Rational administration sequencing of immunochemotherapy elicits powerful anti-tumor effect.

As a research hotspot, immune checkpoint inhibitors (ICIs) is often combined with other therapeutics in order to exert better clinical efficacy. To date, extensive laboratory and clinical investigations into the combination of ICIs and chemotherapy have been carried out, demonstrating augmented effectiveness and broad application prospects in anti-tumor therapy. However, the administration of these two treatment modalities is usually randomized or fixed to a given chronological order. Nevertheless, the pharmacological effect of drug is closely related to its exposure behavior in vivo, which may consequently affect the synergistic outcomes of a combined therapy. In this study, we prepared a lipid nanoparticle encapsulating docetaxel (DTX-VNS), and associated it with the immune checkpoint inhibitor anti-PD-1 antibody (αPD-1) for the treatment of malignant tumors. To identify the optimum timing and sequencing for chemotherapy and immunotherapy, we designed three administration regimes, including the simultaneous delivery of DTX-VNS and αPD-1(DTX-VNS@αPD-1), DTX-VNS delivery before (DTX-VNS plus αPD-1) or post (αPD-1 plus DTX-VNS) PD-1 blockade with an interval of two days. Analysis from mass spectrometry, multi-factor detection and other techniques indicated that DTX-VNS plus αPD-1 initiated a powerful anti-tumor response in multiple tumor models, contributing to a remarkably reshaped tumor microenvironment landscape, which may attribute to the maximum therapeutic additive effects arise from a concomitant exposure of DTX-VNS and αPD-1 at the tumor site. By profiling the exposure kinetics of nanoparticles and αPD-1 in vivo, we defined the administration schedule with utmost therapeutic benefits, which may provide a valuable clinical reference for the rational administration of immunochemotherapy.

An analysis of the biopharmaceutical behaviour of proton pump inhibitors with different physicochemical properties.

At present, little information on the biopharmaceutical behaviour of proton pump inhibitors (PPIs) describing their absorption and biodistribution in vivo has been reported because the extreme instability of PPIs in the gastrointestinal environment makes it difficult to analyze such behaviour. In this work, a modified rat in situ intestinal perfusion model was employed to investigate absorption in the gastrointestinal tract and subsequent biodistribution of several PPIs (ilaprazole, esomeprazole and rabeprazole), which have different physicochemical properties. Our data indicated that PPIs exhibited significantly enhanced absorption rates in the whole intestine, including the duodenum, jejunum, ileum and colon, corresponding to the increase in the oil-water partition coefficient (LogP). PPIs and corresponding salt types showed no obvious differences in absorption, implying that solubility changes in the PPI have little effect on its absorption in the gastrointestinal tract. Among these PPIs, ilaprazole presented a more stable intestinal absorption behaviour, as well as more distribution and longer residence time in the stomach by HPLC-MS/MS analysis and radioactivity counts after 14C radiolabelling. These results may be useful information for PPI optimization and oral formulation design.

The study of intestinal absorption and biodistribution in vivo of proton pump inhibitors.

The major therapeutic strategy for acid-related gastrointestinal diseases in clinic is to reduce the excretion of gastric acid by oral administration of proton-pump inhibitors (PPIs). However, it is quite a challenge to study the oral absorption behaviors of PPIs considering their extreme instability under gastrointestinal environment. As a result, little information has been reported on PPI oral absorption so far, hindering the further development of PPI-contained oral preparations. Here, we first investigated the degradation rate of three representative PPIs, including ilaprazole, ilaprazole sodium and rabeprazole sodium. Then a modified in situ intestine absorption method in rat was established: through the temperature control by the heat exchangers, the perfusate was kept at physiological temperature only when passing through the intestine while it was maintained at 4 °C outside the intestine. Therefore PPIs could maintained sufficiently high stability under proper temperature control. Our data demonstrated that both ilaprazole and ilaprazole sodium exhibited significantly higher absorption efficiency than rabeprazole sodium did through the comparison of their apparent permeability coefficients and steady-state plasma concentrations after perfusion in the duodenum, jejunum, ileum and colon, mainly attributing to their more suitable oil-water partition coefficient. The duodenum could be the best site for the oral absorption of PPIs. Ilaprazole outperformed its sodium salt form with its stable absorption behavior in tested four intestinal segments. Furthermore, after intravenous or oral administration, ilaprazole exhibited a longer residence time and a higher accumulation in the stomach than in most of other tissues/organs. However, it was also found that the accumulation was heterogeneous and mainly located in mucosa cells of the stomach. Our further study indicated that there was no significant difference on the oral absorption efficiency of ilaprazole between female and male rats but ilaprazole underwent a faster metabolism in male rats after oral absorption. Our study provided a valuable guidance for the design of oral formulation and the optimization of PPI-contained formulations.

Selective Intratumoral Drug Release and Simultaneous Inhibition of Oxidative Stress by a Highly Reductive Nanosystem and Its Application as an Anti-tumor Agent.

