Population pharmacokinetics of intravenous, intramuscular, and intranasal naloxone in human volunteers

To investigate the pharmacokinetics of naloxone in healthy volunteers, we undertook an open-label crossover study in which six male volunteers received naloxone on five occasions: intravenous (0.8 mg), intramuscular (0.8 mg), intranasal (0.8 mg), intravenous (2 mg), and intranasal (2 mg). Samples were collected for 4 hours after administration for 128 samples in total. A population pharmacokinetic analysis was undertaken using NONMEM. The data were best described by a three-compartment model with first-order absorption for intramuscular and intranasal administration, between-subject variability on clearance and central volume, lean body weight on clearance, and weight on central volume. Relative bioavailability of intramuscular and intranasal naloxone was 36% and 4%, respectively. The final parameter estimates were clearance, 91 L/hr; central volume, 2.87 L; first peripheral compartment volume, 1.49 L, second peripheral compartment volume, 33.6 L; first intercompartmental clearance, 5.66 L/hr; second intercompartmental clearance, 29.8 L/hr; Ka (intramuscular), 0.65; and Ka (intranasal), 1.52. Median time to peak concentration for intramuscular naloxone was 12 minutes and for intranasal, 6 to 9 minutes. A combination of intravenous and intramuscular naloxone provided immediate high and then detectable concentrations for 4 hours. Intranasal naloxone had poor bioavailability compared with intramuscular. Combined intravenous and intramuscular administration may be a useful alternative to naloxone infusions.     

A novel formulation of ketorolac tromethamine for intranasal administration: preclinical safety evaluation

Ketorolac tromethamine is a potent analgesic and moderately effective anti-inflammatory drug approved for treatment of moderately severe acute pain as an intravenous/intramuscular injectable solution and an oral tablet. ROXRO PHARMA, Inc has developed an intranasal formulation, SPRIX, that delivers the drug with a similar pharmacokinetic profile to that obtained with intramuscular administration. Local tolerance and systemic toxicology studies were performed in rats and rabbits and showed that intranasal administration of SPRIX exhibits toxicity similar to that of other routes of administration and does not result in any adverse effects on the nasal passage and upper and lower respiratory system.     

Brain targeting studies on buspirone hydrochloride after intranasal administration of mucoadhesive formulation in rats

Objectives The purpose of this study was to find out whether nasal application of buspirone could increase its bioavailability and directly transport the drug from nose to brain. Methods A nasal formulation (Bus‐chitosan) was prepared by dissolving 15.5 mg buspirone hydrochloride, 1% w/v chitosan hydrochloride and 5% w/v hydroxypropyl β‐cyclodextrin (HP‐β‐CD) in 5 ml of 0.5% sodium chloride solution. The formulation was nasally administered to rats and the plasma and brain concentration compared with that for buspirone hydrochloride solution after intravenous and intranasal (Bus‐plain) administration. The brain drug uptake was also confirmed by gamma scintigraphic study. Key findings The nasal Bus‐chitosan formulation improved the absolute bioavailability to 61% and the plasma concentration peaked at 30 min whereas the peak for nasal Bus‐plain formulation was 60 min. The AUC_0‐480 in brain after nasal administration of Bus‐chitosan formulation was 2.5 times that obtained by intravenous administration (711 ± 252 ng/g vs 282 ± 110 ng/g); this was also considerably higher than that obtained with the intranasal Bus‐plain formulation (354 ± 80 ng/g). The high percentage of direct drug transport to the brain (75.77%) and high drug targeting index (>1) confirmed the direct nose to brain transport of buspirone following nasal administration of Bus‐chitosan formulation. Conclusions These results conclusively demonstrate increased access of buspirone to the blood and brain from intranasal solution formulated with chitosan and HP‐β‐CD.     

