Browsing Research Output by Author "Hamman, Josias H."
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Aloe vera gel and whole leaf extract: functional and versatile excipients for drug delivery?
Laux, Alex; Gouws, Chrisna; Hamman, Josias H. (Taylor & Francis, 2019)Aloe vera (L.) Burm.f. (Aloe barbadensis Miller) is a perennial xerophyte plant that has many medicinal applications. A. vera leaves contain water storage tissue, which is fundamentally made up of a viscous mucilage contained ... -
Combination therapy of western drugs and herbal medicines: recent advances in understanding interactions involving metabolism and efflux
Gouws, Chrisna; Steyn, Dewald; Du Plessis, Lissinda; Steenekamp, Jan; Hamman, Josias H. (Taylor & Francis, 2012)Introduction: While complementary and alternative medicine markets prosper with an increasing number of consumers of herbal medicines, there is an associated likelihood for herb–drug interactions to occur. Modulation of ... -
Combining chemical permeation enhancers for synergistic effects
Du Toit, Trizel; Malan, Maides M.; Lemmer, Hendrik J.R.; Gouws, Chrisna; Aucamp, Marique E.; Breytenbach, Wilma J.; Hamman, Josias H. (Springer, 2016)Currently, macromolecular drugs such as proteins are mainly administered by means of injections due to their low intestinal epithelial permeability and poor stability in the gastrointestinal tract. This study ... -
Direct compression of chitosan: process and formulation factors to improve powder flow and tablet performance
Buys, Gerhard M.; Du Plessis, Lissinda H.; Marais, Andries F.; Kotzé, Awie F.; Hamman, Josias H. (Bentham Science, 2013)Chitosan is a polymer derived from chitin that is widely available at relatively low cost, but due to compression challenges it has limited application for the production of direct compression tablets. The aim of this study ... -
Excipient-drug pharmacokinetic interactions: effect of disintegrants on efflux across excised pig intestinal tissues
Gerber, Werner; Hamman, Josias H.; Steyn, Johan D. (Elsevier, 2018)Pharmaceutical excipients were designed originally to be pharmacologically inert. However, certain excipients were found to have altering effects on drug pharmacodynamics and/or pharmacokinetics. Pharmacokinetic interactions ... -
Gastrointestinal region specific insulin permeation enhancement by Aloe vera gel
Pretorius, Elizca; Willers, Clarissa; Hamman, Josias H.; Steyn, Johan D. (Bentham Science, 2020)Background: The oral administration route is still the most preferred by patients for drug treatment, but is unfortunately not suitable for all drug compounds. For example, protein and peptide drugs (e.g. insulin) are ... -
Impact of traditional African medicine on drug metabolism and transport
Calitz, Carlemi; Steenekamp, Jan H.; Steyn, Johan D.; Gouws, Chrisna; Viljoen, Joe M.; Hamman, Josias H. (Taylor & Francis, 2014)Introduction: Africa is a continent of rich plant biodiversity with many indigenous plants having a long history of being used for medicinal purposes. A considerable number of patients consult traditional healers in ... -
In vitro evaluation of the cytotoxic and apoptogenic properties of aloe whole leaf and gel materials
Du Plessis, Lissinda H.; Hamman, Josias H. (Taylor & Francis, 2014)Aloe gel and whole-leaf materials have shown biological effects with potential therapeutic applications, and recently, their drug-absorption enhancement properties have been discovered. It is important to establish a ... -
In vitro permeation of mesembrine alkaloids from Sceletium tortuosum across porcine buccal, sublingual, and intestinal mucosa
Shikanga, Emmanuel A.; Hamman, Josias H.; Chen, Weiyang; Combrinck, Sandra; Gericke, Nigel (Thieme, 2012)Sceletium tortuosum is an indigenous South African plant that has traditionally been used for its mood-enhancing properties. Recently, products containing S. tortuosum have become increasingly popular and are commonly ... -
In vitro wound healing and cytotoxic activity of the gel and whole-leaf materials from selected aloe species
Fox, Lizelle T.; Mazumder, Anisha; Dwivedi, Anupma; Gerber, Minja; Du Plessis, Jeanetta; Hamman, Josias H. (Elsevier, 2017)Ethnopharmacological relevance Aloe vera is one of the most important medicinal plants in the world with applications in the cosmetic industry and also in the tonic or health drink product market. Different parts of Aloe ... -
