Formulatiion of PHMB-based nanoparticles for targetted killing of Zoonotic fungi
Lead Research Organisation:
Royal Veterinary College
Department Name: Pathobiology and Population Sciences
Abstract
FIT: BBSRC areas: Animal Diseases, Health and Welfare; Plants, Microbes Food and Sustainability; BBSRC Priority Area: Food Security (incl. animal pathogens); BBSRC iCASE objective: "broadening participation of SMEs".
HYPOTHESIS: existing antifungal drugs can be potentiated by targeted delivery into fungi via nanoparticle formulation with the cationic antimicrobial polymer polyhexanide biguanide (PHMB).
THE PROBLEM: It is difficult to develop much needed new anti-fungal agents. The challenges include stringent fungal cell barriers (limiting drug access to the pathogenic target) and biochemical similarities with host cells (producing undesirable safety liabilities via "drug cross-talk").
IDEA: Antifungal efficacy and safety can be improved via nanoparticle formulation. Nanoparticles can target fungal cells and promote cell entry, and thus improve pathogen killing and safety.
THE PARTNERSHIP: The partnership involves academic labs (RVC, UCL-CNRM & UCL-SoP), and an SME (Blueberry Therapeutics Ltd - BBT). The groups have complementary expertise and already cooperate. Recently, the RVC lab discovered that PHMB is able to enter a wide range of cells, including fungi, and the polymer can be used to deliver drugs into a range of cells (WO/2013/054123, Firdessa et al. 2015 PLoS NTD; Kamaruzzaman et al. 2016 JAC; Chindera et al. 2016, Sci. Rep). The UCL lab currently works with PHMB and other biodegradable polymers generate nanoparticles for drug delivery. UCL-SoP are experts in skin science. BBT has broad experience in drug development and a strategic focus on reformulating antifungal compounds to improve cell and tissue delivery for clinical development. The partnership connects microbiology, nanotechnology, polymer chemistry, engineering, skin science and drug development.
OBJECTIVES
1. Determine the antifungal mechanism(s) of action of PHMB against Candida and Malessezia species. PHMB itself has inherent antifungal activity, which has been attributed to disruption of fungal cell membranes. We suspect alternative mechanisms, and the main possibilities will be tested. The results will guide formulation choices for objective 2 (RVC;UCL-CNRML; month 1 to 15).
2. Design and construct nanoparticles using small molecule antifungals and PHMB. The polymer has a high capacity for electrostatic, hydrophobic and H-bonding interactions. We will use polyene, azole, allylamine, and echinocandin agents combined with PHMB and determine particle shape, size distribution, surface charge, encapsulation ratios and stability. The results will guide formulation selection for objective 3. (RVC, UCL-CNRM, BBT; month 3 to 24).
3. Measure antifungal activities. Minimum inhibitory and cidal concentrations will be determined. The potencies observed will guide formulation selection in objective 4. (RVC, BBT; month 12 to 36).
4. Assess mechanism(s) of cell uptake. Pathways(s) into fungi will be evaluated using microscopy, uptake pathway inhibitors and biophysical methods. (RVC; month 24 to 36).
5. Measure host cell impact. Proliferation or stress will be measured using cultured keratinocytes, lung epithelial cells and ex vivo human skin. The results will guide formulation selection for follow-on in vivo testing (RVC, UCL-SoP, BBT; month 24-36).
6. Assess scale-up feasibility. Effects of scale-up on encapsulation ratio, particle size and particle uniformity will be determined, along with consideration of regulatory aspects (UCL-CNRM, BBT; month 36-42)
HYPOTHESIS: existing antifungal drugs can be potentiated by targeted delivery into fungi via nanoparticle formulation with the cationic antimicrobial polymer polyhexanide biguanide (PHMB).
THE PROBLEM: It is difficult to develop much needed new anti-fungal agents. The challenges include stringent fungal cell barriers (limiting drug access to the pathogenic target) and biochemical similarities with host cells (producing undesirable safety liabilities via "drug cross-talk").
IDEA: Antifungal efficacy and safety can be improved via nanoparticle formulation. Nanoparticles can target fungal cells and promote cell entry, and thus improve pathogen killing and safety.
THE PARTNERSHIP: The partnership involves academic labs (RVC, UCL-CNRM & UCL-SoP), and an SME (Blueberry Therapeutics Ltd - BBT). The groups have complementary expertise and already cooperate. Recently, the RVC lab discovered that PHMB is able to enter a wide range of cells, including fungi, and the polymer can be used to deliver drugs into a range of cells (WO/2013/054123, Firdessa et al. 2015 PLoS NTD; Kamaruzzaman et al. 2016 JAC; Chindera et al. 2016, Sci. Rep). The UCL lab currently works with PHMB and other biodegradable polymers generate nanoparticles for drug delivery. UCL-SoP are experts in skin science. BBT has broad experience in drug development and a strategic focus on reformulating antifungal compounds to improve cell and tissue delivery for clinical development. The partnership connects microbiology, nanotechnology, polymer chemistry, engineering, skin science and drug development.