Pharmacokinetics and pharmacodynamics of midazolam administered as a concentrated intranasal spray. A study in healthy volunteers

AIMS: To investigate the pharmacokinetic and pharmacodynamic profile of midazolam administered as a concentrated intranasal spray, compared with intravenous midazolam, in healthy adult subjects. METHODS: Subjects were administered single doses of 5 mg midazolam intranasally and intravenously in a cross-over design with washout period of 1 week. The total plasma concentrations of midazolam and the metabolite 1-hydroxymidazolam after both intranasal and intravenous administration were described with a single pharmacokinetic model. beta-band EEG activity was recorded and related to midazolam plasma concentrations using an exponential pharmacokinetic/pharmacodynamic model. RESULTS: Administration of the intranasal spray led to some degree of temporary irritation in all six subjects, who nevertheless found intranasal administration acceptable and not painful. The mean (+/-s.d.) peak plasma concentration of midazolam of 71 (+/-25 ng ml-1) was reached after 14 (+/-5 min). Mean bioavailability following intranasal administration was 0.83+/-0.19. After intravenous and intranasal administration, the pharmacokinetic estimates of midazolam were: mean volume of distribution at steady state 1.11+/-0.25 l kg-1, mean systemic clearance 16.1+/-4.1 ml min-1 kg-1 and harmonic mean initial and terminal half lives 8.4+/-2.4 and 79+/-30 min, respectively. Formation of the 1-hydroxymetabolite after intranasal administration did not exceed that after intravenous administration. CONCLUSIONS: In this study in healthy volunteers a concentrated midazolam nasal spray was easily administered and well tolerated. No serious complications of the mode of administration or the drug itself were reported. Rapid uptake and high bioavailability were demonstrated. The potential of midazolam given via a nasal spray in the acute treatment of status epilepticus and other seizure disruptions should be evaluated.     

Pharmacodynamics of acute intranasal administration of verapamil: comparison with i.v. and oral administration

The present study was conducted in order to examine the intranasal administration of verapamil and compare this route to oral and intravenous administration in a 3 way crossover protocol in five dogs. Unanesthetized, adult mongrel dogs were given verapamil intravenously (0.5 mg/kg), orally (2.5 mg/kg) and intranasally (0.75 mg/kg) with at least a 3-4 day washout period between each administration. Blood samples were collected over a 10 hour period and analyzed for verapamil using HPLC with fluorescence detection. A lead II ECG was monitored to determine the effects of verapamil on heart rate and P-R interval. Following intravenous administration, verapamil was distributed according to a two compartment model. Bioavailability (corrected for dose and elimination rate constant) following intranasal administration (36% +/- 7%) was approximately 3 fold that after oral administration (13% +/- 3%). Absorption from the nasal cavity appeared instantaneous compared to an absorption half-life of 50 +/- 6 min after oral administration. All three routes of administration resulted in significant increases in heart rate and increases in the P-R interval. Maximal P-R interval prolongation occurred after peak plasma concentrations of verapamil. The results of this study suggest that the intranasal route is a viable alternative route of administration for verapamil.     

Intranasal administration of midazolam in a cyclodextrin based formulation: bioavailability and clinical evaluation in humans.

Intranasal administration of midazolam has been of particular interest because of the rapid and reliable onset of action, predictable effects, and avoidance of injections. The available intravenous formulation (Dormicum i.v. solution from Hoffmann-La Roche) is however less than optimal for intranasal administration due to low midazolam concentration and acidity of the formulation (pH 3.0-3.3). In this study midazolam was formulated in aqueous sulfobutylether-beta-cyclodextrin buffer solution. The nasal spray was tested in 12 healthy volunteers and compared to intravenous midazolam in an open crossover trial. Clinical sedation effects, irritation, and serum drug levels were monitored. The absolute bioavailability of midazolam in the nasal formulation was determined to be 64 +/- 19% (mean +/- standard deviation). The peak serum concentration from nasal application, 42 +/- 11 ng ml-1, was reached within 10-15 min following administration and clinical sedative effects were observed within 5 to 10 min and lasted for about 40 min. Intravenous administration gave clinical sedative effects within 3 to 4 min, which lasted for about 35 minutes. Mild to moderate, transient irritation of nasal and pharyngeal mucosa was reported. The nasal formulation approaches the intravenous form in speed of absorption, serum concentration and clinical sedation effect. No serious side effects were observed.     

Absorption of clonazepam after intranasal and buccal administration.

