Pharmacokinetics In Rat Plasma Research Articles

An improved ultra-high performance liquid chromatography-tandem mass spectrometry method determining hispidulin and homoplantaginin in rat plasma and associated pharmacokinetic studies

AbstractFlavonoids are the most abundant components in Salvia plebeia, with significant pharmacological antioxidant and hepatoprotective properties. Hispidulin and homoplantaginin are the main flavonoid components in S. Plebeia. In this study, we established an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to determine hispidulin and homoplantaginin in rat plasma samples, which were precipitated using acetonitrile-methanol (9:1, v/v). We used a UPLC HSS T3 (100 mm × 2.1 mm, 1.7 μm diameter) chromatographic column, an acetonitrile-water (containing 0.1% formic acid) mobile phase, and a gradient elution flow rate of 0.4 mL min−1 in an elution time of 4 min. We used electrospray ionization (ESI) detection in positive ion mode, and multiple reaction monitoring mode (MRM) for quantitative analysis: m/z 301 → 286 for hispidulin, m/z 463 → 301 for homoplantaginin, and m/z 465 → 303 for internal standard (IS). In pharmacokinetic studies, 24 rats were orally administered hispidulin and homoplantaginin (5 mg kg−1) and received sublingual intravenous injections (1 mg kg−1) at two different doses, four groups with six rats/group. Differences in hispidulin and homoplantaginin pharmacokinetics in rat plasma were evaluated. The calibration curve showed good linearity in the 0.5–1,000 ng mL−1 range, with r > 0.99. Precision, accuracy, recovery, matrix effects, and stability results all met standard biological sample detection requirements. Our pharmacokinetic studies showed hispidulin bioavailability was much higher than homoplantaginin at 17.8% and 0.1%, respectively.

The Effect of Graviola Leaves Extract (Annona muricata L.) on Pharmacokinetic of Metformin in Rats’ Plasma and Pharmacological Activity of their Combination on Breast and Prostate Cancer Cell Lines

Objectives: Metformin is the most widely given medication for type 2 diabetes mellitus (T2DM). Annona muricata L. is a medicinal plant that belongs to the family Annonaceae, popularly known as graviola. Graviola leaves extract was found useful against diabetes, headache, insomnia, cystitis, inflammation, cancer, and other health benefits. The objectives of the current study are to investigate the effect of graviola leaves extract on metformin pharmacokinetics in rat plasma by applying high performance liquid chromatography (HPLC) method as well as its pharmacological effects on breast cancer (MCF-7) cells and prostate cancer (DU-145) cells. Methods: Wistar rats were classified into two groups; the first group (control group) received metformin (20 mg/kg) alone by oral gavage, while the second group, was administered a combination of metformin (20 mg/kg) and graviola leaves extract (20 mg/kg). Blood samples were collected at different time intervals to be analyzed using a validated HPLC method. Plasma profile and pharmacokinetic parameters were determined for each group. In addition, blood glucose levels at 0 hours and after 2 hours of metformin administration were measured in both groups. Breast cancer (MCF-7) cells and prostate cancer (DU-145) cells were used to investigate the anticancer effect of metformin (40 mg/ml), graviola leaves extract (20 mg/ml) and their combination by the standard MTT assay. Results: In the first group, metformin maximum plasma concentration (Cmax) and the area under the curve (AUC0-last) were (1509.25 ng/ml and 8705.59 h*ng/ml) respectively. In the second group, Pre-administration of graviola leaves extract significantly reduced MET (Cmax) and (AUC0-last), (701.88 ng/ml and 3467.72 h*ng/ml), respectively (P ≤0.05). Further, the use of metformin and graviola leaves extract separately showed strong anticancer activity on (MCF-7) cell lines with IC50 values of (10 and 20 mg/ml), respectively as well as on (DU-145) cell lines with IC50 value of (0.3125 and 5 mg/ml), respectively. In addition, the combination of metformin and graviola leaves extract showed a synergistic effect on (MCF-7) cells since the fractional inhibitory concentration value (FIC = 0.375) was less than 0.5, while it showed an additive effect on (DU-145) cells since the fractional inhibitory concentration value (FIC = 1.5) was between (0.5 and 4). Conclusion: In the current study, pre-administration of graviola leaves extract significantly reduced efficacy of metformin In vivo. The combination of metformin and graviola leaves extract showed a synergistic anticancer effect on breast cancer in vitro, while the combination has an additive effect on prostate cancer. The combination could be a potential therapeutic option to help treat breast cancer. The result achieved in this study is very encouraging to be considered for further investigation.

