Supramolecular Complexation in Biological Media: NMR Study on Inclusion of an Anionic Tetraarylporphyrin into a Per-O-Methylated ß-Cyclodextrin Cavity in Serum, Blood, and Urine.

The supramolecular complexation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) with heptakis(2,3,6-tri-O-methyl)-ß-cyclodextrin (TMCD) has been known to be highly specific in aqueous media. In this study, we have used NMR spectroscopy to reveal that this supramolecular system also works even in biologically crowded media such as serum, blood, and urine. A 13 C-labeled heptakis(2,3,6-tri-O-methyl-13 C)-ß-cyclodextrin (13 C-TMCD) was synthesized and studied using one-dimensional (1D) HMQC spectroscopy in serum and blood. The 1D HMQC spectrum of 13 C-TMCD showed clear signals due to the 2-, 3-, and 6-O13 CH3 groups, whose chemical shifts changed upon addition of TPPS due to quantitative formation of the 13 C-TMCD/TPPS=2/1 inclusion complex in such biological media. The 1 H NMR signals of non-isotope-labeled TPPS included by 13 C-TMCD were detected using the 13 C-filtered ROESY technique. A pharmacokinetic study of 13 C-TMCD and its complex with TPPS was carried out in mice using the 1D HMQC method. The results indicated that (1) 1D HMQC is an effective technique for monitoring the inclusion phenomena of 13 C-labeled cyclodextrin in biological media and (2) the intermolecular interaction between 13 C-TMCD and TPPS is highly selective even in contaminated media like blood, serum, and urine.

Clinical Pharmacokinetics of Sulfobutylether-ß-Cyclodextrin in Patients With Varying Degrees of Renal Impairment.

Delafloxacin, a fluoroquinolone, has activity against Gram-positive organisms including methicillin-resistant S aureus and fluoroquinolone-susceptible and -resistant Gram-negative organisms. The intravenous formulation of delafloxacin contains the excipient sulfobutylether-ß-cyclodextrin (SBECD), which is eliminated by renal filtration. This study examined the pharmacokinetics and safety of SBECD after single intravenous (IV) infusions in subjects with renal impairment. The study was an open-label, parallel-group, crossover study in subjects with normal renal function or mild, moderate, or severe renal impairment, and those with end-stage renal disease undergoing hemodialysis. Subjects received 300 mg delafloxacin IV or placebo IV, containing 2400 mg SBECD, in 2 periods separated by ≥14-day washouts. SBECD total clearance decreased with decreasing renal function, with a corresponding increase in area under the concentration-time curve (AUC0-∞ ). After IV delafloxacin 300 mg administration, SBECD mean total clearance was 6.28 and 1.24 L/h, mean AUC0-∞ was 387 and 2130 h·µg/mL, and mean renal clearance was 5.36 and 1.14 L/h in normal and severe renal subjects, respectively. Similar values were obtained after IV placebo administration. In subjects with end-stage renal disease, delafloxacin 300 mg IV produced mean SBECD AUC0-48 values of 2715 and 7861 h·µg/mL when dosed before and after hemodialysis, respectively. Total SBECD clearance exhibited linear relationships to estimated glomerular filtration rate and creatinine clearance. Single doses of IV delafloxacin 300 mg and IV placebo were well tolerated in all groups. In conclusion, decreasing renal function causes reduced SBECD clearance and increased exposures, but SBECD continues to exhibit a good safety and tolerability profile in IV formulations.

Absence of intestinal microbiota increases ß-cyclodextrin stimulated reverse cholesterol transport.

