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Hickey AJ, Maloney SE, Kuehl PJ, Phillips JE, Wolff RK. Practical Considerations in Dose Extrapolation from Animals to Humans. J Aerosol Med Pulm Drug Deliv 2024; 37:77-89. [PMID: 38237032 DOI: 10.1089/jamp.2023.0041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024] Open
Abstract
Animal studies are an important component of drug product development and the regulatory review process since modern practices have been in place, for almost a century. A variety of experimental systems are available to generate aerosols for delivery to animals in both liquid and solid forms. The extrapolation of deposited dose in the lungs from laboratory animals to humans is challenging because of genetic, anatomical, physiological, pharmacological, and other biological differences between species. Inhaled drug delivery extrapolation requires scrutiny as the aerodynamic behavior, and its role in lung deposition is influenced not only by the properties of the drug aerosol but also by the anatomy and pulmonary function of the species in which it is being evaluated. Sources of variability between species include the formulation, delivery system, and species-specific biological factors. It is important to acknowledge the underlying variables that contribute to estimates of dose scaling between species.
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Affiliation(s)
- Anthony J Hickey
- Department of Technology Advancement and Commercialization, RTI International, Research Triangle Park, North Carolina, USA
| | - Sara E Maloney
- Department of Technology Advancement and Commercialization, RTI International, Research Triangle Park, North Carolina, USA
| | - Phillip J Kuehl
- Division: Scientific Core Laboratories; Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA
| | - Jonathan E Phillips
- Amgen, Inc., Inflammation Discovery Research, Thousand Oaks, California, USA
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Maloney SE, Stewart IE, Mecham JB, Gonzalez-Juarrero M, Meibohm B, Hickey AJ. Disposable Dosators Intended for Dry Powder Delivery to Mice. J Vis Exp 2023. [PMID: 37607097 DOI: 10.3791/65756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023] Open
Abstract
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' 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 µg. 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.
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Affiliation(s)
- Sara E Maloney
- Technology Advancement and Commercialization, RTI International;
| | - Ian E Stewart
- Technology Advancement and Commercialization, RTI International
| | | | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University
| | - Bernd Meibohm
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center
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Maloney SE, Grayton QE, Wai C, Uriyanghai U, Sidhu J, Roy-Chaudhury P, Schoenfisch MH. Correction to "Nitric Oxide-Releasing Hemodialysis Catheter Lock Solutions". ACS Appl Mater Interfaces 2023. [PMID: 37417360 DOI: 10.1021/acsami.3c09211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
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Maloney SE, Grayton QE, Wai C, Uriyanghai U, Sidhu J, Roy-Chaudhury P, Schoenfisch MH. Nitric Oxide-Releasing Hemodialysis Catheter Lock Solutions. ACS Appl Mater Interfaces 2023; 15:28907-28921. [PMID: 37285144 DOI: 10.1021/acsami.3c02506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In an attempt to address the significant morbidity, mortality, and economic cost associated with tunneled dialysis catheter (TDC) dysfunction, we report the development of nitric oxide-releasing dialysis catheter lock solutions. Catheter lock solutions with a range of NO payloads and release kinetics were prepared using low-molecular-weight N-diazeniumdiolate nitric oxide donors. Nitric oxide released through the catheter surface as a dissolved gas was maintained at therapeutically relevant levels for at least 72 h, supporting clinical translatability (interdialytic period). Slow, sustained NO release from the catheter surface prevented bacterial adhesion in vitro by 88.9 and 99.7% for Pseudomonas aeruginosa and Staphylococcus epidermidis, respectively, outperforming a burst NO-release profile. Furthermore, bacteria adhered to the catheter surface in vitro prior to lock solution use was reduced by 98.7 and 99.2% for P. aeruginosa and S. epidermidis, respectively, when using a slow releasing NO donor, demonstrating both preventative and treatment potential. The adhesion of proteins to the catheter surface, a process often preceding biofilm formation and thrombosis, was also lessened by 60-65% by sustained NO release. In vitro cytotoxicity of catheter extract solutions to mammalian cells was minimal, supporting the non-toxic nature of the NO-releasing lock solutions. The use of the NO-releasing lock solution in an in vivo TDC porcine model demonstrated decreased infection and thrombosis, enhanced catheter functionality, and improved outcome (i.e., likelihood of survival) as a result of catheter use.