Strategically Substituted Agmatine Analogs Reduce Neuropathic Pain and Show Improved Pharmacokinetics Compared to Agmatine

Chronic pain remains a serious issue, affecting millions in the United States. Opioids serve as the most powerful therapeutic option but show limited efficacy in neuropathic pain and consequential side‐effects, such as tolerance, addiction, and respiratory depression. Development of novel drugs to treat pain, though, continues to stagnate. Additionally, in conditions in which opioids are required, adjuvants to reduce opioid‐induced neuroplasticity is critical. Agmatine has been shown to reduce neuropathic pain behavior and opioid tolerance, but use remains limited due to potentially reduced CNS penetration due to its hydrophilicity. Therefore, we have developed a series of agmatine‐based compounds that exhibit greater lipophilicity while exhibiting equivalent pharmacological responses (Figure 1). The goal of this study was to assess differences in pharmacokinetics and dynamics of 4 of these strategically substituted agmatines (SSAs). Our hypothesis is that these compounds will have an increased plasma half‐life and CNS distribution compared to agmatine, with equivalent reductions in neuropathic pain and opioid tolerance.Analysis of the pharmacokinetics in rat plasma was done using serial sampling via jugular catheter. All in vivo experiments were reviewed and approved by the University of Minnesota IACUC and the ACURO of the Department of Defense. After intravenous administration, the SSAs exhibit 2‐phase distribution and elimination and have an increased elimination half‐life over agmatine (9 minutes), with SSA3 and SSA4 showing the longest (Table 1). This increased half‐life aligns with the increased lipophilicity of these compounds. Additionally, SSA2 and SSA4 show large volumes of distribution, suggesting increased CNS distribution.To test the impact of these compounds in vivo, we induced neuropathic pain by performing spared nerve injury (SNI). SNI drives robust tactile hypersensitivity measured using the von Frey assay in the ipsilateral hind‐paw, with the contralateral paw serving as a non‐injured control. Following intravenous administration, SSA2‐4 reduced SNI‐induced hypersensitivity at similar doses to agmatine, showing equivalent pharmacological activity. Additionally, after chronic morphine treatment alongside co‐treatment with SSA1 and SSA2, opioid reduction in the warm water (52.5°C) tail flick response was preserved, representing a prevention of opioid tolerance. In conclusion, these chemical alterations to agmatine are able to improve pharmacokinetic parameters while maintaining the pharmacological reduction in neuropathic pain and opioid tolerance, suggesting potential as novel therapeutics to replace opioids in pain treatment.

Target profiling of flavonol glycosides in the extract of Ginkgo biloba leaf and their pharmacokinetics in rat plasma by ultra‐high‐performance liquid chromatography with tandem mass spectrometry

The extract of Ginkgo biloba leaf is a popular herbal product or dietary supplement in the world to treat various diseases, and flavonol glycosides are considered as the main bioactive constituents. In this study, 37 flavonol glycosides were rapidly screened out by precursor ion scanning in positive ion mode with production ions at m/z 287.05, 303.05, and 317.06. Subsequently, a reliable and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry approach was established and validated to quantify the 20 prototype flavonol glycosides in rat plasma. Calibration curves showed good linearity (R2 ≥ 0.9894) over the corresponding concentration range. The precision, accuracy, extraction recovery, matrix effect, and stability were also satisfactory. The validated method was successfully applied to a pharmacokinetic study of prototype flavonol glycosides in rat after oral administration of the extract of G. biloba leaf. As a result, the Tmax of flavonol glycosides was short at 0.11-0.60 h. Quercetin-3-O-(2",6″-di-O-rhamnosyl)-glucoside, kaempferol-3-O-(2'',6''-di-O-rhamnosyl)-glucoside, quercetin-3-O-rutinoside, quercetin- 3-O-glucosyl-(1-2)-O-rhamnoside, and kaempferol-3-O-glucoside presented relatively high systemic exposure levels with AUC0-∞ >500 μg h/L and Cmax >100 μg/L. This study would provide the valuable information for further scientific research and clinical application of the extract of G. biloba leaf.

