Machindra Jayram Chavan

In the pharmaceutical industry an impurity is considered, defined the any other organic material besides the drug substance or pharmaceutical ingredients.  The impurity may be formed during the formulation or upon aging of two APIs in medicines. The highly sophisticated instrumentation, such as mass spectra meters attached to the gas chromatography or HPLC in various matrices. GC is the most useful technique for identification of residual solvent. The advent of hyphenated technique has revolution any impurity profiling, by not only separation but structural identification of impurities as well among all techniques. The most exploited techniques for impurities profiling of drug are LC-MS-MS, LC-NMR, LC-NMR-MS, GC-MS AND LC-MS.

In pharmaceutical industry the major problem of dosage form development is low aqueous solubility. In present review the particle engineering concept and solubility, permeability approaches design and method used in improvement of particle size. The different methods are used in particle engineering like supercritical fluid technology, controlled precipitation, and mechanical technique, evaporation precipitation to aqueous solution, freezing technique, and sonication technology etc. discussed. The improvements of aqueous solubility need to be formulation development for dosage form very essential. The BCS class II drugs modified to soluble form for need of bioavailability of drugs. The solid dispersion method with a different carrier improves the solubility.

The purpose of writing this review article on gastro- retentive drug delivery systems (GRDDS) have been developed; the principle mechanism of floatation to achieve gastric retention. The recent developments of (FDSS) including the physiological and formulation variables affecting the gastric retention. Several techniques such as floating drug delivery system, low density systems, raft systems, mucoadhesive systems, high density systems, super- porous hydro- gels and magnetic systems, have been employed. Floating drug delivery systems have a bulk density less than gastric fluids and so, remain buoyant in the stomach for a prolonged period of time, releasing the drug slowly at the desired rate from the system. Dosage forms available as gastric floating systems include tablets, capsules, granules and microspheres.