The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform
A. G. Mitchell - One of the best experts on this subject based on the ideXlab platform.
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The hydrolysis of propyl benzoate in aqueous solutions of surface-active agents
Journal of Pharmacy and Pharmacology, 2011Co-Authors: A. G. MitchellAbstract:The effect of cetrimide and sodium lauryl sulphate on the alkaline hydrolysis of emulsions and solutions of n-propyl benzoate has been investigated and compared with results obtained previously in Cetomacrogol solutions. Evidence is presented to show that the rate of reaction depends on the degree of saturation of the dispersion expressed as a “Saturation Ratio”, which is the ratio of ester concentration to its solubility in a given concentration of surface-active agent. The hydrolysis rate of solubilised ester decreases with increase in surface-active agent concentration while the effect of such an increase in concentration on the hydrolysis rate of emulsified ester depends on the nature of the surface-active agent. The initial rate in sodium lauryl sulphate and Cetomacrogol is independent of concentration, but in cetrimide the rate increases with cetrimide concentration until sufficient is present to solubilise the ester.
Ann Van Schepdael - One of the best experts on this subject based on the ideXlab platform.
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qualitative analysis of Cetomacrogol creams by thin layer chromatography flame ionization detection tlc fid
SN Applied Sciences, 2020Co-Authors: Lien Secretin, Felix Anyakudo, Liesbeth Gilissen, An Goossens, Ann Van SchepdaelAbstract:Buffered Cetomacrogol cream has been described as the cause of iatrogenic allergic contact dermatitis, while patch testing with all ingredients was, in most cases, unable to identify the sensitizing culprit. Several hypotheses had been put forward, among which the formation of a new allergen by interaction of some of the ingredients, so-called ‘compound allergy’. In order to investigate this hypothesis, a method for the qualitative analysis of Cetomacrogol creams, using thin-layer chromatography with flame ionization detection (TLC–FID), is presented. All Cetomacrogol cream components, i.e., a preservative and excipients were completely separated. A two-step elution system was used to separate the analytes on the Chromarods: in the first step we separated and focussed the paraffins and cetostearyl alcohol with the use of hexane-methanol–methyl tert-butyl ether (100:3:6, v/v). After drying, the same rod was then redeveloped using methanol to resolve sorbic acid from Cetomacrogol 1000, whereupon detection of the cream components could be performed by direct flame ionization detection on the Chromarods. The developed method was then applied for the analysis of commercial non-buffered and buffered Cetomacrogol cream samples. No newly formed allergen could be detected, thus excluding ‘compound allergy’. This method proved to be simple, cheap, and fast, enabling the separation of the auxiliary substances present in Cetomacrogol cream.
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Qualitative analysis of Cetomacrogol creams by thin-layer chromatography–flame ionization detection (TLC–FID)
SN Applied Sciences, 2020Co-Authors: Lien Secretin, Felix Anyakudo, Liesbeth Gilissen, An Goossens, Ann Van SchepdaelAbstract:Buffered Cetomacrogol cream has been described as the cause of iatrogenic allergic contact dermatitis, while patch testing with all ingredients was, in most cases, unable to identify the sensitizing culprit. Several hypotheses had been put forward, among which the formation of a new allergen by interaction of some of the ingredients, so-called ‘compound allergy’. In order to investigate this hypothesis, a method for the qualitative analysis of Cetomacrogol creams, using thin-layer chromatography with flame ionization detection (TLC–FID), is presented. All Cetomacrogol cream components, i.e., a preservative and excipients were completely separated. A two-step elution system was used to separate the analytes on the Chromarods: in the first step we separated and focussed the paraffins and cetostearyl alcohol with the use of hexane-methanol–methyl tert -butyl ether (100:3:6, v/v). After drying, the same rod was then redeveloped using methanol to resolve sorbic acid from Cetomacrogol 1000, whereupon detection of the cream components could be performed by direct flame ionization detection on the Chromarods. The developed method was then applied for the analysis of commercial non-buffered and buffered Cetomacrogol cream samples. No newly formed allergen could be detected, thus excluding ‘compound allergy’. This method proved to be simple, cheap, and fast, enabling the separation of the auxiliary substances present in Cetomacrogol cream.
