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Open access

Regina Kasperek, Lukasz Zimmer, Maria Zun, Dorota Dwornicka, Katarzyna Wojciechowska and Ewa Poleszak

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).

Open access

Katarzyna Wojciechowska, Maria Zun, Dorota Dwornicka, Katarzyna Swiader, Regina Kasperek and Ewa Poleszak

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).

Open access

Krzysztof Lubkowski and Barbara Grzmil

Controlled release fertilizers

The efficiency of nitrogen assimilation by plants is rather low and this is a serious problem in view of environmental protection. Improvement of nitrogen absorption can be carried out through the developing, producing and applying the controlled release fertilizers. Biodegradable chitosan has been proposed as an alternative material in the production of controlled release fertilizers.

Open access

Guangyong Zhu, Zuobing Xiao, Guangxu Zhu, Rujunzhou and Yunwei Niu

Abstract

l-menthol has been widely used in flavour, food and pharmaceuticals. Because of its high volatility and whisker growth, l-menthol-hydroxypropyl-β-cyclodextrin inclusion complex was produced to improve shelf-life, provide protection, and enhance the stability of l-menthol. The inclusion complex was characterized by Fourier transform infrared spectroscopy, X-ray diffraction. The results show that l-menthol was successfully encapsulated in hydroxypropyl-β-cyclodextrin. l-menthol loading capacity is about 8.44%. Geometries and binding energies of l-menthol-hydroxypropyl-β-cyclodextrin inclusion complexes were investigated using molecular mechanics calculations. The shape and orientation of the most stable complex, and the minimum binding energy were determined. L-menthol release from complex was determined by thermogravimetric analysis. Two l-menthol release rate peaks were observed at 69.3 and 279.1°C. The l-menthol release reaction order, release activation energy and the preexponential factor were obtained.

Open access

John W. Nicholson

SUMMARY

The fluoride ion has a well-established beneficial role in dentistry in protecting the teeth from assault by caries. It is known to contribute to the dynamic mineralisation process of the natural tooth mineral, and also to become incorporated with the mineral phase, forming a thin layer of fluorapatite. This is more resistant to acid attack than the native hydroxyapatite, hence protects the tooth against further decay. Other recently discovered aspects of the role and uptake of fluoride will also be discussed.

One of the widely used dental restoratives, the glass-ionomer dental cement, is able to release fluoride in a sustained manner that may continue for many years, and this is seen as clinically beneficial. The closely related resin-modified glass-ionomer cement, and also the polyacid-modified composite resin (“compomer”) are able to do the same. There are also fluoride-containing conventional composite resins able to release fluoride.

These various materials are reviewed and the way in which they release fluoride are described, as well as the effectiveness of the release at the levels involved. Studies of effectiveness of fluoride release from these various classes of material are reviewed, and shown to suggest that release from conventional and resin-modified glass-ionomers is more beneficial than from composite resins. This is attributed to 2 causes: firstly, that it is not possible to replace the lost fluoride in composites, unlike glass-ionomers, and secondly because the other ions released from glass-ionomers (calcium, phosphate) are able to contribute to local remineralisation of the tooth. The absence of these other ions in fluoridated composites means that remineralisation is able to occur to a lesser extent, if at all.

Open access

Dorota Dwornicka, Katarzyna Wojciechowska, Maria Zun, Regina Kasperek, Katarzyna Swiader, Michal Szumilo and Ewa Poleszak

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.