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Affiliation(s)
- Sara E Maloney
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Quincy E Grayton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Christine Wai
- UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Unimunkh Uriyanghai
- UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jasleen Sidhu
- UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Prabir Roy-Chaudhury
- UNC Kidney Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mark H Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Maloney SE, Stewart IE, Podell BK, Gary HE, Mecham JB, Berube BJ, Baldwin SL, Coler RN, Hickey AJ. Preparation Strategies of the Anti-Mycobacterial Drug Bedaquiline for Intrapulmonary Routes of Administration. Pharmaceuticals (Basel) 2023; 16:ph16050729. [PMID: 37242512 DOI: 10.3390/ph16050729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/27/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Mycobacterium tuberculosis (M.tb) has infected one-quarter of the world's population and led to the deaths of 1.6 million individuals in 2021 according to estimates from the World Health Organization. The rise in prevalence of multidrug-resistant and extensively drug-resistant M.tb strains coupled with insufficient therapies to treat such strains has motivated the development of more effective treatments and/or delivery modalities. Bedaquiline, a diarylquinoline antimycobacterial agent, effectively targets mycobacterial ATP synthase but may lead to systemic complications upon oral delivery. Targeted delivery of bedaquiline to the lungs represents an alternative strategy to harness the sterilizing benefits of the drug against M.tb while mitigating off-target side effects. Two pulmonary delivery modalities were developed herein, including dry powder inhalation and liquid instillation. Despite bedaquiline's poor water solubility, spray drying was performed in predominantly aqueous conditions (≥80%) to avoid a closed-loop, inert system. Aerosols of spray-dried bedaquiline with L-leucine excipient outperformed spray-dried bedaquiline alone, demonstrating superior fine particle fraction metrics (~89% of the emitted dose below <5 µm), suitable for inhalation therapies. Furthermore, the use of a 2-hydroxypropyl-β-cyclodextrin excipient allowed a molecular dispersion of bedaquiline in an aqueous solution for liquid instillation. Both delivery modalities were successfully administered to Hartley guinea pigs for pharmacokinetic analysis and were well-tolerated by the animals. Intrapulmonary liquid delivery of bedaquiline led to adequate serum absorption and appropriate peak serum concentrations of the drug. The liquid formulation was superior in systemic uptake compared to the powder formulation. The predominant route via which M.tb bacilli enter the body is aerosol droplets that are deposited onto airway surfaces. For this reason, we believe that further studies should focus on inhalation or intrapulmonary therapies that target the site of entry and primary site of infection for M.tb.
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Affiliation(s)
- Sara E Maloney
- Technology Advancement and Commercialization, RTI International, Research Triangle Park, NC 27709, USA
| | - Ian E Stewart
- Technology Advancement and Commercialization, RTI International, Research Triangle Park, NC 27709, USA
| | - Brendan K Podell
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Hadley E Gary
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Jeffrey B Mecham
- Technology Advancement and Commercialization, RTI International, Research Triangle Park, NC 27709, USA
| | - Bryan J Berube
- Seattle Children's Research Institute, Center for Global Infectious Disease Research, Seattle, WA 98109, USA
| | - Susan L Baldwin
- Seattle Children's Research Institute, Center for Global Infectious Disease Research, Seattle, WA 98109, USA
| | - Rhea N Coler
- Seattle Children's Research Institute, Center for Global Infectious Disease Research, Seattle, WA 98109, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA
- Department of Global Health, University of Washington, Seattle, WA 98195, USA
| | - Anthony J Hickey
- Technology Advancement and Commercialization, RTI International, Research Triangle Park, NC 27709, USA
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Maloney SE, Broberg CA, Grayton QE, Picciotti SL, Hall HR, Wallet SM, Maile R, Schoenfisch MH. Role of Nitric Oxide-Releasing Glycosaminoglycans in Wound Healing. ACS Biomater Sci Eng 2022; 8:2537-2552. [PMID: 35580341 DOI: 10.1021/acsbiomaterials.2c00392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Two glycosaminoglycan (GAG) biopolymers, hyaluronic acid (HA) and chondroitin sulfate (CS), were chemically modified via carbodiimide chemistry to facilitate the loading and release of nitric oxide (NO) to develop a multi-action wound healing agent. The resulting NO-releasing GAGs released 0.2-0.9 μmol NO mg-1 GAG into simulated wound fluid with NO-release half-lives ranging from 20 to 110 min. GAGs containing alkylamines with terminal primary amines and displaying intermediate NO-release kinetics exhibited potent, broad spectrum bactericidal action against three strains each of Pseudomonas aeruginosa and Staphylococcus aureus ranging in antibiotic resistance profile. NO loading of the GAGs was also found to decrease murine TLR4 activation, suggesting that the therapeutic exhibits anti-inflammatory mechanisms. In vitro adhesion and proliferation assays utilizing human dermal fibroblasts and human epidermal keratinocytes displayed differences as a function of the GAG backbone, alkylamine identity, and NO-release properties. In combination with antibacterial properties, the adhesion and proliferation profiles of the GAG derivatives enabled the selection of the most promising wound healing candidates for subsequent in vivo studies. A P. aeruginosa-infected murine wound model revealed the benefits of CS over HA as a pro-wound healing NO donor scaffold, with benefits of accelerated wound closure and decreased bacterial burden attributable to both active NO release and the biopolymer backbone.