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investigation of sorbic acid volatile degradation products in pharmaceutical formulations using static headspace gas chromatography
Journal of Pharmaceutical and Biomedical Analysis, 2007Co-Authors: Sitaramaraju Yarramraju, Kris Wolfs, Jos Hoogmartens, Ann Van Schepdael, Vamsidhar Akurathi, Erwin AdamsAbstract:An analytical method that allows simultaneous analysis of sorbic acid and its degradation products was developed using static headspace gas chromatography (HS-GC). AT-Aquawax-DA, the capillary column used, showed good selectivity and separation towards sorbic acid and its degradation products. Sorbic acid degradation was investigated in both acidic and aqueous media at room and elevated temperatures. In total 12 sorbic acid degradation products were found, 8 of which could be characterized. The method was investigated for its accuracy towards estimation of degradation products. Using the HS-GC method different batches of pharmaceutical preparations such as cold cream, Cetomacrogol cream and vaseline were investigated for sorbic acid degradation products which were estimated by applying the standard addition method. Acetaldehyde was found to be the major degradation product. The other identified degradation products were: acetone; 2-methylfuran; crotonaldehyde; alfa-angelicalactone; 2-acetyl, 5-methylfuran; toluene and 2,5-dimethylfuran. Both mass spectrometeric (MS) and flame ionization detection (FID) were used. The qualitative investigation was done on HS-GC-MS and the quantitative work on HS-GC-FID.
Herman Vromans - One of the best experts on this subject based on the ideXlab platform.
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Scale up of Semisolid Dosage Forms Manufacturing Based on Process Understanding: from Lab to Industrial Scale
AAPS PharmSciTech, 2018Co-Authors: A. J.p. Van Heugten, Herman VromansAbstract:The scale up of production processes is a major challenge in pharmaceutical industry. Using a quality by design approach, upscaling can be based on the design space, which can be assessed on a small scale. In a previous study, the critical process parameters were identified by a definitive screening design on Cetomacrogol ointment. In the current study, this lab scale (0.5 kg) study was scaled up to industrial scale (2000 kg, filling 100g tubes at 75 tubes/min). A similar trend for the influence of filling temperature on ointment yield stress was found for lab and industrial scale production. Furthermore, a process window for ointment filling viscosities was established. It was shown that between 26 and 170 Pa.s ointment could be filled into tubes with a low weight variation (
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the influence of Cetomacrogol ointment processing on structure a definitive screening design
European Journal of Pharmaceutical Sciences, 2017Co-Authors: A. J.p. Van Heugten, C. L. Braal, Herman Vromans, Marjan VersluijshelderAbstract:Batch-to-batch variability is a challenge for the industrial scale production of ointments. Therefore the current investigation focussed on identifying and understanding critical process parameters (CPPs) for Cetomacrogol ointment. This was evaluated using a definitive screening design (DSD) approach in which fourteen batches were produced under predefined and controlled conditions using the following variables: addition of SiO2 nanoparticles, mixing speed, cooling rate, heating temperature, container filling temperature and isothermal mixing at the filling temperature. Ointment structure was evaluated using a number of rheological parameters. One of these parameters, yield stress was found to be strongly influenced by filling temperature and mixing speed (p=0.0065 and p=0.0013 respectively). Both significantly affect ointment structure and they also have a significant interaction (p<0.05). Understanding the ointment production process can help in defining a processing window to produce ointment of constant quality.
