Springer Science and Business Media LLC

Purpose. To demonstrate the utilities of a synthetic low-affinity ligand ((Gal)3) for the asialoglycoprotein receptor (ASGP-R) as a hepatic targeting device for therapeutic cytokines. Methods. The site-specific incorporation of (Gal)3 or a typical high-affinity ligand (GalNAc)3 into IL-2 was catalyzed by microbial transglutaminase. The anti-tumor activities, pharmacokinetic profiles and receptor-mediated endocytosis in hepatocytes of the ligand-IL-2 conjugates were examined in mouse. Results. The (Gal)3 has approximately 50 times lower affinity to ASGP-R than (GalNAc)3. Nevertheless, the antitumor effects were in the order of (Gal)3—IL-2 > unmodified IL-2 > (GalNAc)3—IL-2. The systemic elimination and the hepatic uptake of (GalNAc)3—IL-2 were more rapid than (Gal)3—IL-2. The ratio of the rate constant representing dissociation from the cell-surface receptor (koff) to that representing endocytosis of the ligand (kint) was greater for (Gal)3—IL-2 than (GalNAc)3—IL-2, suggesting that (Gal)3—IL-2 preferably avoids internalization due to its lower affinity to the receptor. The simulation studies demonstrated that (Gal)3—IL-2 was present in the hepatic extracellular space for a longer period than (GalNAc)3 IL-2. Conclusions. The (Gal)3 ligand increases the therapeutic efficacy of IL-2 by enhancing its exposure to the cell-surface. The koff/kint affects the targeting efficacy of the conjugates to ASGP-R.

To determine the in vivo anti-tumor effect of aerosolized Celecoxib (Cxb) in combination with i.v Docetaxel (Doc) and compare the anti-tumor effect with oral Cxb combined with i.v Doc in human orthotopic non-small cell lung cancer (NSCLC) xenograft model. Female Nu/Nu mice were implanted with orthotopic tumors by injecting A549 cells into the lung parenchyma. Seven day after tumor implantation the mice were treated with aerosolized Cxb (30 min exposure/day, 5 mg/ml solution) + i.v Doc (10 mg/kg) and the effect was compared with oral Cxb (150 mg/kg/day) + i.v Doc (10 mg/kg), for 28 days. Small-animal nose only inhalation chamber (CH Technologies, Westwood, NJ) was utilized for aerosol exposure. Therapeutic activity of Cxb (aerosol/oral) + Doc was estimated by differences in lung weight, tumor area and animal body weight. Lung tumor samples isolated from mice were analyzed for (a) PGE2 levels by enzyme immunoassay (EIA) (b) expression of Fas and Factor VIII by immunohistochemistry (c) IL-8 expression using EIA kits and (d) mRNA expression for caspase-3 by Real-Time PCR. Mice treated with Cxb (aerosol/oral) + Doc showed significant reduction (P < 0.001) in lung weight and tumor area as compared to Cxb or Doc treatments. Cxb (aerosol/oral) + Doc showed increased apoptosis mediated via increased Fas and caspase-3 (P < 0.001) expression as compared to untreated control. Further, the combination treatment showed antiangiogenic effect as demonstrated by reduced expression of Factor VIII, IL-8 (P < 0.001) and PGE2 (P < 0.001) in lung tumors as compared to untreated control. Aerosolized Cxb at a significantly lower therapeutic dose (4.56 mg/kg/day) demonstrated comparable anti-tumor efficacy to orally administered Cxb (150 mg/kg/day). Cxb was formulated and effectively delivered via aerosolization to treat orthotopic lung tumors in combination with i.v Doc. Cxb when administered by aerosol produced same therapeutic effect as oral Cxb, but at lower therapeutic dose and thus shows promise for the treatment of lung cancer.

Protein therapeutics often require repeated administrations of drug over a long period of time. Protein instability is a major obstacle to the development of systems for their controlled and sustained release. We describe a surface modification of nanoporous silicon particles (NSP) with an agarose hydrogel matrix that enhances their ability to load and release proteins, influencing intracellular delivery and preserving molecular stability. We developed and characterized an agarose surface modification of NSP. Stability of the released protein after enzymatic treatment of loaded particles was evaluated with SDS-page and HPLC analysis. FITC-conjugated BSA was chosen as probe protein and intracellular delivery evaluated by fluorescence microscopy. We showed that agarose coating does not affect NSP protein release rate, while fewer digestion products were found in the released solution after all the enzymatic treatments. Confocal images show that the hydrogel coating improves intracellular delivery, specifically within the nucleus, without affecting the internalization process. This modification of porous silicon adds to its tunability, biocompatibility, and biodegradability the ability to preserve protein integrity during delivery without affecting release rates and internalization dynamics. Moreover, it may allow the silicon particles to function as protein carriers that enable control of cell function.

The pharmacokinetics of platinum was investigated in 10 cancer patients treated with a 1-hr infusion of 300 mg/m2 of carboplatin which was given 2–4 days after the administration of 100 mg/kg (20-mg/kg bolus and 80-mg/kg intravenous infusion) of methotrexate. Platinum was analyzed in the samples by flameless atomic absorption spectrophotometry. The concentration vs time data for total platinum in plasma followed a two-compartment model and the mean (and SE) values for β, TBC, V c, and RC were 0.0827 (0.22) hr−1, 2.355 (0.252) liters/hr · m2, 10.74 (0.62) liters/m2, and 2.405 (0.228) liters/hr · m2, respectively. There was no significant change in the creatinine clearance or TBC with repeated treatment. The ultrafilterable platinum which was measured in the plasma of two patients constituted 82 and 11.3% of the total platinum at 1 and 24 hr, respectively, and the data conformed to the one-compartment model. The mean (SE) values for t β, TBC, and V d for free platinum were 1.844 (0.208) hr, 4.583 (1.059) liters/hr · m2, and 11.88 (1.45) liters/m2, respectively. The above data are in good agreement with those reported earlier for platinum following the administration of carboplatin as a single agent. These results suggest that high-dose methotrexate therapy, when administered 2–4 days before carboplatin, does not affect the pharmacokinetics of platinum in the plasma.

To formulate a xanthan gum–containing linezolid ophthalmic solution (LZD-XG) as a new antibiotic treatment against ocular bacterial infection. LZD-XG was prepared and evaluated for its in vitro/in vivo ocular tolerance, in vitro/in vivo antibacterial activity, and in vivo ocular penetration. The optimized LZD-XG exhibited good in vitro/in vivo eye tolerance. A prolonged ocular surface residence time of LZD-XG was observed after topical instillation, and the ocular permeation was significantly better for LZD-XG than fora linezolid (LZD) ophthalmic solution. The in vitro antimicrobial activity was significantly better with LZD-XG than with LZD. In vivo evaluation also confirmed a strong therapeutic treatment effect of LZD-XG, as it significantly improved the clinical symptoms, ameliorated the damage of Staphylococcus aureus to ocular tissues, lowered the colony forming unit counts in the cornea, and decreased the myeloperoxidase activity in the cornea. LZD-XG was deemed a viable ophthalmic solution against ocular bacterial infection due to its excellent in vitro and in vivo characterizations.