A rapid and sensitive LC-MS/MS method for quantifying oxycodone, noroxycodone, oxymorphone and noroxymorphone in human plasma to support pharmacokinetic drug interaction studies of oxycodone.

A sensitive and reliable LC-MS/MS method was developed and validated for the quantification of oxycodone and metabolites in human plasma. The method has a runtime of 6 min and a sensitivity of 0.1 µg/L for all analytes. Sample preparation consisted of protein precipitation. Separation was performed on a Kinetix biphenyl column (2.1 × 100 mm, 1.7 µm), using ammonium formate 5 mm in 0.1% aqueous formic acid and methanol LC-MS grade 100% in gradient elution at a flow rate of 0.4 ml/min. Detection was performed in multiple reaction monitoring mode using positive electrospray ionization. The method was linear over the calibration range of 0.1-25.0 µg/L for oxycodone, noroxycodone and noroxymorphone and 0.1-5.0 µg/L for oxymorphone. The method demonstrated good performance in terms of intra- and interday accuracy (86.5-110.3%) and precision (CV 1.7-9.3%). The criteria for the matrix effect were met (CV < 15%) except for noroxymorphone, for which an additional method was applied to compensate for the matrix effect. Whole blood samples were stable for 4 h at room temperature. Plasma samples were stable for 24 h at room temperature and 3 months at -20°C. Furthermore, the method was successfully applied in a pharmacokinetic drug interaction study of oxycodone and enzalutamide in patients with prostate cancer.

Investigating the bioavailabilities of olerciamide A via the rat's hepatic, gastric and intestinal first-pass effect models.

Olerciamide A (OA) is a new alkaloid isolated from Portulaca oleracea L. that has been proved to possess a low bioavailability (F) after oral administration in rats in our previous study. Hence, to clarify the reasons for its low bioavailability, hepatic, gastric and intestinal first-pass effect models were established, and a rapid, sensitive UHPLC method was validated and applied for the determination after dosing via the femoral, portal, gastric and intestinal routes. As inhibitors of CYP3A and P-gp, verapamil, midazolam and borneol in low and high dose groups were selected to improve the low bioavailability of olerciamide A. Moreover, a rectal administration method was also carried out to improve the bioavailability of olerciamide A. The results showed that the bioavailability of olerciamide A using hepatic, gastric and intestinal routes were 92.16%, 84.88% and 5.76%, respectively. The areas under the plasma concentration-time curve from zero to infinity (AUC0 → ∞ ) were increased a little after being dosed with 10 and 30 mg/kg verapamil (p > 0.05), but markedly increased after being dosed with 0.4 and 1.2 mg/kg midazolam as well as 8 and 24 mg/kg borneol (p < 0.05). Besides, the AUC0 â†’ ∞ values after the lower and upper rectal administrations were separately similar to the intravenous and intraportal administrations. Our study showed that the intestinal first-pass effect mainly contributed to the low bioavailability of olerciamide A in rats due to it being a substrate of CYP3A and P-gp as well as to its poor intestinal absorption.

Pharmacokinetics and metabolism of olerciamide A from Portulaca oleracea L. in rats by UHPLC-UV and UHPLC-ESI-Q-TOF/MS.

The aim of this study was to elucidate the pharmacokinetics of olerciamide A in rats after oral and intravenous administration of Portulaca oleracea L. extract by a simple and rapid ultra high-performance liquid chromatography method with bergapten as internal standard. The pharmacokinetic results indicated that olerciamide A was rapidly distributed with a time to peak concentration of 30 min after oral administration and presented a low oral absolute bioavailability of 4.57%. The metabolism of olerciamide A in rats was also investigated using ultra-high-performance liquid chromatography electrospray coupled with quadrupole-time of flight mass spectrometry to elucidate the reason for the low absolute bioavailability of olerciamide A and seven metabolites of oleraciamide A were found in rat plasma and urine.

Determination of oxycodone and its major metabolites noroxycodone and oxymorphone by ultra-high-performance liquid chromatography tandem mass spectrometry in plasma and urine: application to real cases.