Open access

Magdalena Rogowska, Karol Iwaniak, Andrzej Polski, Karolina Slawinska, Karolina Sobotka-Polska, Joanna Modrzewska and Ewa Poleszak

Abstract

Metamizole is an effective non-opioid analgesic drug used in the treatment of acute and chronic pain. Due to induced potentially life-threatening blood disorders, metamizole was withdrawn from market in many parts of the world, however, it is one of the most popular analgesics in Poland that is available as an over the counter drug. Patients tend to prefer capsules over tablets, as they are easier to swallow and taste better. The powder-filled capsules also have greater bioavailability and require less excipients, as compared to tablets. Polymic excipients are mainly used in capsule filling, and have influence upon the physico-chemical properties of the hard gelatin capsules and the powder formulation. The aim of the study was to determine whether various combinations of polymers impact the disintegration time and pharmaceutical availability of hard gelatin capsules with metamizole sodium. The results of our work demonstrated that the 80% of all active substance was released in all tested formulations within 15 minutes. Herein, the capsule containing lactose monohydrate had the longest release (4% after 2 min.), while capsules containing mannitol had the fastest release (81.2% after 2 min.). Moreover, the addition of HPMC to capsules with lactose brought about a slight increase in the metamizole release rate, while the addition of PVP 30 to capsules with microcrystalline cellulose slightly accelerated release. This data suggests that the use of different polymers in capsules formulation brings about changes in the physical properties of powders and modifies the release profile of metamizole. In our study, the most preferred formulation was one containing microcrystalline cellulose (good powder properties and fairly fast release).

Open access

Regina Kasperek1, Krzysztof Galczynski, Magdalena Nalesniak, Karol Iwaniak and Ewa Poleszak

Abstract

Suppositories with cocoa butter containing dehydroepiandrosterone (DHEA) without and with the addition of Span 80 and Tween 80 as surfactants with low and high HLB values were prepared. The physical properties and the drug content of all prepared suppositories were in accordance with the pharmacopoeial requirements. The release study tests in three dissolution media such as water, lactic acid solution at pH 4.2 and phosphate buffer at pH 7.4 were carried out. In acidic and alkalic media only about 10% and 27% of DHEA were released, respectively. The addition of Span 80 to the suppository mass did not improve the release process, but the addition of Tween 80 caused the increase in the amount of DHEA released in the acidic medium to about 35%. The data showed that rectal administration of suppositories with DHEA based on cocoa butter caused about 30% availability and after vaginal administration, only topical activity can be expected. By the addition of Tween 80 to the suppository mass availability of DHEA of about 35% from vaginal suppositories can be achieved.

Open access

Widandi Soetopo, Suhardjono, Ussy Andawayanti, Rini Wahyu Sayekti and Janu Ismoyo

Abstract

Three models of release rule for operating a large reservoir for irrigation water supply are discussed in this paper. The models are a 50-grid storage continuous line restricted release rule, a single rule curve release rule, and a multi 4 rule curves release rule. These three models are to be optimized by stochastic simulation using 30 year inflow data with the maximization of the average monetary annual production in the irrigation area as the objective function. The purpose of this study is to look for the proper release rule for operating the Sutami Reservoir. The optimization is done first by the random search stochastic simulation model to generate a number of alternative solutions. Using these solutions as a generation of solutions, the genetic algorithm model is the applied to improve the solution. Afterward the best of solutions are checked by the Add-Ins Solver of MS-Excel 2010 to see if they can still be improved further. The results show that the 4 rule curves model gives the best solution with the average monetary annual production in the irrigation area of USD 72.248 million.

Open access

Barnabas Wilson, Patel Pritesh Babubhai, M. S. Sajeev, Josephine Leno Jenita and S. R. Brahmani Priyadarshini

In this study, an attempt was made to deliver pantoprazole in a sustained manner using delayed release tablets. The tablets were prepared by the wet granulation method using HPMC, cassava starch and polyvinyl pyrrolidine as polymers, Avicel PH 102 (MCC) as filler and potato starch as binder. The prepared tablets were evaluated for hardness, mass variation, friability and drug content uniformity, and the results were found to comply with official standards. The prepared tablets were coated using an enteric coating polymer such as cellulose acetate phthalate, Eudragit L100 and drug coat L100 by the dip coating method. The in vitro release was studied using pH 1.2 acidic buffer and pH 6.8 phosphate buffer and the study revealed that the prepared tablets were able to sustain drug release into the intestine. The anti-ulcer activity was evaluated by a water immersion stress induced ulcer model. The enteric coated pantoprazole tablets significantly reduced ulcer formation.