A UHPLC-Q-Exactive-Orbitrap-MS method for simultaneous determination of three flavonoids from Parasitic loranthus and their pharmacokinetics in rat plasma

Purpose: To develop and validate a chromatographic method for the simultaneous determination of plasma levels of rutin, avicularin and quercitrin using UHPLC-Q-Exactive-Orbitrap-MS.
 Methods: A sensitive, selective, and reliable UHPLC-Q-Exactive-Orbitrap-MS method was developed and validated for simultaneous determination of the three flavonoids, with puerarin as internal standard (IS). Plasma samples were first treated with methanol, and then acidified using hydrochloric acid (HCl) prior to liquid-liquid extraction with ethyl acetate. The flavonoids were separated on a Syncronis C18 column (100×2.1mm, 1.7 µm) using an elution gradient of acetonitrile and 0.1 % formic acid at a flow rate of 0.3 mL/min.
 Results: A linear correlation was obtained for the three flavonoids over the investigated concentration range, with correlation coefficients > 0.9954. The values of validated lower limit of quantification (LLOQ) were 0.68, 1.42 and 2.54 ng/mL for rutin, avicularin and quercitrin, respectively. Intra- and inter-day precision (RSD) were < 10 %, while accuracy (RE) ranged from −3.76 to 4.04 %.
 Conclusion: The proposed method has been successfully validated and is suitable for studying the pharmacokinetics of the three analytes in rats treated with parasitic loranthus extract (PLE).

Plasma Pharmacokinetics and Pharmacodynamics of SSA3 in Rats

Chronic pain is a serious health issue, affecting millions of people around the world. Some of the most powerful analgesics are opioids, which are not ideal for chronic use due to maladaptive responses, such as abuse and tolerance. Agmatine has been shown to reduce both chronic pain behaviors and opioid-induced neuroplasticity. However, systemic administration of agmatine may demonstrate limited central nervous system penetrance due to its polar character. Therefore, we have developed a series of strategically substituted agmatines (SSAs) to increase the lipophilicity of agmatine and potentially improve the distribution across the blood brain barrier. The goal of this study is to compare one of these compounds, SSA3, to agmatine with regards to pharmacokinetics and pharmacodynamics. Our hypothesis is that SSAs exhibit similar pharmacological action as agmatine at lower doses, with an improved pharmacokinetic profile. Following development of a novel LC-MS/MS protocol for quantification of SSA3 in plasma, we analyzed the pharmacokinetics in rat plasma using serial sampling via jugular catheter. All in vivo experiments were reviewed and approved by the University of Minnesota IACUC and the ACURO of the Department of Defense. After intravenous administration, SSA3 showed a 44±7 min elimination half-life. This half-life is increased compared to agmatine, with a reported elimination half-life of 7 min. Neither clearance nor volume of distribution were dose-dependent at the studied doses, determined as 0.37±0.04 L/min/kg and 21±3 L/kg, respectively. After oral administration, a similar elimination half-life is seen, suggesting no alteration in elimination based on route of administration. The oral bioavailability determined based on area under the curve is 13.1%. To assess the impact of SSA3 on neuropathic pain, SSA3 was administered to rats with spared nerve injury, and the tactile hypersensitivity was assessed using the von Frey monofilament stimulation. Intravenous SSA3 was able to reduce tactile hypersensitivity in injured rats at lower doses than agmatine and increased the duration of reversal at similar doses. SSA3 shows increased distribution and slower elimination as compared to agmatine, serving as a potential explanation for the increased action in nerve-injured animals. In conclusion, alterations in the chemical structure to the parent compound appears to have conferred enhanced biopharmaceutical features accounting for improved pharmacological parameters.

Rp-HPLC Determination of Quercetin in a Novel D-α-Tocopherol Polyethylene Glycol 1000 Succinate Based SNEDDS Formulation: Pharmacokinetics in Rat Plasma.

Despite its proven efficacy in diverse metabolic disorders, quercetin (QU) for clinical use is still limited because of its low bioavailability. D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) is approved as a safe pharmaceutical adjuvant with marked antioxidant and anti-inflammatory activities. In the current study, several QU-loaded self-nanoemulsifying drug delivery systems (SNEDDS) were investigated to improve QU bioavailability. A reversed phase high performance liquid chromatography (RP-HPLC) method was developed, for the first time, as a simple and sensitive technique for pharmacokinetic studies of QU in the presence of TPGS SNEDDS formula in rat plasma. The analyses were performed on a Xterra C18 column (4.6 × 100 mm, 5 µm) and UV detection at 280 nm. The analytes were separated by a gradient system of methanol and phosphate buffer of pH 3. The developed RP-HPLC method showed low limit of detection (LODs) of 7.65 and 22.09 ng/mL and LOQs of 23.19 and 66.96 ng/mL for QU and TPGS, respectively, which allowed their determination in real rat plasma samples. The method was linear over a wide range, (30–10,000) and (100–10,000) ng/mL for QU and TPGS, respectively. The selected SNEDDS formula, containing 50% w/w TPGS, 30% polyethylene glycol 200 (PEG 200), and 20% w/w pumpkin seed oil (PSO), showed a globule size of 320 nm and −28.6 mV zeta potential. Results of the pharmacokinetic studies showed 149.8% improvement in bioavailability of QU in SNEDDS relative to its suspension. The developed HPLC method proved to be simple and sensitive for QU and TPGS simultaneous determination in rat plasma after oral administration of the new SNEDDS formula.