BACKGROUND: Oxycodone is a narcotic drug widely used to alleviate moderate and severe acute and chronic pain. Variability in analgesic efficacy could be explained by inter-subject variations in plasma concentrations of parent drug and its active metabolite, oxymorphone. To evaluate patient compliance and to set up therapeutic drug monitoring (TDM), an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay was developed and validated for the parent drug and its major metabolites noroxycodone and oxymorphone. METHODS: Extraction of analytes from plasma and urine samples was obtained by simple liquid-liquid extraction. The chromatographic separation was achieved with a reversed phase column using a linear gradient elution with two solvents: acetic acid 1% in water and methanol. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI). RESULTS: Separation of analytes was obtained in less than 5 min. Linear calibration curves for all the analytes under investigation in urine and plasma samples showed determination coefficients (r2) equal or higher than 0.990. Mean absolute analytical recoveries were always above 86%. Intra- and inter-assay precision (measured as coefficient of variation, CV%) and accuracy (measured as % error) values were always better than 13%. Limit of detection at 0.06 and 0.15 ng/mL and limit of quantification at 0.2 and 0.5 ng/mL for plasma and urine samples, respectively, were adequate for the purpose of the present study. CONCLUSIONS: Rapid extraction, identification and quantification of oxycodone and its metabolites both in urine and plasma by UHPLC-MS/MS assay was tested for its feasibility in clinical samples and provided excellent results for rapid and effective drug testing in patients under oxycodone treatment.

Dialyzability of Oxycodone and Its Metabolites in Chronic Noncancer Pain Patients with End-Stage Renal Disease.

OBJECTIVES: Opioids are the preferred analgesic drugs to treat severe chronic pain conditions among dialysis patients; however, knowledge about their dialyzability features is limited. Oxycodone is increasingly used for the treatment of chronic pain conditions as oral controlled release (CR) tablets; however, evidence about this drug and its metabolites' dialyzability is lacking. METHODS: We assessed, during 4-hour dialysis sessions, the effect of standard hemodialysis (HD) and online hemodiafiltration (HDF) methods on the plasma concentration of oxycodone and its metabolites in n = 20 chronic pain patients with end-stage renal disease who were stably treated with oral CR oxycodone. Chromatographic techniques were used to evaluate the studied compounds' plasma concentrations at three different time points during dialysis. RESULTS: Mean plasma concentrations of oxycodone and noroxycodone in the sample showed an overall reduction trend over time, but it was less enhanced for noroxycodone. Mean reduction in oxycodone and noroxycodone arterial concentrations was significant and higher with HDF (54% and 27%, respectively) than with HD (22% and 17%, respectively). Analysis of the regression of these compounds' clearance on their increasing arterial concentration showed a more stable and linear clearance prediction with HDF (roughly 85 mL/min); with HD, for increasing arterial concentration, clearance of oxycodone decreased while noroxycodone clearance increased. DISCUSSION: While no oxymorphone or noroxymorphone metabolites were detected, limited dialyzability of oxycodone and noroxycodone was documented along with insignificant postdialysis pain increment. This evidence will contribute toward considerations as to the safety of the use of oxycodone in dialysis patients in the future.

Simple and sensitive LC-MS/MS-based assay for the quantification of dimemorfan in human plasma for use in a pharmacokinetic study.

Dimemorfan phosphate has been widely used for 40 years throughout the world for the treatment of coughs. This is the first report on the use of an LC-MS/MS-based assay for the determination of dimemorfan in human plasma using estazolam as an internal standard after one-step protein precipitation with acetonitrile. Chromatographic separation was achieved on a Phenomenex Luna C18 column (3 µm, 50 × 2.0 mm) using a fast gradient method, which involves water and methanol as the mobile phase (both containing 0.1% formic acid). Dimemorfan and estazolam were detected with proton adducts at m/z values of 255.8 → 155.1 and 295.0 → 267.0, respectively, in the selected reaction monitoring positive mode. The linear dynamic range of the assay was 0.04-5.00 ng/mL. The chromatographic run time for each plasma sample was <5 min. The method was proven to be accurate, precise, and repeatable. Finally, the developed method was successfully applied for the determination of dimemorfan in a pharmacokinetic study using healthy Chinese subjects.

An ultra-high performance liquid chromatographic-tandem mass spectrometric method for the determination of sinomenine in human plasma after transdermal delivery of the zhengqing fengtongning injection.

