The authors wish to acknowledge funding from the National Institutes of Health (R01AI155922). Microscopy was performed at the Chapel Hill Analytical and Nanofabrication Laboratory (CHANL), a member of the North Carolina Research Triangle Nanotechnology Network, RTNN, which is supported by the National Science Foundation, Grant ECCS-1542015, as part of the National Nanotechnology Coordinated Infrastructure, NNCI.

All animal experiments were conducted in accordance with the Animal Welfare Act and the Public Health Service Policy on Humane Care and Use of Laboratory Animals. The study protocol was approved by the Institutional Animal Care and Use Committee of the University of Tennessee Health Science Center. Healthy female BALB/c mice, ~6-8 weeks old, were administered the dry powder content of one dosator by intrapulmonary aerosol delivery for a pharmacokinetic study using spectinamide 1599 dry powders9. The animals were obtained from a commercial source (see Table of Materials).
1. Preparation of the dosator and the filling components
<ol>
	<li>Trim the plastic luer portion of a 2.54 cm (1 inch) blunt stainless-steel needle (21-25 G) using either a precision sectioning saw (see Table of Materials), or a belt sander until 2-3 mm of the plastic luer remains (Figure 1A and Figure 2A). 
	NOTE: If a belt sander is used, the stainless-steel needle may need to be cleaned using a smaller needle or wire to remove the possible obstructions created.</li>
	<li>Cut off the tip (1-1.5 cm) of a 0.6 mL conical centrifuge tube. Fill the tip of the tube with 30-35 mg of powder. 
	&#8203;NOTE: See Representative Results for the details of the example powders used for the present study. The powder aerosol performance should be evaluated prior to use in this application following standard methodology as described in USP General Chapter &#60;601&#62; (see Table of Materials).</li>
	<li>If storing and/or transporting the powder, use the tube cap (cut off) to close the vial. Seal with paraffin film to minimize powder exposure to ambient moisture if storing and/or transporting.</li>
</ol>
2. Loading and assembling dosators
<ol>
	<li>Tamp the trimmed stainless-steel needle into the powder bed in the 0.6 mL conical centrifuge tube tip as many times as needed to achieve the desired dose (Figure 2B). Gently wipe the sides of the stainless-steel needle with a low-lint wiper to remove any excess powder (Figure 3).</li>
	<li>Gently insert the loaded stainless-steel needle into a 3.81 cm (1.5 inch) polypropylene or 5.08 cm (2 inch) polytetrafluoroethylene (PTFE) needle (16-20 G) (see Table of Materials) to avoid dislodging any powder (Figure 1B,C and Figure 2C).</li>
</ol>
3. Actuating dosators
<ol>
	<li>Draw back a disposable syringe to the desired volume, which may vary based on application. 
	NOTE: For intrapulmonary administration in mice, 0.15-0.6 mL is typically appropriate8,9.</li>
	<li>Attach the syringe to the luer lock on the polypropylene or PTFE needle (Figure 2D).</li>
	<li>Insert the needle end of the dosator into the desired target. For analyzing powder content and reproducibility, insert the needle through a perforated rubber septum or paraffin film into a vial containing a small amount (e.g., 1-5 mL) of water and/or organic solvent (e.g., ethanol), with solvent identity and volume dependent on active pharmaceutical ingredient (API) physical characteristics and the quantification method.
	<ol>
		<li>For delivery to mice, insert the needle up to the first bronchial bifurcation of the trachea of anesthetized mice following established protocols9,15.</li>
	</ol>
	</li>
	<li>Depress the syringe forcefully, expelling the powder out of the device into the collection vial (Figure 2E). 
	NOTE: The same technique must be followed for delivering the powder to the murine lungs.</li>
	<li>For analyzing content and reproducibility from the collection vial, utilize an appropriate analytical method for the specific API, such as UV-Visible (UV-Vis) spectrophotometry or high-performance liquid chromatography (HPLC).</li>
</ol>

