Non-invasive Route Of Administration Research Articles

A Double-Blind, Crossover Assessment of the Sedative and Analgesic Effects of Intranasal Dexmedetomidine

The alpha2-receptor agonist, dexmedetomidine, provides sedation with facilitated arousal and analgesia with no respiratory depression. These properties render it potentially useful for anesthesia premedication, although parenteral administration is not practical in this setting. We designed this study to evaluate the sedative, anxiolytic, analgesic, and hemodynamic effects of dexmedetomidine administered intranasally in healthy volunteers. Koch's design for crossover trials (three-treatment and two-period design) was adopted. The study was double-blind and there were three treatment groups: A (placebo), B (intranasal dexmedetomidine 1 microg/kg) and C (intranasal dexmedetomidine 1.5 microg/kg). Each of the 18 subjects participated in two study periods. The study drug was administered intranasally after baseline observations of modified Observer Assessment of Alertness/Sedation Scale, visual analog scale of sedation, bispectral index, visual analog scale of anxiety, pain pressure threshold measured by an electronic algometer, systolic blood pressure (SBP) and diastolic blood pressure, heart rate, respiratory rate, and oxygen saturation. These were repeated during the course of the study. Intranasal dexmedetomidine was well tolerated. Both 1 and 1.5 microg/kg doses equally produced significant sedation and decreases in bispectral index, SBP, diastolic blood pressure, and heart rate when compared with placebo (P < 0.05). The onset of sedation occurred at 45 min with a peak effect at 90-150 min. The maximum reduction in SBP was 6%, 23%, and 21% for Groups A, B, and C respectively. There was no effect on pain pressure threshold, oxygen saturation or respiratory rate. Anxiolysis could not be evaluated as no subjects were anxious at baseline. The intranasal route is effective, well tolerated, and convenient for the administration of dexmedetomidine. Future studies are required to evaluate the possible role of the noninvasive route of administration of dexmedetomidine in various clinical settings, including its role as premedication prior to induction of anesthesia.

Inhaled Insulin and the Lung

Pulmonary delivery of insulin is more than a promise in the treatment of diabetes mellitus. Inhaled insulin seems at least as efficacious as the conventional regimen of subcutaneous insulin and/or oral glucose-lowering agents in both type 1 and type 2 diabetes mellitus. Improved metabolic control and the use of a non-invasive route of administration represent the main benefits of this new treatment. Several physico-chemical factors could reduce the bioavailability of inhaled insulin. Indeed, both deep-lung deposition and adsorption of insulin variously depend on the type of propellants used, speed of air flow, particle size and velocity, drug deposition into the throat and larger bronchial tree. These factors, in turn, depend on the pulmonary delivery systems used and on respiratory mechanics and flows. Furthermore, the pharmacokinetics of inhaled insulin is affected by smoke, which increases its absorption, and by lung diseases, which decrease the available alveolar-capillary surface. Selected abnormalities of respiratory function complicate both type 1 and type 2 diabetes mellitus and a mild depression of carbon monoxide lung transfer after a 6-month period of treatment with inhaled insulin has been reported. Finally, results from some longitudinal studies suggest that diabetes might speed up the age-related decline of lung volumes and probably alter the pharmacokinetics of inhaled insulin, particularly in the elderly. Clarifying these issues is mandatory in order to define the indications and safety of inhaled insulin.