A sensitive, precise and selective ultra-high performance liquid chromatography method coupled with triple-quadrupole mass spectrometry was developed and validated for the determination of trace amounts of sinomenine (ng/mL) in minute volumes of human plasma. Fifty microliter plasma samples were precipitated using methanol to extract sinomenine. Separation was carried out on a C18 column with a water and acetonitrile mobile phase gradient with formic acid as an additive. The mass spectrometry data were obtained in the positive ion mode, and the transition of multiple reactions was monitored at m/z 330.2→181.0 for sinomenine quantification. The working assay range for sinomenine was linear from 0.1173 to 15.02 ng/mL with the lower limit of quantification of 0.1173 ng/mL. The precision and accuracy of the method was less than 15% in intra-day and inter-day experiments with a matrix effect of less than 6.5%. After validation, the quantitative method was applied to analyze sinomenine levels in human plasma after transdermal delivery of the Zhengqing Fengtongning Injection. The results showed that some samples contained sinomenine within the concentration range 0.4131-4.407 ng/mL.

The pharmacokinetic study of sinomenine, paeoniflorin and paeonol in rats after oral administration of a herbal product Qingfu Guanjiesu capsule by HPLC.

An accurate and reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated for determination of sinomenine (SI), paeoniflorin (PF) and paeonol (PA), which was further applied to assess the pharmacokinetics of SI, PF and PA in an anti-arthritic herbal product, Qingfu Guanjieshu (QFGJS) capsule, in rats. Successful separation was achieved with a C18 column and a mobile phase composed of acetonitrile and aqueous phase (containing 0.1% formic acid, adjusted with triethylamine to pH 3.5 ± 0.2). The method was validated with excellent precision, accuracy, recovery and stability in calibration ranges from 0.06 to 11.62 µg/mL for SI, from 0.09 to 35.70 µg/mL for PF, and from 0.15 to 4.53 µg/mL for PA (with r(2) > 0.999 for all three compounds). Our results showed that absorption of PF after administration of QFGJS was similar to that after oral administration of PF alone; the absorption of SI was decreased while the absorption of PA was increased after giving QFGJS orally compared with pure compounds. We may conclude that pharmacokinetic studies of complex herbal products are not only necessary but also feasible by using representative bioactive chemicals as indicators of establishing quality control standards and of determining pharmacokinetic behavior of herbal medicines.

[Determination of dimemorfan in human plasma and urine with HPLC-MS/MS].

OBJECTIVE: To develop a sensitive and reproducible HPLC-MS/MS method for analyzing dimemorfan in human plasma and urine. METHODS: Dimemorfan was extracted from plasma and urine by redistilled ether, with lidocaine serving as the internal standard (IS). The analysis was performed on a column of ultimate C18 (50 mm x 4.6 mm, 5 microm) with the mobile phase consisting of methyl alcohol-water-formic acid = 75:25 : 0.05 at a flow rate of 0. 2 mL/min. Dimemorfan was detected by API 3000 mass spectrometer, with multiple reaction monitoring after protonated with ESI in positive electron ionization mode. The ion pairs being detected were (m/z) 256.4-->155. 3 (dimemorfan) and 235.4-->86.1 (lidocaine), respectively. RESULTS: The regression equation for dimemorfan showed excellent linearity (r = 0.995 7) from 0. 025 to 5.0 ng/mL of plasma with detecting limitation of 0.025 ng/mL and perfect linearity (r = 0.9983) from 0.1 to 20.0 ng/mL of urine with detecting limitation of 0.1 ng/mL. The method recoveries of dimemorfan in plasma and urine were ranging from 103.38% to 106.88% and 90.05% to 101.40%, respectively. The maximum intra-day and inter-day relative standard deviations (RSD) of concentration of dimemorfan were 5.92% and 5. 70% (for plasma), 10.35% and 8.80% (for urine), respectively. CONCLUSION: This new method was validated to be accurate and sensitive to determinate the concentration of dimemorfan in plasma and urine samples, and can be applied for pharmacokinetic studies of dimemorfan.

Do CYP2D6 genotypes reflect oxycodone requirements for cancer patients treated for cancer pain? A cross-sectional multicentre study.