Customizable Disposable Dosators to Deliver Dry Powder Aerosol Drugs to Mice

<ol>
	<li>Wu, X., Li, X., Mansour, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+analytical+techniques+in+solid-state+particle+characterization+for+predicting+performance+in+dry+powder+inhalers.">Surface analytical techniques in solid-state particle characterization for predicting performance in dry powder inhalers.</a> KONA Powder and Particle Journal. 28, 3-18 (2010).</li><li>Maloney, S. E., Mecham, J. B., Hickey, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+testing+for+dry+powder+inhaler+products:+towards+clinical+relevance.">Performance testing for dry powder inhaler products: towards clinical relevance.</a> KONA Powder and Particle Journal. 40, 172-185 (2023).</li><li>Maloney, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spray+dried+tigecycline+dry+powder+aerosols+for+the+treatment+of+nontuberculous+mycobacterial+pulmonary+infections.">Spray dried tigecycline dry powder aerosols for the treatment of nontuberculous mycobacterial pulmonary infections.</a> Tuberculosis. 139, 102306 (2023).</li><li>Kaur, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hand-held+apparatus+for+&amp;#34;nose-only&amp;#34;+exposure+of+mice+to+inhalable+microparticles+as+a+dry+powder+inhalation+targeting+lung+and+airway+macrophages.">A hand-held apparatus for &amp;#34;nose-only&amp;#34; exposure of mice to inhalable microparticles as a dry powder inhalation targeting lung and airway macrophages.</a> European Journal of Pharmaceutical Sciences. 34 (1), 56-65 (2008).</li><li>Yi, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-body+nanoparticle+aerosol+inhalation+exposures.">Whole-body nanoparticle aerosol inhalation exposures.</a> Journal of Visualized Experiments. (75), e50263 (2013).</li><li>Chung, Y. H., Han, J. H., Lee, Y. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+on+subchronic+inhalation+toxicology+of+1-chloropropane.">A study on subchronic inhalation toxicology of 1-chloropropane.</a> Toxicological Research. 31 (4), 393-402 (2015).</li><li>Kuehl, P. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+particle+size+dependent+deposition+of+inhaled+aerosols+in+rats+and+mice.">Regional particle size dependent deposition of inhaled aerosols in rats and mice.</a> Inhalation Toxicology. 24 (1), 27-35 (2012).</li><li>Manser, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+considerations+for+intratracheal+delivery+devices+to+achieve+proof-of-concept+dry+powder+biopharmaceutical+delivery+in+mice.">Design considerations for intratracheal delivery devices to achieve proof-of-concept dry powder biopharmaceutical delivery in mice.</a> Pharmaceutical Research. 40, 1165-1176 (2023).</li><li>Stewart, I. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+characterization+of+a+dry+powder+formulation+for+anti-tuberculosis+drug+spectinamide+1599.">Development and characterization of a dry powder formulation for anti-tuberculosis drug spectinamide 1599.</a> Pharmaceutical Research. 36 (9), 136 (2019).</li><li>Durham, P. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disposable+dosators+for+pulmonary+insufflation+of+therapeutic+agents+to+small+animals.">Disposable dosators for pulmonary insufflation of therapeutic agents to small animals.</a> Journal of Visualized Experiments. (121), e55356 (2017).</li><li>Miwata, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intratracheal+administration+of+siRNA+dry+powder+targeting+vascular+endothelial+growth+factor+inhibits+lung+tumor+growth+in+mice.">Intratracheal administration of siRNA dry powder targeting vascular endothelial growth factor inhibits lung tumor growth in mice.</a> Molecular Therapy: Nucleic Acids. 12, 698-706 (2018).</li><li>Duret, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacokinetic+evaulation+in+mice+of+amorphous+itraconazole-based+dry+powder+formulations+for+inhalation+with+high+bioavailability+and+extended+lung+retention.">Pharmacokinetic evaulation in mice of amorphous itraconazole-based dry powder formulations for inhalation with high bioavailability and extended lung retention.</a> European Journal of Pharmaceutics and Biopharmaceutics. 86 (1), 46-54 (2014).</li><li>Maloney, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+strategies+of+the+anti-mycobacterial+drug+bedaquiline+for+intrapulmonary+routes+of+administration.">Preparation strategies of the anti-mycobacterial drug bedaquiline for intrapulmonary routes of administration.</a> Pharmaceuticals. 16 (5), 729 (2023).</li><li>Price, D. N., Kunda, N. K., Muttil, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+associated+with+the+pulmonary+delivery+of+therapeutic+dry+powders+for+preclinical+testing.">Challenges associated with the pulmonary delivery of therapeutic dry powders for preclinical testing.</a> KONA Powder and Particle Journal. 36, 129-144 (2019).</li><li>Qiu, Y., Liao, Q., Chow, M. Y. T., Lam, J. K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intratracheal+administration+of+dry+powder+formulation+in+mice.">Intratracheal administration of dry powder formulation in mice.</a> Journal of Visualized Experiments. (161), e61469 (2020).</li><li>Fiegel, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+in+vivo+evaluation+of+a+dry+powder+for+inhalation+of+capreomycin.">Preparation and in vivo evaluation of a dry powder for inhalation of capreomycin.</a> Pharmaceutical Research. 25 (4), 805-811 (2008).</li></ol>

