Effect of absorption promoters in intranasal administration of human fibroblast interferon as a powder dosage form in rabbits

The utility of the absorption promoters, sodium glycocholate (GC-Na), ethylenediamine dihydrochloride (EDTA-2Na), sodium caprylate (Cap-Na) and sodium salicylate (Sal-Na), in the intranasal administration of human fibroblast interferon-beta (HuIFN-beta) in rabbits was investigated. The optimal amount of added EDTA-2Na, Cap-Na and Sal-Na with respect to HuIFN-beta was examined for nasal absorption in the powder dosage form. Formulations of HuIFN-beta with GC-Na showed greatly enhanced intranasal HuIFN-beta absorption, as compared to the other absorption promoters. The results of a stability study on HuIFN-beta in homogenates of nasal mucosa suggested that GC-Na behaved as a hydrolysis inhibitor in the nasal mucosa and maintained the activity of HuIFN-beta.     

Enhancing effect of cyclodextrins on nasal absorption of insulin and its duration in rabbits.

The absorption of insulin (from porcine pancreas) in rabbits after the nasal administration of aqueous preparations containing insulin and five kinds of cyclodextrins (CyDs) in phosphate buffer solution at pH 7.0 was investigated. Without CyD, the insulin and glucose levels in plasma were unchanged, whereas a marked increase in the plasma levels of insulin and a decrease in glucose concentrations were observed following the simultaneous administration of insulin and CyD such as alpha- and heptakis (2,6-di-O-methyl)-beta-CyD (DM-beta-CyD). The largest enhancing effect on the nasal absorption of insulin was obtained by DM-beta-CyD. To evaluate the duration of the absorption-enhancing effect of CyDs, preadministration (administration of CyD 0.5, 6, 12 and 24 h before insulin administration) was performed. The area under plasma concentration-time curve (AUC) and Cmax of insulin significantly decreased with the preadministration of DM-beta-CyD 6, 12 and 24 h before nasal administration. The absorption-enhancing effect disappeared 24h after the preadministration. These findings demonstrate that CyDs enhance the nasal absorption of insulin, and the recovery of the membrane transport barrier function in nasal mucosa is achieved, at the latest, 24 h after the administration of CyDs.     

Redispersible dry emulsion system as novel oral dosage form of oily drugs: in vivo studies in beagle dogs.

The absorption characteristics of vitamin E acetate (VEA) formulated into a dry emulsion system after its oral administration to beagle dogs were determined and compared to those of two different dosage forms (an oily mixture of the drug with cottonseed oil and an oil (drug)-in-water emulsion). The three dosage forms were administered in a crossover fashion to six nonfasting subjects, and the drug absorption was assessed from the plasma concentration of the major metabolite (free vitamin E). VEA formulated in the dry emulsion was rapidly absorbed, which suggested that a considerable amount was released as reformed emulsion droplets in the gastrointestinal tract as well as in water in vitro. Based on the analysis of variance, no significant differences in bioavailability parameters (AUC, Cmax or Tmax) were observed among the three dosage forms.     

Absorption enhancement of polypeptide drugs by cyclodextrins. I. Enhanced rectal absorption of insulin from hollow-type suppositories containing insulin and cyclodextrins in rabbits.

The absorption of insulin (from porcine pancreas) from the rectum of rabbits after the administration of hollow-type suppositories containing insulin and five kinds of cyclodextrins (CyDs) was investigated. Three types of suppositories were employed: suppository I containing insulin (approximately 26 IU/mg) and various amounts of each CyD in citric buffer solution at pH 3.0 or powder in its cavity, suppository II containing CyD without insulin, and suppository III containing insulin without CyD. Without CyD, the insulin and glucose levels in plasma were unchanged, whereas a significant increase in the plasma insulin concentration and a marked decrease in the glucose levels were found following simultaneous administration of insulin and CyDs by suppository I. The enhancing effect of CyD on rectal insulin absorption (absorption-enhancing effect) by chemically modified CyDs (heptakis(2,6-di-O-methyl)-beta-CyD (DM-beta-CyD) and 2-hydroxypropyl-beta-CyD (HP-beta-CyD)) was higher than those by natural CyDs (alpha-, beta-, and gamma-CyD). The area under the plasma concentration-time curve (AUC) and Cmax of insulin significantly decreased with the preadministration (administration of CyD 6, 24 and 48 h before rectal insulin administration) of DM-beta-CyD. The absorption-enhancing effect disappeared 24 h after preadministration. These results suggest that CyDs enhance insulin absorption from the rectum, and that attenuation of the membrane transport barrier function in the rectum recovers at a maximum of 24 h after administration of CyDs.     

