Design of experiment approach for formulating multi-unit colon-targeted drug delivery system: in vitro and in vivo studies.

Objective: The objective of the present investigation was to develop systematically optimized multiunit formulation for colon targeted delivery of metronidazole (MTZ) by employing design of experiment (DoE) and evaluate it for in vitro as well as in vivo drug release study.

Methods: Core of mini-tablets of MTZ was prepared using drug along with suitable swelling agents to provide pH sensitive pulsatile drug delivery. Eudragit® S 100 (ES) and ethyl cellulose (EC) were used as coating polymers to prevent initial drug release in gastric region.

Development of a novel tablet-in-capsule formulation of mesalamine for inflammatory bowel disease.

Objective: The objective of the present work was to develop a tablet-in-capsule type of multiunit system, which releases the drug in a controlled manner at pre-programmed time intervals.

Methods: The system consists of an enteric-coated hydroxypropyl methylcellulose capsule filled with four units of mesalamine minitablets, each of which was further coated with different ratios of Eudragit(®) E100 and Eudragit(®) RS100.

Results: In vitro evaluation of tablets coated with Eudragit(®) E100 and Eudragit(®) RS100 at different pH conditions revealed that at lower pH levels (2.

Recent trends in microbially and/or enzymatically driven colon-specific drug delivery systems.

Colon-specific drug delivery systems have recently gained enormous importance for the delivery of a variety of therapeutic compounds. To deliver a drug molecule intact to the colon, the delivery system must pass through the upper part of the gastrointestinal tract without being degraded. Researchers have attempted various approaches in the formulation of colon-specific drug delivery systems.

Polysaccharides: a targeting strategy for colonic drug delivery.

Introduction: Colon targeting has gained increasing importance for the topical treatment of diseases of the colon, such as Crohn's disease, ulcerative colitis, colorectal cancer and amebiasis. Various strategies used for targeting drugs to the colon include formation of a prodrug, coating with time or pH-dependent polymers, use of colon-specific biodegradable polymers, osmotic systems and pressure-controlled drug delivery systems. Among the different approaches used, polysaccharides that are precisely activated by the physiological conditions of the colon hold great promise, as they provide improved site specificity and meet the desired therapeutic needs.

Design and optimization of colon-targeted system of theophylline for chronotherapy of nocturnal asthma.

The objective of the present work was to develop a delayed-onset controlled-release colon-targeted system of theophylline, and to achieve the chronotherapy of nocturnal asthma. The formulation consisted of a core tablet containing hydroxypropyl methylcellulose used for achieving controlled release of drug, and a Eudragit S100:ethyl cellulose (EC) coating capable of delaying the drug release. The system was optimized using a 3(2) full factorial design, wherein two factors [ratio of Eudragit S100:EC and the coating level (% w/w)] were evaluated for lag time, t(50) and t(80) .

Formulation and development of release modulated colon targeted system of meloxicam for potential application in the prophylaxis of colorectal cancer.

The objective of the present study was to develop a colon targeted system of meloxicam for potential application in the prophylaxis of colorectal cancer. Efficacy of selective cyclooxygenase-2 inhibitors has been proven in colorectal cancer. Meloxicam is a selective cyclooxygenase-2 inhibitor with pH-dependent solubility.

Getting into the brain: approaches to enhance brain drug delivery.

Being the most delicate organ of the body, the brain is protected against potentially toxic substances by the blood-brain barrier (BBB), which restricts the entry of most pharmaceuticals into the brain. The developmental process for new drugs for the treatment of CNS disorders has not kept pace with progress in molecular neurosciences because most of the new drugs discovered are unable to cross the BBB. The clinical failure of CNS drug delivery may be attributed largely to a lack of appropriate drug delivery systems.

Design, development and optimization of a novel time and pH-dependent colon targeted drug delivery system.

The aim of present study was to develop a time- and pH-dependent system for delivering mesalamine to the colon. The system consists of the core tablet of mesalamine which is compression coated with hydroxypropyl methylcellulose (HPMC K4M) (time-dependent factor). This is then coated with pH-dependent polymer Eudragit L100.

In vitro and in vivo techniques to assess the performance of gastro-retentive drug delivery systems: a review.

Background: Interest in gastro-retentive drug delivery systems (GRDDS) can be attributed to the desire for increased patient convenience (once daily dosing) and to increase the therapeutic index (reduced C(max), increased C(min)). A range of evaluation techniques for GRDDS exist for in vitro and in vivo evaluation.

Objective: The aim of the present review is to describe the methodologies used for in vitro and in vivo evaluations of GRDDS.

Design, development, and optimization of orally disintegrating tablets of etoricoxib using vacuum-drying approach.

Etoricoxib is a cyclooxygenase 2 (COX-2) inhibitor that selectively inhibits the COX-2 enzyme and decreases the incidences of side effects associated with these agents. It is commonly prescribed for acute pain, gouty arthritis, and rheumatoid arthritis. Conventional tablets of etoricoxib are not capable of rapid action, which is required for faster drug effect onset and immediate relief from pain.

Therapeutic opportunities in colon-specific drug-delivery systems.

Oral colon-specific drug-delivery systems have recently gained importance for delivering a variety of therapeutic agents. The major obstacles to delivering drugs to the colon are the absorption and degradation pathways in the upper gastrointestinal tract. However, a successfully designed colon-targeted system can overcome these obstacles.

Process optimization and characterization of poloxamer solid dispersions of a poorly water-soluble drug.

The objective of the present investigation was to improve the dissolution rate of Rofecoxib (RXB), a poorly water-soluble drug by solid dispersion technique using a water-soluble carrier, Poloxamer 188 (PXM). The melting method was used to prepare solid dispersions. A 3(2) full factorial design approach was used for optimization wherein the temperature to which the melt-drug mixture cooled (X(1) ) and the drug-to-polymer ratio (X(2) ) were selected as independent variables and the time required for 90% drug dissolution (t(90)) was selected as the dependent variable.

Formulation and evaluation of mucoadhesive glipizide microspheres.

The purpose of this research was to formulate and systematically evaluate in vitro and in vivo performances of mucoadhesive microspheres of glipizide. Glipizide microspheres containing chitosan were prepared by simple emulsification phase separation technique using glutaraldehyde as a cross-linking agent. Results of preliminary trials indicate that volume of cross-linking agent, time for cross-linking, polymer-to-drug ratio, and speed of rotation affected characteristics of microspheres.

Gastroretentive drug delivery system of ranitidine hydrochloride: formulation and in vitro evaluation.

The purpose of this research was to prepare a gastroretentive drug delivery system of ranitidine hydrochloride. Guar gum, xanthan gum, and hydroxypropyl methylcellulose were evaluated for gel-forming properties. Sodium bicarbonate was incorporated as a gas-generating agent.

Formulation design and optimization of mouth dissolve tablets of nimesulide using vacuum drying technique.

The purpose of this research was to develop mouth dissolve tablets of nimesulide. Granules containing nimesulide, camphor, crospovidone, and lactose were prepared by wet granulation technique. Camphor was sublimed from the dried granules by exposure to vacuum.