Targeting the brain via nasal administration of drugs has been studied frequently over the last few years. In this study, a suitable gel formulation was designed to provide the absorption of a highly lipophilic drug through nasal mucosa. For this purpose, carbamazepine was chosen as the model drug. Hypromellose and Carbopol were used as mucoadhesive polymers in the formulation to increase the residence time of the gel on the mucosa. The objective of this study was to confirm the existence of a transport pathway for a drug (carbamazepine) to the brain directly from the nasal cavity, by comparing the concentration of drug in the brain after intranasal (i.n.), intravenous (i.v.), and oral (p.o.) administration. A statistically significant high level of the drug was found in the brain following intranasal administration compared with the intravenous and oral routes. These findings suggested the existence of a direct transport pathway for carbamazepine from the nasal cavity to the brain. This pathway may represent a new delivery route to the brain and central nervous system of such drugs which are needed in high and rapid concentration in the brain, especially in emergencies.
Magnetic nanoparticles are attractive targets owing to their unique characteristics that are not shared by bulk materials. Magnetic particles, ranging from nanometer-sized to 1 microm in size, are being used in an increasing number of medical applications. The important properties of magnetic particles for medical applications are nontoxicity, biocompatiblilty, injectability and high-level accumulation in the target tissue or organ. Magnetic nanoparticles modified with organic molecules have been widely used for biotechnological and biomedical applications as their properties can be magnetically controlled by applying an external magnetic field. They offer high potential for numerous biomedical applications, such as cell separation, automated DNA extraction, gene targeting, drug delivery, MRI and hyperthermia. When coated with, for example, an antibody, they can be applied in highly sensitive immunoassays or small substance recoveries. Furthermore, a novel application of magnetic nanoparticles and magnetic forces for tissue engineering, termed 'magnetic force-based tissue engineering' has been proposed. Particular attention had been paid to the preparation methods that allow the synthesis of particles of nearly uniform size and shape.
Abstract. Rectal etodolac-Poloxamer gel systems composed of Poloxamer and bioadhesive polymers were developed and evaluated. Hydroxypropylmethyl cellulose, poly)vinyl) pyrrolidone, methyl cellulose, hydroxyethylcellulose, and carbopol were examined as mucoadhesive polymers. The characteristics of the rectal gels differed according to the properties of mucoadhesive polymers. The physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations were investigated. The analysis of release mechanism showed that the release of etodolac was proportional to the square root of time, indicating that etodolac might be released from the suppositories by Fickian diffusion. The anti-inflammatory effect of etodolac-Poloxamer gel system was also studied in rats. Moreover, liquid suppository of etodolac did not cause any morphological damage to the rectal tissues. These results suggested that in situ gelling liquid suppository with etodolac and mucoadhesive polymer was a physically safe, convenient, and effective rectal dosage form for etodolac.
Abstract. In view of the good skin tolerability, glycofurol was used as a vehicle-based gel, and its effect in the topical penetration of Naproxen (NAP) was investigated. The aims of this study were to develop a suitable gel with bioadhesive property, spreadability, and viscosity for topical anti-inflammatory effect. Three gelling and adhesive agents were examined: Carbopol 974P, Gantrez AN 119, and polyvinylpyrollidone K30. Skin permeation rates and lag times of NAP were evaluated using the Franz-type diffusion cell in order to optimize the gel formulation. The permeation rate of NAP-based gel across the excised rat skin was investigated. A significant increase in permeability parameters such as steady-state flux (J ss ), permeability coefficient (K p ), and penetration index (PI) was observed in optimized formulation containing 2% Transcutol as an permeation enhancer. From skin irritation test, it was concluded that the optimized novel glycofurol-based gel formulation was safe to be used for topical drug delivery. The developed glycofurol-based gel appeared promising for dermal and transdermal delivery of naproxen and could be applicable with water-insoluble drugs, which would circumvent most of the problems associated with drug therapy.
Lipospheres of carbamazepine were prepared by melt dispersion technique using Precifac ATO 5 in the various drug-lipid ratios. The resulting free-flowing lipospheres were evaluated with respect to surface morphology, particle size distribution, encapsulation efficiency, and in vitro release behavior. The effect of druglipid ratio, the surfactant added, emulsion stabilizer, and stirring speed also were identified as the key variables affecting the formation of discrete spherical lipospheres and drug release rate. The preparation conditions were optimized by using 0.4% w/v span 20 (Hydrophilic-Lipophilic Balance, HLB = 8.6) as a surfactant and 1% w/v gelatin solution as a stabilizer in presence of a high level of water. We found that the ratio of drug to lipid affects the size of the spheres. The incorporation efficiency was found to be high at all loadings. Increasing the lipid:drug ratio produced more spherical, smooth, and round lipospheres. All the prepared lipospheres exhibited slow release profiles dictating the Higuchi mode of release. We saw that the higher the sphere size and the ratio of Precifac, the slower is in vitro drug release.
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