Simultaneous Determination of Six Alkaloids in Rat Plasma by SPE-HPLC–MS/MS and Their Pharmacokinetics after Oral Administration ofRadix aconiti PreparataExtract

Simultaneous determination of the content of six alkaloids (aconitine, hypoaconitine, mesaconitine, benzoylaconine, benzoylhypaconine, and benzoylmesaconine) in rat plasma is enabled by HPLC-MS/MS combined with microsolid phase extraction (micro-SPE). To study its pharmacokinetics in rat plasma, the extracted plasma sample was passed through a C18 extraction column and eluted with acetonitrile. The six alkaloids in the Radix aconiti Preparata extract can be completely separated as peaks with good shape. The six components in the plasma sample showed a good linear relationship within their respective linear ranges (R 2 > 0.997). The analysis of the six alkaloids can be completed within 20 min. This method has high intraday and interday precision, and the room temperature stability and freeze-thaw stability are good. The matrix effect of the plasma samples is between 86.4 and 114%. The metabolism of the six Aconitum alkaloids in plasma is analyzed using a two-compartment model, which is characterized by fast absorption, slow elimination, and good linear fit, R 2 > 0.99. The peak time (T max) for aconitine, hypaconitine, and neoaconitine ranged from 29.95 to 42.07 min, while the peak time (T max) for benzoaconitine, benzohypaconitine, and benzoxinaconitine ranged from 42.88 to 73.08 min. With the increased dosage, the bioavailability of Aconitum alkaloids decreased gradually. The method for the determination of Aconitum alkaloids in rat plasma by high performance liquid chromatography-tandem mass spectrometry is sensitive and accurate, which is suitable for rat plasma analysis. The results provide a scientific basis for metabolic study of Aconitum alkaloids in vivo, and pave the way for clinical use of Aconitum medicinal materials and extracts.

Studies on the chiral separation of pheniramine and its enantioselective pharmacokinetics in rat plasma by HPLC-MS/MS

As a highly potent first-generation histamine H1-receptor antagonist, pheniramine is a chiral drug and consists of a pair of enantiomers. In this study, a sensitive and enantioselective HPLC-MS/MS method has been developed for the determination of pheniramine enantiomers in rat plasma for the first time. The enantioseparation was performed on a Chiralpak AGP column with 10 mM ammonium acetate buffer (pH 4.5) as mobile phase. Chlorpheniramine was selected as the internal standard. Both pheniramine and internal standard were detected by mass spectrometry in multiple reaction monitoring mode (MRM) with a positive electrospray ionization source. Transitions of m/z 240.97 → 195.84 and 275.21 → 229.85 were monitored for pheniramine and chlorpheniramine, respectively. The method was validated over the concentration range of 1–400 ng/mL for each pheniramine enantiomer and the lower limit of quantification was 1 ng/mL. The relative standard deviations of the intra-day and inter-day precision were not greater than 11.7%, and relative errors of the accuracy ranged from −3.3% to 1.7%. Finally, the proposed method was applied to the enantioselective pharmacokinetic study of pheniramine enantiomers after oral administration of 20 mg/kg racemic pheniramine to Wistar rats. It was found that the maximum plasma concentration (Cmax), area under the concentration-time curve (AUC), and clearance of S-pheniramine were higher than those of R-pheniramine.