SCOPE: Non-digestible oligosaccharides are used as prebiotics for perceived health benefits, among these modulating lipid metabolism. However, the mechanisms of action are incompletely understood. The present study characterized the impact of dietary ß-cyclodextrin (ßCD, 10%, w/w), a cyclic oligosaccharide, on sterol metabolism and reverse cholesterol transport (RCT) in conventional and also germ-free mice to establish dependency on metabolism by intestinal bacteria. METHODS AND RESULTS: In conventional ßCD-fed C57BL/6J wild-type mice plasma cholesterol decreased significantly (-40%, p < 0.05), largely within HDL, while fecal neutral sterol excretion increased (3-fold, p < 0.01) and fecal bile acid excretion was unchanged. Hepatic cholesterol levels and biliary cholesterol secretion were unaltered. Changes in cholesterol metabolism translated into increased macrophage-to-feces RCT in ßCD-administered mice (1.5-fold, p < 0.05). In germ-free C57BL/6J mice ßCD similarly lowered plasma cholesterol (-40%, p < 0.05). However, ßCD increased fecal neutral sterol excretion (7.5-fold, p < 0.01), bile acid excretion (2-fold, p < 0.05) and RCT (2.5-fold, p < 0.01) even more substantially in germ-free mice compared with the effect in conventional mice. CONCLUSION: In summary, this study demonstrates that ßCD lowers plasma cholesterol levels and increases fecal cholesterol excretion from a RCT-relevant pool. Intestinal bacteria decrease the impact of ßCD on RCT. These data suggest that dietary ßCD might have cardiovascular health benefits.

Preparation, characterization and in vivo evaluation of a formulation of dantrolene sodium with hydroxypropyl-ß-cyclodextrin.

Dantrolene sodium (Da) is an effective skeletal muscle relaxant. However, its pharmacological effects are severely limited owing to its poor solubility and low oral bioavailability. In order to solve these problems, an inclusion complex using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) to improve the oral bioavailability of Da was prepared successfully by freeze-drying. The prepared complex was characterized by Powder X-ray diffractometry (PXRD), Fourier transform infrared spectroscopy (FTIR) and evaluated by a dissolution test and a pharmacokinetic study. The results of PXRD and FTIR proved the formation of a complex between Da and HP-ß-CD. The dissolution rate of Da was markedly improved from inclusion complex with more than 90% being released within 5min. The in vivo pharmacokinetics of Da and dantrolene sodium-hydroxypropyl-ß-cyclodextrin (Da-HP-ß-CD) inclusion complex were investigated in rats using a UPLC/MS/MS method. The Cmax and AUC0-t of the Da-HP-ß-CD inclusion complex were 5- and 3-fold higher than that of the Da. These results suggested that the Da-HP-ß-CD inclusion complex markedly improved the dissolution rate and bioavailability of Da.

Preparation of inclusion complex of apigenin-hydroxypropyl-ß-cyclodextrin by using supercritical antisolvent process for dissolution and bioavailability enhancement.

In this study, an inclusion complex of apigenin (AP)-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) was prepared via supercritical antisolvent (SAS) method using N, N-dimethylformamide (DMF) as solvent and carbon dioxide as antisolvent. The mole ratio of AP and HP-ß-CD (1:1) was established by phase solubility equilibrium experiment. The optimal conditions were determined through single-factor experiments; these conditions included precipitation pressure of 22.5MPa, precipitation temperature of 50°C, and AP concentration of 20mg/ml. The load efficiency and encapsulation efficiency of the AP-HP-ß-CD inclusion complex, with a mean particle size of 392.13±7.56nm, were 13.97%±0.17% and 93.22%±1.17%, respectively, under the optimal conditions. FTIR, (1)H NMR, SEM, XRD, DSC, and TG analyses were also conducted. Results showed that the inclusion complex was formed because of the interaction between AP and HP-ß-CD. DMF residue in the inclusion complex was 0.033% lower than the ICH limit for class II solvents. The solubility of the inclusion complex was approximately 152.43 times higher than that of the raw AP. In the in vitro study, the dissolution rate of the AP-HP-ß-CD inclusion complex was about 7.60 times higher than that of the raw AP. In the in vivo study, the bioavailability of the inclusion complex increased by 6.45 times compared with that of the raw AP. Hence, the prepared AP-HP-ß-CD inclusion complex exhibits potential as a new oral therapeutic agent formulation for clinical applications.

Evaluation of Sulfobutylether-ß-Cyclodextrin Exposure in a Critically Ill Patient Receiving Intravenous Posaconazole While Undergoing Continuous Venovenous Hemofiltration.

