Maria Zuń

Physical properties and caffeine release from creams prepared with different oils

Abstract Caffeine is a methylxanthine typically found in the Coffee Arabica L plant. Generally, caffeine is well-known as a orally administered mild stimulant of the central nervous system. However, for cosmetic purpose, caffeine is an active compound ingredient, at 7% concentration, in several anticellulite products. The efficiency of this mode of delivery is not fully understood. Hence, the aim of the study was to ascertain the effectiveness of particular carriers to release this ingredient. In so doing, we prepared six creams based upon different oils (Sesame oil, Rice oil, Walnut oil, Coconut oil, Sweet almond oil and Jojoba oil), containing 5% of caffeine, and compared the release of the substance from the obtained preparations. Initially, all of the creams were subjected to a variety of physical tests, among these being for slippage and spreadability. Furthermore, their rheological properties were evaluated. Subsequently, the creams were tested for caffeine release. In the slippage and spreadability tests, the coconut oil-based cream was revealed as having the best parameters. However, the rheological tests showed that all of the preparations had the pseudoplastic character of flowing according to the Ostwald de Waele power law model. The power low index (n) for all the preparations was from 0.2467-0.3179 at 20°C and 0.2821-0.3754 at 32°C. At 20°C, the Sesame oil-, Walnut oil-, Sweet almond oil- and Jojoba oil-based creams were thixotropic, but at 32°C, thixotropy appeared only in the Walnut oil-based creams. The release studies, conducted by way of an extracting chamber (according to Polish Pharmacoeia IX) in the Paddle Apparatus (according to Polish Pharamcopoeia IX), showed that the amount of released caffeine is the largest in the case of Jojoba oil-based cream, at 85.23% ± 0.8% (SD), and the least in the case of Coconut oil-based cream, at 62,78%± 0.87% (SD).

The application of povidone in the preparation of modified release tablets

Abstract The aim of the study was to investigate the modified release of a model substance, of tablets containing different types of Kollidon and particular additives. Additionally, the release kinetics and mechanism of prolonged release of certain tablet preparations were investigated. In this work, tablets containing different types of povidone (Kollidon CL, Kollidon 30, Kollidon SR and other excipients) were prepared by the direct compression technique. The results showed that tablets with fast disintegration and release should contain in their composition, Kollidon CL, lactose and Avicel, however, the use of β-CD instead of lactose or Avicel brings about a slight prolongation in the disintegration time of tablets and the release of an active substance. Furthermore, while other tablet compositions generated within this study must be considered as being prolonged release types, only two of these showed the best fitted mathematical models. The in vitro dissolution data reveal that the dissolution profiles of the two formulations, one containing Kollidon SR with the addition of Kollidon 30, and the second with HPMC K15M, Kollidon 30, Kollidon CL and lactose, best fitted the Higuchi model. Moreover, the release mechanism of these two formulations plotted well into Korsmeyer-Peppas, indicating a coupling of drug diffusion in the hydrated matrix, as well as polymer relaxation – the so-called anomalous transport (non-Fickian).

The inflluence of emulsifiers on physical properties and release parameters of creams with caffeine

Abstract Caffeine is well known alkaloid chemical compound belonging to the methyl-xanthines group. It is an active substance that is found in many cosmetic products, as it has a stimulating action on both the central nervous system and the metabolism. Commercially available topical formulations normally contain 3% of caffeine and 7% anticellulite products. The aim of our work was to investigate the properties of four cream preparations. These consisted of 5% of caffeine and one of four different emulsifiers (GSC, Sodium polyacrylate, Emulsifying Base, MDS). In our work, we compared the physical properties (spreadability, slip and tenacity), the rheological structure of the resulting creams and the caffeine release from the obtained preparations. The results showed that the properties of these creams and their drug release depended upon the kind of the emulsifiers utilised. What is more, all preparations have a pseudoplastic character of flow and most of them have significant thixotropy. Furthermore, the amount of released caffeine is the largest from the MDS cream, and this emulsifier seems to be the most optimal in all the examined items.

Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

Abstract In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w) of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w) of urea had the best constancy.