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Affiliation(s)
- Sara E Maloney
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Christopher A Broberg
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Quincy E Grayton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Samantha L Picciotti
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Hannah R Hall
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Shannon M Wallet
- Division of Oral, Craniofacial, and Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Robert Maile
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,North Carolina Jaycee Burn Center Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mark H Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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7
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Stewart IE, Durham PG, Sittenauer JM, Barreda AP, Stowell GW, Moody C, Mecham JB, Simpson C, Daily S, Maloney SE, Williams MD, Severynse-Stevens D, Hickey AJ. Optimization and Scale Up of Spray Dried CPZEN-45 Aerosol Powders for Inhaled Tuberculosis Treatment. Pharm Res 2022; 39:3359-3370. [PMID: 36114362 PMCID: PMC9483285 DOI: 10.1007/s11095-022-03393-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/06/2022] [Indexed: 12/27/2022]
Abstract
PURPOSE Tuberculosis (TB) remains one of the most serious diseases caused by a single organism. Multiple (MDR) and extensively (XDR) drug resistant disease poses a threat to global health and requires new drugs and/or innovative approaches to treatment. A number of drugs have been proposed as inhaled therapy for TB, frequently prepared by spray drying. CPZEN-45 is a novel anti-tubercular drug that has poor oral bioavailability but has shown promise when administered via inhalation. METHODS Excipient-free CPZEN-45 HCl has been spray dried into a powder with physicochemical characteristics, aerodynamic particle size distribution, and delivered dose suitable for consideration as an inhaled product. RESULTS The mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of the powder delivered using a RS01 inhaler were 2.62 ± 0.04 μm and 1.76 ± 0.09, respectively. Additionally, the powder was physically and chemically stable after storage at ambient conditions for >1.5 years with particle size similar to freshly manufactured product. Overages in spray dried powder were recycled the powder and resprayed into drug product likewise resulting in negligible change in quality thus allowing for further preclinical characterization as necessary. CPZEN-45 was scaled up using pilot-scale manufacturing equipment where the density of the powder was increased to facilitate larger delivered doses without affecting the aerodynamic performance properties. CONCLUSION The spray dried powders were suitable for pharmacokinetics, efficacy and preclinical toxicology studies. The final method of manufacture may be used directly for CGMP particle manufacture to support IND and Phase I clinical trials and beyond.
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Affiliation(s)
- Ian E Stewart
- Technology Advancement and Commercialization, RTI International, Durham, NC, USA
| | - Phillip G Durham
- Department of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Grayson W Stowell
- Social, Statistical, and Environmental Sciences, RTI International, Durham, NC, USA
| | - Carmella Moody
- Social, Statistical, and Environmental Sciences, RTI International, Durham, NC, USA
| | - Jeffery B Mecham
- Technology Advancement and Commercialization, RTI International, Durham, NC, USA
| | - Catherine Simpson
- Social, Statistical, and Environmental Sciences, RTI International, Durham, NC, USA
| | - Sharon Daily
- Social, Statistical, and Environmental Sciences, RTI International, Durham, NC, USA
| | - Sara E Maloney
- Technology Advancement and Commercialization, RTI International, Durham, NC, USA
| | | | | | - Anthony J Hickey
- Technology Advancement and Commercialization, RTI International, Durham, NC, USA.