Serum concentrations of clonazepam after intranasal, buccal and intravenous administration were compared in a cross-over study in seven healthy male volunteers. Each subject received a 1.0 mg dose of clonazepam intranasally and buccally and 0.5 mg intravenously. A Cmax of 6.3 +/- 1.0 ng ml-1 (mean; +/- s.d.) was measured 17.5 min (median) (range 15-20 min) after intranasal administration. A second peak (4.6 +/- 1.3 ng ml-1) caused by oral absorption was seen after 1.7 h (range 0.7-3.0 h). After buccal administration a Cmax of 6.0 +/- 3.0 ng ml-1 was measured after 50 min (range 30-90 min) with a second peak of 6.5 +/- 2.5 ng ml-1 after 3.0 h (range 2.0-4.0 h). Two minutes after i.v. injection of 0.5 mg clonazepam the serum concentration was 27 +/- 18 ng ml-1. It is concluded that intranasal clonazepam is an alternative to buccal administration. However, the Cmax of clonazepam after intranasal administration is not high enough to recommend the intranasal route as an alternative to intravenous injection.     

冰片对大鼠经鼻腔给药灯盏花素体内药动学的影响

目的:探索冰片对大鼠经鼻腔给药灯盏花素体内药代动力学的影响。方法:采用同位素标记法125I检测实验大鼠经过尾静脉注射、单纯鼻腔给药和鼻腔给药联合冰片三种途径摄入0.4mg/kg灯盏花素以后的药代动力学,测定1、5、10、30、60、90、120、150、180、210、270min的血浆中灯盏乙素的浓度,绘制药时曲线并比较三种途径的药代动力学参数。结果:经鼻腔给药联合冰片组大鼠的tmax为22min短于单纯鼻腔给药组的tmax30min,差异有统计学意义(t=5.73,P=0.025);经鼻腔联合冰片组和单纯鼻腔给药组的Cmax分别为0.55、0.52μg/mL,绝对生物利用度分别为53.21%和53.71%,差异没有统计学意义。结论:冰片可以在一定程度上影响大鼠经鼻腔灯盏花素给药,使其血浆灯盏乙素浓度的达峰时间缩短,但是对灯盏乙素的绝对生物利用度没有明显影响,可以为灯盏花素新制剂的研究提供新方向。     

Pharmacokinetic studies on micronomicin in rats. Comparison of intramuscular and drip intravenous administration models

Absorption, tissue distribution and excretion of micronomicin (MCR) were studied in rats after intramuscular or 30 minutes drip intravenous administration (10 mg/kg). Serum levels of MCR were measured by bioassay, enzyme immunoassay and high pressure liquid chromatography. The pharmacokinetic studies of MCR after intramuscular or drip intravenous administration were carried out using one-compartment open model or two-compartment open model, respectively. Among 3 assay methods, similar pharmacokinetic parameters of MCR were obtained. In the simulation of serum levels of MCR, the differences between the measured and calculated serum levels after intramuscular or drip intravenous administration were less than 19% of the former levels. After intramuscular or drip intravenous administration of MCR, similar changes of the organ (kidneys, lungs, spleen and liver) levels were observed. Urinary recovery rates of MCR amounted to 82.3% or 91.6% by 24 hours after intramuscular or drip intravenous administration, respectively. After intramuscular or drip intravenous administration of MCR, no metabolites were found in urine of rats.     

Brain microdialysate,CSF and plasma pharmacokinetics of ligustrazine hydrochloride in rats after intranasal and intravenous administration

The aim of this work was to investigate the pharmacokinetics of ligustrazine hydrochloride (LZH) in plasma, cerebrospinal fluid (CSF) and cerebral cortex after intranasal (10 mg/kg) or intravenous administration (10 mg/kg) in male Sprague–Dawley rats. Plasma, CSF and cerebral cortex microdialysates were collected at timed intervals for the measurement of LZH by a quick and sensitive HPLC‐UV method. LZH entered the brain quickly following both routes of administration. No significant difference was observed between the AUC_{CSF or cortex}/AUC_plasma ratio of LZH after intranasal administration (38.4%, 17.4%) and that after intravenous injection (45.9%, 19.9%). The drug targeting index (DTI) was 0.85 and 0.91 in the CSF and cortex, respectively. In conclusion, LZH is rapidly absorbed into the systemic circulation following intranasal administration. There is no direct pathway for LZH transport from the nasal cavity to the brain. The rapidity and magnitude of LZH penetration into the brain indicate that intranasal administration of this agent is a promising alternative to intravenous administration. Copyright © 2013 John Wiley & Sons, Ltd.     