The authors declare that they have no conflict of interest.

As mice are obligate nose breathers, delivery via passive inhalation for initial proof-of-concept studies makes efficiency and dose estimation challenging as the powder must pass the nose and throat in a manner dependent on particle properties and powder dispersion efficiency7,8,14. The use of the dosators developed herein bypasses the nose and throat, with the dosator inserted to the first bronchial bifurcation<sup cla...

The use of dry powder inhalers (DPIs) for pulmonary drug delivery has garnered significant interest over the past three decades due to the global phase-out of chlorofluorocarbon propellants1,2. DPIs offer numerous benefits over other pulmonary delivery systems, such as metered dose inhalers and nebulizers, including formulation stability, portability, ease of use, and propellant-free dispersal mechanisms2. However, before moving DPI products toward clinical translation, several preclinical studies must be conducted, many of which are initially completed using a murine model. Nevertheless, technologies available to deliver dry powders accurately and reproducibly to small animals are limited.
Common methods to deliver dry powders to small animals, such as mice, include passive inhalation3,4,5,6,7 and direct administration8,9,10,11,12,13. Passive inhalation typically requires a custom chamber that utilizes large doses of spray-dried powder to prepare a sufficient aerosol cloud. As mice are obligate nose breathers14, delivery by passive inhalation requires the powder to travel through the nose and throat to reach the lungs, necessitating the maintenance of an aerosol cloud with sufficient particle aerodynamic properties7,8. While a useful technique that is more physiologically relevant than direct delivery due to inhalation as a result of normal breathing14, it may not be suitable for initial studies where powder mass is limited.
Alternatively, a number of intratracheal delivery devices for direct dry powder delivery have been reported8,9,10,11,12,13. Intratracheal devices bypass the nose and throat, delivering the powder directly to the lungs and allowing for finer control over the delivered dose14. Additionally, some devices, especially those prepared using a tamping loading procedure9, can be prepared with smaller quantities, which is an important consideration for initial proof-of-concept studies. The lack of universally available intratracheal delivery devices has hindered their potential for use, limiting availability and leading to interlaboratory differences14. In this study, we propose a simple, inexpensive, disposable dosator for intratracheal delivery that can be utilized for proof-of-concept murine studies in the development of dry powder aerosols.