In vivo skin hydration and anti-erythema effects of Aloe vera, Aloe ferox and Aloe marlothii gel materials after single and multiple applications
Fox, Lizelle T.; Du Plessis, Jeanetta; Gerber, Minja; Van Zyl, Sterna; Boneschans, Banie; Hamman, Josias H. (Medknow, 2014)To investigate the skin hydrating and anti-erythema activity of gel materials from Aloe marlothii A. Berger and A. ferox Mill. in comparison to that of Aloe barbadensis Miller (Aloe vera) in healthy human volunteers. ... -
Intestinal drug absorption enhancers: synergistic effects of combinations
Enslin, Gill M.; Kotzé, Awie F.; Hamman, Josias H. (Taylor & Francis, 2008)Although many absorption enhancers have been investigated, very few are used clinically. A need exists therefore for more effective absorption enhancers. The drug-absorption-enhancing effects of combinations of N-trimethyl ... -
Isolation and in vitro permeation of phenylpropylamino alkaloids from Khat (Catha edulis) across oral and intestinal mucosal tissues
Atlabachew, Minaleshewa; Hamman, Josias H.; Gouws, Chrisna; Combrinck, Sandra; Viljoen, Alvaro M. (Elsevier, 2016)Ethnopharmacological relevance: Khat, the leaves of Catha edulis, is used as a “natural amphetamine-like” stimulant in eastern and southern Africa, as well as in the Arabian Peninsula. Leaves are masticated to elicit a ... -
Moulded cross-linked chitosan matrix systems for controlled drug release
Tarirai, Clemence; Steenekamp, Jan H.; Hamman, Josias H.; Enslin, Gill M. (Taylor & Francis, 2011)Matrix-type drug delivery systems were prepared by moulding and drying cross-linked chitosan gels in 24-well plates and they were evaluated in terms of their physical properties, drug content, surface morphology and swelling. ... -
Paracellular drug absorption enhancement through tight junction modulation
Lemmer, Hendrik J.R.; Hamman, Josias H. (Taylor & Francis, 2013)Introduction: Inclusion of absorption-enhancing agents in dosage forms is one approach to improve the bioavailability of active pharmaceutical ingredients with low membrane permeability. Tight junctions are dynamic protein ... -
Permeation of PLGA nanoparticles across different in vitro models
Nkabinde, Lindiwe A.; Hamman, Josias H.; Shoba-Zikhali, Lungile N.N.; Semete-Makokotlela, Boitumelo; Kalombo, Lonji (Bentham Science, 2012)Many drug delivery systems have indicated improvement in delivery of various drug molecules and among these biodegradable and biocompatible polymers such as poly(D,L-lactide-co-glycolide) (PLGA) have been shown to enhance ... -
Recent advances in three-dimensional cell culturing to assess liver function and dysfunction: from a drug biotransformation and toxicity perspective
Calitz, Carlemi; Hamman, Josias H.; Gouws, Chrisna; Fey, Stephen J.; Wrzesinski, Krzysztof (Taylor & Francis, 2018)The liver is a vital organ fulfilling a central role in over 500 major metabolic functions, including serving as the most essential site for drug biotransformation. Dysfunction of the drug biotransformation processes may ... -
Recent developments in our understanding of the implications of traditional African medicine on drug metabolism
Gouws, Chrisna; Hamman, Josias H. (Taylor & Francis, 2018)Introduction: The use of traditional herbal medicines has become increasingly popular globally, but in some countries, it is the main or sometimes even the only healthcare service available in the most rural areas. This ... -
Review of natural compounds for potential skin cancer treatment
Chinembiri, Tawona N.; Du Plessis, Lissinda H.; Gerber, Minja; Hamman, Josias H.; Du Plessis, Jeanetta (MDPI, 2014)Most anti-cancer drugs are derived from natural resources such as marine, microbial and botanical sources. Cutaneous malignant melanoma is the most aggressive form of skin cancer, with a high mortality rate. Various ... -
The SeDeM expert diagram system: its performance and predictability in direct compressible formulations containing novel excipients and different types of active ingredients
Scholtz, Jacques C.; Steenekamp, Jan H.; Hamman, Josias H.; Tiedt, Louwrens R. (Elsevier, 2017)The SeDeM Expert Diagram System is a galenic pre-formulation system, which evaluates the suitability of excipients and active pharmaceutical ingredients (API's) for direct compression into tablets as well as predicting ...