Emulsions are thermodynamically unstable heterogeneous biphasic system. There are certain parameters which if and emulsion follow considered as stable. There are lots of sign of physical and chemical instability of emulsion are creaming, cracking, phase inversion, flocculation. There are several methods of detect stability of prepared emulsion. Rheological assessment, macroscopic examination, globule size analysis and accelerated stability test. Many types of emulsifying agents are interfacial tension, film formation and electric potential and emulsion rheology. Emulgents form three types of films around dispersed phase globules are monomolecular, multimolecular and particulate film. Regard to the improvement in the effectiveness and stability several enhancements have been made in the emulsion technology micro emulsion, multiple emulsions, non aqueous emulsions, liposome emulsions, nanoemulsions and emulsions polymerization are few advances with the advancement in application of emulsion incorporate in this review.

The purpose of this review is to cover various aspects related with the use of ion exchange resins for taste masking of bitter drugs and for formulating sustained release dosage form. Ion exchange resins are water insoluble cross-linked polymers containing a salt-forming group at repeating positions on the polymer chain and have the ability to exchange counter-ions within aqueous solutions surrounding them. The bitterness of pharmaceutical medicines plays a critical role in patient compliance, as the oral administration of bitter drugs is often hampered by their unpleasant taste which leads to non-compliance and further worsening of diseased condition. One of the popular approaches in the taste masking of bitter drugs is based on IER. For taste masking purpose weak cation exchange or weak anion exchange resins are used, depending on the nature of drug. The drug resin complex is absolutely tasteless with no after taste, and at the same time, its bioavailability is not affected. Sustained release dosage forms are designed to release a drug at a pre determined rate in order to maintain a constant drug concentration for a specific period of time with minimum side effects. The usage of IER during the development of sustained release formulations plays a significant role because of their drug retarding properties. In this review also incorporates various patents related to taste masking and sustained release formulations using IER.

Aceclofenac is aceclofenacum (O-(2, 6-dichloroaniline) phenyl] acetate glycolic acid ester, 2-(2, 6-dichloraniline) phenyl acetoxy acetic acid. Aceclofenac is a Non-Steroidal Anti Inflammatory drug. It is used in the management of osteoarthritis, rheumatoid arthritis and ankylozing spondylitis. Aceclofenac when taken orally shows gastrointestinal disturbances such as GI discomfort, nausea, diarrhea due to its low solubility, in some patient's peptic ulceration and severe gastrointestinal bleeding may also occur. Thus various approaches have been used to overcome problems like gastric irritation and other side effects that are frequently experienced with NSAID drug therapy. Aceclofenac is practically insoluble in water leading to poor dissolution and variable bioavailability upon oral administration. Aceclofenac needs enhancement of solubility and dissolution rate to improve its oral bioavailability and therapeutic efficacy. In order to improve solubility and dissolution of poorly INTRODUCTIONSolubilization is the process by which the apparent solubility of poorly water soluble substance is increased. Solubilization techniques include addition of a co solvent, salt formation, pro-drug design, complexation, particle size reduction, and the use of surface active agents (Micellization). Use of solvate and hydrates, polymorphs, hydro trophy, use of absorbents, pH adjustment, solubilizing vehicles, etc. are the some other physicochemical approaches to enhancing oral absorption of poorly water soluble drugs. A drug substance is considered highly soluble when the highest dose strength is soluble in < 250 ml water over a pH range of 1 to 7.5. A drug substance is considered highly permeable when the extent of absorption in humans is determined to be > 90 % of an administered dose, based on mass-balance or in comparison to an intravenous reference dose. A drug product is considered to be rapidly dissolving when > 85 % of the labeled amount of drug substance dissolves within 30 minutes using USP apparatus I or II in a volume of < 900 ml buffer solutions

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Oral controlled release drug delivery system becomes a very promising approach for those drugs that are given orally but having the high dosing frequency and shorter half-life. Matrix tablets serves as an important tool for oral controlled release dosage forms. Problems like patient compliance, drug targeting, local side effects, frequent administration and fluctuations in blood concentration levels, associated with their counterparts, the conventional dosage forms were rectified. Many of the pharmaceutical dosage form are formulated as sustained release dosage form to retard the release of a therapeutic agent such that its appearance in the systemic circulation is prolonged and its plasma profile is sustained in duration. Tablets offer the lowest cost approach to controlled and sustained release dosage forms. Matrix tablet as controlled release has given a new breakthrough for novel drug delivery system in the field of pharmaceutical technology. This review focuses on the various types of matrix systems based on polymer used and porosity of matrix system i.e. hydrophilic, hydrophobic, fat wax, porous, non-porous, pH sensitive. An effort has been made to consolidate different types of patents granted across the globe for last thirty years in the field of matrix system viz. tablet, pellets etc.