Preliminary studies of the pharmacokinetics and tolerability of zolmitriptan nasal spray in healthy volunteers

Two preliminary studies of the pharmacokinetics and tolerability of zolmitriptan nasal spray were conducted, each involving 12 healthy volunteers. In study 1, an initial double-blind, dose escalation phase (placebo or 2.5, 5.0, or 10 mg zolmitriptan intranasally) was followed by an open crossover phase in which all subjects received 10 mg zolmitriptan as a nasal spray, tablet, and oral solution. In study 2, subjects received, on three separate occasions, zolmitriptan 2.5 mg as an intranasal solution at pH 7.4, at pH 5.0, and as an oral tablet. In study 1, plasma concentrations of zolmitriptan and its active metabolite, 183C91, were broadly dose proportional. Plasma concentrations of zolmitriptan were detected earlier following nasal spray administration than after either tablet or oral solution. Similarly, in study 2, zolmitriptan was absorbed more rapidly following nasal spray administration with detectable plasma concentrations 5 minutes after dosing. Plasma levels were maintained at a plateau between 1 and 6 hours postdose, then decreased with a half-life of approximately 3 hours. There was no statistically significant difference for AUG or C(max) values between the two nasal spray solutions or between nasal spray and oral formulations. Other pharmacokinetic parameters for zolmitriptan were similar between the formulations. Plasma concentrations of 183C91 were higher for the first 2 hours after oral than after nasal spray administration. All formulations of zolmitriptan were well tolerated.     

Effects of imipenem and meropenem on purine content of endothelial cells

Intravenous compatibility of antibacterial agents has been tested in animal models. Use of human umbilical venous endothelial cells (HUVEC) to test antibiotic solutions for intravenous tolerance provides a valuable alternate model. OBJECTIVE: Evaluation of the effect of imipenem and meropenem on intracellular purines reflecting viability, energy production, signal transduction, and DNA/RNA synthesis of these cells. MATERIALS AND METHODS: Levels of intracellular adenosine 5' triphosphate (ATP), adenosine 5' diphosphate (ADP), guanosine 5' triphosphate (GTP) and guanosine 5' diphosphate (GDP) were measured by means of high performance liquid chromatography (HPLC). RESULTS: The total amount of ATP after incubation of cells with 10.0 mg/ml imipenem and meropenem for 20 minutes (12.93 +/- 0.93 nmol/million cells and 13.27 +/- 0.89 nmol/million cells, respectively) did not result in a decrease compared to controls (12.34 +/- 0.87 nmol/million cells). In addition, ATP levels were maintained or actually increased after 60 minutes. Incubation of cells with 5.0 mg/ml and 2.5 mg/ml of imipenem or meropenem for 20 and 60 minutes showed similar results. Purine nucleotide profiles of ADP, GTP, GDP following exposure of 10.0 mg/ml, 5.0 mg/ml and 2.5 mg/ml of imipenem and meropenem did not differ markedly. CONCLUSIONS: These in vitro data show an excellent endothelial compatibility of imipenem and meropenem even in high concentrations.     

Profiles of methotrexate in blood and CSF following intranasal and intravenous administration to rats

The aim of this paper was to investigate the levels of methotrexate (MTX) in blood and the cerebrospinal fluid (CSF) in rats to find out whether there is any direct drug transport from nasal cavity to CSF following intranasal administration. Methotrexate was administered to male Sprague-Dawley rats either intranasally or intravenously. Drug concentrations were determined from CSF and plasma samples collected from the cisterna magna and caudal vein, respectively. To collect CSF sample continuously, blank artificial CSF was infused into the lateral ventricle. The plasma levels achieved following intranasal administration were significantly lower than those after intravenous administration (P<0.01) were, while CSF concentrations achieved after intranasal administration were significantly higher than those after intravenous administration (P<0.01). The ratio of the AUC(CSF) value between the intranasal route and the intravenous injection was 13.76, whereas the absolute bioavailability was only 6.3%, the drug targeting index (DTI) of nasal route was 21.7. In conclusion, these results showed that the antineoplastic MTX must be directly transported from the nasal cavity into the CSF in rats.     