We present a 31-year-old female who had undergone an allogeneic bone marrow transplantation and who was started on intravenous posaconazole for pulmonary mycosis while undergoing continuous venovenous hemofiltration (CVVH). We performed steady-state pharmacokinetic evaluations for both posaconazole and sulfobutylether-ß-cyclodextrin (SBECD). SBECD was effectively removed by CVVH, with observed exposure similar to that for patients with moderate renal impairment. Intravenous posaconazole at standard doses may be utilized in critically ill patients undergoing CVVH without significant risk of SBECD accumulation.

The preparation, characterization, and pharmacokinetic studies of chitosan nanoparticles loaded with paclitaxel/dimethyl-ß-cyclodextrin inclusion complexes.

A novel biocompatible and biodegradable drug-delivery nanoparticle (NP) has been developed to minimize the severe side effects of the poorly water-soluble anticancer drug paclitaxel (PTX) for clinical use. PTX was loaded into the hydrophobic cavity of a hydrophilic cyclodextrin derivative, heptakis (2,6-di-O-methyl)-ß-cyclodextrin (DM-ß-CD), using an aqueous solution-stirring method followed by lyophilization. The resulting PTX/DM-ß-CD inclusion complex dramatically enhanced the solubility of PTX in water and was directly incorporated into chitosan (CS) to form NPs (with a size of 323.9-407.8 nm in diameter) using an ionic gelation method. The formed NPs had a zeta potential of +15.9-23.3 mV and showed high colloidal stability. With the same weight ratio of PTX to CS of 0.7, the loading efficiency of the PTX/DM-ß-CD inclusion complex-loaded CS NPs was 30.3-fold higher than that of the PTX-loaded CS NPs. Moreover, it is notable that PTX was released from the DM-ß-CD/CS NPs in a sustained-release manner. The pharmacokinetic studies revealed that, compared with reference formulation (Taxol(®)), the PTX/DM-ß-CD inclusion complex-loaded CS NPs exhibited a significant increase in AUC(0→24h) (the area under the plasma drug concentration-time curve over the period of 24 hours) and mean residence time by 2.7-fold and 1.4-fold, respectively. Therefore, the novel drug/DM-ß-CD inclusion complex-loaded CS NPs have promising applications for the significantly improved delivery and controlled release of the poorly water-soluble drug PTX or its derivatives, thus possibly leading to enhanced therapeutic efficacy and less severe side effects.

Efficacy of 2-Hydroxypropyl-ß-cyclodextrin in Niemann-Pick Disease Type C Model Mice and Its Pharmacokinetic Analysis in a Patient with the Disease.

Niemann-Pick type C disease (NPC), an autosomal recessive lysosomal storage disorder, is an inherited disease characterized by the accumulation of intracellular unesterified cholesterol. A solubilizing agent of lipophilic compounds, 2-hydroxypropyl-ß-cyclodextrin (HPBCD), is an attractive drug candidate against NPC disease. However, establishment of the optimum dosage of HPBCD remains to be determined. In this study, we evaluated the effective dosage of HPBCD in NPC model (Npc1(-/-)) mice, and determined serum HPBCD concentrations. Subcutaneous injection of 1000-4000 mg/kg HPBCD improved the lifespan of Npc1(-/-) mice. In addition, liver injury and cholesterol sequestration were significantly prevented by 4000 mg/kg HPBCD in Npc1(-/-) mice. Serum HPBCD concentrations, when treated at the effective dosages (1000-4000 mg/kg), were approximately 1200-2500 µg/mL at 0.5 h after subcutaneous injection, and blood HPBCD concentrations were immediately eliminated in Npc1(-/-) mice. Furthermore, we examined serum HPBCD concentrations when treated at 40000 mg (approximately 2500 mg/kg) in a patient with NPC. We observed that the effective concentration in the in vivo study using Npc1(-/-) mice was similar to that in the patient. In the patient, systemic clearance and the volume of distribution of HPBCD were in accordance with the glomerular filtration rate and extracellular fluid volume, respectively. These results could provide useful information for developing the optimal dosage regimen for HPBCD therapy when administered intravenously to NPC patients.

