Gedar Sushma et al. Journal of Biological & Scientific Opinion · Volume 1 (4). 2013 Published by Moksha Publishing House. Website www.mokshaph.com · © All rights reserved. Page 372 Available online through www.jbsoweb.com Review Article ADVANCEMENTS AND PATENTS IN PHARMACEUTICAL SUSPENSION TECHNOLOGIES Gedar Sushma 1 *, Kataria Mahesh Kumar 2 , Bilandi Ajay 3 , Taneja Ruchi 1 1 Student, M. Pharm (Pharmaceutics) III rd Sem, Seth G. L. Bihani S. D. College of Technical Education, Sri Ganganagar, Rajasthan, India 2 Assistant Professor and Head, Department of Pharmaceutics, Seth G. L. Bihani S. D. College of Technical Education, Sri Ganganagar, Rajasthan, India 3 Lecturer, Department of Pharmaceutics, Seth G. L. Bihani S. D. College of Technical Education, Sri Ganganagar, Rajasthan, India *Correspondence Gedar Sushma Student, M. Pharm (Pharmaceutics) IIIrd Sem, Seth G. L. Bihani S. D. College of Technical Education, Sri Ganganagar, Rajasthan, India Abstract Suspensions are solid-liquid dispersion and defined as heterogeneous biphasic liquid dosage form of medicaments in which continuous or external phase is usually a liquid or semisolid and the dispersed or internal phase is made up of particulate matter that is essentially insoluble in, but dispersed through, the continuous phase. They require suspending agents to suspend the fine particles of dispersed phase, proper wetting agents (surfactants), viscosity increasing agents to improve the stability of preparation and suitable preservatives in preparation. Suspensions are generally taken orally or by parenteral route and also used for external applications. Suspension should have heterogeneous nature and product should be resistant to microbial contamination. Various types of suspension are available in pharmaceuticals like oral, parenteral, ophthalmic and suspension for external uses. Several advancements in suspension technologies viz nanosuspension, taste masked suspension, sustained release suspension, aqueous suspension etc. are discussed in detail. Patents related to these advancements are also mentioned in this article of previous 39 years (from 2012 to 1975). This article emphasise on the general introduction of suspension, their types, recent advancements and patents related to these advancements. Keywords: Suspension, nanosuspension, taste masked suspension, sustained release suspension, aqueous suspension, patents. DOI: 10.7897/2321–6328.01420 Article Received on: 02/10/13 Accepted on: 12/11/13 INTRODUCTION Suspensions are solid-liquid dispersion and defined as heterogeneous biphasic liquid dosage form of medicaments in which continuous or external phase is usually a liquid or semisolid and the dispersed or internal phase is made up of particulate matter that is essentially insoluble in, but dispersed through, the continuous phase. The dispersed phase may consist of discrete particles, ranging from 0.5 to 5.0 micrometer 1 . Suspensions are generally taken orally or by parenteral route and also used for external applications. The particle size of disperse phase is very important in formulation of suspension 2 . Suspensions for topical application should have very small particle size to avoid gritty feel on application and to provide greater coverage and protection to the area to which suspension is applied. In case, the solid substance is meant for skin penetration, its small size gives a quicker rate of dissolution and its penetration. In suspensions meant for introduction in to ophthalmic cavity (eye) particle size should be less than 10 micrometer, beyond this suspension gives feeling of pain and discomfort. Suspensions which are meant for parenteral administration (injectable suspension) should have a particle size that can easily pass thorough the syringe needle 3 . Merits and Demerits of Pharmaceutical Suspensions If drug not stable in solution form i.e. Procaine Penicillin G and not soluble in water and non-aqueous solvent, e.g. corticosteroids suspension, then drugs administered in the form of suspension. They sustaining the effect of drug e.g. protamine zinc insulin and procaine penicillin G. These have a higher bioavailability compared to other dosage forms (except solution) due to its large surface area, higher dissolution rate 4 . They require suspending agents to suspend the fine particles of dispersed phase, proper wetting agents (surfactants), viscosity increasing agents to improve the stability of preparation and suitable preservatives in preparation. Characteristics of pharmaceutical suspension Suspension should be smooth and elegant appearance and physically and chemically stable. Rate of sedimentation of disperse phase should be slow. Sediment must be re dispersed upon gentle shacking of container. Particle size of disperse phase must remain fairly constant throughout shelf period of preparation. Flow of suspension must be uniform so that it is readily and evenly available from container. Parenteral suspension should not loose efficiency during sterilization and these should have aesthetic properties with regard to taste