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Dr Yousuf Mohammed
Dr

Yousuf Mohammed

Email: 
Phone: 
+61 7 344 37485
Mobile: 
0433853534

Overview

Background

Dr Yousuf Mohammed completed his PhD in pharmaceutics and skin drug delivery under the guidance of Associate prof Heather Benson, Prof Michael Roberts and Associate prof Tarl Prow. He has been working within the field of skin delivery at the Therapeutics Research Centre, University of Queensland - School of Medicine since 2012. His current research includes managing a five-year (2018-2023) US FDA funded project titled Bioequivalence of Topical products: Elucidating the Thermodynamic and Functional Characteristics of Compositionally Different Topical Formulations as a Principle Investigator and managing the five-year project (2014-2019) Characterization of Critical Quality Attributes for Semisolid Topical Drug Products as a Co-investigator. These projects aims to improve current regulatory guidelines for topical and transdermal semisolid products. Over the last 6 years, his work has been focused on skin penetration and skin toxicology of drugs and xenobiotics including nanoparticulate materials.

Availability

Dr Yousuf Mohammed is:
Available for supervision
Media expert

Qualifications

  • Masters (Coursework), Curtin University of Technology
  • Doctor of Philosophy, Curtin University of Technology

Research interests

  • Bioequivalence of Topical products: Elucidating the sensorial and functional characteristics of Topical Formulations

    In addition to the defined therapeutic effect caused by an active drug in a product, there is also a placebo and, potentially, a nocebo effect associated with those products. In topical products, these latter effects may account from 30% to 50% of the overall response for some products. They may also explain why some topical products with apparently identical bioavailability are associated with different patient outcomes. This application seeks to address the question of when do subtle excipient and manufacturing changes in a topical product cause a sensorial sensation by subjects that the “feel” of a product has changed either before and/or after it is applied to human skin. A second question is whether the “feel” of a product both before and after application can be quantified by instrumental rheology, tribology and texture analysis methods and whether these, in turn, can be related to the reported sensorial behaviour. We will manufacture topical formulations that systematically vary in Q1, Q2, and/or Q3 attributes and have large and borderline perceptive differences. We will then characterized these products using a range of rheology, tribology and texture analysis methods. In parallel, these products will be evaluated by perceptive testing focus groups, with controls, of their sensorial characterisation of the ‘feel’ of the products. We will then relate these sensorial findings with the variations in formulation nature, composition and manufacture, and their resulting instrumental test results. Our goals are, firstly, to understand the relationships between product nature, instrumental findings and sensorial analyses and, secondly, to derive criteria for instrument tests that indicates what product composition subjects suggest do not differ, uncertain if they differ and do differ in their sensorial behaviour. It is hoped that we can define the simplest, robust test that accurately and robustly is in line with sensory perceptions. A range of statistical methods, including (potentially) sophisticated, machine learning and deep learning tools will then be used to model the most appropriate instrumental analysis that can, with reasonable confidence predict perceptive attributes. A key outcome is a potential regulatory guideline advocating that generic products should exhibit similar sensorial behaviour as a reference listed drug product, giving boundaries in rheology, tribology and texture analysis as defined by Q1, Q2 and Q3 differences when that sensorial behaviour between topical products is likely to be different.

  • Bioequivalence of Topical products: Elucidating the Thermodynamic and Functional Characteristics of Compositionally Different Topical Formulations

    The general requirements for generics to be considered are that the product is off-patent, contains an active ingredient in a previously approved medicine and is shown to be bioequivalent to that previously approved medicine. The fundamental forces governing the effects of topical drugs applied to the skin can be summed up in three distinct dimensions. 1. The interaction of the active pharmaceutical ingredient (API) with the excipients (formulation factors, solubility), 2. API with the skin (thermodynamic and pharmacodynamic activity) and 3. Excipient with the skin (penetration enhancement, diffusivity, irritancy). A thoughtful appreciation followed by a thorough understanding and then careful deliberations can help mitigate a number of failure modes that can arise from these three dimensions and result in disapproval of generic drug applications. However, there is an elusive fourth dimension, the psychorheology or the sensory/perceptive judgement of the rheological properties (and other organoleptic properties) that dictates the end user/consumers final acceptance of the product. Through this project we aim to develop meaningful risk mitigating methods and their scientific basis. These will encompass considering product behaviour during various stages of development/manufacturing, all the way to looking at the metamorphosing product as it is being applied to the treatment site on the skin. The development of generic topical products has been hampered by factors such as expensive clinical trials for BE assessment and application costs which get blown out due to the case by case assessment of applications. A burdensome application package is generally needed that wastes valuable resources and time on both sides of the coin. This project will ensure the much needed theoretical and practical framework that can enable a thorough yet efficient assessment of topical generic product applications.