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The influence of Cetomacrogol ointment processing on structure: A definitive screening design
European Journal of Pharmaceutical Sciences, 2017Co-Authors: A. J.p. Van Heugten, C. L. Braal, Marjan Versluijs-helder, Herman VromansAbstract:Batch-to-batch variability is a challenge for the industrial scale production of ointments. Therefore the current investigation focussed on identifying and understanding critical process parameters (CPPs) for Cetomacrogol ointment. This was evaluated using a definitive screening design (DSD) approach in which fourteen batches were produced under predefined and controlled conditions using the following variables: addition of SiO2 nanoparticles, mixing speed, cooling rate, heating temperature, container filling temperature and isothermal mixing at the filling temperature. Ointment structure was evaluated using a number of rheological parameters. One of these parameters, yield stress was found to be strongly influenced by filling temperature and mixing speed (p = 0.0065 and p = 0.0013 respectively). Both significantly affect ointment structure and they also have a significant interaction (p
Joseph Tucci - One of the best experts on this subject based on the ideXlab platform.
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the varying effects of a range of preservatives on myoviridae and siphoviridae bacteriophages formulated in a semi solid cream preparation
Letters in Applied Microbiology, 2020Co-Authors: Heng Ku, George Mnatzaganian, Mwila Kabwe, Steve Petrovski, Teagan L. Brown, Michael J. Angove, Joseph TucciAbstract:: Bacteriophages may be formulated into semi-solid bases for therapeutic delivery. This work investigated the effects of a range of preservatives on the viability of Myoviridae and Siphoviridae bacteriophages when these were formulated into a standard semi-solid cream base. The six preservatives tested included: benzoic acid (0.1%), chlorocresol (0.1%), combination hydroxybenzoates (propyl 4-hydroxybenzoates with methyl 4-hydroxybenzoates) (0.1%), methyl 4-hydroxybenzoate (0.08%), 2-phenoxyethanol (1%), and propyl 4-hydroxybenzoate (0.02%). These were each formulated into Cetomacrogol cream aqueous to generate six individual semi-solid bases into which Myoviridae and Siphoviridae bacteriophages were added and tested for stability. Optimal bacteriophage stability was seen when the preservative chlorocresol was used. Bacteriophage in the acidic benzoic acid were the least stable, resulting in complete loss of viability after four to five weeks. Of the bacteriophages tested, the Myoviridae KOX1 was significantly more stable than the Siphoviridae PAC1 after 91 days in formulations with each of the preservatives. Our results suggest the need for individual testing of specific bacteriophages in pharmaceutical formulations, as their efficacy when exposed to preservatives and excipients in these delivery forms may vary.
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the formulation of bacteriophage in a semi solid preparation for control of propionibacterium acnes growth
PLOS ONE, 2016Co-Authors: Teagan L. Brown, Steve Petrovski, Zoe A. Dyson, Robert J Seviour, Joseph TucciAbstract:Aims To isolate and characterise phage which could lyse P. acnes and to formulate the phage into a delivery form for potential application in topical treatment of acne infection. Methods and Results Using standard phage isolation techniques, ten phage capable of lysing P. acnes were isolated from human skin microflora. Their genomes showed high homology to previously reported P. acnes phage. These phage were formulated into Cetomacrogol cream aqueous at a concentration of 2.5x108 PFU per gram, and shown to lyse underlying P. acnes cells grown as lawn cultures. These phage formulations remained active for at least 90 days when stored at four degrees Celsius in a light protected container. Conclusions P. acnes phage formulated into Cetomacrogol cream aqueous will lyse surrounding and underlying P. acnes bacteria, and are effective for at least 90 days if stored appropriately. Significance and Impact of the Study There are few reports of phage formulation into semi solid preparations for application as phage therapy. The formulation method described here could potentially be applied topically to treat human acne infections. The potential exists for this model to be extended to other phage applied to treat other bacterial skin infections.
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Lytic capacity of the P. acnes phage cream formulation.
2016Co-Authors: Teagan L. Brown, Steve Petrovski, Zoe A. Dyson, Robert Seviour, Joseph TucciAbstract:All PAC1 to PAC10 phage displayed similar behaviour when formulated in Cetomacrogol cream aqueous and placed onto P. acnes lawns. Fig 6 shows results of experiments of cream formulated with PAC1 phage placed onto one of the P. acnes cutaneous strains isolated in this study. Legend: A. Cetomacrogol cream aqueous; B. Cetomacrogol cream aqueous with PBS; C. Phage cream, PAC1 at a concentration of 5.0x103 PFU per gram of cream D. Phage cream, PAC1 at a concentration of 2.5x108 PFU per gram of cream.
