An investigation of the long term chemical stability and physical performance of PMD-citronellal acetal compared with dibutyl phthalate and BIS(2-ethylhexyl) terephthalate as plasticisers in selected cosmetic formulations
- Authors: Marx, Amor
- Date: 2019
- Subjects: Plastics -- Additives , Chemistry, Technical , Cosmetics
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/42574 , vital:36669
- Description: Plasticisers are used by cosmetic manufacturers to improve the film forming abilities of a product and increase flexibility of the film formed on the skin or hair surface, as is desired, for example, in nail lacquers and lip coats. In recent years authorities have banned several plasticisers in cosmetic products (mainly phthalates) since these substances may pose a wide range of health risks and can be harmful to the environment. It is, therefore, necessary to find alternative, safe plasticisers, preferably of natural origin e.g. bio-plasticisers which can replace the toxic phthalates and still impart the same desirable properties to the cosmetic products in which they are used. In this study, the novel bio-plasticiser para-menthane-3,8-diol-citronellal acetal (PMD-citronellal acetal) was selected to compare its stability properties and plasticising behaviour with well-known non-phthalate bis(2-ethylhexyl) terephthalate (DEHT) and the problematic dibutyl phthalate (DBP). The objectives were to determine if the novel bio-plasticiser PMD-citronellal acetal plasticising properties and chemical stability are similar or better than DEHT and DBP within two cosmetic formulations, viz. a nail lacquer and a lip coat formulation, after being incubated at elevated temperature (40 ˚C) over a three month period. The results showed that flexibility for all plasticised formulations remained stable at room temperature (21 ˚C) and elevated temperature (40 ˚C). Adhesion performance of DEHT and PMD-citronellal acetal nail lacquer formulations outperformed DBP nail lacquer formulations. Elevated temperature and storage time had no influence on the organoleptic properties of any plasticised formulation. PMD-citronellal acetal plasticised lip coat and nail lacquer formulations outperformed both DEHT and DBP nail formulations with regard to hardness. Fourier Transform Infrared Spectrometry (FTIR) studies revealed that neat DPB, DEHT and Acetal were chemically stable at room temperature and elevated temperature over a three month incubation period. Furthermore, the three plasticised nail lacquer and lip coat formulations remained chemical stable over the three month incubation period at elevated temperature. Chemical stability of the nail lacquer formulations was further evaluated by means of leaching tests using Solid Phase Extraction [1] and Ultra-Performance Liquid Chromatography (UPLC) at two temperatures (31 and 50 °C) and three time intervals (24, 48 and 72 hours). No leaching out of the nail lacquer formulation for Acetal and DEHT could be detected. It was observed that trace amounts of DBP leached from the nail lacquer formulation at 50 °C. DBP leaching decreased over time and was found to be statistically significant over the studied period. It can be concluded that PMD-citronellal acetal can be selected as bio-plasticiser which exhibits similar properties to DEHT based on the performance stability and non-leaching criteria, and can be used as an alternative plasticiser to the toxic DBP in cosmetic formulations.
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- Date Issued: 2019
To investigate the effect of a change in hard gelatin capsule supplier on a phenytoin sodium capsule formulation
- Authors: Marx, Amor
- Date: 2004
- Subjects: Capsules (Pharmacy) , Phenytoin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10984 , http://hdl.handle.net/10948/265 , Capsules (Pharmacy) , Phenytoin
- Description: Stability studies were undertaken at ambient (25ºC/60%RH) and accelerated conditions (40ºC/75%RH) to determine the effect of changing of hard gelatin capsule supplier on a phenytoin sodium (100 mg) capsule formulation. Three hard gelatin capsule suppliers: RP Scherer (Supplier A), Capsugel (supplier B) and Associated Caps (Supplier C) were used in the study. Capsules were analyzed just after filling of the capsules (T0), after 1 month (T1), after 2 months (T2) and after 3 months (T3) after being stored in securitainers under the above-mentioned conditions. The moisture content of the empty shells as well as the capsule contents were analysed at each time-point. The capsule disintegration time was recorded at each time point. Multi-point dissolution testing was performed at each time point to determine the release of the active substance in each case. Based on the achieved results, the best capsule shell supplier was recommended, and other suggestions were made to improve the capsule formulation.
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- Date Issued: 2004