  • Characterization of Critical Quality Attributes for Semisolid Topical Drug Products

    This US FDA funded project aims to understand the formulation-drug-skin interactions. Certain physicochemical attributes of a pharmaceutical product can be deemed as Critical Quality Attributes based on their influence of the product performance. This 5 year project goes into 16 different quality attributes and tests for their role in the performance of topical products using 22 different tests and numerous instruments and methods.

  • Toxicology of topically applied nanoparticles

    The safety of nanoparticles used in sunscreens has been a controversial international issue in recent years, in part because previous animal exposure studies generally found much higher skin absorption of zinc from dermal application of ZnO sunscreens than human studies. Our group’s work for the last several years has challenged these false alarms and through evidence based volunteer studies, provided the vital confidence boosting evidence for safe use of sunscreens. This is particularly relevant as the typical exposure to dangerous UV radiations has been on the rise.

Research impacts

Dr Yousuf Mohammed completed his PhD in pharmaceutics and skin drug delivery under the guidance of Associate prof Heather Benson, Prof Michael Roberts and Associate prof Tarl Prow. He has been working within the field of skin delivery at the Therapeutics Research Centre, University of Queensland - School of Medicine since 2012. His current research includes managing a five-year (2018-2023) US FDA funded project titled Bioequivalence of Topical products: Elucidating the Thermodynamic and Functional Characteristics of Compositionally Different Topical Formulations as a Principle Investigator and managing a four-year (2019-2023) US FDA funded project titled Bioequivalence of Topical products: Elucidating the sensorial and functional characteristics of Topical Formulations as a Principle Investigator. He is also currently managing the five-year project (2014-2019) Characterization of Critical Quality Attributes for Semisolid Topical Drug Products as a Co-investigator. These projects aims to improve current regulatory guidelines for topical and transdermal semisolid products in its second year of No Cost Extension. Over the last 6 years, his work has been focused on skin penetration and skin toxicology of drugs and xenobiotics including nanoparticulate materials.

Working on the US FDA project over the last two years has given an opportunity to showcase real world translational research. The work Yousuf and team has done has led to FDA guidance for Acyclovir creams which highlight the novel methods developed as a part of the work carried out locally in Brisbane in between TRI and other labs in the St Lucia campus.

Role of dispensers on physicochemical properties of the cream when dispensed. Difference in product performance upon dispensing from different dispensers was first identified and reported by our group and the change in cream product guidance based on this work is one of the biggest achievements. Our work over the last couple of years and specifically in the current year (July 2016- June 2017) has also identified skin and drug properties that determine product performance. Of special mention is our work on testing IVPT performance with different doses, different skin membrane types and different sampling protocols and different study durations. This a part of grant’s Aim 3 where we proposed to develop ideal IVPT conditions based on careful literature review as well as clearly thought-out experiments to investigate each parameter that can effect a products performance. Our IVPT studies have also included developing in-use product application and testing protocols and have assessed direct comparisons of CQAs with product performance.

Locally within the Australian topical and consumer product regulatory scene, Dr Mohammed’s work published in the Journal of Investigative dermatology has helped dispel false alarms regarding the safety and toxicity of ZnO nanoparticles. The story was captured by numerous (>400) printed and online media articles. This work, coming out at the peak of summer in Australia led to improved consumer confidence regarding better sun protection habits.

Works

Search Professor Yousuf Mohammed’s works on UQ eSpace

77 works between 2012 and 2024

61 - 77 of 77 works

2017

Book Chapter

Non-formulation parameters that affect penetrant-skin-vehicle interactions and percutaneous absorption

Grice, Jeffrey E., Moghimi, Hamid R., Ryan, Elizabeth, Zhang, Qian, Haridass, Isha, Mohammed, Yousuf and Roberts, Michael S. (2017). Non-formulation parameters that affect penetrant-skin-vehicle interactions and percutaneous absorption. Percutaneous penetration enhancers drug penetration into/through the skin: methodology and general considerations. (pp. 45-75) edited by Nina Dragicevic and Howard I. Maibach. Berlin, Germany: Springer . doi: 10.1007/978-3-662-53270-6_4

Non-formulation parameters that affect penetrant-skin-vehicle interactions and percutaneous absorption