OBJECTIVE: Opioids are recommended by the World Health Organization for moderate to severe cancer pain. Oxycodone is one of the most commonly used opioids and is metabolized in the liver by CYP3A4 and CYP2D6 enzymes. The aim of this cross-sectional study was to assess the relationship between oxycodone pharmacokinetics, pharmacodynamics and the CYP2D6 genotypes "poor metaboliser" (PM), "extensive metaboliser" (EM) and "ultra-rapid metaboliser" (URM) in a cohort of patients with cancer pain. METHODS: The patients were genotyped for the most common CYP2D6 variants and serum concentrations of oxycodone and metabolites were determined. Pain was assessed using the Brief Pain Inventory (BPI). The EORTC QLQ-C30 was used to assess the symptoms of tiredness and nausea. Cognitive function was assessed by the Mini Mental State (MMS) examination. Associations were examined by analyses of variance (ANOVA) and covariance (ANCOVA), or ordinal logistic regressions with and without covariates. RESULTS: The sample consisted of 27 PM, 413 EM (including heterozygotes) and 10 URM. PM had lower oxymorphone and noroxymorphone serum concentrations and oxymorphone to oxycodone ratios than EM and URM. No differences between PM, EM and URM in pain intensity, nausea, tiredness or cognitive function was found. CONCLUSION: CYP2D6 genotypes caused expected differences in pharmacokinetics, but they had no pharmacodynamic consequence. CYP2D6 genotypes did not influence pain control, the adverse symptoms nausea and sedation or the risk for cognitive failure in this study of patients treated with oxycodone for cancer pain.

Long-acting κ opioid antagonists nor-BNI, GNTI and JDTic: pharmacokinetics in mice and lipophilicity.

BACKGROUND: Nor-BNI, GNTI and JDTic induce κ opioid antagonism that is delayed by hours and can persist for months. Other effects are transient. It has been proposed that these drugs may be slowly absorbed or distributed, and may dissolve in cell membranes, thus slowing elimination and prolonging their effects. Recent evidence suggests, instead, that they induce prolonged desensitization of the κ opioid receptor. METHODS: To evaluate these hypotheses, we measured relevant physicochemical properties of nor-BNI, GNTI and JDTic, and the timecourse of brain and plasma concentrations in mice after intraperitoneal administration (using LC-MS-MS). RESULTS: In each case, plasma levels were maximal within 30 min and declined by >80% within four hours, correlating well with previously reported transient effects. A strong negative correlation was observed between plasma levels and the delayed, prolonged timecourse of κ antagonism. Brain levels of nor-BNI and JDTic peaked within 30 min, but while nor-BNI was largely eliminated within hours, JDTic declined gradually over a week. Brain uptake of GNTI was too low to measure accurately, and higher doses proved lethal. None of the drugs were highly lipophilic, showing high water solubility (> 45 mM) and low distribution into octanol (log D7.4 < 2). Brain homogenate binding was within the range of many shorter-acting drugs (>7% unbound). JDTic showed P-gp-mediated efflux; nor- BNI and GNTI did not, but their low unbound brain uptake suggests efflux by another mechanism. CONCLUSIONS: The negative plasma concentration-effect relationship we observed is difficult to reconcile with simple competitive antagonism, but is consistent with desensitization. The very slow elimination of JDTic from brain is surprising given that it undergoes active efflux, has modest affinity for homogenate, and has a shorter duration of action than nor-BNI under these conditions. We propose that this persistence may result from entrapment in cellular compartments such as lysosomes.

Influences on the pharmacokinetics of oxycodone: a multicentre cross-sectional study in 439 adult cancer patients.

OBJECTIVE: Oxycodone is widely used for the treatment of cancer pain, but little is known of its pharmacokinetics in cancer pain patients. The aim of this study was to explore the relationships between ordinary patient characteristics and serum concentrations of oxycodone and the ratios noroxycodone or oxymorphone/oxycodone in cancer patients. METHODS: Four hundred and thirty-nine patients using oral oxycodone for cancer pain were included. The patients' characteristics (sex, age, body mass index [BMI], Karnofsky performance status, "time since starting opioids", "oxycodone total daily dose", "time from last oxycodone dose", use of CYP3A4 inducer/inhibitor, "use of systemic steroids", "number of medications taken in the last 24 h", glomerular filtration rate (GFR) and albumin serum concentrations) influence on oxycodone serum concentrations or metabolite/oxycodone ratios were explored by multiple regression analyses. RESULTS: Sex, CYP3A4 inducers/inhibitors, total daily dose, and "time from last oxycodone dose" predicted oxycodone concentrations. CYP3A4 inducers, total daily dose, and "number of medications taken in the last 24 h" predicted the oxymorphone/oxycodone ratio. Total daily dose, "time from last dose to blood sample", albumin, sex, CYP3A4 inducers/inhibitors, steroids, BMI and GFR predicted the noroxycodone/oxycodone ratio. CONCLUSION: Women had lower oxycodone serum concentrations than men. CYP3A4 inducers/inhibitors should be used with caution as these are predicted to have a significant impact on oxycodone pharmacokinetics. Other characteristics explained only minor parts of the variability of the outcomes.

