytotoxicity, in vivo biodistribution and antitumor activity of HPMA copolymer-5-fluorouracil conjugates.

5-Fluorouracil (5-FU) is an antimetabolite with a broad-spectrum activity against solid tumors. However, its very short half-life in plasma circulation greatly limited the in vivo antitumor efficacy and clinical application. The current work aimed to solve this problem as well as to increase 5-FU biodistribution to tumor by covalently conjugating 5-FU to a biocompatible, non-toxic and non-immunogenic drug carrier -N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer. The in vitro cytotoxicity, in vivo biodistribution and therapeutic efficacy of HPMA copolymer-5-FU conjugates (P-FU) were reported. Cytotoxicity was evaluated by using a serial of tumor cells (A549, CT-26, Hela, HepG(2) cells and 5-FU resistant HepG(2) cells). In vivo biodistribution and therapeutic efficacy were investigated in Kunming mice-bearing hepatoma 22 (H(22)). Results indicated that P-FU could increase the cytotoxicity of 5-FU in Hela, HepG(2) and 5-FU resistant HepG(2) cells, while it decreases the cytotoxicity of 5-FU in A549 and CT-26. Both in vitro release profile in plasma and biodistribution study showed that P-FU significantly prolonged the drug plasma circulation time. P-FU also showed an over 3-fold larger area under the concentration-time curve (AUC) in tumor when compared with free drug. Therapeutic evaluation also demonstrated that the treatment with P-FU displayed stronger inhibition of the tumor growth when compared with that of control group (physiologic saline) or 5-FU group at the same dose. All the results suggested that P-FU could increase cytotoxicity of 5-FU in certain cancer cell lines, prolong 5-FU circulation time in vivo, enhance 5-FU distribution to tumor and improve therapeutic efficacy. Therefore, HPMA copolymer is a potential carrier for 5-FU for the effective treatment of cancer.

Lung-targeting delivery of dexamethasone acetate loaded solid lipid nanoparticles.

The objective of the present study was to develop a novel solid lipid nanoparticle (SLN) for the lung-targeting delivery of dexamethasone acetate (DXM) by intravenous administration. DXM loaded SLN colloidal suspensions were prepared by the high pressure homogenization method. The mean particle size, drug loading capacity and drug entrapment efficiency (EE%) of SLNs were investigated. In vitro drug release was also determined. The biodistribution and lung-targeting efficiency of DXM-SLNs and DXM-solutions (DXM-sol) in mice after intravenous administration were studied using reversed-phase high-performance liquid chromatography (HPLC). The results (expressed as mean +/- SD) showed that the DXM-SLNs had an average diameter of 552 +/- 6.5 nm with a drug loading capacity of 8.79 +/- 0.04% and an entrapment efficiency of 92.1 +/- 0.41%. The in vitro drug release profile showed that the initial burst release of DXM from DXM-SLNs was about 68% during the first 2 h, and then the remaining drug was released gradually over the following 48 hours. The biodistribution of DXM-SLNs in mice was significantly different from that of DXM-sol. The concentration of DXM in the lung reached a maximum level at 0.5 h post DXM-SLNs injection. A 17.8-fold larger area under the curve of DXM-SLNs was achieved compared to that of DXM-sol. These results indicate that SLN may be promising lung-targeting drug carrier for lipophilic drugs such as DXM.