Evaluation of the impact of sulfobutylether7 -ß-cyclodextrin on the liquid chromatography-mass spectrometry analysis of biological samples arising from in vivo pharmacokinetic studies.

The utility of cyclodextrin (CD) complexation in improving apparent solubility of drugs in parenteral formulations is well established. Administration of these formulations delivers CD directly into the systemic circulation, and it may be necessary to demonstrate unaltered in vivo disposition of a drug coadministered with a CD. Crucial to the undertaking of such a study is the need for bioanalytical assays in which CD presence does not impact drug quantitation. This is of particular importance when assessing the potential impact of in vivo CD complexation on the urinary excretion of a drug, as CDs are predominantly eliminated via glomerular filtration, and hence are present in urine at significantly higher concentration than would be present in blood and plasma. Of 23 publications (in the past 30 years) describing preclinical and clinical assessment of drug pharmacokinetics after i.v. administration of CD-enabled formulations, only two reports clearly stated that the presence of CD had no impact on assay performance. In this work, we describe the simple process involved in (1) predicting the maximum concentrations of a modified CD, sulfobutylether7 -ß-CD (SBE7 -ß-CD), in plasma and urine samples from preclinical studies, and (2) evaluating the impact of SBE7 -ß-CD on the quantitative liquid chromatography-mass spectrometry analysis of rimantadine.

The effect of intravenous sulfobutylether7 -ß-cyclodextrin on the pharmacokinetics of a series of adamantane-containing compounds.

Intravenously administered (i.v.) drug-cyclodextrin (CD) inclusion complexes are generally expected to dissociate rapidly and completely, such that the i.v. pharmacokinetic profile of a drug is unchanged in the presence of CD. The altered pharmacokinetics of a synthetic ozonide in rats has been attributed to an unusually high-binding affinity (2.3 × 10(6) M(-1) ) between the drug and sulfobutylether7 -ß-cyclodextrin (SBE7 -ß-CD) with further studies suggesting a significant binding contribution from the adamantane ring. This work investigated the binding affinity of three adamantane derivatives [amantadine (AMA), memantine (MEM) and rimantadine (RIM)] to SBE7 -ß-CD and the impact of complexation on their i.v. pharmacokinetics. In vitro studies defined the plasma protein binding, as well as the impact of SBE7 -ß-CD on erythrocyte partitioning of each compound. SBE7 -ß-CD binding constants for the compounds were within the typical range for drug-like molecules (10(2) -10(4) M(-1) ). The pharmacokinetics of AMA and MEM were unchanged; however, significant alteration of RIM plasma and urinary pharmacokinetics was observed when formulated with CD. In vitro studies suggested two factors contributing to the altered pharmacokinetics: (1) low plasma protein binding of RIM, and (2) decreased erythrocyte partitioning in the presence of high SBE7 -ß-CD concentrations. This work demonstrated the potential for typical drug-cyclodextrin interactions to alter drug plasma pharmacokinetics.

An upconversion nanocomposite for fluorescence resonance energy transfer based cholesterol-sensing in human serum.

Upconversion nanophosphors (UCNPs) are extremely useful for analytical applications, since they display a high signal-to-noise ratio, and their photobleaching can be ignored. Herein, a novel upconversion nanocomposite composed of ß-cyclodextrin (ß-CD) derivative modified UCNPs and rhodamine B (RB) was prepared for the detection of cholesterol (Cho). The upconversion luminescence (UCL) emission can serve as a Cho-sensing signal by an effective fluorescence resonance energy transfer (FRET) process, using UCNPs as the donor and RB as the quencher. The sensor for Cho detection in human serum shows excellent sensitivity and selectivity, which has the potential for clinical applications in the analysis of other biological and environmental samples.

Hydroxypropyl-ß-cyclodextrin impacts renal and systemic hemodynamics in the anesthetized dog.

