Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: Screening of formulation variables and in vitro investigation

Oral delivery of pectin-chitosan hydrogels entrapping macrophage-targeted curcumin-loaded liposomes for the treatment of ulcerative colitis

The oral delivery of anti-inflammatory drugs has been a promising strategy for enhancing the clinical efficacy of ulcerative colitis (UC) treatment strategies. However, achieving site specific drug delivery to colon tissues and target cells is a challenging task for formulation scientists. In this study, macrophages-targeted liposome-loaded pectin-chitosan hydrogels were developed for UC treatment via oral administration. Folate-functionalized cholesterol was synthesized as lipid membrane materials for the liposomes containing curcumin (CUR). The incorporation of the liposomal CUR within pectin-chitosan hydrogels resulted in a matrix that exhibited considerable sensitivity to colonic enzymes during in vitro release. The targeted delivery of hybrids was able to effectively reach macrophages. They also showed enhanced capability to downregulate TNF-α, IL-6, and IL-1β in the lipopolysaccharide-induced Raw 264.7 cells model. DSS-induced mice modelshowed improved anti-UC effects, including accelerated mucosal repair and decreased inflammation and modulate the immune balance in the intestinal tissue of mice with colitis, which may be attributable to increased drug accumulation in the colonic lumen and improved internalization to target cells. Therefore, the incorporation of folate-modified liposomes containing CUR and pectin-chitosan physical hydrogels could potentially serve as a favorable approach for treating UC through an oral colon-targeted drug delivery system.

New insights on the effects of blend composition on the biodegradation and permeability of Inulin-Eudragit RS film coatings for colon drug delivery

Inulin has been applied in Inulin-Eudragit RS (Inu-ERS) coatings as the component responsible for degradation by human microbiota. However, studies on how bacterial enzymes can degrade polysaccharides like inulin imbedded in water insoluble polymers like Eudragit RS are still elusive. The present work aims at elucidating the complex process of enzyme triggered biodegradation of inulin with various molecular weights in isolated films with Eudragit RS. The ratio of inulin to Eudragit RS was varied to create films with different degree of hydrophilicity. The phase behavior study revealed that blends of inulin and Eudragit RS are phase separated systems. The film permeability was studied by determination of the permeability coefficient of caffeine and the fraction of inulin that was released from the films in a buffer solution with or without inulinase was quantified. Together with the morphology characterization of the Inu-ERS films with and without incubation in the enzyme solution, these results suggest that the action of the enzyme was only limited to the fraction of inulin released in the buffer solution. Inulin fully embedded in the Eudragit RS matrix was not degraded. The permeation of the model drug caffeine occurred in the phase-separated film as a result of pores formed as a consequence of inulin release. The inulin to Eudragit RS blend ratio and the molecular weight of inulin affected the percolation threshold, the release of inulin, the morphology of the film formed thereafter and the connectivity of the formed water channels, thus influencing the drug permeation properties.

Osmotic Pump Drug Delivery Systems-A Comprehensive Review

In the last couple of years, novel drug delivery systems (NDDS) have attracted much attention in the food and pharmaceutical industries. NDDS is a broad term that encompasses many dosage forms, one of which is osmotic pumps. Osmotic pumps are considered to be the most reliable source of controlled drug delivery, both in humans and in animals. These pumps are osmotically controlled and release active agents through osmotic pressure. To a large extent, drug release from such a system is independent of gastric fluids. Based on such unique properties and advantages, osmotic pumps have made their mark on the pharmaceutical industry. This review summarizes the available osmotic devices for implantation and osmotic tablets for oral administration.