A sensitive LC-MS/MS method for the quantitation of oxycodone, noroxycodone, 6α-oxycodol, 6ß-oxycodol, oxymorphone, and noroxymorphone in human blood.

The objective of this study was to develop and validate a highly sensitive method for the detection of oxycodone, noroxycodone, 6ß-oxycodol, 6α-oxycodol, oxymorphone, and noroxymorphone in blood by liquid chromatography tandem mass spectrometry. The analytes were extracted from blood (0.5 mL) using Bond Elut Certify Solid Phase Extraction columns, evaporated to dryness and reconstituted before analysis was performed on an Acquity UPLC® I-class coupled to a Waters Xevo TQD. Academy Standards Board Standard Practices for Method Development in Forensic Toxicology were used for the validation of this method. The limit of quantitation for all analytes was established at 0.5 ng/mL. Calibration range for noroxymorphone, oxymorphone, 6α-oxycodol and 6ß-oxycodol was 0.5-25 ng/mL and 0.5-100 ng/mL for noroxycodone and oxycodone. Precision (2.90-17.3%) and bias studies resulted in a ±15% deviation. There were no interferences observed from internal standard, matrix, or common drugs of abuse. Stability of all analytes at two concentrations at 24, 48, and 72 h in the autosampler did not exceed ±20% difference from the initial T0. Dilution integrity at a ten-fold dilution was acceptable as analyte concentrations ranged between (±18%) of the target concentration. Once validated, the method was used in a pilot dosing study of one male subject after taking a 10 mg immediate release tablet of oxycodone. Blood samples were collected at 0.25, 0.50, 0.75, 1.0, 1.5, 2, 3, 4, 5, 6, 8, 9, and 24 h after ingestion. Oxycodone and noroxycodone both reached Tmax at 1.5 h and had Cmax values of 25.9 and 12.8 ng/mL, respectively. Oxycodone, 6α-oxycodol, and 6ß-oxycodol were detectable up to 9 h, while noroxymorphone and noroxycodone were still detected at 24 h.

Oxycodone findings and CYP2D6 function in postmortem cases.

Genetic disposition can cause variation in oxycodone pharmacokinetic characteristics and decrease or increase the expected clinical response. In forensic medicine, determination of cause of death or assessing time between drug intake and death can be facilitated by knowledge of parent and metabolite concentrations. In this study, the aim was to investigate if CYP2D6 genotyping can facilitate interpretation by investigating the frequency of the four CYP2D6 phenotypes, poor metabolizer, intermediate metabolizer, extensive metabolizer, and ultra-rapid metabolizer in postmortem cases, and to study if the CYP2D6 activity was associated with a certain cause of death, concentration, or metabolic ratio. Cases positive for oxycodone in femoral blood (n = 174) were genotyped by pyrosequencing for CYP2D6*3, *4, and *6 and concentrations of oxycodone, noroxycodone, oxymorphone, and noroxymorphone were determined by LC-MS/MS (LLOQ 0.005 µg/g). Digital droplet PCR was used to determine the copy number variation for CYP2D6*5. Cases were categorized by cause of death. It was found that poor and intermediate CYP2D6 metabolizers had significantly higher oxycodone and noroxycodone concentrations compared to extensive and ultra-rapid metabolizers. CYP2D6 phenotype were equally distributed between cause of death groups, showing that no phenotype was overrepresented in any of the cause of death groups. We also found that the concentration ratio between oxymorphone and oxycodone depended on the CYP2D6 activity when death was unrelated to intoxication. In general, a low metabolite to parent ratio indicate an acute intake. By using receiver operating characteristic (ROC) analysis, we conclude that an oxymorphone/oxycodone ratio lower than 0.075 has a high sensitivity for separating intoxications with oxycodone from other intoxications and non-intoxications. However, the phenotype needs to be known to reach a high specificity. Therefore, the ratio should not be used as a biomarker on its own to distinguish between different causes of death but needs to be complemented by genotyping.