Hydroxypropyl-ß-cyclodextrin (HPßCD) is a complexation agent used to enhance drug solubilization and formulation stability. Although its toxicity is well characterized, its cardiovascular effects are less known. To investigate them, HPßCD was infused intravenously over 10 min in anesthetized dogs (10-40% (w/v, i.e. 200-800 mg/kg) in non-denervated animals and at 40% in denervated animals). HPßCD increased renal arteriolar resistance and decreased renal blood flow at all doses, almost immediately after infusion start, more drastically in females. A less pronounced increase in total peripheral resistance occurred in females only due to sex difference in sympathetic tone. Pulmonary hemodynamic parameters remained unaffected, suggesting that the renal effect was rather selective. As a consequence of the increased systemic blood pressure, heart rate decreased in normal animals without direct effect on cardiac conductance. This effect was abolished in denervated animals. This suggests that autonomous nervous feedback loops are functional in normal animals and that HPßCD has no direct chronotropic effect. In conclusion, systemic and renal hemodynamic changes should be considered as potential background effects at 200-400 mg/kg. At higher doses (800 mg/kg), changes are more pronounced and could mask/exacerbate hemodynamic response of drug candidate; such doses should be avoided in nonclinical safety studies.

The water-soluble inclusion complex of ilexgenin A with ß-cyclodextrin polymer--a novel lipid-lowering drug candidate.

A new water-soluble inclusion complex of ilexgenin A (IGA) with ß-cyclodextrin polymer (CDP) was prepared by a facile strategy and characterized by (1)H NMR , FT-IR, and UV-vis spectroscopy. Compared with IGA and the inclusion complex of IGA with ß-cyclodextrin (IGA-CD), the solubility of IGA-ß-cyclodextrin polymer (IGA-CDP) was greatly enhanced due to the water-soluble CDP host. The ratio of ß-cyclodextrin (ß-CD) units in CDP to IGA was determined as 2 : 1. KD of the inclusion complex was evaluated as 2.6 × 10(-3) mol L(-1). The effects of IGA-CDP on a hyperlipidemia mouse model were studied by intragastric administration. After 4 weeks, the IGA-CDP treatment resulted in decreased serum levels of total cholesterol and low-density lipoprotein-cholesterol. The effects of IGA-CDP on serum apolipoprotein levels were similar to its effects on lipid levels. By comparing liver area, the effects of IGA-CDP on pre-existing lesions were assessed. Furthermore, the efficacy and potency of water-soluble inclusion complex of IGA-CDP was 2-3 times higher than that of IGA. Taken together, it was possible to develop it to a novel drug candidate to regulate lipid abnormality.

A novel sensor based on electropolymerization of ß-cyclodextrin and L-arginine on carbon paste electrode for determination of fluoroquinolones.

An electrochemical sensor for fluoroquinolones (FQs) based on polymerization of ß-cyclodextrin (ß-CD) and L-arginine (L-arg) modified carbon paste electrode (CPE) (P-ß-CD-L-arg/CPE) was built for the first time. Synergistic effect of L-arg and ß-CD was used to construct this sensor for quantification of these important antibiotics. Scanning electron microscope (SEM) image shows that polymer of ß-CD and L-arg has been successfully modified on electrode. Electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV) further indicate that polymer of ß-CD and L-arg efficiently decreased the charge transfer resistance value of electrode and improved the electron transfer kinetic between analyte and electrode. Under the optimized conditions, this modified electrode was utilized to determine the concentrations of ciprofloxacin, ofloxacin, norfloxacin and gatifloxacin. The differential pulse voltammogram (DPV) exhibits the oxidation peak currents were linearly proportional to their concentration in the range of 0.05-100 µM for ciprofloxacin, 0.1-100 µM for ofloxacin, 0.1-40 µM for norfloxacin and 0.06-100 µM for gatifloxacin, respectively. This method was also successfully used to detect the concentrations of each drug in pharmaceutical formulations and human serum samples. In addition, this proposed fluoroquinolones sensor exhibited good reproducibility, long-term stability and fast current response.

Determination of docetaxel in rat plasma and its application in the comparative pharmacokinetics of Taxotere and SID530, a novel docetaxel formulation with hydroxypropyl-ß-cyclodextrin.