Local delivery of macromolecules to treat diseases associated with the colon

Current treatments for intestinal diseases including inflammatory bowel diseases, irritable bowel syndrome, and colonic bacterial infections are typically small molecule oral dosage forms designed for systemic delivery. The intestinal permeability hurdle to achieve systemic delivery from oral formulations of macromolecules is challenging, but this drawback can be advantageous if an intestinal region is associated with the disease. There are some promising formulation approaches to release peptides, proteins, antibodies, antisense oligonucleotides, RNA, and probiotics in the colon to enable local delivery and efficacy. We briefly review colonic physiology in relation to the main colon-associated diseases (inflammatory bowel disease, irritable bowel syndrome, infection, and colorectal cancer), along with the impact of colon physiology on dosage form design of macromolecules. We then assess formulation strategies designed to achieve colonic delivery of small molecules and concluded that they can also be applied some extent to macromolecules. We describe examples of formulation strategies in preclinical research aimed at colonic delivery of macromolecules to achieve high local concentration in the lumen, epithelial-, or sub-epithelial tissue, depending on the target, but with the benefit of reduced systemic exposure and toxicity. Finally, the industrial challenges in developing macromolecule formulations for colon-associated diseases are presented, along with a framework for selecting appropriate delivery technologies.

Effects of coating layer and release medium on release profile from coated capsules with Eudragit FS 30D: an in vitro and in vivo study

The aim of the present research was to evaluate the impact of coating layers on release profile from enteric coated dosage forms. Capsules were coated with Eudragit FS 30D using dipping method. The drug profile was evaluated in both phosphate buffer and Hank's solutions. Utilization X-ray imaging, gastrointestinal transmission of enteric coated capsules was traced in rats. According to the results, no release of the drug was found at pH 1.2, and the extent of release drug in pH 6.8 medium was decreased by adding the coating layers. The results indicated single-layer coated capsules in phosphate buffer were significantly higher than that in Hank's solution. However, no significant difference was observed from capsules with three coating layers in two different dissolution media. X-ray imaging showed that enteric coated capsules were intact in the stomach and in the small intestine, while disintegrated in the colon.

Development of a chitosan based double layer-coated tablet as a platform for colon-specific drug delivery

A double layer-coated colon-specific drug delivery system (DL-CDDS) was developed, which consisted of chitosan (CTN) based polymeric subcoating of the core tablet containing citric acid for microclimate acidification, followed by an enteric coating. The polymeric composition ratio of Eudragit E100 and ethyl cellulose and amount of subcoating were optimized using a two-level factorial design method. Drug-release characteristics in terms of dissolution efficiency and controlled-release duration were evaluated in various dissolution media, such as simulated colonic fluid in the presence or absence of CTNase. Microflora activation and a stepwise mechanism for drug release were postulated. Consequently, the optimized DL-CDDS showed drug release in a controlled manner by inhibiting drug release in the stomach and intestine, but releasing the drug gradually in the colon (approximately 40% at 10 hours and 92% at 24 hours in CTNase-supplemented simulated colonic fluid), indicating its feasibility as a novel platform for CDD.

Development and Evaluation of a Once-Daily Controlled Porosity Osmotic Pump of Tapentadol Hydrochloride

The present study aimed to prepare, optimize, and evaluate Tapentadol hydrochloride controlled porosity osmotic pump (CPOP) and to achieve the drug release at nearly zero-order. The CPOP was prepared by the coating of polymers (Eudragit RSPO and RLPO) on a directly compressed core tablet. A Box-behnken experimental design was applied to optimize the parameters for CPOP. The optimized batch was characterized for in vitro drug release study, effect of pH, osmolarity and agitation intensity, and surface morphology and stability study. In vivo pharmacokinetic studies were performed on New Zealand white rabbits for CPOP and marketed tablet. All the batches showed a drug release ranging from 29.87 to 56.92% after 12 h; and from 59.64 to 99.96% after 24 h. There was no change in the drug release pattern at different pH and agitation intensities. The drug release was found to decrease with increasing osmolarity of dissolution media.An in vivo study showed a higher mean residence time, area under the curve, and biological half-life (T 1/2) than the marketed tablet with low rate of elimination (Ke) and a 2.35-fold increase in relative bioavailability. The result showed that the amounts of sodium chloride and PEG 400 were contributing positively while the number of coats was negatively affecting the drug release. The drug release was found to be independent of physiological conditions. The stability testing showed that the prepared CPOP was stable for 3 months at accelerated conditions. The prepared CPOP was found to deliver Tapentadol hydrochloride at zero-order for up to 24 h.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning electron microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were jointly reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24 h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