Kinetic disposition of dietary polyphenols and methylxanthines in the rat mammary tissue

We recently showed that methylxanthines and conjugated phenolic-derived metabolites reached the mammary tissue (MT) of breast cancer patients after consuming a blend of phenolic-rich extracts. The pre-surgery fasting could prevent the detection of some (including those non-conjugated) metabolites. We investigated here the pharmacokinetics in rat plasma and MT of phenolic-derived metabolites and methylxanthines using the same blend (pomegranate, olive, cocoa, orange, lemon, and grapeseed extracts plus resveratrol; containing 37 phenolics, theobromine, and caffeine). We also compared the pharmacokinetics of resveratrol when administered in the blend or individually. We show for the first time that micromolar levels of methylxanthines and conjugated-derived (but not free) metabolites from resveratrol, dihydroresveratrol, hesperetin, urolithins, and hydroxytyrosol reached the MT. Resveratrol-3-glucuronide and resveratrol-3-sulfate showed shorter Tmax (plasma and MT) and resveratrol-3-sulfate higher Cmax (MT) when resveratrol was administered individually. This study could help to conveniently design preclinical studies using physiologically relevant conditions in (breast) cell models.

Pharmacokinetics in rat plasma and tissue distribution in mice of galangin determined by UHPLC–MS/MS

Galangin (GAL), the major bioactive flavonol extracted from Alpinia officinarum Hance (Zingiberaceae), has attracted much attention due to its multiple biological activities. To develop a fast, reliable, and sensitive ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for the quantification of GAL in rat plasma and mouse tissues. UHPLC–MS/MS using electrospray ionization operating in negative-ion mode was used to determinate GAL in 18 rats receiving three doses of GAL (2 and 9 mg/kg by intravenous injection, 5 mg/kg by oral administration), with six rats for each dose. Blood samples were collected at 0.0333, 0.25, 0.5, 1, 2, 4, 6 and 8 h. A total of 25 mice received 18 mg/kg GAL by intraperitoneal injection. Liver, heart, lung, spleen, brain, and kidney tissue samples were collected at 0.25, 0.5, 2, 4, and 6 h. The precision of the method was better than 12.1%, while the accuracy ranged from −4.8% to 8.1%. The results of pharmacokinetics demonstrated rapid GAL absorption (tmax of 0.25 h), fast elimination (t1/2 <1.1 h) after three different dosages, and an absolute bioavailability of ~7.6%. Tissue distribution analysis revealed abundant GAL in liver, kidney, spleen, and lung and smaller amounts in brain. The developed method proved fast (3 min), efficient, and reliable, with high selectivity for the quantitative analysis of GAL in biological samples. This is the first study to identify the target tissues of GAL, and the results may help to elucidate the mechanisms underlying its therapeutic effects in vivo.

Pharmacokinetics of panasenoside in rats and tissue distribution in mice by ultra-performance liquid chromatography tandem mass spectrometry

We developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method for quantification of panasenoside pharmacokinetics in rat plasma and tissue distribution in mouse. Twelve male Sprague-Dawley rats were used for pharmacokinetics after intravenous (2 or 10 mg/kg) administration of panasenoside, six rats for each dose. Thirty mice were randomly divided into six groups (five mice for each group, one group for each time point) and received 20 mg/kg of panasenoside by intraperitoneal administration. Calibration plots were in the range of 2–2000 ng/mL for panasenoside in rat plasma and 2–3000 ng/mL in mouse tissues. The relative standard deviation (RSD) of inter-day and intra-day precision was less than 14%. The accuracy was between 89.6% and 110.0%. The AUC(0–t) was 160.8 ± 13.0 and 404.9 ± 78.0 ng/mL*h, and t1/2 of 3.2 ± 1.2 and 4.6 ± 1.7 h, CL (clearance) of 10.0 ± 2.0, and 21.4 ± 2.0 L/h/kg after intravenous administration 2 mg/kg and 10 mg/kg of panasenoside, respectively. The tissue distribution results indicated that the panasenoside diffuses rapidly and widely into major organs. The level of panasenoside was highest in mouse liver, followed by kidney, lung, and spleen. The overwhelming accumulation in liver indicated that liver was responsible for the extensive metabolism.

Simultaneous determination of seven bioactive compounds and pharmacokinetics in rat plasma after oral administration of Yindan Xinnaotong Ruanjiaonang by UPLC-MS/MS

