Li-Hui Quan

An LC–MS/MS method for the simultaneous determination of chlorogenic acid, forsythiaside A and baicalin in rat plasma and its application to pharmacokinetic study of Shuang-huang-lian in rats

An LC-MS/MS method was developed for the simultaneous determination of chlorogenic acid, forsythiaside A and baicalin, three major ingredients in Shuang-huang-lian preparations, in rat plasma. Following extraction by methanol-ethyl acetate-trifluoroacetic acid (49:49:2, v/v/v), the extracted analytes were separated on a reverse phase C12 column using a gradient mobile phase system of acetonitrile-water containing 0.1% formic acid. The limits of quantification were between 1.0 and 2.1ng/mL, the precision was <7% and the accuracy was between 94% and 107%. The validated method was applied to a comparative pharmacokinetic study in rats after administration of Shuang-huang-lian solutions via intravenous, peroral or intratracheal routes. The results showed that the three chemical markers were more rapidly and thoroughly absorbed following pulmonary delivery as compared with peroral administration.

Pulmonary delivery of scutellarin solution and mucoadhesive particles in rats.

The objectives of this study were to investigate the effects of mucoadhesive excipients on systemic bioavailability of an inhaled drug and to evaluate the feasibility of using the pulmonary route for non-invasive systemic delivery of scutellarin, a poorly orally absorbed flavonoid glucuronide. Following intratracheal spray of the scutellarin solution, the bioavailability was found to be approximately 77% in rats, which was >30-fold higher than that via the peroral route. In addition, the pulmonary absorption of scutellarin appeared to avoid the intestinal first-pass metabolism accompanied by peroral administration. Spray-dried scutellarin particles with the presence of mucoadhesive excipients were found to affect the corresponding mucociliary transport rate (MTR) as evaluated by a frog palate model. The pharmacokinetic results indicated that the magnitude of AUC(0-480) of intrapulmonary delivered drug particles was not correlated to the fine particle fraction (FPF) but inversely related to the MTR. Incorporating mucoadhesive polymeric mixtures into the scutellarin particles, the MTR decreased by sixfold, and the absolute bioavailability of the drug was found to increase from 70.1% to 97.9% despite a decrease in the FPF. Moreover, in vitro results evaluated using Calu-3 and A549 cell lines showed that scutellarin and spray-dried particles with or without the presence of mucoadhesives exhibited no local cell cytotoxic effects in the tested concentration range. In conclusion, the conducting airway is well permeable to scutellarin, and scutellarin may be effectively delivered systemically through inhalation of respirable droplets or particles.

Oily nanosuspension for long-acting intramuscular delivery of curcumin didecanoate prodrug: Preparation, characterization and in vivo evaluation

The objective of this study was to prepare the nanocrystals of curcumin didecanoate (CurDD) by wet ball milling and to investigate the comparative pharmacokinetics of oily nano- and micro-suspensions after intramuscular (i.m.) administration to rats. Upon optimizing the wet ball milling parameters, CurDD nanocrystals were produced with median particle size of ~500 nm and the freeze-dried nanocrystals were readily dispersed in peanut oil to form stable nanosuspensions. Although the nanosuspension appeared to exhibit slower clearance from the injection site after i.m. injection, compared to microsuspension (~5 μm), a significantly higher maximum plasma curcumin concentration (69.0 ng/ml) was observed for the former than that for the latter (18.5 ng/ml). In addition, the nanosuspension provided significant higher plasma curcumin concentrations and brain CurDD contents for at least 15 days than the microsuspension, except for the initial times. A single i.m. injection of nanosuspension appeared to achieve reversal effect on reserpine-induced hypothermia for at least 13 days. This study demonstrates that CurDD nanosuspension may act as a long-acting i.m. injectable for sustained delivery of curcumin, potentially applicable to elicit a long-lasting antidepressant effect.

Stabilization and sustained release of zeylenone, a soft cytotoxic drug, within polymeric micelles for local antitumor drug delivery.

