Design of a colonic delivery system based on cationic polymethacrylate (Eudragit E100)-mesalamine complexes

Microbiota-sensitive drug delivery systems based on natural polysaccharides for colon targeting

Colon targeting is an ongoing challenge, particularly for the oral administration of biological drugs or local treatment of inflammatory bowel disease (IBD). In both cases, drugs are known to be sensitive to the harsh conditions of the upper gastrointestinal tract (GIT) and, thus, must be protected. Here, we provide an overview of recently developed colonic site-specific drug delivery systems based on microbiota sensitivity of natural polysaccharides. Polysaccharides act as a substrate for enzymes secreted by the microbiota located in the distal part of GIT. The dosage form is adapted to the pathophysiology of the patient and, thus, a combination of bacteria-sensitive and time-controlled release or pH-dependent systems can be used for delivery.

A Systematic Overview of Eudragit® Based Copolymer for Smart Healthcare

Eudragit, synthesized by radical polymerization, is used for enteric coating, precise temporal release, and targeting the entire gastrointestinal system. Evonik Healthcare Germany offers different grades of Eudragit. The ratio of methacrylic acid to its methacrylate-based monomers used in the polymerization reaction defines the final product's characteristics and consequently its potential range of applications. Since 1953, these polymers have been made to use in a wide range of healthcare applications around the world. In this review, we reviewed the "known of knowns and known of unknowns" about Eudragit, from molecule to material design, its characterization, and its applications in healthcare.

Additive Manufacturing of Oral Tablets: Technologies, Materials and Printed Tablets

Additive manufacturing (AM), also known as three-dimensional (3D) printing, enables fabrication of custom-designed and personalized 3D constructs with high complexity in shape and composition. AM has a strong potential to fabricate oral tablets with enhanced customization and complexity as compared to tablets manufactured using conventional approaches. Despite these advantages, AM has not yet become the mainstream manufacturing approach for fabrication of oral solid dosage forms mainly due to limitations of AM technologies and lack of diverse printable drug formulations. In this review, AM of oral tablets are summarized with respect to AM technology. A detailed review of AM methods and materials used for the AM of oral tablets is presented. This article also reviews the challenges in AM of pharmaceutical formulations and potential strategies to overcome these challenges.

Characteristics, Properties and Analytical/Bioanalytical Methods of 5-Aminosalicylic Acid: A Review

Five-aminosalicylic acid (5-ASA) is an anti-inflammatory drug indicated in the treatment of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. Among the analytical methods of quantification of 5-ASA described in the literature, the High Efficiency Liquid Chromatography stands out, a sensitive technique but with a high cost. In recent years, alternative methods have been developed, presenting efficiency and reduced cost, such as UV/visible spectrophotometric, spectrofluorescent, and electrochemical methods, techniques recommended for the application in quality control and quantification of 5-ASA in pharmaceutical forms and biological fluids. This article aims to review the physicochemical characteristics, pharmacokinetics, mechanisms of action, controlled release systems, and the different analytical and bioanalytical methods for the quantification of 5-ASA.

Interpolymer Complexes of Eudragit® Copolymers as Novel Carriers for Colon-Specific Drug Delivery

Interpolymer complexes (IPC) based on Eudragit^® EPO and Eudragit^® S100 were investigated as potential carriers for oral controlled drug delivery to the colon. IPC samples were prepared by mixing copolymer solutions in organic solvents (ethanol, isopropanol:acetone mixture (60:40, % v/v) and tetrahydrofuran). According to the data of elemental analysis, FTIR-spectroscopy, X-ray photoelectron spectroscopy and thermal analysis these IPCs have excess of anionic copolymer (Eudragit^® S100) in their structure; they are stabilized by hydrogen and ionic intermacromolecular bonds and do not include free copolymer domains. IPC have pH-independent swelling properties in the media mimicking gastrointestinal tract (GIT) conditions and provide colon-specific delivery of indomethacin in buffer solutions (pH 1.2; 5.8; 6.8; 7.4) and in biorelevant media (fasted state simulated gastric fluid, fasted state simulated intestinal fluid—version 2 and fasted stated simulated colonic fluid).

A review on 5-aminosalicylic acid colon-targeted oral drug delivery systems

Site-specific colon drug delivery is a practical approach for the treatment of local diseases of the colon with several advantages such as rapid onset of action and reduction of the dosage of the drug as well as minimization of harmful side effects. 5-aminosalicylic acid (5-ASA) is a drug of choice in the treatment of inflammatory bowel disease and colitis. For the efficient delivery of this drug, it is vital to prevent 5-ASA release in the upper part of the gastrointestinal tract and to promote its release in the proximal colon. Different approaches including chemical manipulation of drug molecule for production of prodrugs or modification of drug delivery systems using pH-dependent, time-dependent and/or bacterially biodegradable materials have been tried to optimize 5-ASA delivery to the colon. In the current review, the different strategies utilized in the design and development of an oral colonic delivery dosage form of 5-ASA are presented and discussed.

Interpolymer complexes of carbopol® 971 and poly(2-ethyl-2-oxazoline): Physicochemical studies of complexation and formulations for oral drug delivery

Carbopol® 971 and poly(2-ethyl-2-oxazoline) form hydrogen-bonded interpolymer complexes in aqueous solutions and their complexation is strongly dependent on solution pH. This work investigated the complexation between these polymers in aqueous solutions. The compositions of interpolymer complexes as well as the critical pH values of complexation were determined. The structure of these complexes was studied in solutions using transmission electron microscopy and in solid state using elemental analysis, FTIR spectroscopy and differential scanning calorimetry. Solid compacts were prepared based on interpolymer complexes and physical blends of these polymers and their swelling behaviour was studied in aqueous solutions mimicking the fluids present in the gastrointestinal tract. These materials were used to prepare oral formulations of mesalazine and its release from solid matrices was studied in vitro. It was demonstrated that the complexation between Carbopol® 971 and poly(2-ethyl-2-oxazoline) has a profound effect on the drug release from matrix tablets.

Design, development, and optimization of polymeric based-colonic drug delivery system of naproxen

The aim of present investigation deals with the development of time-dependent and pH sensitive press-coated tablets for colon specific drug delivery of naproxen. The core tablets were prepared by wet granulation method then press coated with hydroxypropyl cellulose (HPC) or Eudragit RSPO : RLPO mixture and further coated with Eudragit S-100 by dip immerse method. The in vitro drug release study was conducted in different dissolution media such as pH 1.2, 6.8, and 7.4 with or without rat caecal content to simulate GIT conditions. Surface morphology and cross-sectional view of the tablets were visualized by scanning electron microscopy (SEM). All prepared batches were in compliance with the pharmacopoeial standards. The tablets which are compression coated with HPC followed by Eudragit S-100 coated showed highest in vitro drug release of 98.10% in presence of rat caecal content. The SEM of tablets suggested that the number of pores got increased in pH 7.4 medium followed by dissolution of coating layer. The tablets coat erosion study suggested that the lag time depends upon the coating concentrations of polymers. A time-dependent hydrophilic polymer and pH sensitive polymer based press-coated tablets of naproxen were promising delivery for colon targeting.