methylcellulose and propylparaben

We designed ophthalmic formulations containing dexamethasone-loaded solid nanoparticles (DEX

Topics: Animals; Cell Line, Transformed; Cornea; Dexamethasone; Drug Compounding; Drug Delivery Systems; Escherichia coli; Humans; Methylcellulose; Microbial Sensitivity Tests; Nanoparticles; Ophthalmic Solutions; Parabens; Permeability; Rabbits; Rats

The aim of the study was to provide a controlled release system, which could be used for the oral administration of highly water-insoluble drugs. Pellets have been prepared by extrusion/spheronization containing two model drugs (methyl and propyl parabens) of low water solubility. One type of pellets contained the drugs mixed with lactose and microcrystalline cellulose (MCC) and the other types of pellets contained the model drugs dissolved in a self-emulsifying system (4.8%) consisting of equal parts of mono-diglycerides and polysorbate 80 and MCC. Pellets of all types in the same size fraction (1.4-2.0 mm) were coated to different levels of weight gain, with ethylcellulose, talc and glycerol. A sample of pellets containing methyl parabens in the self-emulsifying system was pre-coated with a film of hydroxypropylmethyl cellulose from an aqueous solution and then coated as above. Dissolution experiments established that the presence of the self-emulsifying system enhanced the drug release of both model drugs and that the film coating considerably reduced the drug release from pellets made with just water, lactose and MCC. The coating reduced the drug release from the pellets containing the self-emulsifying system to a lesser extent but in relation to the quantity of coat applied to the pellets. The application of a sub-coating of hydroxypropylmethyl cellulose was able to reduce the release rate of methyl parabens self-emulsifying system ethyl cellulose coated pellets. Thus, the formulation approach offers the possibility of formulating and controlling the in vitro release of water-insoluble drugs from solid oral dosage forms.

Topics: Capsules; Cellulose; Chemistry, Pharmaceutical; Delayed-Action Preparations; Diglycerides; Emulsions; Excipients; Hypromellose Derivatives; Lactose; Methylcellulose; Monoglycerides; Parabens; Particle Size; Pharmaceutical Preparations; Polysorbates; Solubility; Technology, Pharmaceutical; Time Factors; Water

The stability of captopril in several extemporaneously prepared oral liquid formulations was studied. Captopril 1-mg/mL oral liquid formulations were prepared from either powder or tablets in two grades of water, syrup, methylcellulose, and edetate disodium. The liquids were stored at 5 degrees C in amber glass containers, and samples were removed at intervals up to 30 days for assay of captopril concentration by stability-indicating high-performance liquid chromatography. The pH of the formulations remained fairly stable for 30 days. In general, captopril was more stable in formulations containing captopril from tablets than from powder. Captopril in formulations in which the only vehicle was highly purified water was slightly but not significantly more stable than in formulations made with sterile water for irrigation. Formulations made with undiluted syrup were more stable than formulations in which water was used to dilute syrup or formulations containing methylcellulose. The formulations containing edetate disodium were much more stable than those that lacked this component. The stability of captopril 1 mg/mL in oral liquid formulations was influenced by the captopril source (tablets versus powder) and by the presence of syrup, methylcellulose, and edetate disodium. Captopril in a preparation made with tablets and undiluted syrup was stable for 30 days at 5 degrees C, and the formulation should be palatable.

Topics: Captopril; Drug Stability; Hydrogen-Ion Concentration; Methylcellulose; Parabens; Preservatives, Pharmaceutical; Temperature