To estabish ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of quercetin(QCT), isorhamnetin(ISR), kaempferol(KMF), ginkgolide A(GA), ginkgolide B(GB), ginkgolide C(GC) and bilobalide(BB) in rat plasma and investigate the pharmacokinetic process of seven compounds after oral administration of Yindan Xinnaotong Ruanjiaonang, The results indicated that all calibrations curves showed good linearity (r≥0.997 1). RSD of intra-day and inter-day precisions were all within 11%. The matrix effects and extraction recovery were in the range of 93.28%-103.6% and 72.43%-95.77% respectively. The peak concentration (Cmax) of QCT, ISR, KMF, GA, GB, GC and BB were (45.02±11.28), (49.90±13.82), (27.85±8.38), (76.31±18.19), (76.54±15.43), (35.35±10.28), (48.70±12.34) μg•L⁻¹, respectively. The peak time (tmax) of seven constituents were (0.33±0.11), (0.50±0.23), (0.33±0.14), (0.75±0.29), (1.0±0.35), (1.5±0.23), (0.75±0.50) h, respectively. UPLC-MS/MS method established in this research was proved to be so rapid and sensitive that it can be applied to the pharmacokinetic study of seven bioactive constituents in Yindan Xinnaotong Ruanjiaonang.

Abstract LB-190: IT-141 and IT-147, iron stabilized micellar nanoparticles for therapeutic and diagnostic applications

Abstract Site-specific delivery of oncology drugs using nanoparticle technology has been a decades-long goal. IT-141 and IT-147 are polymer micelles that encapsulate (i.e. physically entrap without covalent bonds) hydrophobic chemotherapeutics in the core of the micelle. IT-141 incorporates SN-38, the active moiety of irinotecan, in its core with a weight loading (v/v) of 2%. IT-141 shows increased pharmacokinetics in rat plasma, increased maximum tolerated dose (MTD) and improved anti-tumor efficacy in HCT116 and HT-29 xenograft models over irinotecan in all studies. IT-147 incorporates epothilone D, a microtubule-stabilizing anti-metabolite with a weight loading (v/v) of 2%. IT-147 shows increased pharmacokinetics in rat plasma, increased MTD and improved anti-tumor efficacy in HCT116 colorectal, A549 lung and NCI-H460 lung xenograft models over epothilone D free drug treatment. Both micelles are 70-100 nm diameter clusters of surfactant triblock copolymers stabilized by the interaction between iron and multiple polymer chains. The iron-polymer dative bonds are unstable at low pH, providing a mechanism for environment-dependent micelle stability and subsequent drug release. Furthermore, these stabilized micelles in vivo possess relaxivity constants suitable to provide contrast in magnetic resonance imaging (MRI). The spin-lattice relaxivity value (r1) was 7-16 mM-1s-1 and the spin-spin relaxivity values (r2) were 65-80 mM-1s-1. Small molecule complexes of iron do not typically provide sufficient MR contrast. Because contrast is not observed with individual iron complexes, and the MR contrast is directly related to the properties of the iron-stabilized nanoparticle, only intact nanoparticles provide contrast in MRI. When these iron-stabilized micelle formulations are administered to tumor bearing xenograft mice, increased contrast in the tumor is observed, peaking between 24 and 48 hours. MRI was performed with IT-141 in HCT116, HT-29, and A549 subcutaneous tumor models. IT-147 contrast imaging was performed in HCT116 and NCI-H460 subcutaneous, and MCF-7 orthotopic tumor models. Our technology has produced stable micelles that encapsulate chemotherapeutic drugs to include SN-38, daunorubicin, epothilone D, panobinostat, paclitaxel, and aminopterin with improved pharmacokinetics, decreased toxicity and increased efficacy. The MRI imaging results hold potential for use in the clinic where delivery of the chemotherapeutic-loaded nanoparticle can be monitored non-invasively. Citation Format: Kevin Sill, Tara Lee Costich, Adam Carie, Jyothi Sethuraman, Taylor Buley, Tyler Ellis, Tomas Vojkovsky, Bradford Sullivan, J. Edward Semple, Suzanne Bakewell. IT-141 and IT-147, iron stabilized micellar nanoparticles for therapeutic and diagnostic applications. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-190.

An LC/MS quantitative and microdialysis method for cyclovirobuxine D pharmacokinetics in rat plasma and brain: The pharmacokinetic comparison of three different drug delivery routes.