<table><tbody><tr><td>0.6 mL microcentrifuge tubes</td><td>Fisher Scientific</td><td>05-408-120</td><td></td></tr><tr><td>Analytical balance</td><td>Mettler Toledo</td><td>AR1140</td><td>Any analytical balance with sufficient range can be used</td></tr><tr><td>Blunt stainless-steel needle, 1 inch, 21 G</td><td>McMaster-Carr</td><td>75165A681</td><td></td></tr><tr><td>Blunt stainless-steel needle, 1 inch, 22 G</td><td>McMaster-Carr</td><td>75165A683</td><td></td></tr><tr><td>Blunt stainless-steel needle, 1 inch, 25 G</td><td>McMaster-Carr</td><td>75165A687</td><td></td></tr><tr><td>Disposable syringe with luer lock (1 mL)</td><td>Fisher Scientific</td><td>14-823-30</td><td>3-mL syringes can also be used</td></tr><tr><td>Female BALB/c mice&amp;nbsp;</td><td>Charles River, Wilmington, MA, USA</td><td></td><td></td></tr><tr><td>High-performance cascade impactor&amp;nbsp;</td><td>Next Generation Impactor</td><td>Apparatus 5</td><td></td></tr><tr><td>Lab film (e.g., Parafilm)</td><td>Fisher Scientific</td><td>S37440</td><td></td></tr><tr><td>Low-lint wiper (e.g., Kimwipes)</td><td>Kimberly-Clark Professional</td><td>34133</td><td></td></tr><tr><td>Low-resistance dry powder inhaler&amp;nbsp;</td><td>RS01 mod 7</td><td></td><td></td></tr><tr><td>Polypropylene needle, 1.5 inch, 16 G</td><td>McMaster-Carr</td><td>6934A111</td><td></td></tr><tr><td>Polypropylene needle, 1.5 inch, 18 G</td><td>McMaster-Carr</td><td>6934A53</td><td></td></tr><tr><td>Polypropylene needle, 1.5 inch, 20 G</td><td>McMaster-Carr</td><td>6934A55</td><td></td></tr><tr><td>Precision sectioning saw</td><td>TedPella</td><td>812-300</td><td>Belt sander can be used as an alternative</td></tr><tr><td>PTFE needle, 2 inch, 20 G</td><td>McMaster-Carr</td><td>75175A694</td><td></td></tr><tr><td>USP General Chapter &amp;lt;601&gt;&amp;nbsp;</td><td></td><td></td><td>http://www.uspbpep.com/usp31/v31261/usp31nf26s1_c601.asp</td></tr></tbody></table>

disposable dosators intended for dry powder delivery to mice

Dry powder inhalers offer numerous advantages for delivering drugs to the lungs, including stable solid-state drug formulations, device portability, bolus metering and dosing, and a propellant-free dispersal mechanism. To develop pharmaceutical dry powder aerosol products, robust in vivo testing is essential. Typically, initial studies involve using a murine model for preliminary evaluation before conducting formal studies in larger animal species. However, a significant limitation in this approach is the lack of suitable device technology to accurately and reproducibly deliver dry powders to small animals, hindering such models&#39; utility. To address these challenges, disposable syringe dosators were developed specifically for intrapulmonary delivery of dry powders in doses appropriate for mice. These dosators load and deliver a predetermined amount of powder obtained from a uniform bulk density powder bed. This discrete control is achieved by inserting a blunt needle to a fixed depth (tamping) into the powder bed, removing a fixed quantity each time. Notably, this dosing pattern has proven effective for a range of spray-dried powders. In experiments involving four different model spray-dried powders, the dosators demonstrated the ability to achieve doses within the range of 30 to 1100 &#181;g. The achieved dose was influenced by factors such as the number of tamps, the size of the dosator needle, and the specific formulation used. One of the key benefits of these dosators is their ease of manufacturing, making them accessible and cost-effective for delivering dry powders to mice during initial proof-of-concept studies. The disposable nature of the dosators facilitates use in animal procedure rooms, where cleaning and refilling reusable systems and weighing materials is inconvenient. Thus, developing disposable syringe dosators has addressed a significant hurdle in murine dry powder delivery for proof-of-concept studies, enabling researchers to conduct more accurate and reproducible preliminary studies in small animal models for pulmonary drug delivery.

The aerosol performance&#160;of various spray-dried powders was established prior to use in this study. The aerodynamic particle size distribution (APSD) was described by the mass median aerodynamic diameter (MMAD), representing the size that divides the distribution in two at the 50th percentile (d50), and the geometric standard deviation (GSD), reflecting the breadth of the distribution. The GSD is defined by the square root of the aerodynamic diameter at the 80th percentile divided by ...