Preparation, physicochemical and pharmaceutical characterization of chitosan from Catharsius molossus residue

Polypeptide from Catharsius molossus L. is an active ingredient in the treatment of benign prostatic hyperplasia. The residue after extraction is harmful to the environment and is also a waste of resources. Chitosan was extracted from C. molossus L. residue with chemical methods and with an improved intermittent heating method. Physicochemical and pharmaceutical characteristics of chitosan from C. molossus L. and shrimp were mainly measured by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM). The results showed chitosan from C. molossus L. was superior to commercial medical-grade chitosan from shrimp in the aspects of degree of deacetylation, crystallinity, heavy metal content, viscosity, protein residue, ash content, and in vitro adhesion. In addition, properties of chitosan membrane were studied, including water vapor permeability, light transmittance, enzymatic hydrolysis, swelling behavior, mechanical properties, and SEM images. It was found that the membrane of chitosan from C. molossus L. had better performance. This preliminary result shows chitosan from C. molossus L. is more suitable than shrimp's as a pharmaceutical excipient in colonic adhesive drug delivery system.

In vitro, ex vivo and in silico mechanistic elucidation of the performance of an optimized porosity-controlled multi-elemental transbuccal system

PURPOSE

To elucidate the mechanisms of construction and performance of a porosity controlled, multi-elemental transbuccal system employing experimental and computational approaches.

METHODS

The production of the formulation was guided through a Box-Benkhen design employing homogenization coupled with lyophilization. The physicochemical and physicomechanical properties of the experimental design formulations were quantified with relevant analytical techniques. The influence of changes in porosity measures on the magnitude of these physical properties were explored mathematically. Furthermore, experimental outputs from the Box-Behnken design formulations were fitted into set limits and optimized using the response surface method. The optimized porosity-controlled formulation was subjected to mechanistic experimental and computational elucidations.

RESULTS

In general, the changes in magnitudes of studied porosity quantities had significant impact on formulation physicochemical and physicomechanical properties. The generation of an optimized formulation validated the stability and accuracy of the Box-Behnken experimental design. Experimental investigations revealed that the construction of this formulation is as a result of non-destructive physical interactions amongst its make-up compounds while its mechanism of performance is anchored mainly upon a gradual collapse of its ordered porous structure. Furthermore, the molecule mechanics simulations quantitatively predicted the molecular interactions inherent to multicomponent matrix formation and the mucoadhesion mechanism.

CONCLUSIONS

The fabrication and performance mechanisms of the porosity-controlled transbuccal system was successfully explored.

Hydroxyapatite nanowhiskers embedded in chondroitin sulfate microspheres as colon targeted drug delivery systems

An inorganic/organic hybrid material with a triggering mechanism for specific drug delivery at the colon is synthesized.

Formulation and evaluation of controlled porosity osmotic pump for oral delivery of ketorolac

Background:

The osmotic drug delivery systems suitable for oral administration typically consist of a compressed tablet core that is coated with a semipermeable membrane that has an orifice drilled on it by means of a laser beam or mechanical drill. Ketorolac is a nonsteroidal agent with powerful analgesic. Oral bioavailability of ketorolac was reported to be 90% with very low hepatic first-pass elimination; the biological half-life of 4-6 hours requires frequent administration to maintain the therapeutic effect.

Aim:

The aim of the current study was to design a controlled porosity osmotic pump (CPOP)based drug delivery system for controlled release of an NSAID agent, ketorolac tromethamine, which is expected to improve patient compliance due to reduced frequency; it also eliminates the need for complicated and expensive laser drilling and maintain continuous therapeutic concentration.

Design:

The CPOP was designed containing pore-forming water-soluble additives in the coating membrane, which after coming in contact with water, dissolve, resulting in an in situ formation of a micro porous structure.

Materials and Methods:

The effect of different formulation variables, namely level of pore former (PVP), plasticizer (dibutyl phthalate) in the membrane, and membrane weight gain were studied.