Excessive oxidative stress is always associated with the serious side effects of chemotherapy. In the current study, we developed a vitamin E based strongly reductive nanosystem to increase the loading efficiency of docetaxel (DTX, DTX-VNS), reduce its side toxicity and enhance the antitumor effect. Methods: We used Förster Resonance Energy Transfer (FRET) to reveal the in vivo and in vitro fate of DTX-VNS over time. All FRET images were observed using the Maestro imaging system (CRI, Inc., Woburn, MA) and Fluo-View software (Olympus LX83-FV3000). Results: Through FRET analyzing, we found that our nanosystem showed a selective rapider release of drugs in tumors compared to normal organs due to the higher levels of ROS in tumor cells than normal cells, and the accumulation of DTX at tumor sites in the DTX-VNS group was also notably more than that in the Taxotere group after 24 h injection. Meanwhile, DTX-VNS had a prominently stronger anti-tumor effect in various models than Taxotere, and had a synergistic effect of immunotherapy. Conclusions: Our work presented a useful reference for clinical exploration of the in vivo behavior of nanocarriers (DTX-VNS), inhibition oxidative stress and selective release of drugs at tumor sites, thus reducing the side effects and enhancing the anti-tumor effects.

Preparation and evaluation of regioselectively substituted amylose derivatives for chiral separations.

Six novel regioselectively substituted amylose derivatives with a benzoate at 2-position and two different phenylcarbamates at 3- and 6-positions were synthesized and their structures were characterized by 1 H nuclear magnetic resonance (NMR) spectroscopy. Their enantioseparation abilities were then examined as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) after they were coated on 3-aminopropyl silica gels. Investigations indicated that the substituents at the 3- and 6-positions played an important role in chiral recognition of these amylose 2-benzoate serial derivatives. The derivatives demonstrated characteristic enantioseparation and some racemates were better resolved on these derivatives than on Chiralpak AD, which is one of the most efficient CSPs, utilizing coated amylose tris(3,5-dimethylphenylcarbamate) as the chiral selector. Among the derivatives prepared, amylose 2-benzoate-3-(phenylcarbamate/4-methylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate) exhibited chiral recognition abilities comparable to that of Chiralpak AD and may be useful CSPs in the future. The effect of mobile phase on chiral recognition was also studied. In general, with the decreased concentration of 2-propanol, better resolutions were obtained with longer retention times. Moreover, when ethanol was used instead of 2-propanol, poorer resolutions were often achieved. However, in some cases, improved enantioselectivity was achieved with ethanol rather than 2-propanol as the mobile phase modifier.

[Study on the chromatographic fingerprints of Reineckia carnea from different habitats by HPLC-ELSD].

OBJECTIVE: To investigate the HPLC-ELSD fingerprints of Reineckia carnea from different habitats and provide a theoretical evidence to evaluate its quality. METHODS: The chromatographic conditions were Diamonsil (R) C18 column (4.6 mm x 250 mm, 5 microm) by linear gradient elution using water and acetonitrile as mobile phase at a flow rate of 0.8 mL/min, column temperature at 25 degrees C and sample injection 30 microL. An Agilent 1260 infintiy ELSD operated at 85 degrees C, gain 6 and 3.5 bar nitrogen. RESULTS: The HPLC-ELSD fingerprints were established with 6 common peaks and methodology reached the required standard. CONCLUSION: The method is simple, rapid, accurate, and can be used for quality evaluation of Reineckia carnea from different habituts.

Improved preparation of chiral stationary phases via immobilization of polysaccharide derivative-based selectors using diisocyanates.

The classical method for the preparation of immobilized polysaccharide-based chiral stationary phases (CSPs) with a diisocyanate was improved. Cellulose or amylose was directly coated onto 3-aminopropyl silica gel after it was dissolved in a mixture of N,N-dimethylacetamide, LiCl, and pyridine, then immobilized onto silica gel with a diisocyanate, and finally allowed to react with an excess of corresponding isocyanate. Four polysaccharide derivatives, 3,5-dimethylphenylcarbamate and 3,5-dichlorophenylcarbamate of cellulose, and 3,5-dimethylphenylcarbamate and 5-chloro-2-methylphenylcarbamate of amylose, were immobilized onto silica gel utilizing this method. Compared with the classical diisocyanate method, the improved procedure avoided the derivatization and regeneration of 6-hydroxyl groups of cellulose and amylose, and thus showed an advantage for simple and economical preparation. The relationships among the amount of diisocyanate used, immobilization efficiency, and enantioseparation on the cellulose-based CSPs were investigated. Also, the solvent durability of the obtained CSPs was examined with eluents containing chloroform or THF. By utilizing these eluents, the chiral recognition abilities of the obtained CSPs for some of the tested racemates were improved.

[Preparation and evaluation of amylose and cellulose tris (3-trifluoromethylphenylcarbamates)-based chiral stationary phases].

To broaden the category of polysaccharide-based chiral stationary phases (CSPs), coated CSPs based on tris (3-trifluoromethylphenylcarbamates) of amylose and cellulose were prepared for enantioseparation in high performance liquid chromatography. Their performances were evaluated by eight racemates using hexane-isopropanol as mobile phase. Compared with the most widely used, commercially available polysaccharide-based CSPs, Chiralpak AD and Chiralcel OD, utilizing tris (3,5-dimethylphenylcarbamates) of amylose and cellulose as the chiral selector, respectively, the obtained CSPs exhibited lower enantioseparation abilities. However, cellulose tris(3-trifluoromethylphenylcarbamate)-based CSP exhibited characteristic enantioseparation and some chiral compounds were better resolved on this CSP than on Chiral-cel OD. The chiral recognition abilities of the obtained CSPs were increased with the decrease of the portion of isopropanol in the mobile phase and relatively high enantioseparation was obtained with the mobile phase of hexane-isopropanol (95: 5, v/v). The obtained amylosic phase demonstrated slightly higher chiral resolving ability than the cellulosic one for the test racemates. In addition, it was revealed that the enantioseparations of the cellulosic and amylosic CSPs were complementary.