Effect of formulation parameters on the drug release and floating properties of gastric floating two-layer tablets with acetylsalicylic acid

Exploring the Potentials of Corn Fiber Gum in Fabricating Mucoadhesive Floating Tablet of Poorly Gastro-retainable Drug

AIM

To formulate and preliminary evaluated polysaccharide based mucoadhesive floating tablets of Cinnarizine.

BACKGROUND

Gastro-retentive drug delivery systems has proved to be a successful approach to enhance the gastric residence with site specific targeting for achieving local or generalized effect. Various patents has also been filed globally employing gastro-retentive approach.

OBJECTIVE

The study is designed to explore the mucoadhesive and low density characteristics of corn fibre gum (CFG) for preparation of gastro-retentive floating tablets of cinnarizine.

METHODS

Floating tablets were prepared by direct compression technique using different concentrations of CFG (45, 50, 60% w/w). The formulated floating tablet batches were evaluated for their hardness, friability, drug content, floating duration/ lag time, swelling behavior, bioadhesive strength and in vitro drug release.

RESULTS

Mucoadhesive strength was found to increase with an increment in the polysaccharide concentration. Swelling index was found to increase both with the increase in CFG concentration and with duration for which tablet remains in medium. The in vitro drug release studies indicated decrease in drug release (91% to 77%) with the increase in polymer concentration. The release data was further fitted to various kinetic models which revealed the drug release to be in accordance with Zero-order and Higuchi models, indicating polymer to exhibit the swellable matrix forming abilities. The value of n (between 0.458 and 0.997) from Korsemeyer Peppas model depicted the possibility of drug to follow more than one mechanism of release from the formulation i.e. diffusion and erosion. Stability studies revealed the preparations to retain their integrity and pharmaceutical characteristics at variable storage conditions.

CONCLUSION

Thus from the research findings, CFG could be concluded to possess potential binder, release retardant and mucoadhesive characteristics which could be successfully employed for the formulation of gastro-retentive floating tablets.

The development of sustained release drug delivery platforms using melt-extruded cellulose-based polymer blends

OBJECTIVES

This research examined the application of hot melt extrusion (HME) in the preparation of matrix formulations containing hydroxypropyl cellulose (HPC) as a base polymer in combination with methyl cellulose (MC) and hydroxypropyl methylcellulose (HPMC).

METHODS

The limit to which formulations could control drug release under varying paddle speeds, high alcohol environments and high and low drug loads was investigated on a Caleva 10 ST dissolution tester. Rheological studies and hot plate imaging highlighted the impact of thermoresponsive polymers on drug release. The rate and percentage release of drug were analysed using a one-way ANOVA and Tukey's HSD test.

KEY FINDINGS

No significant differences in the amount of drug released were calculated as a result of paddle speed variation or in the presence of 40% v/v ETOH. The phase separation effects of temperature-sensitive polymers HPC and MC and the characteristic gel shrinkage and fluid expulsion were shown to be contributing factors. The use of the partition activity, α, identified the extent to which formulations were affected by phase separation.

CONCLUSION

Hot melt extrusion was successfully used to manufacture cellulose-based formulations. Thermoresponsive polymers HPC and MC significantly impacted drug release properties.

Gastroretentive Matrix Tablets of Boswellia Oleogum Resin: Preparation, Optimization, In Vitro Evaluation, and Cytoprotective Effect on Indomethacin-Induced Gastric Ulcer in Rabbits

Currently available anti-ulcer drugs suffer from serious side effects which limited their uses and prompted the need to search for a safe and efficient new anti-ulcer agent. Boswellia gum resin (BR) emerged as a safe, efficient, natural, and economic potential cytoprotective agent. Thus, it is of medical importance to develop gastroretentive (GR) formulations of BR to enhance its bioavailability and anti-ulcer efficacy. Early attempts involved the use of organic solvents and non-applicability to large-scale production. In this study, different tablet formulations were prepared by simple direct compression combining floating and bioadhesion mechanisms employing hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (SCMC), pectin (PC), and/or carbopol (CP) as bioadhesive polymers and sodium bicarbonate (SB) as a gas former. The prepared tablets were subjected for assessment of swelling, floating, bioadhesion, and drug release in 0.1 N HCl. The optimized GR formulation was examined for its protective effect on the gastric ulcer induced by indomethacin in albino rabbits compared with lactose tablets. The obtained results disclosed that swelling, floating, bioadhesion, and drug release of the GR tablets of BR depend mainly on the nature of the matrix and the ratio of polymer combinations. Moreover, a combination of SCMC-CP in a ratio of 2:1 (SCP21) exhibited desirable floating, bioadhesion, swelling, and extended drug release. Also, a 6-h pretreatment with SCP21 tablets decreased the severity of inflammation and number of bleeding spots among ulcer-induced rabbits in comparison to those treated with lactose tablets.

S, Zachariah AK, V. VK, M. A. S, Bose S, Souza FG, Thomas S. Percolated network formation in biocidal 3D porous PCL/clay nanocomposite scaffolds: effect of organic modifier on interfacial and water sorption properties

The influence of chemical interaction between poly(ε-caprolactone) (PCL) and Cloisite 10A on rheology, water permeability and antibacterial properties were subjected to detailed investigation.

Decades of research in drug targeting to the upper gastrointestinal tract using gastroretention technologies: where do we stand?

A major constraint in oral controlled release drug delivery is that not all the drug candidates are absorbed uniformly throughout the gastrointestinal tract (GIT). Drugs having "absorption window" are absorbed in a particular portion of GIT only or are absorbed to a different extent in various segments of the GIT. Thus, only the drug released in the region preceding and in close vicinity to the absorption window is available for absorption. The drug must be released from the dosage form in solution form; otherwise, it is generally not absorbed. Hence, much research has been dedicated to the development of gastroretentive drug delivery systems that may optimize the bioavailability and subsequent therapeutic efficacy of such drugs, as these systems have unique properties to bypass the gastric emptying process. These systems show excellent in vitro results but fail to give desirable in vivo performance. During the last 2-3 decades, researchers from the academia and industries are giving considerable importance in this field. Unfortunately, till date, few so-called gastroretentive dosage forms have been brought to the market in spite of numerous academic publications. The manuscript considers strategies that are commonly used in the development of gastroretentive drug delivery systems with a special attention on various parameters, which needs to be monitored during formulation development.