Results and Conclusion:

Drug release was inversely proportional to the membrane weight but directly related to the initial concentration of pore former (PVP) in the membrane. Drug release was independent of pH and agitational intensity, but dependent on the osmotic pressure of the release media. Based on the in vitro dissolution profile, formulation F3C1 (containing 0.5 g PVP and 1 g dibutyl phthalate in coating membrane) exhibited Peppas kinetic with Fickian diffusion-controlled release mechanism with a drug release of 93.67% in 12 hours and hence it was selected as optimized formulation. SEM studies showed the formation of pores in the membrane. The formulations were stable after 3 months of accelerated stability studies. CPOP was designed for effective administration of drugs for prolonged period of time.

Chitosan as a pore former in coated beads for colon specific drug delivery of 5-ASA

A multiparticulate product for colon-specific delivery of a small molecule drug has been developed and characterized. Microcrystalline cellulose core beads containing 5-aminosalicylic acid produced by extrusion-spheronization were coated with chitosan and Aquacoat(®) ECD mixtures according to a factorial design. Coated beads were characterized in terms of drug release, shape, and friability. The optimum formulation was enteric coated and exposed to media simulating conditions in the stomach, small intestine, and colon. Release studies in simulated intestinal fluid revealed that the drug release rate from the coated beads, which were spherical and rugged, depended on the level of chitosan in the coat and the coat thickness. Enlarged pores observed on the surface of the coated beads exposed to the medium containing rat cecal and colonic enzymes are believed to have caused a significant enhancement of the drug release rate compared to the control exposed only to simulated gastric and intestinal fluids. The release mechanisms involved polymer relaxation and dissolved drug diffusion for simulated intestinal fluid and simulated colonic fluid, respectively. From the facilitated drug release in a colonic environment and the inhibition of drug release under gastric and intestinal conditions, it can be concluded that this multiparticulate system demonstrates the potential for colon-specific drug delivery.

Design, Development, and Optimization of Sterculia Gum-Based Tablet Coated with Chitosan/Eudragit RLPO Mixed Blend Polymers for Possible Colonic Drug Delivery

The purpose of this study is to explore the possible applicability of Sterculia urens gum as a novel carrier for colonic delivery system of a sparingly soluble drug, azathioprine. The study involves designing a microflora triggered colon-targeted drug delivery system (MCDDS) which consists of a central polysaccharide core and is coated to different film thicknesses with blends of chitosan/Eudragit RLPO, and is overcoated with Eudragit L00 to provide acid and intestinal resistance. The microflora degradation property of gum was investigated in rat caecal medium. Drug release study in simulated colonic fluid revealed that swelling force of the gum could concurrently drive the drug out of the polysaccharide core due to the rupture of the chitosan/Eudargit coating in microflora-activated environment. Chitosan in the mixed film coat was found to be degraded by enzymatic action of the microflora in the colon. Release kinetic data revealed that the optimized MCDDS was fitted well into first-order model, and apparent lag time was found to be 6 hours, followed by Higuchi release kinetics. In vivo study in rabbits shows delayed T max, prolonged absorption time, decreased C max, and absorption rate constant (Ka), indicating a reduced systemic toxicity of the drug as compared to other dosage forms.

An oral colon-targeting controlled release system based on resistant starch acetate: synthetization, characterization, and preparation of film-coating pellets