Gastro-intestinal absorption of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionate from different dosage forms in rats and dogs

To obtain information as to a suitable formulation of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)-phenyl]propionate (AL-294), an antihyperlipidemic drug of low water solubility, the bioavailability after its oral administration in various dosage forms was evaluated in rats and dogs. After AL-294 was administered orally, AL-294 acid (2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionic acid), which is a metabolite of AL-294, was detected in the plasma. Therefore, absorbability of AL-294 was evaluated using plasma AL-294 acid levels. AL-294 in an oil solution or in a gelatin capsule showed poor absorption, whereas it's absorption was greatly enhanced in the form of an emulsion. The postprandial administration also showed better absorption. The elimination rate of AL-294 acid from the plasma after oral administration of the emulsion was similar to that after intravenous administration of a sodium salt of AL-294 acid.     

Identification of metabolites of novel Anti‐MRSA fluoroquinolone WCK 771 in mouse,rat, rabbit,dog, monkey and human urine using liquid chromatography tandem mass spectrometry

WCK 771 is an l ‐arginine salt of levonadifloxacin (LND) being developed in intravenous dosage form and has recently completed a phase III trial in India. The pharmacokinetics of WCK 771, a novel anti‐MRSA fluoroquinolone, were examined in mice, rats, rabbits, dogs, monkeys and humans after systemic administration during pre‐clinical and clinical investigations. Urine and serum were evaluated for identification of metabolites. It was observed that LND mainly follows phase II biotransformation pathways. All of the species showed a different array of metabolites. In mice, rabbit and dog, the drug was mainly excreted in the form of O‐glucuronide (M7) and acyl glucuronide (M8) conjugates, whereas in rat and human major metabolite was sulfate conjugate (M6). Monkeys exhibited equal distribution of sulfate (M6) and glucuronide conjugates (M7, M8). In addition to these three major phase II metabolites; five phase I oxidative metabolites (M1, M2, M3, M4 and M5) were identified using liquid chromatography tandem mass spectrometry. Out of these eight metabolites M2, M3, M5, M7 and M8 are reported for the first time.     

High-performance liquid chromatographic analysis of amphotericin B in plasma, blood, urine and tissues for pharmacokinetic and tissue distribution studies.

A sensitive and reproducible high-performance liquid chromatographic method was developed to assay ampherotericin B in plasma, blood, urine and various tissue samples. Amphotericin B was isolated from each sample matrix by solid-phase extraction (Bond-Elut). The eluate from Bond-Elut containing amphotericin B was injected onto a reversed-phase C18 column (Waters, mu Bondpak, 10 microns, 300 mm x 3.9 mm I.D.) with a mobile phase of 45% acetonitrile in 2.5 mM Na2EDTA at 1 ml/min. Detection of amphotericin B was by ultraviolet absorption at 382 nm. Blood and tissues were homogenized and extracted with methanol prior to Bond-Elut extraction. The extraction efficiencies of amphotericin B from plasma, blood and tissues were approximately 90, 70 and 75%, respectively. The sensitivity of the assay was less than or equal to 5 ng/ml for plasma, less than or equal to 25 ng/ml for blood, 2.5 ng/ml for urine and 50 ng/g for tissues. The linearity of the assay method was up to 2.5 micrograms/ml for plasma, 5 micrograms/ml for blood, 500 ng/ml for urine and 500 micrograms/g for tissues. The assay was reproducible with an intra-day coefficient of variation (C.V., n = 3) of less than 5% in general for plasma, blood and tissues. The inter-day C.V. of the assay was less than 5% for plasma (n = 5), less than 10% for blood (n = 4) and less than 5% for tissues (n = 3). The overall variability in the urine assay was generally less than 10%. This method has demonstrated significant improvement in the sensitivity and reproducibility in assaying amphotericin B in plasma and especially in blood, urine and tissues. We have employed this assay to compare the pharmacokinetic and tissue distribution profiles of amphotericin B in rats and dogs following administration of Fungizone and ABCD (amphotericin B-cholesteryl sulfate colloidal dispersion), a lipid-based dosage form. In addition, the assay method for plasma and urine samples can also be applied to pharmacokinetics studies of amphotericin B in man.     

