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Some of the purpose of tablet coating are masking flavour, fragrance overlapping, Environmental protection, prevent drug from gastric acid .Enteric coated tablets are solid unit dosage forms which are designed to bypass the stomach and release the drug in small intestine and are meant for oral administration. The word “enteric” indicates small intestine; therefore enteric coatings prevent release of medication before it reaches the small intestine.Most enteric coating works by presenting a surface that is stable at the highly acidic pH found in stomach, but breaks down rapidly at a less acidic pH. For e.g. they will not dissolve in the acidic juices of the stomach (pH-3), but will in the alkaline (pH7-9) environment present in the small intestine. Materials used for enteric coatings include CAP, CAT, PVAP and HPMCP, fatty acids, waxes, shellac, plastics and plant fibres.

Novel Drug Delivery system (NDDS) refers to the approaches, formulations, technologies, and systems for transporting a pharmaceutical compound in the body as needed to safely achieve its desired therapeutic effects. Applications of liposomes in medicine and pharmacology can be divided into diagnostic and therapeutic applications of liposomes containing various markers or drugs. The aim of the study was to formulate and evaluate Tolbutamide liposomes for a sustained drug delivery system. The tolbutamide was prepared as a liposomal drug delivery system by using two different techniques such as physical dispersion method and ether injection method. The morphological characters of prepared liposomes were determined with the help of optical microscope. The results of the particle size showed, when the concentration of soya lecithin was increased the size of the particle was reduced. The in vitro release showed that as the concentration of soya lecithin was increased the release rate of drug was retarded. Among the two methods ether injection method showed prolonged action when compared to physical dispersion method. The stability studies for all the formulations were performed by keeping the formulations at two different temperatures 4ºC±2ºC and 25ºC±2ºC for a period of 30 days. There was no change in morphological characters at 4ºC±2ºC, but there was a slight reduced in particles size at 25ºC±2ºC. The percentage drug entrapment was reduced in all the formulations at both the conditions.

The major challenge with conventional dosage forms of Pioglitazone is poor aqueous solubility. Through this study are to improve its aqueous solubility by preparing its solid dispersion by fusion method using various carriers that will improve its absorption and subsequent bioavailability. The solid dispersions of Pioglitazone were prepared using PEG-4000, PEG-6000 and PVP K30 as carrier, using fusion method. Solid dispersions of Pioglitazone were prepared using PEG-4000, PEG-6000 and PVP K30 as carrier, using fusion method and total 9 formulation (F1-F9) were prepared. Tablets were prepared (TF5) from the optimum formulation (F5). The prepared tablets (TF5) were subjected to evaluation for parameters like shape and size, weight variation, hardness, friability, disintegration time, drug content etc. The solid dispersion (F5) as well as the tablet (TF5) showed greater rate and extent of dissolution as compared to pure drug. Keywords: bioavailability, dissolution rate, PEG, PVP K30, solid dispersion, Pioglitazone

Co-crystals are defined as crystalline complexes of two or more neutral molecular constituents bound together in the crystal lattice through non covalent interactions. This article summarized about the co-crystal definition, its importance along with characterizations and screening and production methods. From the literature survey, it can be concluded that improvement of performance characteristics of APIs using co-crystallization is a shows potential approach. One of the key aspects of this technique is that it can be useful to all APIs affliction from poor aqueous solubility. Co-crystallization moves toward is flourishing now adays due to its immaculate effect of solubility on poorly dissolvable drugs, especially those having weakly ionisable group and neutral compounds. Meanwhile co-crystallization will also put an effort into upgrading of other physicochemical properties of drugs such as chemical stability, flowability etc. Keywords: Co-crystals, characteristics, screening, productions, solubility

Floating drug delivery systems are retained in the stomach and are useful for drugs that are poorly soluble or unstable in intestinal fluid. Floating drug delivery system have a bulk density less than that of gastric fluids and so remain buoyant in the stomach without affecting the gastric emptying rate for a prolong period of time. Research work emphasized on design and evaluates nifedipine floating matrix tablets in which polymers i.e. hydroxyprophyl methyl cellulose (HPMC K100M, K4, and K15) was used. About 15-35 % of HPMC can be used as a polymer in the extended release formulations. So, here the polymer was used in the range of 16-36 %. Sodium bicarbonate (40%) is used as a gas generating agent. It can be used in the range of 25-50 %. The granules are prepared by wet granulation method. The prepared granules were evaluated for the bulk density, tapped density, bulkiness, angle of repose, compressibility index and hausner ratio. The values indicate good flow property. The compressed tablets were evaluated for hardness, uniformity of weight, friability, drug content, buoyancy lag time and duration of buoyancy. All the readings are within the prescribed limits. There was no interaction between the drug, polymer and excipients it was found out by IR studies. The in vitro drug release data indicate that the release of the drug depends upon the proportion of polymer present in the formulation. As the polymer ratio increases the release rate of the drug is prolonged. Keywords: Floating tablet, HPMC K100M, nifedipine, HPMC K4