Comparative pharmacokinetics of single doses of doxylamine succinate following intranasal,oral and intravenous administration in rats

The intranasal route of administration provides a potential useful way of administering a range of systemic drugs. In order to assess the feasibility of this approach for the treatment of nausea and vomiting, doxylamine succinate was studied in rats for the pharmacokinetics (AUC, C(max), t(max)) following intranasal, oral and intravenous administrations. Subjects (six male Sprague-Dawley rats per time interval for each route of administration) received 2-mg doses of doxylamine succinate orally and I-mg doses intranasally and intravenously, respectively. The various formulations were formulated in isotonic saline (0.9% w/v) at 25 +/- 1 degrees C. Doxylamine succinate concentrations in plasma were determined with a high-performance liquid chromatographic assay and a liquid-liquid extraction procedure. Intranasal and oral bioavailabilities were determined from AUC values relative to those after intravenous dosing. Intranasal bioavailability was greater than that of oral doxylamine succinate (70.8 vs 24.7%). The intranasal and oral routes of administration differed significantly from the intravenous route of administration. Peak plasma concentration (C(max)) was 887.6 ng/ml (S.D. 74.4), 281.4 ng/ml (S.D. 24.6) and 1296.4 ng/ml (S.D. 388.9) for the intranasal, oral and intravenous routes, respectively. The time to achieve C(max) for the intranasal route (t(max)=0.5 h) was faster than for the oral route (t(max)=1.5 h), but no statistically significant differences between the C(max) values were found using 95% confidence intervals. The results of this study show that doxylamine succinate is rapidly and effectively absorbed from the nasal mucosa.     

Absorption of diazepam in man following rectal and parenteral administration.

Serum concentrations of diazepam and N-desmethyldiazepam were measured in six adult patients following administration of 10 mg diazepam in solution by the rectal, intravenous, and intramuscular routes. Maximum serum concentrations of 121--200 ng/ml were recorded from 10 to 20 min. after the rectal instillation, whereas following intramuscular injection the levels rose slowly and irregularly, reaching a maximum (62--186 ng/ml) in 1 to 24 hours. The bioavailability of diazepam given by rectal instillation was found to be 50 +/- 17 per cent (mean +/- S. D.) as compared with the intravenous administration. The possible reasons for the low bioavailability are discussed. It is concluded that administration by rectal tube provides a useful alternative to the tablets (and intramuscular injections) when a rapid onset of effect of the drug is wanted, and when intravenous administration is not applicable or practical.     

Ukrain: acute toxicity after intravenous, intramuscular and oral administration in rats

The acute toxicity of Ukrain (1 g/30 ml) was determined after a single intravenous, intramuscular or oral administration in rats, performed in accordance with Good Laboratory Practice and the relevant European Community directive. Groups of five (male and/or female) Him:OFA rats were treated once with the following doses: intravenous route: 1.0 ml/kg (males and females), 1.7 ml/kg (males and females) and 3.0 ml/kg (females); intramuscular route: 5.0 ml/kg (males and females); oral route: 15.0 ml/kg (females), 27.0 ml/kg (males and females) and 50 ml/kg (females). The animals were kept for up to 14 days afterwards while clinical observations and body weight determinations were made and were then necropsied. An intravenous injection of Ukrain (1 g/30 ml) induced immediate effects (short-term unconsciousness, followed by cardiovascular signs and, later, signs of general malaise), which if not lethal, disappeared in a short time. It was found that the intravenous LD50 was greater than 43 mg active ingredient/kg body weight in the males and 76 mg active ingredient/kg body weight in the females. An intramuscular injection of Ukrain (1 g/30 ml) in the maximum technically feasible dose induced some transient signs of minor clinical importance which did not become life threatening. In both sexes the intramuscular LD50 was greater than 165 mg active ingredient/kg body weight.     