HPLC and LC-MS analysis of sinomenine and its application in pharmacokinetic studies in rats.

AIM: To improve and validate analytical methods based on HPLC and liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the quantitative measurement of sinomenine in rat plasma and brain tissue. METHODS: The separation of analytes and the internal standard (IS), chloramphenicol, was performed on an Agilent TC-C18 column (250×4.6 mm, 5 µm). Blood samples were measured with a Surveyor photodiode array (PDA) detector at a wavelength of 263 nm. The LCQ DECA XP(Plus) mass spectrometer was operated in the multiple reactions monitoring mode using positive electrospray ionization, and the transition from the precursor ion (m/z 279) to the product ion (m/z 224) for sinomenine was measured in brain tissue. RESULTS: Measurements were linear over the concentration range of 0.1-100 µg/mL for sinomenine in plasma and over the range of 0.01-5.00 µg/g for sinomenine in brain tissue. The intra- and inter-day variabilities were less than 10% of the relative standard deviation (RSD), and the extraction and recovery of sinomenine was 72.48%-80.26% from plasma and 73.75%-80.26% from brain tissue. The limit of quantification (LOQ) was 0.1 µg/mL for plasma, and 0.01 µg/g for brain tissue. Identification of sinomenine was reproducible at 0.5, 5, and 50 µg/mL in the plasma and at 0.05, 0.50, and 2.00 µg/g in brain tissue. The concentration of sinomenine measured in brain tissue after a single ip dose had a neuroprotective effect on H2O2-induced injury in PC12 cells in vitro. CONCLUSION: Our methods offered a sensitivity within a wide linear concentration range for sinomenine. These methods were successfully applied to evaluate sinomenine pharmacokinetics over time in rat brain tissue after a single ip dose of 30 mg/kg.

[Rat in vitro plasma-binding percentage determination of sinomenine hydrochloride by using microdialysis method and ultrafiltration].

OBJECTIVE: To assess feasibility of plasma protein-binding percentage by using microdialysis method. METHOD: Sinomenine hydrochloride was selected as model drug. The in vitro rat plasma protein-binding percentage of three kinds of concentration was determinated by using microdialysis sampling tool and HPLC-UV. At the same time the classical study method, such as ultrafiltration method, was also used to determinate the protein-binding percentage to compare the difference between the two methods. RESULT: The in vitro rat plasma protein-binding percentage of sinomenine hydrochloride using microdialysis method was about 26% and kept relative stable at the concentration range. There was no significant difference between the two methods. CONCLUSION: The results shows that the binding percentage is relative low. Microdialysis method is a new method for the study of protein-binding degree.

[The pharmacokinetics study on Sinomenine transdermal patch on anaesthetized Beagle dogs].

OBJECTIVE: To explore the pharmacokinetic of Sinomenine transdermal patch. METHODS: The plasma drug concentration of Beagle dogs was determined after administration with HPLC-UVD as analysis tools. The pharmacokinetics parameters were fitted with kinetica software package. RESULTS: The exclusive analysis method was established with the following pharmacokinetics parameters: T (peak) = 8 h, Cmax = 366 ng/mL, MRT = 13 h. The pharmacokinetic characteristics was accordance with one-order rate and two-compartment model. CONCLUSION: The method is preferable to be applied to the pharmacokinetics research and further applied pharmacological study which will play a reference role in clinical application.

Monoterpenes-containing PEGylated transfersomes for enhancing joint cavity drug delivery evidenced by CLSM and double-sited microdialysis.

