Lead sulfide quantum dots for the near-infrared IIb window fluorescence imaging of colon cancer / 药学学报

The near-infrared-IIb (NIR-IIb, 1 500-1 700 nm) window fluorescence with long emission wavelength has reduced light scattering and tissue auto-fluorescent background, achieving deep tissue imaging with high spatial resolution. Herein, we prepared an NIR-IIb fluorescent quantum dots (QDs) composed of lead sulfide (PbS). The fluorescence spectrum of PbS QDs were adjusted by controlling the size of the PbS core. Cadmium sulfide (CdS) shell was synthesized by the cation exchange method to form the core/shelled lead sulfide/cadmium sulfide quantum dots (CSQDs). The surface of CSQDs was modified with polyethylene glycol (PEG) to increase their stability in aqueous solution. The resulting PEG-modified CSQDs (PEG-CSQDs) had the emission peak at ~1 550 nm with quantum yield of 7.2%. The animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) of Fudan University School of Pharmacy. At 2 h postinjection, PEG-CSQDs clearly delineated the tumor region of mice bearing orthotopic CT26-Luc colon cancer model in the NIR-IIb fluorescence imaging. The fluorescent intensity ratio of primary tumor and adjacent normal tissue was 42.3, and that of metastatic tumor and adjacent normal tissue was 22.3, which allowed to detect the primary tumor of 3.4 mm×2.5 mm in dimension and the metastatic tumor of 1.2 mm×0.9 mm in dimension, and accurately guided the excision of tumors. The PEG-CSQDs prepared in this study provided a new approach for the early diagnosis and guidance of surgical resection of colon cancer.

Pharmacokinetic study on dry powder inhalation administration of α-asarone in rats / 中国中药杂志

To study the pharmacokinetic characteristics and absolute bioavailability of α-asarone through dry powder inhalation in rats, and compare with that through oral administration and intravenous injection. A HPLC method was established for the determination of α-asarone in rat plasma to detect the changes in plasma concentrations of α-asarone through dry powder inhalation (20 mg · kg(-1)), oral administration (80 mg · kg(-1)) and intravenous injection (20 mg · kg(-1)) in rats. DAS 2.0 software was used to calculate the pharmacokinetic parameters. The absolute bioavailability of α-asarone was calculated according to AUC(0-t)) of administration routes and administration doses. According to the results, α-asarone showed good linear relations (r = 0. 999 4) at concentrations between 0.282-14.1 mg · L(-1), with the limit of detection (LOD) at 0.212 mg · L(-1). Through dry powder inhalation, oral administration and intravenous injection of α-asarone, the metabolic processes of α-asarone in rats conformed to one, two and three compartment models respectively, with the elimination half-life of (95.48 ± 48.28), (64.34 ± 27.59), (66.99 ± 29.76) min. According to the bioavailability formula, the absolute bioavailability of α-asarone through dry powder inhalation and oral administration were 78.32% and 33. 60%, respectively. This study showed that significant increase in elimination half-life and absolute bioavailability of α-asarone through dry powder inhalation, which lays a theoretical foundation for preparing α-asarone dry powder inhalers.

Studies on baicalin ethylcellulose microspheres for intranasal administration / 中国中药杂志

In this study, solvent evaporation method was used to preparing baicalin ethylcellulose microspheres for intranasal administration. The prepared microspheres were round with certain rough surface. The average drug loading and entrapment efficiency was (33. 31 ± 0. 045)% , (63. 34 ± 0. 11)% , respectively. As the characteristic crystalline peaks of baicalin were observed in the microspheres sample, the result of X-ray diffractometric analysis indicated that the baicalin was present in crystalline form after its entrapment in ethylcellulose matrix. By investigating the thermogram of microspheres sample, it was found that endothermic peak of baicalin was shifted from 211. 8 °C to 244. 2 °C and associated with the first broad endothermic peak of ethylcellulose. This could confirm that baicalin was loaded into ethylcellulose, nor simply physical mixture. The powder flowability test exhibited that the specific energy of microspheres was 3. 57 mJ . g-1 and the pressure drop was 2. 22 mBar when air kept the speed of 2 mm . s-1 through the powder bed with the force was 15 kPa. The consequence of the baicalin in vitro released from microspheres showed that the pure baicalin sample displayed faster (90%) release than microspheres sample (75%) in 7 h. Fitting model for release curve before 7 h, the results showed that the pure baicalin sample and the microsphere sample accorded with first order model (R2 = 0. 990 4) and Riger-Peppas model(R2 = 0. 961 2), respectively. Ex vivo rabbit nasal mucosa permeability experiment revealed that the value of cumulative release rate per unit area of the microsphere sample was 1. 56 times that of the pure baicalin sample. This provided the foundation for the in vivo pharmacokinetic study.