In this study, a sensitive, simple and reliable method for the quantification of docetaxel in rat plasma was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The plasma samples were prepared by protein precipitation, and paclitaxel was used as an internal standard (IS). Chromatographic separation was achieved using a Gemini C(18) column (2.0 × 150 mm, 5 µm) with a mobile phase consisting of 0.1% formic acid-acetonitrile (30:70, v/v). The precursor-product ion pairs used for multiple reaction monitoring were m/z 808.5 → 527.5 (docetaxel) and m/z 854.2 → 286.5 (IS, paclitaxel). A calibration curve for docetaxel was constructed over the range 1-1000 ng/mL. The developed method was specific, precise and accurate, and no matrix effect was observed. The validated method was applied in a comparative pharmacokinetic study in which two docetaxel formulations, SID530, a new parenteral formulation of docetaxel with hydroxypropyl-ß-cyclodextrin (HP-ß-CD), and Taxotere, were administered to rats at a dose of 5 mg/kg. For SID530 and Taxotere, the mean C(0) values were 1494 and 1818 ng/mL, respectively, and the AUC(last) values were 837 and 755 h ng/mL, respectively. These two formulations did not show any statistical differences with regard to the pharmacokinetic parameters, thus establishing that the SID530 and Taxotere products are pharmacokinetically comparable in male rats.

The effect of parenterally administered cyclodextrins on the pharmacokinetics of coadministered drugs.

Cyclodextrins are used increasingly to formulate otherwise poorly soluble molecules for clinical use. Cyclodextrins, such as 2-hydroxypropyl-ß-cyclodextrin (HPßCD) and sulfobutylether ß-cyclodextrin (SBEßCD), are found in marketed parenteral drug formulations. Depending upon the relative affinities of a coadministered medication for cyclodextrin and plasma proteins, complexation with HPßCD or SBEßCD may alter its pharmacokinetics (PK). To explore this possibility, we applied a previously developed model for competitive binding of drugs with HPßCD and human serum albumin to a variety of commonly administered medications. We modeled this potential interaction in medications chosen on the basis of a hypothetical detrimental effect of HPßCD complexation with their therapeutic action (e.g., antibiotics), supplemented by a composite listing of concurrent medications. Stability constant (K(1:1)) values for drug-HPßCD 1:1 inclusion complexes were extracted from our own data and the literature. The K(1:1) values for the drugs tested ranged from 2 to 40,000 M(-1) and the plasma protein binding from about 20% to over 99%. None of the 63 drugs examined in the present study had a sufficiently high K(1:1) value for HPßCD complexation to affect plasma protein binding to a degree that would be expected to alter their PK substantively, for example, to require increased doses.

Comparative canine pharmacokinetics-pharmacodynamics of fospropofol disodium injection, propofol emulsion, and cyclodextrin-enabled propofol solution following bolus parenteral administration.

The pharmacokinetics and pharmacodynamics of fospropofol (FP) disodium injection, propofol emulsion (PE), and cyclodextrin-enabled propofol (CDP) solution following bolus parenteral administration in dogs was evaluated. Three healthy male beagle dogs were treated in a three-way cross-over study (14 day washout period) with 6 mg/kg propofol equivalents. Blood samples were collected predose and at 16 points postdose through 1440 min and analyzed for propofol and FP, when appropriate. From 5 min predose to 30 min postdose, brain electrical activity [electroencephalography (EEG)] was recorded and analyzed by power spectrum analysis techniques. Each formulation appeared to be well tolerated with transient discomfort observed in the PE and CDP animals and minor excitability in the FP animals prior to loss of consciousness. Blood propofol followed three-compartment pharmacokinetic behavior and derived parameters were not statistically different except for elimination half-life from the CDP formulation and onset, and duration of anesthesia from the FP formulation. The effect site concentrations at 50% the maximum EEG effect for the FP and CDP formulations were approximately one-half that of the PE formulation. Onset and duration of anesthesia are correlated with modeled effect site propofol concentrations. The implications of formulation on pain on injection and propofol activity are discussed.

Pharmacokinetic equivalence of Taxotere and SID530, a novel docetaxel formulation containing hydroxypropyl-beta-cyclodextrin in monkeys.