To explore the brain-targeting of cyclovirobuxine D(CVB-D) after administered intranasally, the pharmacokinetics of CVB-D via three different drug delivery routes: intragastric (i.g.), intranasal (i.n.), and intravenous (i.v.) in rat brain and blood was compared. Firstly, an in vivo microdialysis method for sampling CVB-D in both plasma and brain of the rat was established. Secondly, a liquid chromatography-tandem mass spectrometry method has been developed and validated for determination of CVB-D in microdialysis samples. For plasma and brain microdialysis samples, liquid-liquid extraction was used and donepezil was chosen as internal standard. Both were followed by HPLC separation and positive electrospray ionization tandem mass spectrometry detection (ESI-MS/MS). Chromatographic separation was achieved on a agilent C18 column with a mobile phase of methanol-water (50:50, v/v) (pH 3.2) containing 0.1% formic acid and 5mM ammonium acetate. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (MRM) of the transitions at m/z 403.4→372.3 for CVB-D and m/z 380.2→243.1 for donepezil (IS). Good linearities were obtained in the range of 10-4000ng/mL in rat microdialysates for CVB-D. The lowest limit of quantitation was 5ng/mL, with an extraction recovery >75%, and no significant matrix effects. Intra- and inter-day precisions were all <15% with accuracies of 97.26-116.20%. All of which proved that the established method was successfully applied to the pharmacokinetic study of CVB-D. Simultaneously, brain uptake and pharmacokinetic studies were performed by determination of CVB-D concentration in blood and brain respectively for CVB-D i.g., i.n. and i.v.. Results showed that the intranasal CVB-D could improve brain targeting and had advantages for direct nose to brain transport of CVB-D when compared with injection and oral delivery routes, which indicates that intranasal administration of CVB-D could be a promising approach for the treatment of cerebrovascular disease.

Determination of N6-(4-hydroxybenzyl) adenine riboside in rat plasma by ultra performance liquid chromatography-quadrupole time of flight mass spectrometry

An ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) method was developed and validated for the determination of N6-(4-hydroxybenzyl) adenine riboside and its pharmacokinetics in rat plasma. The chromatographic conditions were optimized. The separation was performed on an Agilent ZORBAX SB-C18 column(150 mm x 3 mm, 1.8 μm) with a gradient elution of 0.2% (v/v) formic acid aqueous solution and acetonitrile as the mobile phases at a flow rate of 0.35 mL/min. The detection was accomplished in positive mode with electrospray ionization (ESI) by UPLC-QTOF-MS, and 6-benzylamino purine was used as the internal standard (IS). The results showed that the linear range of calibration curve was 0.625-160 ng/mL for N6-(4-hydroxybenzyl) adenine riboside in rat plasma with the correlation coefficient more than 0.99. The recoveries were 88.41%-108.26%. The limit of detection was 0.1 ng/mL. The intra-day and inter-day precisions (RSDs) were less than 6%, and intra-day and inter-day accuracies (REs, RE = (measured concentration-spiked concentration)/spiked concentration x 100%) were less than ±15%. The method is rapid, sensitive and accurate for the quantitation of N6-(4-hydroxybenzyl) adenine riboside, which can be used for the study of pharmacokinetics of N6-(4-hydroxybenzyl) adenine riboside.

Simultaneous determination of calycosin-7-O-β-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of Radix Astragali extraction for their pharmacokinetic studies by ultra-pressure liquid chromatography with tandem mass spectrometry.

A sensitive and reliable ultra-pressure liquid chromatography with tandem mass spectrometry (UPLC-MS) was developed and validated for simultaneous quantification of six main bioactive components, i.e., calycosin-7-O-β-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of the 95 % ethanol extraction from Radix Astragali. Plasma samples were extracted with Waters Oasis(TM) HLB 1 cc (30 mg) Extraction Cartridges (SPE) separated on an UPLC™ BEH C18 column and detected by MS with electro spray ionization interface in positive selective ion monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r (2) > 0.99. The method had the lower limit quantification of 1.30, 0.73, 1.17, 2.33, 0.63, and 0.83 ng/mL for ononin, calycosin, calycosin-7-O-β-D-glucoside, formononetin, astragaloside IV, and astragaloside II, respectively, with precision less than 10 %. The RSD of intra- and inter-day variations ranged from 1.66 to 6.46 and 3.39 to 6.58 %. This developed method was applied subsequently to pharmacokinetic studies of the six compounds in rats successfully. The proposed method was for the first time to compare the pharmacokinetic difference between calycosin-7-O-β-D-glucoside and calycosin in rat plasma, so as between ononin and formononetin, and studied to the astragaloside II pharmacokinetics in rat plasma.

