An Overview on Microsponge Delivery System

Microsponge were prepared by liquid-liquid suspension polymerization of styrene and methyl methacrylate. Microsponges were dispersed in gel prepared by using carbopol 940 and evaluated for drug release using Franz diffusion cell. Free flowing powder with size distribution 30 to 107 μm was obtained. The average drug release from the gels containing microspongic fluconazole was 67.81% in 12 h. drug release from the gels containing microsponge loaded fluconazole and marketed formulation has followed zero order kinetics. Microspongic system for topical delivery of fluconazole was observed potential in extending the release. A microsponge system for retinoic acid was developed and tested for drug release and anti-acne efficiency. Statistically significant greater reductions in inflammatory and non-inflammatory lesions were obtained with entrapped tretinoin in the microsponge system. A new formulation of Hydroquinone (HQ) 4% with retinol 0.15% entrapped in microsponge reservoirs was developed to release HQ gradually to prolong exposure to treatment and to reduce skin irritation. Introduction There has been an ever-increasing interest by the consumer, primarily the female in skin treatment products. This interest has been fostered by the widespread use of ingredients like α-hydroxy acids and vitamins in topical products that can induce perceivable and demonstrable benefits especially in aging or photodamaged skin. In many instances, these ingredients may produce irritation. Such irritation can be perceived as redness, burning or stinging and particularly occurs in individuals with sensitive skin1. These approaches in many cases also reduce the beneficial effects of the final product. Drug delivery systems can precisely control the release rates or target drugs to to a specific body site have had an enormous impact on the health care system. Several predictable systems were developed for systemic drugs under the title of transdermal delivery system (TDS) using the skin as portal of entry2. Controlled release of drug onto the epidermis with assurance that the drug remains primarily localized and does not enter the systemic circulation in significant amounts is an area of research. No efficient vehicles have been developed for controlled and localized delivery of drugs into the stratum corneum and not beyond the epidermis. The application of topical drugs suffers many problem such as ointment, which are often aesthetically unappealing, stickiness and greasiness that results into lack of peatient compliance3. The drawbacks are unpleasant odour, uncontrolled evaporation of active ingredient and potential incompatibility of drugs with the vehicles3. The microsponge delivery system have resulted in a new generation of very well tolerated, and highly efficacious, novel products. Microsponge The microsponge technohlogy was developed by Won in 1987 and the original patents were assigned to Advanced Polymer Systems, Inc3. Presently, this technology has been licensed to Cardinal Health, Inc., for use in topical products. The size of the microsponge varied from 5-300 μm in diameter. Although the microsponge size may vary, a typical 25 μm sphere can have upto 250000 pores and an internal pore structure equivalent to 10 ft in length providing a total pore volume of about 1 ml/g. The microsponge particles are too large to be absorbed into the skin and this adds a measure of safety to these microsponge materials. Bacterial contamination of the materials entrapped in the microsponge, because the size of pore diameter is smaller than bacteria, ranging from 0.007 to 0.2 μm. Microsponges are polymeric delivery systems consisting of porous microspheres that can entrap active ingredients such as fragrances, sunscreen, essential oil, emollients, anti-fungal, anti-infective and anti-inflammatory agents4. Like a true sponge, each microspheres consists of myriad of interconnecting voids within a non-collapsible structure with a large porous surface. Microsponge Preparation Microsponges are prepared by two methods • Quasi-Emulsion Solvent Diffusion5: To prepare the inner organic phase, Eudragit RS 100 is dissolved in ethyl alcohol. The drug is added to solution and dissolved under ultrasonication at 35o C the inner phase is poured into the polyvinyl alcohol solution in water. Following stirring for 60 min, then mixture is filtered to separate the microsponge. The microsponges are dried in an air-heated oven at 40o C for 12 h. ingredients can be entrapped in microsponge polymers