Crosslinked Porous Starch Particles--a Promising Carrier (original) (raw)
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Journal of Polymer Science Part A-polymer Chemistry, 2008
Synthesis and characterization of a new hydrogel were carried out using a chemically modified starch (starch-M) consisting of coupling CC bounds coming from glycidil methacrylate (GMA) onto the polysaccharide structure. 13C NMR, 1H NMR, and FT-IR spectroscopies were used to confirm the incorporation of such groups onto the starch-M. The hydrogel was prepared by a crosslinking polymerization of starch-M using sodium persulfate as an initiating agent. The starch-M hydrogel shows morphology clearly different from that of the raw starch film due to the presence of voids on its surface. The swelling process of the starch-M hydrogel was not significantly affected by changes on the temperature or on pH of the surrounding liquid, indicating the such behavior can be then understood by a diffusional process, resulting from its physical–chemical interactions with the solvent. The values of the diffusional exponent n were on the order of 0.45–0.49 for the range of pHs investigated, demonstrating that the water transport mechanism of starch-M hydrogel is more dependent on Fickian diffusion, that is, controlled by water diffusion. Such starch-M hydrogel is a promising candidate to be used in transporting and in preserving acid-responsive drugs, such as corticoids, for the treatment of colon-specific diseases, for example, Crohn's disease. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2567–2574, 2008
Structural Modifications and Strategies for Native Starch for Applications in Advanced Drug Delivery
BioMed Research International
Pharmaceutical excipients are compounds or substances other than API which are added to a dosage form, these excipients basically act as carriers, binders, bulk forming agents, colorants, and flavouring agents, and few excipients are even used to enhance the activity of active pharmaceutical ingredient (API) and various more properties. However, despite of these properties, there are problems with the synthetic excipients such as the possibility of causing toxicity, inflammation, autoimmune responses, lack of intrinsic bioactivity and biocompatibility, expensive procedures for synthesis, and water solubility. However, starch as an excipient can overcome all these problems in one go. It is inexpensive, there is no toxicity or immune response, and it is biocompatible in nature. It is very less used as an excipient because of its high digestibility and swelling index, high glycemic index, paste clarity, film-forming property, crystalline properties, etc. All these properties of starch ...
Modified Starch and Its Potentials as Excipient in Pharmaceutical Formulations-Mini Review
Despite its vast commercial value, native starch has some inherent weaknesses when it comes to pharmaceutical application, to mention few include; poor compressibility, low flow ability values and often drug/excipient compatibility problems. In this review, some potentials of modified starch with particular emphasis on their improved functionalities and applicability in pharmaceutical formulations were discussed. Basic requirements for pharmaceutical excipients and various modification methods for starch i.e chemical modification, physical and biotechnological methods were highlighted.Pharmaceutical applications of modified starches as tablet super disintegrant, sustained/controlled release polymer, plasma volume expanders and as directly compressible excipient in tablet formulations have been cited. Keywords: Starch; Excipient; Pharmaceutical and Formulation
Porous bioactive calcium carbonate implants processed by starch consolidation
Materials Science and Engineering: C, 2000
. Macroporous calcium carbonate CaCO materials with porous structures suitable for implantation purposes were prepared in the 3 present work. A new ''direct consolidation'' technique that uses starch granules as consolidator agent and as pore formers, combined with other larger organic inclusions, enabled us to tailor the porous microstructure for the intended application. Pore sizes as large as several hundreds of micrometers could be generated without matrix cracking, due to the high solid loading of the starting suspensions.
A series of starch/methacrylic acid (MAAc) copolymer hydrogels of different compositions were synthesized using c-rays induced polymerization and crosslinking. The effects of the preparation conditions such as the feed solution concentration, feed solution composition and irradiation dose on the gelation process of the synthesized copolymer were investigated. The swelling behavior of the starch/methacrylic acid (MAAc) copolymer hydrogels was characterized by studying the effect of the hydrogel composition on the time- and pH-dependent swelling. Swelling kinetics showed that the synthesized hydrogels possessed Fickian diffusion behavior at pH 1 and non-Fickian diffusion at pH 7 which recommend them as good candidate for colon specific drug delivery systems. The synthesized hydrogels were loaded with ketoprofen as a model drug to investigate the release behavior of the synthesized hydrogels. The results showed the ability of the hydrogels to keep the loaded drug at pH 1 and release it at pH 7. The data also showed that the release rate can be controlled by controlling the preparation conditions such as comonomer concentration and composition and irradiation dose.
