Polymer

Gastroretentive drug delivery systems (GRDDS) have emerged as an advanced approach to overcome the limitations of conventional oral dosage forms by prolonging gastric residence time and improving drug bioavailability. The objective of these systems is to remain buoyant in gastric fluid for extended periods, allowing controlled release of drugs and enhanced absorption of medications with limited absorption windows. Floating tablets achieve buoyancy using low-density excipients, such as gas-generating substances like sodium bicarbonate, or swellable polymers like hydroxypropyl methylcellulose (HPMC). Formulation strategies generally employ polymeric matrices, effervescent components, or coating technologies to regulate release kinetics and enhance stability. Evaluation parameters, such as floating lag time, total floating duration, and in vitro and in vivo correlation, are essential for assessing system performance. GRDDS can improve the therapeutic efficacy of medicines used in gastrointestinal disorders and those requiring localized gastric delivery. Despite significant advancements, variability in gastric motility and physiological factors limit the reproducibility and scalability of formulations. This review consolidates current progress and identifies future directions for optimized gastroretentive floating tablet technology.

The aim of this research work was to Evaluation of Some Natural Polymer used as Sustained Release Matrix Tablet, any pharmaceutical formulation contains two ingredients one is the active ingredient and other is an excipients. An excipients help in the manufacturing of dosage form and it also improves physicochemical parameters of the dosage form. Polymers play an important role as excipients in any dosage form. They influence drug release and should be compatible, non-toxic, stable, economic etc. and develop a fixed Dose Combination product in a two different strength using same blend for both the strengths of tablet as a SR tablet formulation. In the tablet, Extended Release layer consist of Antihypertensive Drug belonging to class β-selective adrenergic blocking agent without partial agonist or membrane stabilizing properties. Extended release preparation provides sustained release and reduces the chances of tough related side effects. In selected cases of extended release preparation of this drug used in treatment of hypertension and congestive heart failure. The clinical studies have shown beneficial role of this drug as an extended release preparation. The main objective of the present study was to develop, formulate and evaluate a matrix tablet by using hydrophilic natural retardant polymers which would retard drug release in upper GI tract and should start releasing the drug when it reaches the alkaline environment of small intestine. Okara and Tramarind Gum Mucilage were investigated as the model hydrophilic retardant polymers. Wet granulation method was and nine batches of tablets were prepared. The prepared tablets were subjected for pharmacopoeial and non-pharmacopoeial evaluation parameters including loose and tapped bulk density, compressibility index, hausner ratio, angle of repose, friability, hardness, thickness, weight variation, % drug content and in-vitro drug release studies. It can be concluded that the combination of hydrophilic polymers that are retardant in nature are better suited for sustained and controlled drug delivery system than the hydrophilic polymer alone.

When gels and emulsions are used in combined form the dosage form are referred as emulgel. Also there has been incredible interest for the utilization of novel polymers and drug molecules. A one of the feature of topical drug delivery is the immediate availability of the skin as  target organ for diagnosis and treatment. Among the different group of semisolid planning, the utilization of gel has extended both in cosmetics and in the pharmaceuticals. Although Gel has many advantages, there is many limitation in delivery of hydrophobic drugs, so to overcome this limitation an emulsion base novel approach is being most used. That is emugel system used so that even a hydrophobic moiety can enjoy the unique properties of gels and having characteristics of dual control release i.e. emulsion as well as gel. The formulation is prepared by various polymer which behave as an emulsifer and thickening agent because of gelling capacity of these compounds give rise to stable emulsions and creams by diminishing surface and interfacial pressure while in the meantime expanding the thickness of the aqueous phase. In order to understand the potential of emulgel as delivery vehicles, this review gives an overview of the ideal properties, formation, and characterization of emulgels. So this can be use as analgesics and antifungal drugs, as superior topical drug delivery systems over present conventional systems available in market.

Complex of Carboxymethyl cellulose (CMC) sodium salt and β-cyclodextrin (β-CD) were evaluated as sustained release polymers. Diclofenac sodium (DS), CMC sodium salt and β-CD were taken for the preparation of spray dried sustained release microparticles in the different ratio of 1: 0.125:0.125, 1:0.188:0.187 and 1: 0.25: 0.25 (wt/wt) respectively. The DS loaded microparticles were evaluated for particle size, surface morphology by atomic force microscopy (AFM), structural interaction by Fourier transform infrared spectroscopy (FTIR) and thermal characterization by differential scanning calorimetry(DSC). These microparticles further formulated into the tablet dosage form and evaluated for different parameters. Several kinetic models were employed to evaluate the possible changes in the release mechanism. The drug: polymer ratio of 1:0.25:0.25 shows better result of sustained release than the other ratios. The particle size of the optimized microparticles was found to be in the range of 300 nm to 5 µm. FTIR and DSC result reveals the complex formation between DS, CMC sodium and β-CD. X-ray diffraction results indicated that the degree of crystallinity was reduced and most of the drug existed in amorphous state. . The reported method is easy and reproducible and can be used for the batch scale production.

  Diltiazem hydrochloride, a calcium channel blocker, is widely used for the treatment of angina pectoris, hypertension and arrhythmias. The usual dose of diltiazem hydrochloride is 180-240 mg/day. The conventional tablet or capsule is administered 3 or 4 times a day due to its low biological half-life of about 3.7 h. The problems of frequent administration and variable low bioavailability (36-50%) after oral administration of conventional tablet or capsules have been attenuated by designing diltiazem hydrochloride in the form of mucoadhesive microspheres. Diltiazem hydrochloride loaded mucoadhesive microspheres were successfully prepared by emulsification-internal gelation technique with a maximum encapsulation efficiency of 99.48± 0.32%.The order of increasing release rate observed with various microspheres was as follows Sodium alginate < Sodium alginate+ NaCMC < Sodium alginate+ HPMC. The order of increasing release rate observed with various cross linking agents was as follows Aluminum chloride < Barium chloride< Calcium chloride. The release behaviour of microspheres, with different cross-linking agents depends upon the valency and size of the cations of the respective cross-linking agent. The dissolution profiles follow zero order kinetics and the mechanism of drug release was governed by peppas model. The in vitro wash-off test indicated that the wash-off was faster at simulated intestinal fluid (phosphate buffer, pH 7.4) than that at simulated gastric fluid (0.1 M HCl, pH 1.2). The mucoadhesive microspheres formulated with sodium alginate+HPMC and calcium chloride showed a satisfactory sustained release profile for 12 hours.