Local and Systemic Delivery of High-Molecular Weight Drugs by Powder Inhalation

The pulmonary route has recently attracted attention as a noninvasive administration route for peptide and protein drugs, and an insulin powder for inhalation was approved by authorities in Europe and the USA. The present study examined usefulness of insulin and gene powders for systemic and local inhalation therapy. We prepared several dry insulin powders by spray drying to examine the effect of additives on insulin absorption. Citric acid appears to be a safe and potent absorption enhancer for insulin in dry powder. However, in the powder with citric acid (MIC0.2 SD) insulin was unstable compared with the other powders examined. To improve insulin stability, a combination of insulin powder and citric acid powder was prepared (MIC Mix). MIC Mix showed hypoglycemic activity comparable to MIC0.2 SD while the insulin stability was much better than that of MIC SD. Next, dry insulin powders with mannitol were prepared with supercritical carbon dioxide (SCF); the powder thus prepared reduced blood glucose level rapidly and was more effective than that prepared by spray drying. Chitosan-pDNA complex powders as a pulmonary gene delivery system were also prepared with SCF and their in vivo activity was evaluated. The addition of chitosan suppressed the degradation of pCMV-Luc during preparation and increased the storage stability. The luciferase activity in mouse lung was evaluated after pulmonary administration of the powders. The chitosan-pDNA powder with an N/P ratio=5 increased the luciferase activity to 27 times that of the pCMV-Luc solution. These results suggest that gene powder with chitosan is a useful pulmonary gene delivery system.

Monomeric Fc Fusions

The delivery of therapeutic proteins by noninvasive routes of administration has been a challenging goal, hence current modes of delivery generally require injections. However, we have recently shown that a naturally occurring receptor, the neonatal Fc receptor (FcRn) can be utilized to carry aerosolized therapeutic proteins conjugated to a portion of its respective ligand (Fc domain of immunoglobulin G) across epithelial cells of the lung to effectively deliver biologically active molecules to the bloodstream. First-generation dimeric Fc fusion molecules were successfully transported by the pulmonary route and biologic activity was demonstrated in both non-human primates and human volunteers. Continuing efforts to improve transport efficiency have led to the development of an alternate configuration of Fc fusion proteins with improved characteristics. These second generation Fc fusion molecules are monomeric with respect to the therapeutic protein and dimeric with respect to the Fc region, and have been termed Fc fusion 'monomers'. Several different Fc fusion monomers have demonstrated improved transport efficiency, achieving high bioavailabilities for pulmonary delivery in non-human primates. While the traditional dimeric Fc fusion molecule generally increases the half-life compared with the unconjugated effector molecule, the monomer configuration has been shown to result in an even greater extension of the circulating half-life, which improves pharmacokinetic parameters for protein therapeutics, whether administered by pulmonary delivery or injection. Finally, many of the Fc monomer fusions have enhanced biologic activity compared with the dimeric configuration. Because of these many advantages, the monomer configuration promises to be an enabling advance to achieve clinically relevant, noninvasive delivery with potentially less frequent administration regimens for a broad range of protein therapeutics. In addition, molecules that are comprised of heterodimeric subunits or multi-subunit complexes can also be constructed as Fc fusions that result in a molecule with enhanced pharmacokinetics and greater bioactivity. Several examples of novel Fc fusion proteins, both monomer and heterodimer are described herein.

Insulin Therapy: Current Alternatives

In normal humans, blood glucose and insulin are maintained within a narrow range despite wide variations in physical activity and dietary intake. At present, reproducing this pattern is an impossible task in type 1 diabetes and extremely difficult in type 2 DM. New approaches using novel insulin analogs and routes of administration, attempting to replicate physiological insulin secretion in diabetic patients, are improving the profiles of glucose levels and, thus, the quality of life. Ultra-short-acting insulin analogues and ultra-long-acting analogues are being used for prandial and basal effects with better results, lower prevalence of hypoglycemia, and, hopefully, fewer chronic complications. Non-invasive routes of administration are being developed. The most promising appears to be inhaled insulin according to studies demonstrating excellent control, apparently without significant side effects, although in relatively short-term trials. Longer-term studies to assure the safety are still necessary before recommending its extended use. This is an extensive, up-to-date review of recent advances in insulin therapy.

New strategies in insulin treatment: analogues and noninvasive routes of administration

Abstract Recent years have seen the development of alternatives to human insulin for the treatment of diabetes. Both rapid-acting and long-acting analogues are available. Alternative routes of insulin administration are emerging. The present review briefly summarizes the present knowledge on insulin analogues and alternative administration routes.

Overcoming obstacles: new management options.