2017

Book Chapter

The influence of emollients on dermal and transdermal drug delivery

Leite-Silva, V. R., Grice, Jeffrey E., Mohammed, Yousuf, Moghimi, Hamid R. and Roberts, Michael S. (2017). The influence of emollients on dermal and transdermal drug delivery. Percutaneous penetration enhancers drug penetration into/through the skin: methodology and general considerations. (pp. 77-93) edited by Nina Dragicevic and Howard I. Maibach. Berlin, Germany: Springer. doi: 10.1007/978-3-662-53270-6_5

The influence of emollients on dermal and transdermal drug delivery

2016

Journal Article

Skin models for the testing of transdermal drugs

Abd, Eman, Yousef , Shereen A., Pastore, Michael N., Telaprolu, Krishna, Mohammed, Yousuf H., Namjoshi, Sarika, Grice, Jeffrey E. and Roberts, Michael S. (2016). Skin models for the testing of transdermal drugs. Clinical Pharmacology: Advances and Applications, 8, 163-176. doi: 10.2147/CPAA.S64788

Skin models for the testing of transdermal drugs

2016

Journal Article

Mechanistic evaluation of hydration effects on the human epidermal permeation of salicylate esters

Yousef, Shereen, Mohammed, Yousuf, Namjoshi, Sarika, Grice, Jeffrey, Sakran, Wedad and Roberts, Michael (2016). Mechanistic evaluation of hydration effects on the human epidermal permeation of salicylate esters. AAPS Journal, 19 (1), 1-11. doi: 10.1208/s12248-016-9984-0

Mechanistic evaluation of hydration effects on the human epidermal permeation of salicylate esters

2016

Journal Article

Estimating maximal in vitro skin permeation flux from studies using non-sink receptor phase conditions

Yousef, Shereen, Liu, Xin, Mostafa, Ahmed, Mohammed, Yousuf, Grice, Jeffrey E., Anissimov, Yuri G., Sakran, Wedad and Roberts, Michael S. (2016). Estimating maximal in vitro skin permeation flux from studies using non-sink receptor phase conditions. Pharmaceutical Research, 33 (9), 2180-2194. doi: 10.1007/s11095-016-1955-8

Estimating maximal in vitro skin permeation flux from studies using non-sink receptor phase conditions

2016

Journal Article

Cyclic dipeptide shuttles as a novel skin penetration enhancement approach: preliminary evaluation with diclofenac

Mohammed, Yousuf, Teixido, Meritxell, Namjoshi, Sarika, Giralt, Ernest and Benson, Heather (2016). Cyclic dipeptide shuttles as a novel skin penetration enhancement approach: preliminary evaluation with diclofenac. PLoS One, 11 (8) e0160973, e0160973. doi: 10.1371/journal.pone.0160973

Cyclic dipeptide shuttles as a novel skin penetration enhancement approach: preliminary evaluation with diclofenac

2016

Journal Article

Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment

Leite-Silva, V. R., Sanchez, W. Y., Studier, H., Liu, D. C., Mohammed, Y. H., Holmes, A. M., Ryan, E. M., Haridass, I. N., Chandrasekaran, N. C., Becker, W., Grice, J. E., Benson, H. A. E. and Roberts, M. S. (2016). Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment. European Journal of Pharmaceutics and Biopharmaceutics, 104 (4), 140-147. doi: 10.1016/j.ejpb.2016.04.022

Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment

2016

Journal Article

Permeation of topically applied magnesium ions through human skin is facilitated by hair follicles

Chandrasekaran, Navin Chandrakanth, Sanchez, Washington Y., Mohammed, Yousuf H., Grice, Jeffrey E., Roberts, Michael S. and Barnard, Ross T. (2016). Permeation of topically applied magnesium ions through human skin is facilitated by hair follicles. Magnesium Research, 29 (2), 35-42. doi: 10.1684/mrh.2016.0402

Permeation of topically applied magnesium ions through human skin is facilitated by hair follicles

2016

Journal Article

Effect of flexing and massage on in vivo human skin penetration and toxicity of zinc oxide nanoparticles

Leite-Silva, Vania R., Liu, David C., Sanchez, Washington Y., Studier, Hauke, Mohammed, Yousuf H., Holmes, Amy, Becker, Wolfgang, Grice, Jeffrey E., Benson, Heather A. E. and Roberts, Michael S. (2016). Effect of flexing and massage on in vivo human skin penetration and toxicity of zinc oxide nanoparticles. Nanomedicine, 11 (10), 1193-1205. doi: 10.2217/nnm-2016-0010

Effect of flexing and massage on in vivo human skin penetration and toxicity of zinc oxide nanoparticles

2016

Journal Article

Synergistic skin penetration enhancer and nanoemulsion formulations promote the human epidermal permeation of caffeine and naproxen

