Browsing by Author "Liebenberg, Wilna"
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Amorphous azithromycin with improved aqueous solubility and intestinal membrane permeability
Aucamp, Marique; Odendaal, Roelf; Liebenberg, Wilna; Hamman, Josias (Taylor & Francis, 2015)Azithromycin (AZM) is a poorly soluble macrolide antibacterial agent. Its low solubility is considered as the major contributing factor to its relatively low oral bioavailability. The aim of this study was to improve the ... -
Amorphous sulfadoxine: a physical stability and crystallization kinetics study
Aucamp, Marique; Milne, Marnus; Liebenberg, Wilna (Springer Nature, 2016)Poor aqueous solubility of drugs and the improvement thereof has always been a challenge for the pharmaceutical industry.With this, one of the focuses of the pharmaceutical research scientist involves investigating ... -
Channel inclusion of primary alcohols in isostructural solvates of the antiretroviral nevirapine: an X-ray and thermal analysis study
Stieger, Nicole; Liebenberg, Wilna; Wessels, Johanna C.; Samsodien, Halima; Caira, Mino R. (Springer, 2010)X-ray structural and thermoanalytical data for a series of solvates 2–7 of the anti-HIV drug nevirapine containing primary alcohols CH3(CH2)nOH with n = 2–7 are reported. The structures of 2–7 are based on a common ... -
Characterisation of the adsorbate-adsorbent interaction between drugs or pesticides and carbon/silica compounds
Van Eeden, Charlotte May (North-West University, 2004)Administering adsorbates such as activated charcoal can treat acute poisoning from chemicals and pesticides. It has been suggested that activated charcoal is an effective antidote for virtually all organic and inorganic ... -
Characterization of polymorph transformations that decrease the stability of tablets containing the who essential drug mebendazole
Brits, Marius; Liebenberg, Wilna; De Villiers, Melgardt M. (Elsevier, 2010)This study investigated the influence of moisture and heat on the stability of mebendazole polymorph C in tablets. The polymorphic forms of mebendazole display significant differences in solubility and therapeutic efficacy ... -
Co-crystals of the antiretroviral nevirapine: crystal structures, thermal analysis and dissolution behaviour
Caira, Mino R.; Liebenberg, Wilna; Stieger, Nicole; Aucamp, Marique; Bourne, Susan A. (RSC, 2012)Synthesis and physicochemical characterization of co-crystals of the antiretroviral drug nevirapine (NV) with the pharmaceutically acceptable co-formers saccharin, rac-tartaric acid, maleic acid, glutaric acid and salicylic ... -
Crystal polymorphism and its occurance among active pharmaceutical ingredients in South Africa / Wilna Liebenberg
Liebenberg, Wilna (Potchefstroom : Noordwes-Universiteit, Potchefstroomkampus (Suid-Afrika), 2005) -
Crystallization of toxic glycol solvates of rifampin from glycerin and propylene glycol contaminated with ethylene glycol or diethylene glycol
De Villiers, Melgardt M.; Strydom, Schalk J.; Liebenberg, Wilna; Caira, Mino R.; Li, Jinjing (ACS, 2011)This study was initiated when it was suspected that syringe blockage experienced upon administration of a compounded rifampin suspension was caused by the recrystallization of toxic glycol solvates of the drug. Single ... -
Development of microporous drug-releasing films cast from artificial nanosized latexes of poly (styrebe-co-methyl methacrylate) or poly (styrene-co-ethyl methacylate)
Otto, Daniel P.; Vosloo, Hermanus C.M.; Liebenberg, Wilna; De Villiers, Melgardt M. (Elsevier, 2008)Two sets of copolymers comprising of styrene and either methyl or ethyl methacrylate as comonomer were conveniently synthesized by microemulsion copolymerization. The purified materials were characterized by GPC-MALLS and ... -
The development of ritonavir and pyrimethamine amorphous solid dispersions
Denner, R. (North-West University (South-Africa), 2021)Poorly soluble drugs are a major problem in the pharmaceutical industry. Not only does it lead to formulation difficulties, but it also leads to poor absorption and poor bioavailability of drugs. Ritonavir (RTV) is a ... -
Different amorphous solid-state forms of roxithromycin: a thermodynamic and morphological study