Watch this Scientific Journal Video about Developing a Disposable Dosator for Preclinical Testing of Dry Powder Inhalers in Small Animal Models at JoVE.com

Author Spotlight: Developing a Disposable Dosator for Preclinical Testing of Dry Powder Inhalers in Small Animal Models 

Pharmaceutical dry powder development necessitates reliable in vivo testing, often using a murine model. Device technology for accurately and reproducibly delivering dry powder aerosols to mice is restricted. This study presents disposable dosators for pulmonary drug delivery at mouse-relevant doses, aiding initial proof-of-concept research.

Disposable Dosators Intended for Dry Powder Delivery to Mice

Dry powder inhalers offer numerous advantages for delivering drugs to the lungs, including stable solid-state drug formulations, device portability, bolus ...

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Pharmacokinetics and Pharmacodynamics: Introduction

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790 Views.  RTI International. We ontwikkelen nieuwe en bestaande geneesmiddelen voor inhalatietherapie van mycobacteriële ziekten. Onze focus ligt op een nieuwe benadering voor de behandeling van resistente organismen, waarbij de veiligheid en werkzaamheid met behulp van droge poeders worden gegarandeerd. De eerste preklinische tests van inhalatorproducten met droog poeder vinden meestal plaats in een muizenmodel voordat wordt overgestapt op een groter diermodel.Een belangrijke beperking van deze aanpak is het ont...

Video: Auteur in de schijnwerpers: Ontwikkeling van een wegwerpdoseerder voor preklinische tests van droge poederinhalatoren in kleine diermodellen 

Delivery of Therapeutic Agents Through Intracerebroventricular (ICV) and Intravenous (IV) Injection in Mice

Despite the protective role that blood brain barrier plays in shielding the brain, it limits the access to the central nervous system (CNS) which most often results in failure of potential therapeutics designed for neurodegenerative disorders 1,2. Neurodegenerative diseases such as Spinal Muscular Atrophy (SMA), in which the lower motor neurons are affected, can benefit greatly from introducing the therapeutic agents into the CNS. The purpose of this video is to demonstrate two different injection paradigms to deliver therapeutic materials into neonatal mice soon after birth. One of these methods is injecting directly into cerebral lateral ventricles (Intracerebroventricular) which results in delivery of materials into the CNS through the cerebrospinal fluid 3,4. The second method is a temporal vein injection (intravenous) that can introduce different therapeutics into the circulatory system, leading to systemic delivery including the CNS 5. Widespread transduction of the CNS is achievable if an appropriate viral vector and viral serotype is utilized. Visualization and utilization of the temporal vein for injection is feasible up to postnatal day 6. However, if the delivered material is intended to reach the CNS, these injections should take place while the blood brain barrier is more permeable due to its immature status, preferably prior to postnatal day 2. The fully developed blood brain barrier greatly limits the effectiveness of intravenous delivery. Both delivery systems are simple and effective once the surgical aptitude is achieved. They do not require any extensive surgical devices and can be performed by a single person. However, these techniques are not without challenges. The small size of postnatal day 2 pups and the subsequent small target areas can make the injections difficult to perform and initially challenging to replicate.

Delivery of Therapeutic Agents Through Intracerebroventricular ICV and Intravenous IV Injection in Mice

This article demonstrates two very different methods of injection: 1) into the brain (intracerebroventricular) and 2) systemic (intravenous) to introduce the therapeutic agents into the central nervous system of neonatal mice.

Despite the protective role that blood brain barrier plays in shielding the brain, it limits the access to the central nervous system (CNS) which most ...

The Measurement and Treatment of Suppression in Amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.
Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia9,10 .
Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations.
In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.

Amblyopia is a developmental disorder of the visual cortex that is often accompanied by strong suppression of one eye. We present a new technique for measuring and treating interocular suppression in patients with amblyopia that can be deployed using virtual reality goggles or a portable iPod Touch device.

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current ...