The outlook for patients with type 2 diabetes looks set to improve with the availability of new diabetes management options that provide more comprehensive control of blood glucose levels and/or encourage better patient compliance than previous alternatives. New insulin analogues, such as insulin lispro, aspart and glargine, allow more physiological insulin replacement and greater freedom in the timing and content of meals, compared with regular insulin preparations. The development of novel non-invasive routes of insulin administration promises to further improve diabetes management. Many barriers to initiating insulin relate to the need for frequent insulin injections, fears that insulin injections will be painful and difficult to administer, and concerns about hypoglycaemia and weight gain. Thus, each measure that reduces these barriers will help to prevent inappropriate delays in starting insulin therapy as well as to promote better compliance with therapy. The output from continuous glucose monitoring devices will assist accurate insulin replacement, which is difficult using point-estimates of blood glucose. Such devices will hopefully also circumvent the need for finger stick tests. There are several novel therapies in development that will further expand the portfolio of treatment options for patients with type 2 diabetes. Improved quality and choice of diabetes management options will provide doctors with the tools they require to develop tailored treatment plans, increase the probability that treatment goals are achieved and thereby reduce the risk of patients developing late-stage diabetes-related complications.

371. Complete Inhibition of Hepatitis B Virus Gene Expression In Vivo with Short Hairpin RNA Expressed from a Novel Double-Stranded, Bi-Cistronic Adeno-Associated Virus Pseudotype 8 Vector

Top of pageAbstract We report the generation and in vivo evaluation of novel Adeno-Associated Viral (AAV) vectors for the expression of short hairpin RNA (shRNA) against human Hepatitis B Virus (HBV), and demonstrate their superior efficiency over conventional AAV vectors. Our approach combines two recent major advances in the AAV field: pseudotyping of AAV-2-based vector genomes with capsids from another serotype, and development of “double-stranded” (ds) vectors, that express faster and more strongly than standard, single-stranded (ss) recombinant AAV. In detail, we cross-packaged AAV genomes comprising our most robust anti-HBV shRNA, or a control shRNA against luciferase, into capsids from AAV-8, which is the AAV serotype with the highest known transduction rate in liver. To force their encapsidation as ds genomes, we replaced one AAV-2 packaging signal with a mutant derived from AAV-4 or -5, which concurrently improved vector genome stability and particle titers. The small size of the shRNA inserts enabled us to encapsidate a second cistron, encoding a fluorescence protein for easy detection of shRNA-expressing cells. Specificity and efficiency of all vectors was first analysed in a human HBV-transformed cell line. As hoped for, only the two anti-HBV vectors significantly reduced HBV surface antigen (sAg) expression. Importantly, the novel dsAAV showed a much stronger effect, and more rapidly, than the standard ssAAV. All vectors were next evaluated in transgenic mice carrying and expressing an integrated HBV genome. Particles were given intraportally or by peripheral intravenous infusion, at doses from 5e10 up to 7e12 vector genomes (vg) per animal. Most remarkably, analyses of serum before and after systemic delivery of the ds anti-HBV vector showed complete elimination of sAg between day 4 and 11 after injection. This was found at doses as low as 3e11 vg per animal, whereas to get the same effect with the ss vector, 20-fold higher doses and longer incubation were required. No significant change in sAg was seen with the anti-luciferase control vectors or after PBS injection. Those results were corroborated by HBV mRNA and DNA analyses, and were confirmed in a second lineage of HBV-transgenic mice. Interestingly, we noted a dose-dependent toxicity of the anti-HBV vectors, resulting in hypoproteinemia and ultimately death of animals given high particle doses (1.8e12 vg and greater). This was seen as early as 5 days after injection, and in both strains of HBV-transgenic as well as in normal mice, ruling out a role for the integrated HBV target genome. The fact that toxicity was absent from the control shRNA vectors indicated an adverse off-target effect specific for the anti-HBV shRNA used here, which is a current matter of further investigation. In sum, our novel dsAAV-8 vector system provides an utmost efficient means for delivery of shRNA to the liver, allowing the use of minimal vector doses and non-invasive routes of administration. This makes it highly interesting for further development towards clinical exploitation of RNA interference to treat hepatitis and other liver diseases.

