This salting-out taste-masking system is used for taste-masking of solifenacin succinate in a launched oral disintegrating tablet. The concept, in vitro drug release data, taste-masking sensory tests, and verification in the clinical studies indicate that this system is versatile and applicable to other drugs that require rapid release for absorption and therapeutic effect after taste-masking. Coating of water-insoluble polymers on drug’s particles without resin has no driving force for promoting drug release and cannot release drugs completely in the gastrointestinal fluids. The drug-resin complexed DDSs have the significant advantage of complete drug release caused by the ionic equilibrium.
28. A method as claimed in Claim 26 or Claim 27, wherein said third polymeric material is said polycarboxylic acid polymer that is at least partially neutralised, said method comprising dispersing a polycarboxylic acid polymer in a solvent, optionally with a buffer agent, and adding base to at least partially neutralise the polycarboxylic acid polymer to form the inner coating preparation. coating the core using an inner coating preparation comprising a third polymeric material that is soluble in intestinal fluid or gastrointestinal fluid, in a solvent system to form an inner coated core and; coating the inner coated core with an outer coating preparation comprising a first polymeric material which is susceptible to attack by colonic bacteria and a second polymeric material which has a pH threshold of about pH 5 or above in a solvent system, to form an outer coated core, wherein the third polymeric material is selected from the group consisting of a polycarboxylic acid that is at least partially neutralised, and a non-ionic polymer, provided that, where the third polymeric material is a non-ionic polymer, said inner coating preparation comprises at least one additive selected from a buffer agent and a base.
For example, PEG-b-poly(ethyl glyoxylate)-b-PEG , polyacetal-b-Pluronic , and PEG-b-poly (2,4,6-trimethoxybenxylidenepentaerythritol carbonate) , have been used for forming drug-loaded polymeric micelles showing faster drug lease at acidic pH than at neutral pH. Protein-based vaccines have been synthesized by copolymerizing benzylidene acetal cross-linking monomers and acrylamide in the presence of the protein payloads [69,70]. Using ovalbumin as the model protein, ovalbumin-loaded polymeric particles with diameters of 35 nm to 3.5 Î¼m were generated. Moreover, the particles demonstrated faster hydrolysis at acidic pH than at neutral pH . Results from animal studies showed that, compared with free ovalbumin, ovalbumin-loaded polymeric particles stimulated T-cell proliferation and protected animal from tumor development more efficiently, indicating that the polymeric particles dissociated in the endosomes after cellular uptake due to acetal hydrolysis and released the protein intracellularly.
There were no reports on IPN hydrogels as pH-sensitive delivery system for glipizide. The objective of this study is to prepare IPN hydrogels of glipizide employing gelatin and methacrylic acid as monomers and glutaraldehyde and methylene bisacrylamide as crosslinking agents. Glipizide, an effective antidiabetic, which requires controlled release owing to its short biological half-life of 3.4Â±0.7 h, was used as the drug in this study . Moreover, 5-Flouruoracil (5-FU) is an anti-tumor and anti-metabolite drug that has been used for few decades [27, 28].
Product Innovation on Modified Release Coatings (Enteric Coatings and Sustained Release)
Osmotic pressure provides constant drug release and acts as the driving force. When osmotic system is exposed to body fluid, it enters the core due to the osmotic pressure difference across the coating membrane. For this the drug must be osmotically active and is mixed with osmotically active excipients e.g., NaCl, KCl.
The hybrid of carboxymethyl chitosan and poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO-PPO-PEO) cross-linked with glutaraldehyde for ophthalmic drug delivery of nepafenac is an example of a hybrid of natural and synthetic hydrogels. The controlled delivery of this model drug was observed and delivery was found to be maximum at 35 Â°C and pH 7.4.
pH- and ion-sensitive polymers for drug delivery
Hence, it can be used as a pH sensitive hydrogel for loading and controlled release of drugs in the intestinal region (pH 7.4). Bueno et al. studied the controlled release of BSA from xanthan hydrogels in the presence as well as the absence of citric acid. It was observed that BSA release is maximum at neutral and basic media due to the ionization of the carboxylic acid group and the negative charge on the hydrogel which causes swelling .
- The chemical structure of glycosaminoglycan is shown in Figure 5c.
- These micrographs show the high micro porosity, with a three dimensional interconnected microstructure by virtue of crosslinked network formation, resembling other reported macromolecular hydrogel structures.
- However, CS with a degree of deacetylation more than 50% starts dissolving in acidic medium.
- The exponential heuristic equation was used to analyze the swelling mechanism of the prepared hydrogels in different pH buffer solutions.
Their major disadvantage (i.e., their relatively low mechanical strength) can be overcome by formation of IPNs [1-3]. A pH-sensitive acrylic IPN hydrogel using N-isopropylacrylamide and Naminopropylmethacrylamide, crosslinked with methylene bisacrylamide was prepared by Lorenzo, C.A.
(H. Pylori ) which inhabits the mucous layer adhering to gastric epithelial cells, is responsible for the above mentioned gastric diseases which are treated with amoxicillin, metronidazole, and clarithromycin. Therapies using a single antibiotic may not appear successful due to inadequate permeation of the drug across the gastric mucous layer and its lower stability in acidic medium. To increase the drug resident time in the stomach and its sustained release, chitosan, its derivatives and its blends are used as successful carriers . Kumar et al. prepared pH sensitive hydrogels for stomach targeted drug delivery of clarithromycin. Acrylic acid was used to graft chitosan by free radical polymerization using ammonium persulfate as initiator, blended with poly(vinyl pyrrolidone) and cross-linked using glutaraldehyde and N ,N â€²-methylenebisacrylamide as cross-linker.
Prabaharan, M. Prospective of guar gum and its derivatives as controlled drug delivery systems. Int. J. Biol. Macromol. Samanta, H.S.; Ray, S.K. Controlled release of tinidazole and theophylline from chitosan based composite hydrogels.
3.1. Dissolution Controlled Release
These smart materials underwent phase changes at pH 5.15-5.6. This property enabled the amphiphilicity of the copolymers to be switched on or off. By doing so in in vitro drug release studies with ibuprofen as the model hydrophobic drug, the copolymers were able to inhibit drug release in simulated stomach conditions to up to 13% while enhancing drug release in simulated intestinal conditions to up to 75% within 6 hours. These indicate that copolymers based on MAA and PEGMEMA have potential as smart materials for drug delivery applications.
J. Biol. Macromol. Lim, L.S.; Ahmad, I.; Lazim, M.A.S.M. pH sensitive hydrogel based on poly (acrylic acid) and cellulose nanocrystals.
Plasma concentration-time profile of this system has been reported to be similar to those of marketed products in beagle dogs . The two polymers described above are the only FDA-approved cationic polymers; however, combination of the polymers and other components might result in more specific response to gastric pH and better controlled drug release in the oral cavity and stomach. The synthesis of N-succinyl chitosan and hydrogels was analyzed through characterization using FTIR, NMR, powder XRD, TGA, and FESEM. Furthermore, SP2 hydrogel was characterized using FTIR, XRD and TGA.
Hence, swelling data has significant fitting in second order rate equation . In vitro release of 5-FU was observed at 37Â°C in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4). At specific time intervals, 3 ml of sample solution containing released drug was taken. The absorbance of released drug was determined by UV-vis spectrometer at 266 nm.