Intranasal Administration of CNS Therapeutics to Awake Mice

Intranasal administration is a method of delivering therapeutic agents to the central nervous system (CNS). It is non-invasive and allows large molecules that do not cross the blood-brain barrier access to the CNS. Drugs are directly targeted to the CNS with intranasal delivery, reducing systemic exposure and thus unwanted systemic side effects1. Delivery from the nose to the CNS occurs within minutes along both the olfactory and trigeminal neural pathways via an extracellular route and does not require drug to bind to any receptor or axonal transport2. Intranasal delivery is a widely publicized method and is currently being used in human clinical trials3.
Intranasal delivery of drugs in animal models allows for initial evaluation of pharmacokinetic distribution and efficacy. With mice, it is possible to administer drugs to awake (non-anesthetized) animals on a regular basis using a specialized intranasal grip. Awake delivery is beneficial because it allows for long-term chronic dosing without anesthesia, it takes less time than with anesthesia, and can be learned and done by many people so that teams of technicians can dose large numbers of mice in short periods. Efficacy of therapeutics administered intranasally in this way to mice has been demonstrated in a number of studies including insulin in diabetic mouse models 4-6 and deferoxamine in Alzheimer's mouse models. 7,8
The intranasal grip for mice can be learned, but is not easy and requires practice, skill, and a precise grip to effectively deliver drug to the brain and avoid drainage to the lung and stomach. Mice are restrained by hand using a modified scruff in the non-dominant hand with the neck held parallel to the floor, while drug is delivered with a pipettor using the dominant hand. It usually takes 3-4 weeks of acclimating to handling before mice can be held with this grip without a stress response. We have prepared this JoVE video to make this intranasal delivery technique more accessible.

A method to intranasally administer drugs to awake mice for the purpose of targeting the brain is described. This method allows for repeat dosing over long periods using intranasal administration of drug without anesthesia, and nose-to-brain delivery with minimal systemic exposure.

Intranasal administration is a method of delivering  therapeutic agents to the central nervous system (CNS). It is  non-invasive and allows large ...

Heterotopic Mucosal Engrafting Procedure for Direct Drug Delivery to the Brain in Mice

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high molecular weight compounds from the bloodstream and into brain tissue. Some direct delivery success in humans has been achieved via implantation of transcranial catheters; however this method is highly invasive and associated with numerous complications. A less invasive alternative would be to dose the brain through a surgically implanted, semipermeable membrane such as the nasal mucosa that is used to repair skull base defects following endoscopic transnasal tumor removal surgery in humans. Drug transfer though this membrane would effectively bypass the BBB and diffuse directly into the brain and cerebrospinal fluid. Inspired by this approach, a surgical approach in mice was developed that uses a donor septal mucosal membrane engrafted over an extracranial surgical BBB defect. This model has been shown to effectively allow the passage of high molecular weight compounds into the brain. Since numerous drug candidates are incapable of crossing the BBB, this model is valuable for performing preclinical testing of novel therapies for neurological and psychiatric diseases.

A mouse model of human endoscopic skull base reconstruction has been developed that creates a semipermeable interface between the brain and nose using nasal mucosal grafts. This method allows researchers to study delivery to the central nervous system of high molecular weight therapeutics which are otherwise excluded by the blood-brain barrier when administered systemically.

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high ...

Disposable Dosators for Pulmonary Insufflation of Therapeutic Agents to Small Animals

Development of new therapeutic products requires efficacy testing in an animal model. The pulmonary route of administration can be utilized to deliver drugs locally and systemically. Evaluation of dry powder aerosols necessitates an efficient dispersion mechanism to maintain high concentrations in an exposure chamber or for direct endotracheal administration. While solutions exist to expose animals by passive inhalation to dry powder aerosols, most require masses of powder in large excess of the dose delivered. This precludes conducting early feasibility studies as insufficient drug is available at the research or early development stage to support the dose delivery requirements for conventional aerosol delivery systems. When designing an aerosol drug product, aerodynamic performance can relate directly to delivery efficiency and efficacy. Dispersion of powder into an aerosol requires energy input sufficient to overcome interparticulate forces, and particle engineering approaches can substantially improve aerosol performance. We have developed a dispersion system (dosator) which can aerosolize engineered dry powder aerosols efficiently for the purpose of direct pulmonary insufflation, dispersion into an exposure system or generation for analytical purposes.