Studies on the intravenous administration of amikacin to neonates

Amikacin (AMK) was administered mainly to neonates by either intravenous drip infusion or intramuscular injection and its pharmacokinetic changes were investigated. The results obtained are summarized as follows. 1. Serum half-lives of AMK in neonates at ages 0 to 3 days were longer than those at ages 4 to 10 days. Serum half-lives were prolonged particularly in neonates at an age 0 day. Neonates at ages 11 to 15 days, also showed longer half-lives in comparison to infants. Similar peak serum levels were observed in all the neonates with ages 0-15 days. 2. Similar serum AMK levels were obtained in neonates through intravenous drip infusion and through intramuscular injection at a same dose level. 3. When the drug was administered to neonates at 3.0 to 6.0 mg/kg by intravenous drip infusion, peak serum levels did not reach 30 micrograms/ml which is considered to be the critical level for AMK to be toxic. 4. Urinary excretion rates in neonates 11 day or older were almost the same levels as in infants. 5. AMK, when administered through intravenous drip infusion, was observed to have a higher migration rate to saliva when compared with kanamycin administered through intramuscular injection. 6. Based on the results obtained from the present study, the following doses seem to be optimal for neonates, but further studies are required to be conclusive. For neonates: 2.0 to 5.0 mg/kg daily in 1 to 2 divided doses. (For those at ages of 0 to 3 days: 2.0 to 3.0 mg/kg) For infants: 3.0 to 8.0 mg/kg daily in 1 to 2 divided doses through intravenous drip infusion over a period of 30 minutes to 1 hour.     

Pharmacokinetics of tramadol in rat plasma and cerebrospinal fluid after intranasal administration

We have evaluated the potential of intranasal administration of tramadol. The pharmacokinetic behaviour of tramadol in rat plasma and cerebrospinal fluid (CSF) after intranasal administration was determined and compared with those after intravenous and oral administration. Serial plasma and CSF samples were collected for 6 h, and the drug concentrations were assayed by an HPLC-fluorescence method. The plasma absolute bioavailability values of tramadol after intranasal and oral administration were 73.8% and 32.4%, respectively, in conscious rats. The Cmax (maximum concentration) value after the intranasal dose was lower (P<0.05), and the MRT (mean retention time) was longer (P<0.05) than the values obtained after intravenous administration. A pharmacokinetic study of tramadol in plasma and CSF was undertaken in anaesthetized rats. The absolute bioavailability values in plasma and CSF after intranasal administration were 66.7% and 87.3%, respectively. The Cmax values in plasma and CSF after a nasal dose were lower (P<0.05) than after the intravenous dose. The values of Cmax and AUC0-->6 h in plasma and CSF after intranasal administration were higher than after the oral dose. The mean drug-targeting efficiency after intranasal administration was significantly greater than after the oral dose. In conclusion, intranasal administration of tramadol appeared to be a promising alternative to the traditional administration modes for this drug.     

Evaluation of brain-targeting for the nasal delivery of ergoloid mesylate by the microdialysis method in rats.

The aim of this study was to quantify the nasal delivery of ergoloid mesylate (EM) to the brain by comparing cerebrospinal fluid (CSF) and plasma EM levels after nasal administration at a dose of 4 mg/kg with those after intravenous administration. Following nasal delivery, EM reached a Cmax value (mean+/-SD) in plasma of 348.41+/-19.47 ng/ml and in CSF of 87.35+/-6.37 ng/ml after 107 and 20 min, respectively, while after intravenous injection, EM reached a Cmax value (mean+/-S.D.) in CSF of 54.81+/-4.92 ng/ml at 60 min and the Cmax in plasma was 1255.51+/-133.59 ng/ml. The AUC(CSF)/AUC plasma ratio (0.48+/-0.05) after intranasal delivery differed greatly from the ratio (0.14+/-0.04) observed after intravenous injection (P<0.05). The further analyzed data demonstrated a statistically significant distribution advantage of EM to the brain via the nasal route, and further suggesting that nasal administration can be a promising alternative for EM that undergoes first-pass metabolism following oral administration.     

盐酸纳洛酮鼻腔喷雾剂的药效学研究

目的:评价盐酸纳洛酮鼻腔喷雾剂的药效。方法:以新西兰大耳白兔为动物模型,通过给予中毒剂量的盐酸二氢埃托啡建立阿片类药物中毒模型,考察高、中、低三个浓度盐酸纳洛酮鼻腔喷雾剂的药效,并与肌内注射及静脉注射盐酸纳洛酮注射液的救治效果进行比较。结果:盐酸纳洛酮鼻腔喷雾剂治疗效果与肌注相当。结论:盐酸纳洛酮鼻腔喷雾剂起效迅速,救治效果显著,使用方便,特别适合危重症病人的自救与互救。