Effect of glucomannan and the dosage form on ethinylestradiol oral absorption in rabbits

A developed composite hard-gelatin capsules: delayed-release enteric properties

Present study focused on improvement of the formulation of conventional hard gelatin capsules using gastric acid-resistant polymers. We have utilized the same approach of making conventional drug capsules to develop novel capsules with delayed release properties. For this purpose, delayed-release capsules were produced by improving the formulation of hard gelatin capsules. In addition, the effect of adding intestinal polymers such as Hydroxy propyl methyl cellulose phthalate, Glucomannan, and Polyvinyl alcohol to hard gelatin capsules were investigated. The capsules' release rate was determined. The degradation tests in an acidic environment were performed and the results were recorded. In fact, the delayed-release hard gelatin capsules pass through the stomach with small amount of the drug release; but their shell remains intact and dissolves as it enters the intestine environment. This article shows that enteric polymers with out interactions, only by changing the formulations will have delayed release properties. this makes sensitive drugs pass through stomach environment and have higher absorption.

Attitudes and knowledge toward natural products safety in the pharmacy setting: an Italian study

The lack of a professional supervision may expose consumers of natural products to risks; pharmacists play an important role in giving information about these substances. A survey was designed to investigate the attitudes and knowledge of consumers and pharmacists toward the safety of natural products. Twenty-three pharmacies participated in the project. On the basis of a pre-structured 17-item questionnaire, face-to-face interviews were conducted with consumers buying a natural product over a 6-month period. A further 8 items had to be compiled by pharmacists about the purchased product. During the study period, 1420 interviews were carried out. The most frequently purchased products were echinacea, propolis, garlic, guggul, ginkgo, liquorice, ginseng, glucomannan, guarana, valerian, and passionflower; 71.8% of consumers reported to have been taking conventional medicines along with natural products. Some (3.9%) referred to adverse effects in the last year: allergic reactions after cartilage of shark, propolis and thyme; anxiety after hypericum; hypotension and tachycardia after a mix containing chamomile, valerian and melissa; pyrosis and stomach-ache after laxative-depurative herbs. Pharmacists referred to some adverse effects observed in the past in relation to the products bought by consumers involved in this study. Findings from this study demonstrate that in general consumers need information on herbal safety and pharmacists are more likely to answer correctly about the use of herbs rather than about cautions, adverse effects and interactions.

Synthesis, Characterization, and Evaluation of Phosphated Cross-Linked Konjac Glucomannan Hydrogels for Colon-Targeted Drug Delivery

Hydrogel systems of konjac glucomannan (KGM) cross-linked with trisodium trimetaphosphate (STMP) were prepared for colon-targeting drug delivery. Swelling degrees of the hydrogels were measured in artificial gastrointestinal fluids and in sodium chloride solution with different concentrations to study their dependence on the cross-linking density and the ionic strength. The absorption of methylene blue was used to characterize the degree of the KGM cross-linking. In vitro release of model drug hydrocortisone was studied in presence and absence of beta -mannanase. KGM cross-linked with STMP was able to retard the release of the poorly water-soluble drug and could be biodegraded enzymatically. Hydrocortisone release was cross-linking density dependent and controlled by degradation of the hydrogles.

Konjac glucomannan/xanthan gum enzyme sensitive binary mixtures for colonic drug delivery

The polysaccharide konjac glucomannan (KGM) is degraded in the colon but not the small intestine, which makes it potentially useful as an excipient for colonic drug delivery. With xanthan gum (XG) KGM forms thermoreversible gels with hitherto unexplored biodegradation properties. In this work, rheological measurements of KGM and KGM/XG systems incubated with and without Aspergillus niger beta-mannanase (used to mimic colonic enzymes) showed that KGM was degraded by the enzyme even when interacting with XG. Tablets with KGM/XG/sucrose matrices that varied in accordance with a simplex design and bore diltiazem as a typical highly soluble drug load were prepared by wet granulation, and in most cases were found to possess satisfactory mechanical strength and exhibit slow, nearly zero-order drug release. Drug release from these tablets remained zero-order, but was accelerated (presumably due to degradation of KGM), in the presence of A. niger beta-mannanase at concentrations equivalent to human colonic conditions. However, marked differences between Japanese and American varieties of KGM as regards degree of acetylation and particle size led to significant differences in swelling rate and drug release between formulations prepared with one and the other KGM: whereas a formulation with Japanese KGM released its entire drug load within 24h in the presence of beta-mannanase, only 60% release was achieved under the same conditions by the corresponding formulation with American KGM, suggesting that with this KGM it will be necessary to optimize technological variables such as compression pressure in order to achieve suitable porosity, swelling rate, and drug release. To sum up, the results of this study suggest that sustained release of water-soluble drugs in the colon from orally administered tablets may be achieved using simple, inexpensive formulations based on combinations of KGM and XG that take the variability of KGM characteristics into account.

Characterization of diffusion of macromolecules in konjac glucomannan solutions and gels by fluorescence recovery after photobleaching technique

Konjac glucomannan (KGM) is a neutral polysaccharide with interesting properties as gelling agent and thickener. Its peculiar biodegradability, being not degradable in the small intestine but degradable by the anaerobic human intestinal bacteria, turn it into a promising candidate for colonic drug delivery systems. In this study aqueous systems (0.5%, w/v,) of KGM from three different origins and their mixtures with xanthan gum (XG) (1:1) were evaluated as regards their rheological properties and the diffusion coefficients and mobile fraction of macromolecules (dextrans of different molecular weight). Rheological data illustrate the synergism between KGM and XG at a stoichiometric relationship 1:1. Moreover, fluorescence recovery after photobleaching (FRAP) data indicate that diffusion of probes through the polysaccharide systems cannot be completely explained by the macroscopic properties of the medium but it is related to their molecular size and as a consequence to a sieving mechanism. The strong differences between KGM from different suppliers suggest the convenience of establishing specifications for this material in order to use it as pharmaceutical excipient.