Membrane-controlled transdermal therapeutic system containing clonazepam and anticonvulsant activity after its application

A trial transdermal dosage form designed to sustain a suitable plasma concentration of clonazepam (CZP) was produced using a porous membrane (Hipore 2100 or 4050) and applied to rabbits and rats for pharmacokinetic and pharmacodynamic evaluations. The release rate constants for the drug through the porous membranes were significantly smaller than that without any membrane. The transdermal system (Hipore 4050 system, ointment 0.25 g, 2.25 cm2) provided a well sustained plasma concentration of CZP and the therapeutic plasma concentration range was maintained for about 26 h. When the Hipore 4050 system with an increased amount of ointment and enlarged absorption area (0.5 g, 4.0 cm2) was applied, the therapeutic range was sustained for about 40 h, and slightly higher plasma levels over the whole application period and much higher bioavailability (37%) were obtained compared with those after the 2.25 cm2-Hipore 4050 system. The transdermal system exerted an excellent anticonvulsant activity in rats, with the best (3+ or 4+) protective score. The plasma concentrations of CZP when the activity was estimated were in the therapeutic range. Thus, the transdermal system has the potential to be an efficient drug delivery system.     

Enhancement of oral bioavailability of d-alpha-tocopherol acetate by lecithin-dispersed aqueous preparation containing medium-chain triglycerides in rats

In order to evaluate oral dosage forms of d-alpha-tocopherol acetate (VEA), d-alpha-tocopherol (VE) concentration in the plasma was examined following oral administration of three VEA preparations; lecithin-dispersed aqueous preparation, polysorbate 80 (PS-80)-solubilized aqueous solution and soybean oil solution. The lecithin-dispersed preparation gave the highest Cmax and the largest AUC0-24h, while Tmax was delayed. In the thoracic duct fistula rat, no increase in VE plasma concentration was observed after intraduodenal administration of lecithin-dispersed VEA preparation via the lymphatic route. The delayed Tmax and prolonged VE plasma concentration obtained with the lecithin-dispersed preparation in comparison with PS-80-solubilized aqueous solution could be explained by the different route of absorption.     

Interspecies differences in pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1,4-diazepin-1-yl) benzimidazole difumarate (KG-2413) after intravenous administration to rats, guinea pigs and dogs

Interspecies differences in the pharmacokinetics of an antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1,4-diazepin-1-yl)benzimid azole difumarate (KG-2413) after intravenous administration were investigated in rats, guinea pigs and dogs. The disappearance of unchanged KG-2413 base was described by biexponential curves in all three animal species. The areas under the plasma concentration-time curves (AUC) in rats, guinea pigs and dogs were 218, 421 and 369 ng.h/ml, respectively, at a dose of 2 mg/kg. The volume of distribution in rats was comparable to that in dogs, and was about three times greater than that in guinea pigs. This might be due to the difference in the unbound fractions of KG-2413 base in plasma (fu), that is, the values of fu in rats, dogs and guinea pigs were 0.607, 0.603 and 0.189, respectively. The first-order elimination rate constant from the central compartment (kcl) in dogs were smaller than those in rats and guinea pigs. Total body clearances (CLtot) of KG-2413 base in rats and guinea pigs were comparable to the hepatic blood flow rate (Q) of each animal. Assuming that KG-2413 base is only eliminated in the liver, relatively rapid metabolism of KG-2413 base occurred in the liver of rats and guinea pigs. In dogs, extrahepatic elimination was suggested because the value of CLtot seemed to be greater than that of Q.     