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8
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Maloney SE, McGrath KV, Ahonen MJR, Soliman DS, Feura ES, Hall HR, Wallet SM, Maile R, Schoenfisch MH. Nitric Oxide-Releasing Hyaluronic Acid as an Antibacterial Agent for Wound Therapy. Biomacromolecules 2020; 22:867-879. [PMID: 33372774 DOI: 10.1021/acs.biomac.0c01583] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Taking advantage of their respective wound-healing roles in physiology, the dual activity of hyaluronic acid (HA) and nitric oxide (NO) was combined to create a single-agent wound therapeutic. Carboxylic acid groups of HA (6 and 90 kDa) were chemically modified with a series of alkylamines via carbodiimide chemistry to provide secondary amines for subsequent N-diazeniumdiolate NO donor formation. The resulting NO-releasing HA derivatives stored 0.3-0.6 μmol NO mg-1 and displayed diverse release kinetics (5-75 min NO-release half-lives) under physiological conditions. The 6 kDa HA with terminal primary amines and intermediate release kinetics exhibited broad-spectrum bactericidal activity against common wound pathogens, including planktonic methicillin-resistant Staphylococcus aureus as well as planktonic and biofilm-based multidrug-resistant Pseudomonas aeruginosa. The treatment of infected murine wounds with NO-releasing HA facilitated more rapid wound closure and decreased the quantity of the P. aeruginosa genetic material in the remaining wound tissue. Hyaluronidase readily degraded the HA derivatives, indicating that NO donor modification did not prohibit endogenous biodegradation pathways.
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Affiliation(s)
- Sara E Maloney
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kyle V McGrath
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mona Jasmine R Ahonen
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Daniel S Soliman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Evan S Feura
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Hannah R Hall
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Shannon M Wallet
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Division of Oral, Craniofacial, and Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Robert Maile
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,North Carolina Jaycee Burn Center Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mark H Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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9
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Abstract
A simplified diffusion cell methodology was employed to measure the diffusion coefficient of nitric oxide (NO) through phosphate buffered saline (PBS) and artificial sputum medium (ASM)—an in vitro analog for airway mucus. Diffusion through the proteinaceous ASM yielded a significantly lower diffusion coefficient compared to PBS, which is attributed to both the physical obstruction by the mucin mesh and reactive nature of NO radicals towards the biological compounds in ASM. To further confirm that ASM was restricting NO from diffusing freely, a macromolecular propylamine-modified cyclodextrin donor (CD-PA) was employed to release the NO more slowly. The NO diffusion characteristics in ASM via the NO donor were also slower relative to PBS. As NO is likely to interact with lung cells after passing through the mucus barrier, the diffusion of both NO and the CD-PA macromolecular NO donor through differentiated lung tissue was investigated with and without an ASM layer. Comparison of NO diffusion through the three diffusion barriers indicated that the lung tissue significantly impeded NO penetration over the course of the experiment compared to PBS and ASM. In fact, the diffusion of CD-PA through the lung tissue was hindered until after the release of its NO payload, potentially due to the increased net charge of the NO donor structure. Of importance, the viability of the tissue was not influenced by the NO-releasing CD-PA at bactericidal concentrations. Nitric oxide diffusion monitored through artificial sputum medium using an adaptable diffusion cell and released from donor through human lung tissue.![]()
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Affiliation(s)
- Jackson R Hall
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Sara E Maloney
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Haibao Jin
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - James B Taylor
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Mark H Schoenfisch
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
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10
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Abstract
Nitric oxide (NO) represents a potential wound therapeutic agent due to its ability to regulate inflammation and eradicate bacterial infections. Two broad strategies exist to utilize NO for wound healing; liberating NO from endogenous reservoirs, and supplementing NO from exogenous sources. This progress report examines the efficacy of a variety of NO-based methods to improve wound outcomes, with particular attention given to diabetes-associated chronic wounds.