OBJECTIVES
1. Determine the antifungal mechanism(s) of action of PHMB against Candida and Malessezia species. PHMB itself has inherent antifungal activity, which has been attributed to disruption of fungal cell membranes. We suspect alternative mechanisms, and the main possibilities will be tested. The results will guide formulation choices for objective 2 (RVC;UCL-CNRML; month 1 to 15).
2. Design and construct nanoparticles using small molecule antifungals and PHMB. The polymer has a high capacity for electrostatic, hydrophobic and H-bonding interactions. We will use polyene, azole, allylamine, and echinocandin agents combined with PHMB and determine particle shape, size distribution, surface charge, encapsulation ratios and stability. The results will guide formulation selection for objective 3. (RVC, UCL-CNRM, BBT; month 3 to 24).
3. Measure antifungal activities. Minimum inhibitory and cidal concentrations will be determined. The potencies observed will guide formulation selection in objective 4. (RVC, BBT; month 12 to 36).
4. Assess mechanism(s) of cell uptake. Pathways(s) into fungi will be evaluated using microscopy, uptake pathway inhibitors and biophysical methods. (RVC; month 24 to 36).
5. Measure host cell impact. Proliferation or stress will be measured using cultured keratinocytes, lung epithelial cells and ex vivo human skin. The results will guide formulation selection for follow-on in vivo testing (RVC, UCL-SoP, BBT; month 24-36).
6. Assess scale-up feasibility. Effects of scale-up on encapsulation ratio, particle size and particle uniformity will be determined, along with consideration of regulatory aspects (UCL-CNRM, BBT; month 36-42)
People |
ORCID iD |
| Liam Good (Primary Supervisor) | |
| Winnie Ntow-Boahene (Student) |
Publications
Ntow-Boahene W
(2023)
Fungal cell barriers and organelles are disrupted by polyhexamethylene biguanide (PHMB).
in Scientific reports
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M009513/1 | 30/09/2015 | 31/03/2024 | |||
| 1906777 | Studentship | BB/M009513/1 | 30/09/2017 | 29/06/2022 | Winnie Ntow-Boahene |
| Description | I developed 2 antifungal nanoformulations that have been shown to be stable over 6 months. These formulations also show superior antifungal effect when cultured with fungi and show superior killing over 24 hrs when compared to exisitng antifungals. They also do not display any significant toxicity when compared to existing antifungals. I have modified a bacterial keratitis model into a fungi keratitis model. This involves infecting pig corneas with fungi and has allowed me to test the ability of these antifungal nanoformualtions to reverse infections to recover the corneas to prevent further damage in the disease state. |
| Exploitation Route | Fungi of the Candida, Aspergillus and Trichophyton geni also show acquired resistance to current first line antifungals (Azoles, Eichinocandins and Polyenes). The general increase in fungal infections and antifungal resistance, combined with the slow development of new antifungals suggests a significant social and economic impact in the future. Economically, an increase in fungal morbidity results in a size reduction of global workforce and productivity. Modelled projections of unresolved AMR, which includes resistance to antifungals, by the World Bank Group and the O'Neill report suggest a global economic crisis by 2050 with no relief due to increased costs of antimicrobials. To avoid the future of antifungals becoming as bleak as antibiotics, the use of newly developed antifungals should be measured wit bch national policies to maintain their efficiency. This is a collaborative project supported by an industrial partner (BBT), who are experienced in taking drugs from initial ideas through to the market place. As BBT possesses an established pipeline for this purpose, the potential impact for successful antifungal nanoformulations is substantial with access to the global commercial market. |
| Sectors | Agriculture Food and Drink Communities and Social Services/Policy Healthcare Pharmaceuticals and Medical Biotechnology |
| Description | Ex vivo Cornea fungal keratitis model with SCARAB (Sheffield Collaboratorium for Antimicrobial Resistance and Biofilms) |
| Organisation | University of Sheffield |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I aim to develop an ex vivo fungal keratitis model in order to test different newly improved anti fungal treatment options for improved efficacy. |
| Collaborator Contribution | I was on placement for 3 months from 7th July - 7th September 2019 to learn the techniques of developing an ex vivo cornea model. This included cornea excision and the principles of infection. |
| Impact | Ex vivo fungal keratitis model |
| Start Year | 2019 |