Past work done on Floting Microspheres

About author
Sreekanh K *, Taj khan H , Dr. Hindustan Abdul Ahad
M. Pharmacy, Department of pharmaceutics, Balaji College of Pharmacy, Ananthapuram, AP, India
E-mail: pandasri814@gmail.com

Introduction
Sivakumar and Jagdish Chandra Rathi *., (2011)^[1] In the present study, gelatin microspheres containing of loxacin were prepared by coacervation phase separation method and characterized by optical microscopy and scanning electron microscopy. The microspheres were analyzed for drug entrapment, bulk density, angle of repose, particle size and In-vitro release pattern. The effect of process variables on microsphere size was studied and based on these preliminary studies, different batches of microspheres were prepared by altering the drug: polymer ratio and cross-linking with glutaraldehyde. The size of microspheres was in range of 42- 45μm. They were spherical in shape as evidenced by photomicrographs and scanning electron microscopy. The percent drug entrapment was in the range of 78-90 % and they could sustain drug release over a period of 8 hrs.
KC Ofokansi*., (2007)^[2]Swellable microspheres based on polymers or their admixtures are frequently employed as drug delivery systems to achieve a controlled release and site-specific targeting of the incorporated drug. The objective of the present study was to enhance the rectal delivery of cefuroxime sodium by entrapping it into water-swellable gelatin-mucin microspheres.
Naisarg D. Pujara*.,( 2012)^[3] The purpose of writing this review on floating microspheres was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. Recent advances indicate that floating microspheres are especially suitable for achieving sustained or delayed release oral formulations with flexibility of blending to attain different release patterns, low risk of dose dumping as well as reproducible and short gastric retention time. One of the approaches toward this goal is to develop the floating microspheres so as to increase the gastric retention time. The development of floating microspheres involves different solvent evaporation techniques to create the hollow inner core. In this review,  the current status of microspheres including hollow microspheres (micro balloons) and their characterization, advantages, disadvantages, application, mechanism and method of preparation for gastric retention of drug are discussed. This review also summarizes the in vitro and in vivo studies to evaluate the performance and applications of floating microspheres. These system sare useful to encounter several difficulties during the development of  pharmaceutical dosage form.
RajkumarK*, Sainath Goud R., (2012)^[4] Floating microspheres (Hollow Microspheres) are gastro-retentive drug delivery systems based on noneffervescent approach. Hollow microspheres are in strict sense, spherical empty particles without core, free flowing powders consisting of proteins or synthetic polymers, ideally having a size in the range 1-1000 micrometer. Gastro-retentive floating microspheres are low-density systems that have sufficient buoyancy to float over gastric contents and remain in stomach for prolonged period. The drug is released slowly atdesired rate resulting in increased gastric retention with reduced fluctuations in plasma drug concentration. Floating microspheres to improve patient compliance by decreasing dosing frequency, better therapeutic effect of short half-life drugs can be achieved. Enhanced absorption of drugs which solubilise only instomach, Gastric retention time is increased because of buoyancy. Floating microspheres are prepared by solvent diffusion and evaporation methods to create the hollow inner core. Floating microspheres are characterized by their micromeritic properties such as particle size, tapped density, compressibility index, true density and flow properties including angle of repose, scanning electron microscopy, in vitrofloatability studies, in vivo floatability studies in dogs, in-vitro drug release studies and stability studies etc. In the present review preparation methods, characterization, advantages, mechanism of drug release from microspheres, applications and list of the drugs formulated as floating microspheres are discussed.
Key words: Gelatin microspheres, Swell able microspheres, Gastric retention, scanning electron microscopy
Conclusion
Floating microspheres has emerged as an efficient approach for enhancing the bioavailability and controlled delivery of various therapeutic agents. Significant attempts have been made worldwide to explore these systems according to patient requirements, both in terms of therapeutic efficacy and compliance. Floating microspheres as gastro retentive dosage forms precisely control the release rate of target drug to a specific site and facilitates an enormous impact on health care. Optimized multi-unit floating microspheres are expected to provide clinicians with a new choice of an economical, safe and more bioavailable formulation in the effective management of diverse diseases. These systems also provide tremendous opportunities in the designing of new controlled and delayed release oral formulations, thus extending the frontier of futuristic pharmaceutical development. Increased sophistication of this system will ensure the successful advancements in the avenue of gastro retentive microspheres therapy so as to optimize the delivery of molecules in a more efficient manner. Furthermore, recent innovations in pharmaceutical investigation will surely provide real prospects for establishment of novel and effective means in the development of these promising drug delivery systems.
Reference
1. Sengodan Tamizharasi, T. Sivakumar and Jagdish Chandra Rathi * Preparation and of        Aceclofenac floating oral delivery system, Pelagia Research Library, ISSN: 0976-8688 CODEN (USA): PSHIBD, Der Pharmacia Sinica, 2011, 2 (5):43-53
2. KC Ofokansi*, Formulation and Evaluation of Microspheres Based on Gelatin-Mucin Admixtures for the Rectal Delivery of Cefuroxime Sodium, Research Article, Trop J Pharm Res, December 2007; 6 (4), http://www.tjpr.org
3. Naisarg D. Floating  microspheres, World Journal of pharmacy and  Pharmaceutical  Science, Volume 1, Issue 3, 872-895. Review Article ISSN 2278 – 4357,
4. Rajkumar K*, Floating  microspheres, Review Article ,Journal Of Drug Delivery  Research, ISSN 2319-1074, Volume 1 Issue 4, 2012 www.earthjournals.org