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Biomedical subjects

G W Cuff

Publications and source records attributed to G W Cuff.

5 recordsLinked to original sources
PubMed1989

Sustained release of isomazole from matrix tablets administered to dogs.

Isomazole matrix tablet formulations, with various concentrations of hydroxypropyl methylcellulose (HPMC) hydrogel, were prepared and tested for sustained-release activity. Sustained-release activity was determined by administering isomazole test formulations orally to conscious dogs, instrumented with an indwelling left ventricular pressure transducer, and monitoring cardiac inotropic changes for 12 h thereafter. The HPMC hydrogel incorporated into the tablets at a concentration of 20-30% did not significantly change the magnitude of inotropic response or duration of action. Increasing the HPMC concentration to 40 and 42.5% in the formulations decreased the peak LVdP/dt60 response (cardiac inotropic activity) to isomazole, increased the response duration, and maintained the area under the curve (AUC) of LVdP/dt60 versus time. Higher concentrations of HPMC decreased both LVdP/dt60 peak activity and AUC without producing a sustained response. A very narrow range of HPMC concentration in the matrix tablet is thus required to achieve isomazole sustained-release activity.

Administration, Oral↗
PubMed1981

Influences of matrixes on nylon-encapsulated pharmaceuticals.

The preparation and properties of nylon microcapsules containing three different matrixes (formalized gelatin, calcium alginate, and calcium sulfate) are described. Microcapsules containing each matrix were dense and free flowing and could be made of very small diameter by controlling the stirring speed during nylon formation. The preparation of microcapsules containing calcium alginate employed freeze-drying procedures. Lyophilization was not necessary with the formalized gelatin and calcium sulfate systems. Various representative drugs (anionic, cationic, nonionic, quaternary, and amphoteric compounds) were used in the formulation studies. The effects of pH, matrix, and encapsulated species on retention of drug in the microcapsules are described. In addition, the surface morphology of the microcapsules was examined using scanning electron microscopy.

Capsules↗
PubMedDate not supplied

Effect of formulation factors on the matrix pH of nylon microcapsules.

The application of nylon microencapsulation as a drug delivery system inherently demands that the microencapsulated matrix should not cause degradation of the encapsulated drug. The presence of alkaline hexamethylenediamine (HMD) in the microcapsule core will affect the final pH of the microcapsules and may influence the stability of some drugs. To follow the pH within the microcapsule core during manufacture, pH indicators were encapsulated. The final pH was found to depend on the formulation used and could be controlled by the addition of acid. Several other variables affecting the nylon wall formation were examined to determine optimum processing conditions. Increased agitation produced a decrease in microcapsule size. This cause an increase in nylon weight recovered. The increased recovery of nylon was due in part to nylon formation over a larger surface area. Varying the amounts of HMD and sebacyl chloride (SC) used also affected the total weight of nylon formed. In general, more nylon is recovered as the level of each reactant increases. However, the molar ratio of HMD:SC determined the total amount of nylon formed when SC was present in excess.

Alginates↗