Abd, Eman, Namjoshi, Sarika, Mohammed, Yousuf H., Roberts, Michael S. and Grice, Jeffrey E. (2016). Synergistic skin penetration enhancer and nanoemulsion formulations promote the human epidermal permeation of caffeine and naproxen. Journal of Pharmaceutical Sciences, 105 (1), 212-220. doi: 10.1002/jps.24699

Synergistic skin penetration enhancer and nanoemulsion formulations promote the human epidermal permeation of caffeine and naproxen

2016

Book Chapter

Formulation effects on topical nanoparticle penetration

Benson, H. A. E., Mohammed, Y., Grice, J. E. and Roberts, M. S. (2016). Formulation effects on topical nanoparticle penetration. Nanoscience in dermatology. (pp. 115-126) edited by Michael R. Hamblin, Pinar Avci and Tarl W. Prow. London, United Kingdom: Academic Press. doi: 10.1016/B978-0-12-802926-8.00009-4

Formulation effects on topical nanoparticle penetration

2015

Journal Article

Real-time histology in liver disease using multiphoton microscopy with fluorescence lifetime imaging

Wang, Haolu, Liang, Xiaowen, Mohammed, Yousuf H., Thomas, James A., Bridle, Kim R., Thorling, Camilla A., Grice, Jeffrey E., Xu, Zhi Ping, Liu, Xin, Crawford, Darrell H. G. and Roberts, Michael S. (2015). Real-time histology in liver disease using multiphoton microscopy with fluorescence lifetime imaging. Biomedical Optics Express, 6 (3), 780-792. doi: 10.1364/BOE.6.000780

Real-time histology in liver disease using multiphoton microscopy with fluorescence lifetime imaging

2014

Journal Article

Polarized immune responses modulated by layered double hydroxides nanoparticle conjugated with CpG

Yan, Shiyu, Rolfe, Barbara E., Zhang, Bing, Mohammed, Yousuf H., Gu, Wenyi and Xu, Zhi P. (2014). Polarized immune responses modulated by layered double hydroxides nanoparticle conjugated with CpG. Biomaterials, 35 (35), 9508-9516. doi: 10.1016/j.biomaterials.2014.07.055

Polarized immune responses modulated by layered double hydroxides nanoparticle conjugated with CpG

2014

Journal Article

Microneedle enhanced delivery of cosmeceutically relevant peptides in human skin

Mohammed, Yousuf H., Yamada, Miko, Lin, Lynlee L., Grice, Jeffrey E., Roberts, Michael S., Raphael, Anthony P., Benson, Heather A. E. and Prow, Tarl W. (2014). Microneedle enhanced delivery of cosmeceutically relevant peptides in human skin. PLoS One, 9 (7) e101956, e101956.1-e101956.9. doi: 10.1371/journal.pone.0101956

Microneedle enhanced delivery of cosmeceutically relevant peptides in human skin

2014

Book Chapter

Topical microneedle drug delivery enhanced with magnetophoresis

Prow, T. W., Mohammed, Y. H., Ansaldo, A. B. and Benson, H. A. E. (2014). Topical microneedle drug delivery enhanced with magnetophoresis. Advances in dermatological sciences. (pp. 169-177) edited by Robert Chilcott and Keith R. Brain. Piccadilly, London, United Kingdom: Royal Society of Chemistry. doi: 10.1039/9781849734639-00169

Topical microneedle drug delivery enhanced with magnetophoresis

2012

Conference Publication

Microparticle and microneedle drug delivery in human skin

Lin, L. L., Prow, T. W., Raphael, A. P., Ansaldo, A. B., Mohammed, Y., Primiero, C. A. and Soyer, H. (2012). Microparticle and microneedle drug delivery in human skin. Conjoint 3rd Australasian Wound & Tissue Repair Society and 9th Australasian Society for Dermatology Research Conference, Sydney, NSW, Australia, 22-24 May 2012. Hoboken, NJ, United States: Wiley-Blackwell. doi: 10.1111/j.1524-475X.2012.00835.x

Microparticle and microneedle drug delivery in human skin

2012

Conference Publication

Skin penetration enhancement by cell penetrating peptides: preliminary skin permeation and efficacy assessment with diclofenac

Benson, H. A. E., Mohammed, Y. H., Teixido, M. and Giralt, E. (2012). Skin penetration enhancement by cell penetrating peptides: preliminary skin permeation and efficacy assessment with diclofenac. Stratum Corneum Vll Conference 2012, Cardiff, United Kingdom, *. Chichester, West Sussex, United Kingdom: Wiley-Blackwell . doi: 10.1111/j.1468-2494.2012.00720.x