Teagan L. Brown - One of the best experts on this subject based on the ideXlab platform.
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the varying effects of a range of preservatives on myoviridae and siphoviridae bacteriophages formulated in a semi solid cream preparation
Letters in Applied Microbiology, 2020Co-Authors: Heng Ku, George Mnatzaganian, Mwila Kabwe, Steve Petrovski, Teagan L. Brown, Michael J. Angove, Joseph TucciAbstract:: Bacteriophages may be formulated into semi-solid bases for therapeutic delivery. This work investigated the effects of a range of preservatives on the viability of Myoviridae and Siphoviridae bacteriophages when these were formulated into a standard semi-solid cream base. The six preservatives tested included: benzoic acid (0.1%), chlorocresol (0.1%), combination hydroxybenzoates (propyl 4-hydroxybenzoates with methyl 4-hydroxybenzoates) (0.1%), methyl 4-hydroxybenzoate (0.08%), 2-phenoxyethanol (1%), and propyl 4-hydroxybenzoate (0.02%). These were each formulated into Cetomacrogol cream aqueous to generate six individual semi-solid bases into which Myoviridae and Siphoviridae bacteriophages were added and tested for stability. Optimal bacteriophage stability was seen when the preservative chlorocresol was used. Bacteriophage in the acidic benzoic acid were the least stable, resulting in complete loss of viability after four to five weeks. Of the bacteriophages tested, the Myoviridae KOX1 was significantly more stable than the Siphoviridae PAC1 after 91 days in formulations with each of the preservatives. Our results suggest the need for individual testing of specific bacteriophages in pharmaceutical formulations, as their efficacy when exposed to preservatives and excipients in these delivery forms may vary.
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the formulation of bacteriophage in a semi solid preparation for control of propionibacterium acnes growth
PLOS ONE, 2016Co-Authors: Teagan L. Brown, Steve Petrovski, Zoe A. Dyson, Robert J Seviour, Joseph TucciAbstract:Aims To isolate and characterise phage which could lyse P. acnes and to formulate the phage into a delivery form for potential application in topical treatment of acne infection. Methods and Results Using standard phage isolation techniques, ten phage capable of lysing P. acnes were isolated from human skin microflora. Their genomes showed high homology to previously reported P. acnes phage. These phage were formulated into Cetomacrogol cream aqueous at a concentration of 2.5x108 PFU per gram, and shown to lyse underlying P. acnes cells grown as lawn cultures. These phage formulations remained active for at least 90 days when stored at four degrees Celsius in a light protected container. Conclusions P. acnes phage formulated into Cetomacrogol cream aqueous will lyse surrounding and underlying P. acnes bacteria, and are effective for at least 90 days if stored appropriately. Significance and Impact of the Study There are few reports of phage formulation into semi solid preparations for application as phage therapy. The formulation method described here could potentially be applied topically to treat human acne infections. The potential exists for this model to be extended to other phage applied to treat other bacterial skin infections.
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Lytic capacity of the P. acnes phage cream formulation.
2016Co-Authors: Teagan L. Brown, Steve Petrovski, Zoe A. Dyson, Robert Seviour, Joseph TucciAbstract:All PAC1 to PAC10 phage displayed similar behaviour when formulated in Cetomacrogol cream aqueous and placed onto P. acnes lawns. Fig 6 shows results of experiments of cream formulated with PAC1 phage placed onto one of the P. acnes cutaneous strains isolated in this study. Legend: A. Cetomacrogol cream aqueous; B. Cetomacrogol cream aqueous with PBS; C. Phage cream, PAC1 at a concentration of 5.0x103 PFU per gram of cream D. Phage cream, PAC1 at a concentration of 2.5x108 PFU per gram of cream.