Resistant starch as a carrier for oral colon-targeting drug matrix system
Journal of Materials Science-materials in Medicine, 2007
In this study, a novel tablet of protein drug matrix for colon targeting was developed using resistant starch as a carrier prepared by pre-gelatinization and cross-linking of starch. The effects of pre-gelatinization and cross-linking on the swelling and enzymatic degradation of maize starch as well as the release rate of drug from the matrix tablets were examined. Cross-linked pre-gelatinized maize starches were prepared by double modification of pre-gelatinization and cross-linked with POCl3, and bovine serum albumin was used as a model drug. For in vitro drug release assays, the resistant starch matrix tablets were incubated in simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid, respectively. The content of resistant starch and swelling property of maize starch were increased by pre-gelatinization and cross-linking, which retarded its enzymatic degradation. Drug release studies have shown that the matrix tablets of cross-linked pre-gelatinized maize starch could delivery the drug to the colon. These results indicate that the resistant starch carrier prepared by pre-gelatinization and cross-linking can be used for a potential drug delivery carrier for colon-targeting drug matrix delivery system.
Journal of Materials Science: Materials in Medicine, 2010
The inability to maintain high concentrations of antibiotic at the site of infection for an extended period of time along with dead space management is still the driving challenge in treatment of osteomyelitis. Porous bioactive ceramics such as hydroxyapatite (HAp) and beta-tri calcium phosphate (b-TCP) were some of the alternatives to be used as local drug delivery system. However, high porosity and high interconnectivity of pores in the scaffolds play a pivotal role in the drug release and bone resorption. Ceftriaxone is a cephalosporin that has lost its clinical popularity. But has recently been reported to exhibit better bactericidal activity in vitro and reduced probability of resistance development, in combination with sulbactam, a b-lactamase inhibitor. In this article, a novel approach of forming HAp and pure b-TCP based porous scaffolds by applying together starch consolidation with foaming method was used. For the purpose, pure HAp and b-TCP were prepared in the laboratory and after thorough characterization (including XRD, FTIR, particle size distribution, etc.) the powders were used for scaffold fabrication. The ability of these scaffolds to release drugs suitably for osteomyelitis was studied in vitro. The results of the study indicated that HAp exhibited better drug release profile than b-TCP when drug was used alone indicating the high influence of the carrier material. However, this restriction got relaxed when a bilayered scaffold was formed using chitosan along with the drug. SEM studies along with EDAX on the drug-chitosan bilayered scaffold showed closest apposition of this combination to the calcium phosphate surface.
Ampholytic and Polyelectrolytic Starch as Matrices for Controlled Drug Delivery
Pharmaceutics
The potential of the polyampholytic and polyelectrolytic starch compounds as excipients for drug controlled release was investigated using various tracers differing in terms of solubility and permeability. Ampholytic trimethylaminecarboxymethylstarch (TMACMS) simultaneously carrying trimethylaminehydroxypropyl (TMA) cationic groups and carboxymethyl (CM) anionic groups was obtained in one-step synthesis in aqueous media. Trimethylaminestarch (TMAS) and carboxymethylstarch (CMS) powders were also synthesized separately and then homogenized at equal proportions in liquid phase for co-processing by spray drying (SD) to obtain polyelectrolytic complexes TMAS-CMS (SD). Similarly, equal amounts of TMAS and CMS powders were dry mixed (DM) to obtain TMAS:CMS (DM). Monolithic tablets were obtained by direct compression of excipient/API mixes with 60% or 80% drug loads. The in vitro dissolution tests showed that ampholytic (TMACMS) and co-processed TMAS-CMS (SD) with selected tracers (one fro...
Polymers
Due to its abundance in nature and low cost, starch is one of the most relevant raw materials for replacing synthetic polymers in a number of applications. It is generally regarded as non-toxic, biocompatible, and biodegradable and, therefore, a safe option for biomedical, food, and packaging applications. In this review, we focused on studies that report the use of starch as a matrix for stabilization, incorporation, or release of bioactive compounds, and explore a wide range of applications of starch-based materials. One of the key application areas for bioactive compounds incorporated in starch matrices is the pharmaceutical industry, especially in orally disintegrating films. The packaging industry has also shown great interest in using starch films, especially those with antioxidant activity. Regarding food technology, starch can be used as a stabilizer in nanoemulsions, thus allowing the incorporation of bioactive compounds in a variety of food types. Starch also presents pote...