Noninvasive gene transfer to the lung for systemic delivery of therapeutic proteins

This study evaluates the use of vectors based on adeno-associated viruses (AAVs) to noninvasively deliver genes to airway epithelial cells as a means for achieving systemic administration of therapeutic proteins. We intranasally delivered AAV vectors to mice in which the same AAV2 genome encoding a cellular marker was packaged in capsids from AAV1, 2, or 5 (AAV2/1, AAV2/2, or AAV2/5, respectively). Gene expression levels achieved in both airways and alveoli were higher with AAV2/5 than with AAV2/1 and were undetectable with AAV2/2. The same set of vectors encoding a secreted therapeutic protein, erythropoietin (Epo), under the control of a lung-specific promoter (CC10) was intranasally delivered to mice, resulting in polycythemia with the highest levels of serum Epo obtained with AAV2/5 vectors. After a single intranasal administration of this vector, secretion of Epo was documented for 150 days. Similarly, intranasal administration of an AAV2/5-CC10-factor IX vector resulted in secretion of functional recombinant protein in the bloodstream of hemophiliac, factor IX-deficient mice. In addition, we demonstrate successful readministration of AAV2/5 to the lung 5 months after the first delivery of the same vector. In conclusion, we show that intranasal administration of AAV vectors results in efficient gene transfer to the lung only when the vector contains the AAV5 capsid and that this noninvasive route of administration results in sustained secretion of therapeutic proteins in the bloodstream.

Synergistic effect of enhancers for transdermal drug delivery.

Transdermal drug delivery offers a non-invasive route of drug administration, although its applications are limited by low skin permeability. Various enhancers including iontophoresis, chemicals, ultrasound, and electroporation have been shown to enhance transdermal drug transport. Although all these methods have been individually shown to enhance transdermal drug transport, their combinations have often been found to enhance transdermal transport more effectively than each of them alone. This paper summarizes literature studies on these combinations with respect to their efficacy and mechanisms.

Gut epithelial cells as targets for gene therapy of hemophilia.

Gut epithelium is an attractive target for gene therapy of hemophilia due to the large number of rapidly dividing cells that should be readily accessible to a wide range of vectors by a noninvasive route of administration. We have performed in vitro tests to determine the suitability of gut epithelial cells for gene transfer, protein synthesis, and secretion of coagulation factors VIII and IX. The results with retroviral vectors indicate that transduced epithelial cells from human, rat, or porcine small or large intestine can synthesize significant amounts of factor VIII or factor IX and that two-thirds or more of the recombinant protein is secreted in a basolateral direction (i.e., away from the lumen and toward underlying capillaries and lymphatics). Furthermore, we have demonstrated that intestinal epithelial cells are susceptible to efficient gene transfer by lipofection and adenovirus vectors. In the case of factor IX, we have produced a high-titer adenovirus vector capable of transducing gut epithelial cells resulting in synthesis of factor IX. The results of our in vitro studies indicate that gene transfer targeting gut epithelium as a new approach to hemophilia gene therapy is rational and merits in vivo studies in hemophilia animal models.

Pharmacokinetics of inhaled liposome-encapsulated fentanyl.