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Affiliation(s)
- Maggie J Malone-Povolny
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Sara E Maloney
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Mark H Schoenfisch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Abstract
Thermophilic (75 degrees C), anaerobic biodegradation of chlorobenzoates was investigated using different inocula from geothermal and non-geothermal environments. Microbial dehalogenation of 3-chlorobenzoate (0.5 mmol l-1 was achieved by two mixed cultures growing anaerobically at 75 degrees C. One culture consisted of a facultative anaerobe and two obligate anaerobes, one of which was a methanogen, isolated from terrestrial sediments from hot springs in New Zealand. The other culture, derived from a non-geothermal environment, consisted of a Clostridium spp. and a non-spore-forming obligate anaerobe. No degradation of either 2-chlorobenzoate or 4-chlorobenzoate was achieved by these thermophilic cultures over the same time period. This is the first reported biotransformation of this chlorinated aromatic at a temperature of 75 degrees C.
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Affiliation(s)
- S E Maloney
- Centre for Applied Microbiology and Research, Salisbury, Wilts, UK
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Maloney SE, Maule A, Smith AR. Purification and preliminary characterization of permethrinase from a pyrethroid-transforming strain of Bacillus cereus. Appl Environ Microbiol 1993; 59:2007-13. [PMID: 8357241 PMCID: PMC182228 DOI: 10.1128/aem.59.7.2007-2013.1993] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Bacillus cereus SM3 was isolated on a mineral salts medium with Tween 80 as the primary carbon source. It was able to hydrolyze second- and third-generation pyrethroids, thereby generating noninsecticidal products. The enzyme responsible for this hydrolytic reaction was named permethrinase for this study. This is the first instance in which pyrethroid detoxification has been achieved with a cell-free microbial enzyme system. Permethrinase was purified by ion-exchange chromatography and gel filtration chromatography. The molecular mass of native permethrinase was 61 +/- 3 kDa, as estimated by Sephadex G-100 gel filtration. This novel microbial esterase seems to be a carboxylesterase. Permethrinase activity had an optimum pH of 7.5 and a temperature optimum of 37 degrees C. No cofactors or coenzymes were required for permethrinase activity. The enzyme may be a serine esterase, as it seems to be sensitive to the organophosphorus compound tetraethylpyrophosphate at concentrations in the micromolar range. Addition of dithiothreitol afforded permethrinase protection against the inhibitory effects of the sulfydryl agents p-chloromercuribenzoate and N-ethylmaleimide. The enzyme was stable over a range of temperatures. Cell extracts of strain SM3 also contained another esterase, which was active towards beta-naphthylacetate, but this enzyme was distinct from permethrinase.
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Affiliation(s)
- S E Maloney
- Division of Biotechnology, Centre for Applied Microbiology and Research, Salisbury, Wiltshire, United Kingdom
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Abstract
Employing a mineral salts medium containing Tween 80 as the primary carbon source, a strain of Bacillus stearothermophilus was isolated which was able to hydrolyse selected second and third-generation pyrethroids to non-insecticidal products. Of a range of pyrethroid insecticides the trans-isomer of permethrin was the most readily transformed by this microbial isolate, whilst flumethrin was the least. 3-Phenoxybenzoic acid and the respective halovinyl or haloacid moieties were detected as the major hydrolytic products of the pyrethroids. It is believed that 3-phenoxybenzoic acid was formed from 3-phenoxybenzyl alcohol which was not however detected as an intermediate in these systems. 3-Phenoxybenzoic acid was further transformed to 4-hydroxy-3-phenoxybenzoic acid. A potential metabolic pathway has been described.
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Affiliation(s)
- S E Maloney
- Division of Biotechnology, Centre for Applied Microbiology and Research, Salisbury, Wiltshire, UK
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Maloney SE, Maule A, Smith AR. Microbial transformation of the pyrethroid insecticides: permethrin, deltamethrin, fastac, fenvalerate, and fluvalinate. Appl Environ Microbiol 1988; 54:2874-6. [PMID: 3145715 PMCID: PMC204391 DOI: 10.1128/aem.54.11.2874-2876.1988] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pure cultures of Bacillus cereus, Pseudomonas fluorescens, and Achromobacter sp. were shown to transform five pyrethroid insecticides in the presence of Tween 80. One of the major products, 3-phenoxybenzoic acid, was further transformed to 4-hydroxy-3-phenoxybenzoic acid. Permethrin was the most rapidly transformed of the pyrethroids, with a half-life of less than 5 days.
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Affiliation(s)
- S E Maloney
- Division of Biotechnology, Centre for Applied Microbiology & Research, Salisbury, Wiltshire, United Kingdom
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