The relationship between the drug concentration profiles in plasma and the drug doses in the colon

After the dosing of an extended-release (ER) formulation, compounds may exist in solutions at various concentrations in the colon because the drugs are released at various speeds from the ER dosage form. The aim of this study was to investigate the relationship between the drug concentration profiles in plasma and the drug doses in the colon. Several drug solutions of different concentrations were directly administered into the ascending colon of dogs using a lubricated endoscope, and the effects of the drug dose on colonic absorption were estimated. As a result, dose-dependency of colonic absorption varied from compound to compound. Although the relative bioavailability of colonic administration of diclofenac, metformin and cevimeline compared to oral administration was similar regardless of the drug doses in the colon, colonic absorption of diltiazem varied according to the doses. From the results of the co-administration of verapamil and fexofenadine, it was clear that diltiazem underwent extensive hepatic and gastrointestinal first-pass metabolism, resulting in a low area under the curves (AUC) at a low drug dose. During the design of oral ER delivery systems, a colonic absorption study of candidate compounds should be carried out at several solutions of different drug concentrations and assessed carefully.     

Enhancement of bioavailability of dopamine via nasal route in beagle dogs.

Dopamine (DA), which is ineffective by oral administration due to first pass metabolism and is usually injected, was administered to dogs via rectal, dermal, buccal and nasal routes. The nasal route had the highest bioavailability and best avoided first pass metabolism. The effects of the addition of hydroxypropyl cellulose (HPC), sodium deoxycholate, POE (6) hydrogenated caster oil (HCO-60) and Azone on the nasal absorption increased bioavailability from 11.7% (control) to about 20%, 35%, 25% and 68%, respectively. Further, with a combination of 2% HPC and 5% Azone, bioavailability was increased to almost the same level as with i.v. administration. At the same time, plasma concentrations were maintained at a high level for more than 7 h. The increase in bioavailability is presumed to be caused by an enhancement in absorption and prolongation of the time DA is retained in the nasal cavity due to Azone and HPC, respectively.     

朱砂中汞的生物可接受性及其吸收与排泄

研究了朱砂中汞的生物可接受性及其在体内的吸收与排泄.采用体外消化透析法测定了朱砂中汞的生物可接受性;计算了大鼠灌胃给予临床剂量(50mg/kg)朱砂后汞的药动学参数;测定了给予临床剂量的朱砂后大鼠粪样中汞的排泄量.结果表明,朱砂中汞的溶出率为0.011%,生物可接受率为0.003 3%.大鼠灌胃给予临床剂量的朱砂后,汞的药动学参数为:最高血药浓度(ρmax)为(6.3±1.3)μg/L,达峰时间(tmax)为(1.3±0.4)h,半衰期(t1/2)为(4.2±0.5)h,血药浓度-时间曲线下面积(AUC)为(54.7±8.7)μg.h.L-1.给予朱砂12h后汞在粪便中排泄量最大,96h后在粪样中仍可检测到少量汞.朱砂中汞的生物可接受性较低,在体内吸收少,滞留时间较长,排泄缓慢,长期服用可在体内蓄积,产生毒性.     

Enhanced rectal absorption of insulin in rabbits from hollow-type suppositories containing insulin and glyceryl-1-monooctanoate.

The absorption of two kinds of insulin (from porcine or bovine pancreas) from the rectum of rabbits after the administration of hollow-type suppositories containing insulin and glyceryl-1-monooctanoate (GMO) as an absorption-enhancing agent was investigated. Two types of suppositories were employed: type I containing insulin in an aqueous solution (approx. 25 IU/mg/100 microliters citric buffer solution at pH 3.0) in the cavity of the suppository and GMO mixed with a base material (Witepsol H-15), and type II containing insulin in a crystalline form in the same amount as in type I. Without GMO, the insulin and glucose levels in plasma were unchanged, whereas a marked increase in the plasma levels of insulin and a decrease of glucose concentrations were found following coadministration of insulin and GMO by the type I suppository. Similar enhancement of rectal absorption of insulin was obtained from porcine and bovine sources. In the case of the crystalline insulin, despite the use of the same amount of GMO, porcine insulin was more efficiently absorbed than bovine insulin by the type II suppository. GMO enhances the absorption of insulin in an aqueous solution or a crystalline form, and the dissolution rate of insulin may be an important factor in the rectal absorption of insulin.     