The synovial tissues are natural sites of drug delivery for the treatment of rheumatoid arthritis. Our previous study showed that mixed monoterpenes edge-activated PEGylated transfersomes (MMPTs) could significantly enhance the percutaneous absorption of sinomenine (SIN), an anti-inflammation drug. The aim of this study was to investigate the potential of MMPTs for delivery of SIN to the synovial tissues in joint cavities. To this end, conventional liposomes (LPSs) were used as a reference. Transmission electron microscope, constant pressure extrusion method, and differential scanning calorimetry (DSC) were used for physicochemical characterization of the formulations. Confocal laser scanning microscopy (CLSM) and double-sited microdialysis coupled with LC-MS/MS were exploited to study the distribution of MMPTs in different skin layers and pharmacokinetics of SIN in the blood and the joint cavities. The results showed that mixed monoterpenes could significantly enhance the elasticity of MMPTs, evidenced by a decrease in the main transition temperature (Tm) and transition enthalpy (△H). CLSM analyses demonstrated that MMPTs were distributed in deep layers of the skin, indicating that MMPTs might transport SIN through the skin. In contrast, LPSs were confined in the stratum corneum, which deterred SIN from penetrating through the skin. The results from double-sited microdialysis pharmacokinetics showed that in the joint cavities the steady state concentration (Css) and AUC0→t of SIN from MMPTs were 2.1-fold and 2.5-fold of those from LPSs, respectively. In contrast, in the blood the Css and AUC0→t of SIN from MMPTs were about 1/3 of those from LPSs. This study suggested that MMPTs could enhance the delivery of SIN to the joint cavities. A combination of CLSM and double-sited microdialysis could give an insight into the mechanism of transdermal and local drug delivery.

Positron emission tomography imaging of D(2/3) agonist binding in healthy human subjects with the radiotracer [(11)C]-N-propyl-norapomorphine: preliminary evaluation and reproducibility studies.

OBJECTIVE: (-)-N-[(11)C]-propyl-norapomorphine (NPA) is a full dopamine D(2/3) receptor agonist radiotracer suitable for imaging D(2/3) receptors configured in a state of high affinity for agonists using positron emission tomography. The aim of the present study was to define the optimal analytic method to derive accurate and reliable D(2/3) receptor parameters with [(11)C]NPA. METHODS: Six healthy subjects (four females/two males) underwent two [(11)C]NPA scans in the same day. D(2/3) receptor-binding parameters were estimated using kinetic analysis (using one- and two-tissue compartment models) as well as simplified reference tissue method in the three functional subdivisions of the striatum (associative striatum, limbic striatum, and sensorimotor striatum). The test-retest variability and intraclass correlation coefficient were assessed for distribution volume (V(T)), binding potential relative to plasma concentration (BP(P)), and binding potential relative to nondisplaceable uptake (BP(ND)). RESULTS: A two-tissue compartment kinetic model adequately described the functional subdivisions of the striatum as well as cerebellum time-activity data. The reproducibility of V(T) was excellent (0.75) in the three functional subdivisions of the striatum. Although SRTM led to an underestimation of BP(ND) values relative to that estimated by kinetic analysis by 8-13%, the values derived using both the methods were reasonably well correlated (r(2) = 0.89, n = 84). Both methods were similarly effective in detecting the differences in [(11)C]NPA BP(ND) between subjects. CONCLUSION: The results of this study indicate that [(11)C]NPA can be used to measure D(2/3) receptors configured in a state of high affinity for the agonists with high reliability and reproducibility in the functional subdivisions of the human striatum.

In situ hexagonal liquid crystal for intra-articular delivery of sinomenine hydrochloride.

The aim of this study was to investigate the release behaviors of sinomenine hydrochloride loaded via in situ hexagonal liquid crystal (ISH), and its potential to improve the local bioavailability in knee joints of sinomenine hydrochloride (SMH) after intra-articular administration. The ISH was prepared by a liquid precursor mixture containing phytantriol (PT), Vitamin E acetate (VEA), ethanol (ET), and water. The in vitro release profiles revealed a sustained release of SMH from the optimized ISH formula (PT/VEA/ET/water, 60.8:3.2:16.0:20.0, w/w/w/w), which was selected for the in vivo pharmacokinetics and preliminary pharmacodynamics studies. In both healthy and adjuvant-induced arthritis (AA) rats, the SMH loaded ISH showed significantly smaller SMH AUC0-∞ in plasma (P < 0.01), and higher SMH concentration in synoviums (2˜168 h) than that of SMH solution, indicating that the ISH significantly reduced the leakage of SMH into systemic circulation. The t1/2α of SMH loaded ISH in the knee joints of AA rats, was longer (13.42 h) than that of healthy rats (1.34 h) (P < 0.05), most likely that in vivo drug release behavior of SMH loaded ISH was affected by the physiological environment of the joint. It was found that the SMH loaded ISH could benefit AA-rats by suppressing the level of IL-1ß in comparison to SMH solutions. The results of the histopathology of knee joints in AA rats displayed that the SMH loaded ISH might be suitable for the development of treatment strategies for rheumatoid arthritis diseases.