Pulmonary administration of fentanyl solution can provide satisfactory but brief postoperative pain relief. Liposomes are microscopic phospholipid vesicles that can entrap drug molecules. Liposomal delivery of fentanyl has the potential to control the uptake of fentanyl by the lungs and thus provide sustained drug release. To demonstrate that inhalation of a mixture of free and liposome-encapsulated fentanyl can provide a rapid increase and sustained plasma fentanyl concentrations (CfenS), this study determined the pharmacokinetic profiles after the inhalation of free and liposome-encapsulated fentanyl in healthy volunteers. After obtaining institutional approval and informed consent, ten healthy volunteers (five men, five women) were studied. Each subject received 200 micrograms intravenous fentanyl and inhaled 2,000 micrograms of free (50%) and liposome-encapsulated fentanyl (50%) on separate occasions. Frequent venous blood samples were collected, and CfenS were determined by radioimmunoassay. The pharmacokinetics and absorption characteristics of the inhaled mixture of free and liposome-encapsulated fentanyl were determined using moment analysis and least-squares numeric deconvolution. The mean (+/- SD) volume of distribution at steady-state and clearance of fentanyl after the intravenous administration were comparable to previous studies: 435 +/- 1821 and 0.584 +/- 0.209 l.min-1, respectively. The mean (+/- SD) peak Cfen was significantly greater for the intravenous administration compared to the aerosol mixture of free and liposome-encapsulated fentanyl (4.67 +/- 1.87 vs. 1.15 +/- 0.36 ng.ml-1). However, CfenS at 8 and 24 h after aerosol administration were greater compared to intravenous (0.25 +/- 0.14 and 0.12 +/- 0.16 ng.ml-1 for aerosol versus 0.16 +/- 0.10 and 0.05 +/- 0.06 ng.ml-1 for intravenous). The peak absorption rate, time to peak absorption, and bioavailability after inhalation were 7.02 (+/- 2.34) micrograms.min, -1(16) (+/- 8.0) min, and 0.12 (+/- 0.11), respectively. The data suggest that this analgesic method offers a simple and noninvasive route of administration with a rapid increase of Cfen and a prolonged therapeutic fentanyl concentration. Future studies are required to determine the optimal liposome composition that would produce a sustained stable Cfen within analgesic therapeutic concentrations.

Recent Advances in Noninvasive Systemic Delivery of Pharmaceuticals and Biopharmaceuticals

AbstractMany systemically-active Pharmaceuticals and biopharmaceuticals are reportedly subjected to extensive pre-systemic elimination when taken orally.To circumvent this dilemma in systemic delivery, extensive research efforts have recently been devoted to explore various nonparenteral (noninvasive) routes of administration for enhancing systemic bioavailability of pharmaceuticals and biopharmaceuticals, which have been reportedly subjected to extensive pre-systemic elimination, via the bypassing of hepatogastrointestinal “first-pass” metabolism. Using nicotine, a pharmaceutical, and enkephalin, a biopharmaceutical, the systemic delivery of pharmaceuticals and biopharmaceuticals through the skin and the various absorptive mucosae has been illustrated. The mechanisms and kinetic processes involved for their systemic delivery are explored and various technical issues encountered are discussed in this article.

2 - The Use of Prostaglandins and their Analogues for Abortion

In general, termination of second trimester pregnancy is associated with three to five times higher morbidity and mortality risks than termination during the first trimester. The procedures mainly used are extra- or intra-amniotic administration of solutions such as hypertonic saline, ethacridine lactate, PGF2α and PGE2. In comparison with these procedures, the use of prostaglandin analogues may offer important advantages, the most important one being the possibility of using non-invasive routes of administration. The continuous development of new analogues has now resulted in compounds that are highly effective in stimulating uterine contractility and are associated with a low frequency of side-effects; these compounds are suitable for both vaginal and intramuscular administration and are applicable for termination of pregnancy during both the early and late parts of the second trimester. The most widely used method for termination of first trimester pregnancy is vacuum aspiration. It is a highly effective procedure and the overall complication rate is low. One problem with vacuum aspiration is the mechanical dilatation of the cervical canal which is necessary from at least the 8th week and onwards. Pretreatment with laminaria tents or with prostaglandin analogues eliminates or reduces the need for mechanical dilatation and significantly facilitates the procedure. Pretreatment with prostaglandin analogues also reduces the risk of both operative and postoperative complications. The prostaglandins also offer a possibility as a non-surgical procedure for termination of very early pregnancy. Both vaginal and intramuscular administration of the latest generation of PG analogues have been shown in several studies to be equally as effective as vacuum aspiration if the treatment is restricted to the first three weeks following the first missed menstrual period. Gastrointestinal side-effects are still a problem although of significantly less importance than if natural prostaglandins are used. Preliminary studies in which one of these PGE analogues was administered by the vaginal route indicate that self-administration at home starts to be a reality in selected patients.