Use of soft drugs has resulted in mixed success with the applicability to chemotherapeutics yet being confirmed. We hypothesize that incorporation of a soft cytotoxic agent into polymeric micelles, which confer to stabilizing and sustained release effect, will improve and prolong the local antitumor efficacy, thus achieving the therapeutic potential of soft cytotoxic agents. We incorporated a model soft cytotoxic agent, zeylenone, into mPEG-PLGA micelles by solvent evaporation method. The drug loaded micelles were characterized in terms of drug encapsulation, dynamic size, zeta potential, drug stability and in vitro and in vivo release. The in vivo antitumor efficacy was evaluated in A549 tumor-bearing mice. Zeylenone-loaded micelles exhibited core-shell morphology with dynamic size of about 36 nm and offered efficient solubilizing and stabilizing effects. In vitro release and in vivo pharmacokinetic results indicated sustained release of zeylenone in micelles. In addition, local delivered zeylenone-loaded micelles showed improved and sustained antitumor effect in vivo, compared with intravenous administration or local delivery of free drug solution. This study demonstrates the feasibility of soft cytotoxic agent to achieve local antitumor efficacy after the drug was stabilized and sustained the release within polymeric micelles.

Evaluating pulmonary toxicity of Shuang–Huang–Lian in vitro and in vivo

UNLABELLED ETHNOPHARMAOCOLOGICAL RELEVANCE: Shuang-Huang-Lian (SHL) is a traditional Chinese formula and has been used for the treatment of respiratory tract infections by inhalation. However, the pulmonary toxicity via inhalation is largely uninvestigated. AIM OF STUDY To evaluate the pulmonary toxicity of SHL following in vivo intratracheal spray to rats and in vitro exposures to A549 and Calu-3 cells. METHODS Calu-3 and A549 cells were exposed to SHL, chlorogenic acid, baicalin and forsythin solutions and in vitro cytotoxicity was evaluated using an MTT assay, whilst rats were subjected to intratracheal administration of SHL solutions and in vivo toxicity was indicated by assaying the LDH activity and total protein content in bronchoalveolar lavage fluid (BALF) and observing the histopathologic changes of the lungs. Secretion of inflammatory mediators, including IL-6, IL-8 and TNF-α, in cell culture media and BALF was quantified by ELISA. RESULTS The MTT cell viability data revealed the presence of minor toxicity to Calu-3 or A549 cells following exposure to SHL and its major ingredients for 24h or 48 h. However, the cell cultural media showed no sign of inflammatory responses. The in vivo results showed that exposures to SHL at doses of up to 50mg/kg did not significantly increase the total protein content, the LDH activity and the concentrations of IL-6, IL-8 and TNF-α in BALF. However, although intratracheal sprayed SHL at doses of up to 6 mg/kg for histopathologic study and up to 25mg/kg for cell counts showed no sign of adverse effects, inhaled SHL at elevated doses appeared to induce alveolar fusion in the lung and significant increases in the cell number of monocytes and granulocytes in the BALF. CONCLUSION The results demonstrated that the pulmonary safety of inhaled SHL was dependent on the administered dose. Inhalation therapy of SHL may be safely used when the inhaled dose was properly controlled.

Solid lipid nanoparticles for sustained pulmonary delivery of Yuxingcao essential oil: Preparation, characterization and in vivo evaluation.

The objective of this study was to prepare solid lipid nanoparticles (SLNs) for sustained pulmonary delivery of Yuxingcao essential oil (YEO). Three YEO loaded SLNs (SLN-200, SLN-400 and SLN-800) with different particle size were prepared and separated following a high-shear homogenization technique using Compritol 888 ATO as lipid and polyvinyl alcohol as an emulsifier. The particle size, zeta potential, drug encapsulation efficiency and drug loading of the SLNs were determined to be between 171 and 812nm, -17.1 and -19.3mV, between 76.6 and 90.2% and between 2.34 and 3.12%, respectively whereas the in vitro release data showed that the SLNs led to sustained drug release up to 48h. In addition, the SLN suspensions after nebulization conferred the fine particle fractions (<5.4μm) of 67.4-75.8%. Following intratracheal administration to rats, YEO loaded SLNs not only prolonged pulmonary retention up to 24h, but also increased AUC values (15.4, 18.2 and 26.3μg/gh for SLN-200, SLN-400 and SLN-800, respectively) by 4.5-7.7 folds compared to the intratracheally dosed YEO solution and by 257-438 folds to the intravenously dosed YEO solution, respectively. The present results were the first to show that YEO loaded SLNs may sustain YEO inhalation delivery and improve local bioavailability, representing a promising inhalable carrier to attain once daily application.

Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC-MS/MS assay for pharmacokinetic study.

Six esterase inhibitors, namely EDTA·2Na(+), NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis-nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mM) and BNPP (5 mM), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q-Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter- and intra-run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions.