Studies in the Development of Nateglinide Loaded Calcium Alginate and Chitosan Coated Calcium Alginate Beads

Abstract

The drug delivery systems using biodegradable natural polymeric particles are becoming a clinical reality with many benefits for the patient. The versatility of polymeric materials allows the fabrication of the delivery device with desirable degree of swelling, and drug release. Alginate is a natural biopolymer which forms a hydrogel in the presence of divalent cations like Ca 2ϩ . 1,2) The inert environment within the biopolymer network of alginates allows for the entrapment of a wide range of bioactive substances, cells and drug molecules, with minor interactions between them.3)The use of calcium-alginate beads in controlled drug delivery technology for the gastro-intestinal administration of proteins 4) and other drug molecules 5-7) are well known. Much attention has been received in recent years regarding the use of chitosan-alginate polyelectrolyte complex in controlled drug delivery. [8][9][10][11] The use of chitosan has been repeated in the literature is either for coating alginate beads in order to alter the diffusion rate of the encapsulated substances 12) or as an additive for the bulk modification of the beads structure. 13,14) Nateglinide is an antidiabetic drug used for the treatment of Type-II diabetes mellitus and has a short half-life of 1.5 h, and the usual oral dosage regimen is 60-240 mg taken 3 times a day. Thus Nateglinide is a suitable candidate for oral sustained release drug delivery. Keeping these in view, the present study has been undertaken. The investigation was phased out in the following manner. Firstly the effect of calcium ion and chitosan in the coagulation fluid on drug release characteristics and its mechanism was considered. Then the physical state of the drug in the beads and the swelling behavior of the bead formulations were undertaken. ExperimentalMaterials The following materials were obtained from the indicated suppliers and used as received: sodium alginate (low viscosity; viscosity of 2% solution 25°C, Ϸ250 cps from SNAP Natural and alginate products limited, Ranipet, India), chitosan (85% degree of deacetylation, molecular weight more than 10 3 kDa from India sea foods, Cochin, India). Calcium chloride dihydrate (Qualigens, Mumbai, India), di-sodium hydrogen phosphate anhydrous, potassium di-hydrogen phosphate, sodium acetate, potassium chloride, sodium hydroxide, dichloromethane, ethanol (99%), hydrochloric acid and acetic acid glacial (Merck, Mumbai, India). Nateglinide was of pharmaceutical grade (Alembic chemical works Ltd., Vadodara, India). Preparation of Nateglinide Loaded Calcium Alginate Beads (CAB)In this method the Nateglinide loaded calcium alginate beads were prepared using varying concentration of calcium chloride in the gelation medium [2% (w/v), 5% (w/v)] while maintaining the drug : polymer ratio as 1 : 3 and 1 : 4 separately for varying concentration of calcium chloride on each occasion. Required amount of Nateglinide dissolved in dichloromethane was slowly dispersed in sodium alginate solution with constant stirring for 3 h, maintaining the drug :...

Preparation and characterization of biodegradable paclitaxel loaded alginate microparticles for pulmonary delivery

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Development of Sustained-Release Microbeads of Nifedipine and <i>In vitro</i> Characterization

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