Simultaneous determination of gastrodin and puerarin in rat plasma by HPLC and the application to their interaction on pharmacokinetics

Gastrodin (Gas) and puerarin (Pur) are bioactive substances derived from traditional Chinese medicine Gastrodia elata and Radix Puerariae, respectively, which were often used together in Chinese clinical prescriptions. Their injections were used in combined way for treatment of some cardiocerebrovascular diseases in clinic, especially for vertigo due to vertebrobasilar ischemia. In this paper, interaction of gastrodin and puerarin in rat plasma pharmacokinetics via intragastic (i.g.)/intravenous (i.v.) administration was investigated. A reliable HPLC method was developed for simultaneous determination of Gas and Pur in rat plasma with a linear range of 0.101–101μg/mL for Gas and 0.0500–5.98μg/mL for Pur (r2>0.993). The LLOQ, LOD of Gas and Pur were determined to be 0.101, 0.0486μg/mL, and 0.05, 0.0245μg/mL, respectively. The intra-day and inter-day precision were all less than 12.0%, whilst the accuracy were all within 96.4±6.00%. The proposed method has been successfully applied to the pharmacokinetic study of the analytes in rats after i.g./i.v. administration of Gas and Pur alone or combined with each other (i.g.: 40mg/kg Gas, 400mg/kg Pur; i.v.: 20mg/kg Gas, 20mg/kg Pur). Blood samples were collected from retinal vein plexus of rats at predetermined time points and plasma containing the internal standard tyrosol (IS) were precipitated by methanol and chromatography was carried out on a C18 column with a gradient mobile phase of ACN–H2O with 0.05% phosphoric acid as a modifier. The pharmacokinetic profiles of combined administration were found to be distinct from those of given alone. The Cmax, Tmax, T1/2, MRT of Gas administrated alone or combined with Pur via i.g. were 21.7μg/mL, 0.250h, 2.81h, 0.830h and 18.4μg/mL, 0.550h, 0.970h, 1.37h, respectively, of Pur administrated alone or combined with Gas via i.g. were 0.490μg/mL, 1.95h, 1.33h, 2.10h and 2.01μg/mL, 0.570h, 4.00h, 5.10h, respectively. The relative oral bioavailability of Pur in combined administration was 10.7 times as much as that of single administration, whilst 1.52 folds in Gas. These results indicate that co-administration of Gas and Pur is a promising combination to gain higher bioavailability and it is suggested that doctors pay more attention to the dosages of the two when simultaneously using both of them.

Determining the pharmacokinetics of psilocin in rat plasma using ultra-performance liquid chromatography coupled with a photodiode array detector after orally administering an extract of Gymnopilus spectabilis

This study established ultra-performance liquid chromatography coupled with a photodiode array detector for determining psilocin and its pharmacokinetics in rat plasma after orally administering an extract of Gymnopilus spectabilis. The extract was separated on an ODS C18 column (2.3 μm, 100 mm × 2.1 mm I.D.) by gradient elution with (A) water containing 50 mM AcONH 4 and (B) acetonitrile. The wavelength was set at 265 nm and the injection volume was 10 μL. Under these conditions, the calibration curve was linear over the concentration range 0.2–20 μg/mL with a correlation coefficient of r 2 = 0.9992. The inter- and intraday precision levels were less than 7% and the accuracies (%) were within the range 92.0–102.5%. The method was sufficiently valid to be applied to a pharmacokinetics study of psilocin in rat plasma. The pharmacokinetic parameters of psilocin in rat plasma after the oral administration of a G. spectabilis extract were as follows: C max, 0.43 ± 0.12 μg/mL; T max, 90 ± 2.1 min; AUC 0→ t , 1238.3 ± 96.4 (μg/mL) min; and T 1/2, 117.3 ± 40.3 min.

The optical resolution of racemic chlorpheniramine and its stereoselective pharmacokinetics in rat plasma.

An ovomucoid-conjugated column has been developed for the chiral stationary-phase liquid chromatographic resolution of racemic chlorpheniramine with a quantitation limit of 0.05 microgram mL-1. The assay was used to study the stereoselective kinetics of chlorpheniramine enantiomers in rats. After bolus intravenous administration of racemic chlorpheniramine maleate (20 mg kg-1), plasma concentration of the (-)-form was higher than that of the (+)-form. In the elimination phase, the concentrations of (+)- and (-)-chlorpheniramine in the plasma declined biexponentially with half-lives of 18.2 and 50.0 min, respectively. Although there was no significant difference in blood-to-plasma concentration ratio of both enantiomers, the apparent total blood clearance of (+)-chlorpheniramine was twice as large as that of the (-)-isomer. Binding of (-)-chlorpheniramine to rat plasma protein was stronger than that of (+)-chlorpheniramine suggesting stereoselective pharmacokinetics may be due to a difference in the plasma protein binding.