Skin penetration enhancement by cell penetrating peptides: preliminary skin permeation and efficacy assessment with diclofenac

Funding

Past funding

  • 2019 - 2024
    Elucidating Sensorial and Functional Characteristics of Topical Formulations
    United States Food and Drug Administration
    Open grant
  • 2019 - 2023
    Bioequivalence of Topical Products: Elucidating the Thermodynamic and Functional Characteristics of Compositionally Different Topical Formulations (USFDA grant admin. by University of South Australia)
    University of South Australia
    Open grant
  • 2018 - 2021
    Formulation drug product quality attributes in dermal physiologically-based pharmacokinetic models for topical dermatological drug products and transdermal delivery systems
    United States Food and Drug Administration
    Open grant

Supervision

Availability

Dr Yousuf Mohammed is:
Available for supervision

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Available projects

  • Advanced microneedle platform for localized delivery

    This project is an exceptionally innovative combination of pharmaceutical science, materials science, nanotechnology, and clinical science to develop a state-of-the art drug delivery technology for an optimal treatment and overdose risk management of highly potent medicinal compounds. The project will trigger a paradigm shift towards safer dosing of abuse and misuse prone drugs, which suffer from unreliable bioavailability due to solubility or permeation challenges.

  • Bioequivalence of Topical products: Elucidating the Thermodynamic and Functional Characteristics of Compositionally Different Topical Formulations

    The purpose of this project is to support the research necessary to elucidate how systematic alterations to the qualitative (Q1) and/or quantitative (Q2) composition of topical formulations impacts their physical, structural, and functional properties. A key aspect of the research relates to understanding how the thermodynamic properties of a topical dosage form change as it undergoes metamorphosis during dose application and drying on the skin, how the drug's thermodynamic activity profile during the metamorphosis of the dosage form may compare between compositionally different (non-Q1 and/or non-Q2) topical formulations, and how these and other forces may modulate the rate and extent to which topically applied drugs may become available at or near their site(s) of action in the skin. Another key aspect of the research relates to identifying and understanding other potential failure modes for bioequivalence (BE) and/or therapeutic equivalence (TE) (e.g., differences in irritation potential) that may arise between compositionally different (non-Q1 and/or non-Q2) topical formulations.

  • Bioequivalence of Topical Products: Elucidating the Sensorial and Functional Characteristics of Compositionally Different Topical Formulations

    The purpose of this project is to support research relevant to topical semisolid drug products that will help elucidate the relationship between a product's quality attributes and its functional properties. A specific purpose is to elucidate how characterizations of the arrangement of matter, including rheological characterizations (e.g., texture analysis, tribology) may correlate with and/or be predictive of sensorial differences perceived by human subjects (or patients). Upon the successful completion of this research, it should be possible to predict, based upon product quality characterizations, whether test and reference products that may be compositionally different are likely to have a comparable look and feel, including comparable perceptions of grittiness, silky-smoothness, and cooling sensation.

Supervision history

Current supervision

  • Doctor Philosophy

    Strategies for Vitamin D transdermal supplementation

    Principal Advisor

  • Doctor Philosophy

    Transdermal delviery of NAD+ precursor molecule Nicotinamide Mononucleotide using Advanced Microneedle arrays

    Principal Advisor

  • Doctor Philosophy

    Stimuli responsive drug delivery systems for topical delivery

    Principal Advisor

  • Doctor Philosophy

    Simultaneous absorption and evaporation PBPK models for topical drugs and inactive agents

    Principal Advisor

    Other advisors: Dr Abbas Shafiee

  • Doctor Philosophy

    Thermodynamic dependence of Topical Formulations

    Principal Advisor

    Other advisors: Emeritus Professor Michael Roberts, Associate Professor Peter Moyle

  • Doctor Philosophy

    Development of topical delivery system (TDS): Role of intrinsic and extrinsic factors on performance

    Principal Advisor

    Other advisors: Professor Roger Wepf

Completed supervision

Media

Enquiries

Contact Dr Yousuf Mohammed directly for media enquiries about:

  • Bioequivalence of Pharmaceutical Products
  • Cosmetics
  • Dermatology
  • FLIM
  • Healthcare products
  • Multiphoton Microscopy
  • Personal care products
  • Regulatory Guidelines
  • Rheology
  • Skin feel
  • Skin Imaging
  • Skin Toxicology
  • Topical Products
  • Toxicology
  • Tribology
  • •Drug delivery devices

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