An oral colon-targeting controlled release system based on resistant starch acetate (RSA) as a film-coating material was developed. The RSA was successfully synthesized, and its digestion resistibility could be improved by increasing the degree of substitution (DS), which was favorable for the colon-targeting purpose. As a delivery carrier material, the characteristics of RSA were investigated by polarized light microscopy, FTIR spectroscopy, and X-ray diffraction. The results revealed a decrease of the crystallinity of RSA and a change of its crystalline structure from B + V hydrid type to V type. To evaluate the colon-targeting release performance, the RSA film-coated pellets loaded with different bioactive components were prepared by extrusion-spheronization and then by fluid bed coating. The effects of the DS, plasticizer content, and coating thickness of the RSA film and those of the content and molecular weight of the loaded bioactive component on the colon-targeting release performance of the resulting delivery system were investigated. By adjusting the DS, the coating thickness, and the plasticizer content of the RSA film, either the pellets loaded with a small molecular bioactive component such as 5-aminosalicylic acid or those with a macromolecular bioactive peptide or protein such as bovine serum albumin, hepatocyte growth-promoting factor, or insulin showed a desirable colon-targeting release performance. The release percentage was less than 12% in simulated upper gastrointestinal tract and went up to 70% over a period of 40 h in simulated colonic fluid. This suggests that the delivery system based on RSA film has an excellent colon-targeting release performance and the universality for a wide range of bioactive components.

Fabrication of chitosan--polyacrylic acid complexes as polymeric osmogents for swellable micro/nanoporous osmotic pumps

AIM

The aims of this study were to prepare and evaluate chitosan-polyacrylic acid complex (CS-PAA) as polymeric osmogents for swellable micro/nanoporous osmotic pump propranolol tablets.

METHODS

The complexes were characterized and evaluated for their swelling characteristics. The selected complexes were incorporated into the core propranolol tablets as polymeric osmogents. The core tablets were formulated, compressed as monolithic and two-layered tablets, and finally coated with cellulose acetate containing PEG 400 and PVP K30 as plasticizers and pore formers, respectively. As a final point, the drug release was determined.

RESULTS

A direct correlation was found between the CS content in the complex and the maximum swelling force and swelling ratio of the complex mixture. In vitro drug release revealed that the percent drug release increased with the amount of osmogent in the two-layered tablets. Drug release could be prolonged up to 12h and conformed to the USP 31 criteria. In contrast, percent release decreased with the increasing amount of complexes in monolithic tablets. It was postulated that two opposing mechanisms were involved. Following water uptake, the complexes of polymers swelled and pushed the drug out of the tablets, and the drug bound to the polymer network and remained in the tablets.

CONCLUSIONS

The results indicated that the complex of CS-PAA at optimal proportion and amount was a promising polymeric osmogent for a zero-order controlled release from two-layered swellable micro/nanoporous osmotic pump tablets.

Oral osmotically driven systems: 30 years of development and clinical use

The number of marketed oral osmotically driven systems (OODS) has doubled in the last 10 years. The main clinical benefits of OODS are their ability to improve treatment tolerability and patient compliance. These advantages are mainly driven by the capacity to deliver drugs in a sustained manner, independent of the drug chemical properties, of the patient's physiological factors or concomitant food intake. However, access to these technologies has been restricted by the crowded patent landscape and manufacturing challenges. In this review article, we intend to give an overview of the OODS development in the last 30 years, detailing the technologies, specific products and their clinical use. General guidance on technology selection is described in light of the recent advances in the field. The clinical performance of these technologies is also discussed, with a focus on food effects and the in vivo-in vitro correlation. Special attention is paid to safety given the controversial case study of Osmosin. Overall, oral osmotically driven systems appear to be a promising technology for product life-cycle strategies.

Colon-targeted delivery of live bacterial cell biotherapeutics including microencapsulated live bacterial cells

There has been an ample interest in delivery of therapeutic molecules using live cells. Oral delivery has been stipulated as best way to deliver live cells to humans for therapy. Colon, in particular, is a part of gastrointestinal (GI) tract that has been proposed to be an oral targeted site. The main objective of these oral therapy procedures is to deliver live cells not only to treat diseases like colorectal cancer, inflammatory bowel disease, and other GI tract diseases like intestinal obstruction and gastritis, but also to deliver therapeutic molecules for overall therapy in various diseases such as renal failure, coronary heart disease, hypertension, and others. This review provides a comprehensive summary of recent advancement in colon targeted live bacterial cell biotherapeutics. Current status of bacterial cell therapy, principles of artificial cells and its potentials in oral delivery of live bacterial cell biotherapeutics for clinical applications as well as biotherapeutic future perspectives are also discussed in our review.