Chemical and mechanical modulation of polymeric micelle assembly.

Recently, polymeric micelles self-assembled from amphiphilic polymers have been studied for various industrial and biomedical applications. This nanoparticle self-assembly typically occurs in a solvent-exchange process. In this process, the quality of the resulting particles is uncontrollably mediated by polymeric solubility and mixing conditions. Here, we hypothesized that improving the solubility of an amphiphilic polymer in an organic solvent via chemical modification while controlling the mixing rate of organic and aqueous phases would enhance control over particle morphology and size. We examined this hypothesis by synthesizing a poly(2-hydroxyethyl)aspartamide (PHEA) grafted with controlled numbers of octadecyl (C18) chains and oligovaline groups (termed "oligovaline-PHEA-C18"). The mixing rate of DMF and water was controlled either by microfluidic mixing of laminar DMF and water flows or through turbulent bulk mixing. Interestingly, oligovaline-PHEA-C18 exhibited an increased solubility in DMF compared with PHEA-C18, as demonstrated by an increase of mixing energy. In addition, increasing the mixing rate between water and DMF using the microfluidic mixer resulted in a decrease of the diameter of the resulting polymeric micelles, as compared with the particles formed from a bulk mixing process. Overall, these findings will expand the parameter space available to control particle self-assembly while also serving to improve existing nanoparticle processing techniques.

Thin Films of Highly Planar Semiconductor Polymers Exhibiting Band-like Transport at Room Temperature.

We report the observation of band-like transport from printed polymer thin films at room temperature. This was achieved from donor-acceptor type thiophene-thiazole copolymer that was carefully designed to enhance the planarity of the backbone and the resulting transfer integral between the macromolecules. Due to the strong molecular interaction, the printed polymer film exhibited extremely low trap density comparable to that of molecular single crystals. Moreover, the energy barrier height for charge transport could be readily reduced with the aid of electric field, which led formation of extended electron states for band-like charge transport at room temperature.

A multicenter phase II study of gemcitabine and S-1 combination chemotherapy in patients with unresectable pancreatic cancer.

PURPOSE: To confirm the efficacy and toxicity of gemcitabine and S-1 combination chemotherapy when used as a first-line therapy in patients with unresectable pancreatic cancer. METHODS: Patients with locally advanced or metastatic or recurrent pancreatic adenocarcinoma, which was histologically or cytologically proven, with at least one measurable lesion were eligible for the study. Gemcitabine at a dose of 1,000 mg/m2 was intravenously given over 30 min on days 1 and 8, while S-1 at a dose of 40 mg/m2 was orally given twice daily from day 1 to 14, and the cycle was repeated every 3 weeks. The objective response rate, which was assessed according to RECIST criteria, was the primary end point. RESULTS: A total of 38 patients were enrolled between June 2006 and June 2007. The median number of treatment courses was 5.5 (range 1-22). Thirty-four patients were evaluable for response. Although no complete response was seen, partial responses were achieved in 11 patients, resulting in an overall response rate of 32% [95% confidence interval (CI) 17-48%]. The median response duration was 6.0 months (95% CI 4.6-8.3 months), the median time-to-progression was 5.4 months (95% CI 2.9-8.0 months), and the median overall survival was 8.4 months (95% CI 5.7-11.1 months). The major grade 3/4 hematologic toxicities were neutropenia (39.5%), leukopenia (15.8%), thrombocytopenia (2.6%), and anemia (7.9%). The major grade 3/4 non-hematologic toxicities included anorexia (10.5%), stomatitis (2.6%), rash (7.9%), fatigue (7.9%) and hyperbilirubinemia (5.3%). CONCLUSIONS: Gemcitabine and S-1 combination chemotherapy was effective and tolerable in patients with unresectable pancreatic cancer.

A multi-center phase II study of S-1 plus paclitaxel as first-line therapy for patients with advanced or recurrent unresectable gastric cancer.

PURPOSE: This study was conducted to evaluate the safety and efficacy of S-1 and paclitaxel combination therapy for patients with advanced gastric cancer. METHODS: Eligible patients had previously untreated advanced or relapsed gastric cancer with measurable lesion(s) and an ECOG PS of 0-2. Treatment consisted of S-1 35 mg/m(2) p.o. b.i.d. on days 1-14 followed by a 7-day off plus paclitaxel 70 mg/m(2) i.v. on days 1 and 8 of a 21-day cycle. RESULTS: Fifty-six patients (M/F = 37/19) were enrolled. The median age was 59 years. The median number of cycles administered was six (range 1-18). Out of the 53 patients evaluated, there was 1 (1.9%) CR, 20 (37.7%) confirmed PRs, 5 (9.4%) unconfirmed PRs, 21 (39.6%) SDs, and 6 (11.3%) PDs. The objective tumor response was 39.6%. The median time to progression was 29 weeks. The median survival was 51 weeks. All 56 patients were assessed for treatment safety. The treatment was well tolerated with grade 3/4 neutropenia in 20%/13%, grade 3 febrile neutropenia in 7%, grade 2/3 diarrhea in 9%/4%, vomiting in 11%/0%, stomatitis in 4%/4%, and neuropathy in 4%/0% of patients. CONCLUSIONS: S-1 and paclitaxel combination treatment is an effective regimen with a favorable toxicity profile in patients with advanced gastric cancer.

Reduced dose intensity FOLFOX-4 as first line palliative chemotherapy in elderly patients with advanced colorectal cancer.

To evaluate the toxicity and efficacy of a reduced dose intensity (mini-) FOLFOX-4 regimen as a first-line palliative chemotherapy in elderly patients (> or =70 yr of age) with advanced colorectal cancer, data from prospective databases at Seoul National University Bundang Hospital and Seoul Municipal Boramae Hospital were analyzed. A total of 20 patients were enrolled between January 2001 and August 2004, and were treated with oxaliplatin 65 mg/m2 on day 1, and with 2-hr infusions of leucovorin 150 mg/m2 followed by a 5-FU bolus (300 mg/m2) and 22-hr continuous infusions (450 mg/m2) for 2 consecutive days every 2 weeks until progression, unacceptable toxicity or patient refusal. Sixteen patients were evaluable for response with an overall response rate of 43.8%. Median progression-free survival was 4.8 months (95% CI: 3.0-6.7) and overall survival was 13.5 months (95% CI: 11.1-16.0). The main side effects were anemia and neutropenia, which were observed in 20.8% and 17.7%, respectively, of the total cycles administered. There were no grade 4 toxicities and only one patient suffered from febrile neutropenia. No grade 3 toxicities occurred except for anemia (5.2%) and vomiting (1.0%). In conclusion, the mini-FOLFOX-4 regimen was found to be well tolerated with acceptable toxicity, and to provide a benefit for elderly patients with colorectal cancer.