During development of drugs for pulmonary delivery, it is necessary to evaluate pharmacokinetics and efficacy in an animal model. We present a method to build a disposable aerosol dispersion system from of-the-shelf components that can be used to administer intrapulmonary dry powder aerosol to rodents.

Development of new therapeutic products requires efficacy testing in an animal model. The pulmonary route of administration can be utilized to deliver ...

Dry Powder and Nebulized Aerosol Inhalation of Pharmaceuticals Delivered to Mice Using a Nose-only Exposure System

Obstructive respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD) are currently treated by inhaled anti-inflammatory and bronchodilator drugs. Despite the availability of multiple treatments, both diseases are growing public health concerns. The majority of asthma patients are well controlled on current inhaled therapies but a substantial number of patients with severe asthma are not. Asthma affects an estimated 300 million people worldwide and approximately 20 percent have a severe form of the disease. In contrast to asthma, there are few effective therapies for COPD. An estimated 10% of the population has COPD and the trend in death rates is increasing for COPD while decreasing for other major diseases. Although developing drugs for inhaled delivery is challenging, the nose-only inhalation unit enables direct delivery of novel drugs to the lung of rodents for pre-clinical efficacy and safety/toxicology studies. Inhaled drug delivery has multiple advantages for respiratory diseases, where high concentration in the lung improves efficacy and minimizes systemic side effects. Inhaled corticosteroids and bronchodilators benefit from these advantages and inhaled delivery may also hold potential for future biologic therapies. The inhalation unit described herein can generate, sample for characterization, and uniformly deposit a drug aerosol in the lungs of rodents. This enables the pre-clinical determination of the efficacy and safety of drug doses deposited in the lungs of rodents, key data required before initiating clinical development.

The inhalation unit described herein can generate, sample for characterization, and uniformly deposit a drug aerosol in the lungs of rodents. This enables the pre-clinical determination of the efficacy and safety of drug doses deposited in the lungs; key data enabling clinical inhaled drug development.

Obstructive respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD) are currently treated by inhaled anti-inflammatory and ...

Optimized LC-MS/MS Method for the High-throughput Analysis of Clinical Samples of Ivacaftor, Its Major Metabolites, and Lumacaftor in Biological Fluids of Cystic Fibrosis Patients

Defects in the cystic fibrosis trans-membrane conductance regulator (CFTR) are the cause of cystic fibrosis (CF), a disease with life-threatening pulmonary manifestations. Ivacaftor (IVA) and ivacaftor-lumacaftor (LUMA) combination are two new breakthrough CF drugs that directly modulate the activity and trafficking of the defective CFTR-protein. However, there is still a dearth of understanding on pharmacokinetic/pharmacodynamic parameters and the pharmacology of ivacaftor and lumacaftor. The HPLC-MS technique for the simultaneous analysis of the concentrations of ivacaftor, hydroxymethyl-ivacaftor, ivacaftor-carboxylate, and lumacaftor in biological fluids in patients receiving standard ivacaftor or ivacaftor-lumacaftor combination therapy has previously been developed by our group and partially validated to FDA standards. However, to allow the high-throughput analysis of a larger number of patient samples, our group has optimized the reported method through the use of a smaller pore size reverse-phase chromatography column (2.6 &#181;m, C8 100 &#197;; 50 x 2.1 mm) and a gradient solvent system (0-1 min: 40% B; 1-2 min: 40-70% B; 2-2.7 min: held at 70% B; 2.7-2.8 min: 70-90% B; 2.8-4.0 min: 90% B washing; 4.0-4.1 min: 90-40% B; 4.1-6.0 min: held at 40% B) instead of an isocratic elution. The goal of this study was to reduce the HPLC-MS analysis time per sample dramatically from ~15 min to only 6 min per sample, which is essential for the analysis of a large amount of patient samples. This expedient method will be of considerable utility for studies into the exposure-response relationships of these breakthrough CF drugs.

Ivacaftor and ivacaftor-lumacaftor combination are two new CF drugs. However, there is still a dearth of understanding on their PK/PD and pharmacology. We present an optimized HPLC-MS technique for the simultaneous analysis of ivacaftor and its major metabolites, and lumacaftor.