Enantiomer ratio of MK-0767 in humans and nonclinical species

MK-0767, (+/-)-5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[(4-trifluoromethyl)phenyl]methyl]benzamide, is a thiazolidinedione-containing dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist that has been studied as a potential treatment for patients with type 2 diabetes. MK-0767 contains a chiral center at the C-5 position of the thiazolidinedione ring and was being developed as the racemate, due to the rapid interconversion of its enantiomers in biological samples. In the present work the in vitro and in vivo concentration ratios of the (+)-(R) to (-)-(S) enantiomers of MK-0767 were determined in plasma from humans (in vitro only) and nonclinical species used in the toxicological evaluation of rac-MK-0767, namely CD-1 mice, Sprague-Dawley rats, beagle dogs, New Zealand white rabbits, and rhesus monkeys. The R/S ratio was determined by chiral liquid chromatography/tandem mass spectrometry. Species differences were observed in the in vitro and in vivo enantiomeric ratios, as well as differences between in vitro and in vivo in some species. The in vitro R/S ratio was similar in dogs and humans (approximately 1.5-1.7). In rats and monkeys, the ratio was approximately unity, both in vitro and in vivo. In mice, the ratio was higher in vitro (approximately 1) than in vivo (approximately 0.6), while in rabbits it was higher in vivo (approximately 1) than in vitro (approximately 0.5). These results suggested that differential binding of the MK-0767 enantiomers to plasma and tissue proteins and other macromolecules may be affecting the R/S ratio both in vitro and in vivo, since in protein-free systems MK-0767 exists as the racemate.     

Effect of gastric acidity on bioavailability of N,N-dimethylcarbamoylmethylalpha, 2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetate, a new prodrug-type anti-inflammatory agent

The effect of gastric acidity on the bioavailability of N,N-dimethylcarbamoylmethyl alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b] pyridine-7-acetate (1), a new anti-inflammatory agent, was investigated in gastric acidity-controlled beagle dogs. The dissolution rates of this compound in media of pH 1.2 and 3.0 were greater than those in media of pH 5.0 and 6.8. Reflecting these dissolution characteristics, the peak plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC0-12h) were reduced by shifting the gastric acidity to low levels (more than pH 6) with omeprazole treatment. In designing dosage forms of 1, it is necessary to develop pharmaceutical preparations whose bioavailability is not affected by the gastric acidity.     

Antihyperglycemic effect of insulin from self-dissolving micropiles in dogs

As a percutaneous delivery device, self-dissolving micropiles (SDMPs) composed of chondroitin sulfate and insulin were prepared under room temperature from highly concentrated solution, glue. The mean weight of SDMP was 1.03+/-0.04 mg. One insulin SDMP was percutaneously administered to the shaved abdominal skin of four beagle dogs at insulin dose level of 1.0 and 2.0 IU/dog. After administration, blood samples were collected for 6 h and plasma glucose levels were measured. The time when minimum plasma glucose level appeared, T(min), was 1.38+/-0.2 h for 1.0 IU study and 1.38+/-0.1 h for 2.0 IU study and clear dose-dependent hypoglycemic effect of insulin was observed in the dose range. By comparing the area above the plasma glucose level vs. time curve (AAC) between insulin SDMP and subcutaneous (s.c.) injection solution, the relative pharmacological availabilities were 99% (1.0 IU) and 90% (2.0 IU), respectively. To ascertain the usefulness of insulin SDMP, oral glucose tolerance test (OGTT) was performed. When dogs were treated with insulin SDMPs, 2.0 IU, followed by an OGTT 30 min, glycemia did not appear for 5 h. On the other hand, when OGTT was performed at 1 h after insulin SDMP administration, hypoglycemia appeared as in the case of s.c. injection of insulin solution, 2.0 IU. Insulin SDMP improved the oral glucose challenge for 3 h, with a maximum effect at 30 min before the administration of glucose. Those results suggest the usefulness of a SDMP for the percutaneous delivery of peptide/protein drugs like insulin.     