SID530 is a new parenteral formulation of docetaxel containing hydroxypropyl-beta-cyclodextrin (HP-ß-CD). In this study, a comparative pharmacokinetic study of 2 docetaxel parenteral solutions, SID530 and Taxotere, was carried out. In a crossover experimental design, 6 male cynomolgus monkeys received each formulation by intravenous infusion of a single dose. The concentration of docetaxel in whole blood and plasma was determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The 2 formulations showed similar pharmacokinetic parameters in both whole blood and plasma, and displayed comparable values for maximum serum concentration (Cmax), time to peak concentration (Tmax), and area under the concentration-time curve (AUC). The 90% confidence intervals for the ratios of Cmax and AUC values for SID530 to Taxotere were within the acceptable range of 0.80-1.20 in both plasma and whole blood. These findings indicate that SID530 and Taxotere are comparable in terms of their distribution in the blood and their plasma profile; consequently, these drugs are bioequivalent in the monkey.

Simultaneous identification of the enantiomers and diastereomers of N,O-di-trifluoroacetylated ephedrine and norephedrine in blood plasma using chiral capillary gas chromatography-mass spectrometry with selected ion monitoring.

A method for identifying the enantiomers of N,O-di-trifluoroacetylated ephedrine (EP) and norephedrine (NE) and the enantiomers of pseudoephedrine (PEP) and pseudonorephedrine (PNE) in plasma was developed using chiral capillary gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM). N,O-Di-trifluoroacethyl (TFA) derivatization was accomplished in a dried hydrochloride extract of plasma (minimum quantity of 0.2 mL). An SIM GC-MS method with a ß-cyclodextrin chiral capillary column allowed the successful and simultaneous detection of each TFA-derivatized stereoisomer of EP, NE, PEP, PNE, and an internal standard (IS; S-(+)-ethylamphetamine). Each TFA-drivatized stereoisomer was identified using four mass fragment ions (m/z 140, 154, 168, and 230). The TFA-derivatized stereoisomers of EP, NE, PEP, PNE, and IS were separated completely and were detected with sufficient sensitivity. The assay allowed the stereoisomers to be determined in a linear range of 12.5-1250 ng/mL for the EP stereoisomers and a linear range of 5-1250 ng/mL for the PEP, NE, and PNE stereoisomers. The detection limits were 7.5 ng/mL for the EP stereoisomers and 2.5 ng/mL for the PEP, NE, and PNE stereoisomers. The intra- and interday precisions were less than 5.9% and 8.2%, respectively. This chiral capillary SIM GC-MS method was sufficiently effective in the analysis of plasma from users of over-the-counter cold medicines and was also fully applicable to the plasma analysis of guinea pigs following their treatment with racemic EP.

Absorption and tissue tolerance of ricobendazole in the presence of hydroxypropyl-beta-cyclodextrin following subcutaneous injection in sheep.

Post-injection precipitation may cause poor and erratic drug absorption and tissue irritation at the injection site. Tissue tolerance and pharmacokinetics of a low pH ricobendazole (RBZ) injectable containing 20% hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were simultaneously investigated after subcutaneous injection in sheep compared to a reference formulation without HP-beta-CD. Each animal received a RBZ containing formulation on one side of the back and the respective vehicle on the contralateral side. The HP-beta-CD vehicle showed good tissue tolerance and the acidic solution caused minimal injection site reactions. Both RBZ containing formulations caused pain on injection and tissue histological changes in some animals. Lack of elevation of plasma creatine kinase indicated that none of the formulations caused significant damage to the underlying muscle tissue. Compared to the reference formulation, AUC and C(max) of the HP-beta-CD formulation were 1.6 and 2.2 times higher, respectively, whereas t(max), MRT and t(1/2) were significantly shorter suggesting faster and greater absorption of RBZ in the presence of HP-beta-CD. This was attributed to the effect of inhibition of post-injection drug precipitation and drug absorption enhancement of HP-beta-CD. In conclusion, HP-beta-CD was shown to be a tissue-compatible excipient with potential to inhibit post-injection precipitation and increase absorption of poorly water soluble drugs. Additionally, the HP-beta-CD formulation showed promise as an injectable that potentially minimizes irritation by reducing the dose required.