Defects in the cystic fibrosis trans-membrane conductance regulator (CFTR) are the cause of cystic fibrosis (CF), a disease with life-threatening ...

Adeno-Associated Virus-Mediated Delivery of CRISPR for Cardiac Gene Editing in Mice

The clustered, regularly interspaced, short, palindromic repeat (CRISPR) system has greatly facilitated genome engineering in both cultured cells and living organisms from a wide variety of species. The CRISPR technology has also been explored as novel therapeutics for a number of human diseases. Proof-of-concept data are highly encouraging as exemplified by recent studies that demonstrate the feasibility and efficacy of gene editing-based therapeutic approach for Duchenne muscular dystrophy (DMD) using a murine model. In particular, intravenous and intraperitoneal injection of the recombinant adeno-associated virus (rAAV) serotype rh.74 (rAAVrh.74) has enabled efficient cardiac delivery of the Staphylococcus aureus CRISPR-associated protein 9 (SaCas9) and two guide RNAs (gRNA) to delete a genomic region with a mutant codon in exon 23 of mouse Dmd gene. This same approach can also be used to knock out the gene-of-interest and study their cardiac function in postnatal mice when the gRNA is designed to target the coding region of the gene. In this protocol, we show in detail how to engineer rAAVrh.74-CRISPR vector and how to achieve highly efficient cardiac delivery in neonatal mice.

Here we provide a detailed protocol to carry out in vivo cardiac gene editing in mice using recombinant Adeno-Associated Virus(rAAV)-mediated delivery of CRISPR. This protocol offers a promising therapeutic strategy to treat dystrophic cardiomyopathy in Duchenne muscular dystrophy and can be used to generate cardiac-specific knockout in postnatal mice.

The clustered, regularly interspaced, short, palindromic repeat (CRISPR) system has greatly facilitated genome engineering in both cultured cells and ...

Intratracheal Administration of Dry Powder Formulation in Mice

In the development of inhalable dry powder formulations, it is essential to evaluate their biological activities in preclinical animal models. This paper introduces a noninvasive method of intratracheal delivery of dry powder formulation in mice. A dry powder loading device that consists of a 200 &#181;L gel loading pipette tip connected to an 1 mL syringe via a three-way stopcock is presented. A small amount of dry powder (1-2 mg) is loaded into the pipette tip and dispersed by 0.6 mL of air in the syringe. Because pipette tips are disposable and inexpensive, different dry powder formulations can be loaded into different tips in advance. Various formulations can be evaluated in the same animal experiment without device cleaning and dose refilling, thereby saving time and eliminating the risk of cross-contamination from residual powder. The extent of powder dispersion can be inspected by the amount of powder remaining in the pipette tip. A protocol of intubation in mouse with a custom-made light source and a guiding cannula is included. Proper intubation is one of the key factors that influences the intratracheal delivery of dry powder formulation to the deep lung region of the mouse.

Dry powder formulations for inhalation have great potential in treating respiratory diseases. Before entering human studies, it is necessary to evaluate the efficacy of the dry powder formulation in preclinical studies. A simple and noninvasive method of the administration of dry powder in mice through the intratracheal route is presented.

In the development of inhalable dry powder formulations, it is essential to evaluate their biological activities in preclinical animal models. This paper ...

A Technique to Generate and Deliver Drug Aerosols Directly to Mouse Lungs

Source: Phillips, J. E. et al., <a href="https://app.jove.com/v/55454">Dry Powder and Nebulized Aerosol Inhalation of Pharmaceuticals Delivered to Mice Using a Nose-only Exposure System.</a>&#160;J. Vis. Exp. (2017)
This video demonstrates the generation of drug aerosols and the targeted nose-only delivery of these aerosols to mice using an inhalation unit equipped with an aerosol generator. The mouse is restrained in a nose-only restrainer and connected to the inhalation unit, which delivers the drug directly into the mouse&#39;s nasal cavity. Subsequently, the drug passes through the trachea and enters the lungs.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
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Disposable Dosators Intended for Dry Powder Delivery to Mice

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