Preparation of bupleurum nasal spray and evaluation on its safety and efficacy

Radix Bupleuri is widely used in traditional medicine for the treatment of fever, pain, and inflammation associated with influenza or the common cold. The essential oil extracted from the herb is generally claimed to play the major role in the efficacious treatment of fever. The purpose of the present study was to formulate an intranasal delivery system for the essential oil in an aqueous solution used in the form of nasal spray. From 450 g Radix Bupleuri was extracted the essential oil in the amount of about 0.2 ml, which was slightly water-soluble and viscous with low-fluidity. In order to dissolve the essential oil evenly in the aqueous solution, tween-80 (TW-80, used in 10% (w/v) solution), propylene glycol (PG) and diethylene glycol monoethyl ether (TC) were selected as the favorable solubilizing agents, whose amount was respectively determined by L16(4(5)) orthogonal design. An aqueous solution with clarity and no ciliotoxicity was prepared when TW-80 8% (v/v), PG 14.4% (v/v) and TC 14.4% (v/v) were added. Employed to evaluate the acute toxicity, the rats grew well and were kept active and healthy within 14 d after an intranasal administration of this preparation at the dose of oil from 10 g Bupleuri/kg (50-fold higher than the clinical dose), indicating that there would be no serious toxicity at the normal dose. Intranasal administration of this preparation to 2 kg rabbits with fever induced by subcutaneous injection of turpentine decreased body temperature markedly (0.5, 0.8 and 1.0 degrees C respectively at the dose of oil from 1, 2 and 4 g Bupleuri/body). In addition, the administration significantly reduced fever in 200 g rats induced by intramuscular injection of colicine suspension (0.6 degrees C at the dose of oil from 0.8 g Bupleuri/body). The results suggest that the formulation of nasal spray for the essential oil from Radix Bupleuri can be potentially effective in the treatment of fever.     

Enhancing effect of glyceryl-1-monooctanoate on the rectal absorption of gentamicin from hollow-type suppositories in rabbits

A hollow-type suppository containing gentamicin (GM) in its cavity was prepared using Witepsol H-15 (H-15) mixed with glyceryl-1-monooctanoate (MO) or MO alone in the body of the suppository (type I) and a suppository (type II) containing GM and MO in the cavity was constructed using H-15 in the body of the suppository. Without MO, GM (60 mg) was not absorbed (plasma GM levels less than 1 microgram/ml). However, the absorption of GM from the rectum of rabbits was enhanced by coadministered MO in types I and II. Even when the amount of GM was decreased to 6 mg (1/10), GM was observed in the plasma (Cmax, 3.5 +/- 0.3 micrograms/ml) after administration of the suppository made from MO mixed with H-15. The enhancing effect of MO on the rectal absorption of GM could not be further increased by incorporating an amount of MO larger than approximately 300 mg into the suppository. This study demonstrates that MO can be used in the two types of hollow suppositories as an effective enhancing agent of rectal absorption of poorly absorbed drugs such as GM.     

High-performance liquid chromatographic assay with ultraviolet detection for the determination of etoperidone and two active metabolites, 5-(1-hydroxyethyl) etoperidone and 1-(3-chlorophenyl)piperazine, in plasma

A selective and sensitive high-performance liquid chromatographic assay with ultraviolet detection for the determination of the antidepressant drug etoperidone and two active metabolites in plasma is described. The drug, metabolites and internal standard are isolated from plasma using a two-step liquid-liquid extraction procedure. The resulting sample is chromatographed on a C18 column (10 cm x 2.1 mm I.D.) with ultraviolet detection at 254 nm. Standard curves are linear for each compound over the concentration range 2-1000 ng/ml. The accuracy and precision of the assay, expressed as the percentage deviation of measured values from the true value and the relative standard deviation (inter-run), are less than or equal to 10% at all concentrations except the minimum quantification limit. Using an automated injector and computerized data acquisition, eighty samples can be routinely processed in one day. The assay has been successfully used for the analysis of plasma samples from pharmacokinetic studies in mice, rats, dogs and humans.