Milne, Marnus; Liebenberg, Wilna; Aucamp, Marique Elizabeth (Elsevier, 2016)The striking impact that different preparation methods have on the characteristics of amorphous solidstate forms has attracted considerable attention during the last two decades. The pursuit of more extensive knowledge ... -
The effect of temperature and moisture on the amorphous-to-crystalline transformation of stavudine
Strydom, Schalk; Liebenberg, Wilna; Yu, Lian; De Villiers, Melgardt (Elsevier, 2009)Stavudine is a nucleoside reverse transcriptase inhibitor active against HIV, and is known to exist in two polymorphic forms designated as forms I and II, and a hydrate form III. An amorphous solid of stavudine was ... -
Effects of the cosurfactant 1-butanol and feed composition on nanoparticle properties
Otto, Daniel P.; Vosloo, Hermanus C.M.; Liebenberg, Wilna; De Villiers, Melgardt M. (Wiley, 2008)The concentration of the cosurfactant 1-butanol (BuOH) determined the polymer weight and size for a series of poly(styrene-co-methyl methacrylate)s (P(St-co-MMA)) synthesized by the free-radical (o/w) microemulsion technique. ... -
Influence of the composition of water/ethanol mixtures on the solubility and recrystallization of nevirapine
Stieger, Nicole; Liebenberg, Wilna; Tiedt, Louwrens R.; Wessels, Johanna C.; Caira, Mino R. (ACS, 2010)Anhydrous nevirapine was recrystallized from ethanol containing various amounts of water to determine its effects on the products obtained. The solubility of the anhydrous form was determined for each of the binary solvent ... -
Inulin suitable as reduced-kilojoule carrier for production of microencapsulated spray-dried green Cyclopia subternata (honeybush) extract
Pauck, Claire; Aucamp, Marique; Liebenberg, Wilna; Stieger, Nicole; De Beer, Dalene (Elsevier, 2017)Retention of phenolic compounds during spray-drying of an anti-diabetic C. subternata extract and physicochemical characteristics of spray-dried powders (pure extract and extract-carrier mixtures) were evaluated. Extract-carrier ... -
Optimal 10-aminoartemisinins with potent transmission-blocking capabilities for new artemisinin combination therapies-activities against blood stage P. falciparum including PfKI3 C580Y mutants and liver stage P. berghei parasites
Wong, Ho Ning; Liebenberg, Wilna; Padin-Irizarry, Vivian; Van der Watt, Mariëtte E.; Reader, Janette (Frontiers, 2020)We have demonstrated previously that amino-artemisinins including artemiside and artemisone in which an amino group replaces the oxygen-bearing substituents attached to C-10 of the current clinical artemisinin derivatives ... -
Phenolic and physicochemical stability of a functional beverage powder mixture during storage: effect of the microencapsulant inulin and food ingredients
De Beer, Dalene; Aucamp, Marique; Liebenberg, Wilna; Stieger, Nicole; Pauck, Claire E. (Wiley, 2018)BACKGROUND The need for a convenience herbal iced tea product with reduced kilojoules merited investigation of the shelf-life of powder mixtures containing a green Cyclopia subternata Vogel (honeybush) extract with proven ... -
Physicochemical properties of amorphous roxithromycin prepared by quench cooling of the melt or desolvation of a chloroform solvate
Aucamp, Marique; Liebenberg, Wilna; Strydom, Schalk J.; Van Tonder, Elsa C.; De Villiers, Melgardt M. (Springer, 2012)Roxithromycin is a poorly soluble antibacterial drug. The aim of this study was to prepare and characterize an amorphous form of roxithromycin. The amorphous form was prepared by desolvation of its chloroform solvate, and ... -
Poly(amidoamine) dendrimer-mediated synthesis and stabilization of silver sulfonamide nanoparticles with increased antibacterial activity
Strydom, Schalk J.; Otto, Daniel P.; Liebenberg, Wilna; Rose, Warren E.; De Villiers, Melgardt M. (Elsevier, 2013)Silver sulfadiazine (AgSD) is a topical antibiotic with limited aqueous solubility. In this study, it was shown that poly(amido amine) (PAMAM) dendrimer complexes with SD (SDZ) and silver (Ag) could be used for a bottom-up ... -
Preparation and characterization of directly compactible layer-by-layer nanocoated cellulose
Strydom, Schalk J.; Liebenberg, Wilna; Otto, Daniel P.; Lvov, Yuri M.; De Villiers, Melgardt M, (Elsevier, 2011)Microcrystalline cellulose is a commonly used direct compression tablet diluent and binder. It is derived from purified α-cellulose in an environmentally unfriendly process that involves mineral acid catalysed hydrolysis. ...