Formulation and evaluation of sustained release tablets containing antioxidants

Deficiency in nutrients especially antioxidants play an important role in the pathogenesis of acquired immuno-deficiency syndrome [AIDS,]. Antioxidants; vitamin A, vitamin C, vitamin E, zinc and selenium are available in market as capsules. The release rate is very fast followed by fast elimination. It is necessary to prolong the residence time of antioxidants. Sustained release tablet formulation was designed and evaluated on small scale and on large scale preparations. Low attention has been discuss the use of sustained release formula in treatment of AIDS. Sustained release tablet formulation was designed and evaluated on small scale and on large scale preparations. The formulated tablets contained beta-carotene, vitamin C, tocopherol acetate, selenium, yeast and zinc pidolate. Vitamin C was chosen as tracer for detection and evaluation of tablet dosage form. Vitamin C was found to be stable in 0.1 N HCl [pH 1.2] along 8 hrs at 37°C. The formulated tablets passed the pharmacopeial requirements for all tablet tests. The formulated tablets showed sustained release characteristics of vitamin C as a tracer, within 8 hrs

utilization of a hydrophilic waxy binder in the preparation of orally disintegrating tablets by means of two different granulation methods

The demand for rapidly disintegrating tablets [RDT] has been growing during the last decade especially for elderly and children who have swallowing difficulties. The problem of certain RDT is their low physical resistance and high friability. This work describes a new approach to prepare RDT with sufficient mechanical integrity, involving the use of a hydrophilic waxy binder [Superpolystate®, PEG-6-stearate]. Superpolystate® is a waxy material with a melting point of 33 degree-37 degree and an HLB value of 9. So it will not only act as a binder and increase the physical resistance of tablets but it will also help the disintegration of the tablets as it melts in the mouth and solublises rapidly leaving no residues. The incorporation of Superpolystate® in the formulation of RDT was realized by means of two different granulation methods: wet granulation by using an emulsion of this waxy binder as granulating liquid and melt granulation where the molten form of the binder was used. Granule size distributions of both wet and melt granulates of crystallised Paracetamol and D-mannitol were compared using laser light diffractometer. Scanning electron microscopy [SEM] was used to examine their morphological characteristics. The potential of the intragranular addition of croscarmellose as a disintegrating agent was also evaluated. The subsequent step encompassed the preparation and the evaluation of the tablets, including the effect of the extragranular introduction of croscarmellose. An improvement in tablet hardness and friability was observed with both granulation methods where we were able to obtain RDT with a disintegration time of 40 +/- 2 s and a hardness of 47.9 +/- 2.5 N

Anti-free radicals: source, role and application in dermo-cosmetology

Many environmental factors attack our skin continuously: Sun, wind, pollutants and tobacco which constitute the principle skin aggressors. Free radicals which are highly reactive chemical compounds, induce cellular and tissue injuries, and subsequently lead to aging. These free radicals are normally produced by cellular metabolism. They are represented by: OH[degree], RCOO[degree], NO[degree] radicals and singlet oxygen. Free radicals are involved in cutaneous aging. Normally these radicals are neutralised by natural or human antiradical agents like superoxide dismutase, glutathione reductase, glutathione peroxidase and others. Some pathologic situations [cancer, Alzheimer disease, Crohn's disease, atherosclerosis, diabetes mellitus …] are characterized by an over production of these radicals where the natural defences become overwhelmed. Oral administration of exogenous substances like vitamin A, C, E, oligoelements Cu, Zn, Se, Mn decrease free radical harmful and deleterious effects. Nature has several means to fight against oxidative stress: polyphenols, flavonoides and lipids are antiradical substances of plant origin. The future belongs to understand natural antiradical mechanisms as well as the synthesis of new molecules which would be effective in prevention of harmful effects produced by these radicals