Anthony Palmieri

Suppository Dissolution Testing: Apparatus Design and Release of Aspirin

AbstractPresent methods of in vitro dissolution testing for suppositories were found to be lacking in universal acceptance, reproducibility, and difficult to perform. Initially a USP basket for tablet dissolution with one-hundred milliliters of phosphate buffer of pH 8 to approximate rectal pH was used. A slow constant stirring speed was maintained by means of a Hanson dissolution drive control and hollow spindle-stirrer apparatus as well as a constant temperature of 37.5±0.1° Aspirin in polyethylene glycol bases gave plausible, reproducible results with this apparatus. However, oil bases (i.e. cocoa butter) gave unacceptable, irreproducible results since the base blocked the openings of the basket mesh. This report describes a modified basket method where the basket is polyurethane of the same size and configuration as the USP basket. The basket described has twelve linear vertical slots of 0.25 mm width allowing for a porosity of 52%. Results of aspirin release from four PEG bases prepared in this labor...

Production of a Coacervate Film for Microcapsule Diffusion Studies

AbstractUntil the last five years, study of microcapsules formed by complex coacervation has been approached almost entirely on an empirical basis. The gelatin-acacia coating formed through complex coacervation is responsible for the sustained release characteristics of the dosage form. Because dissolution of the drug from microcapsules is often limited by the structure and nature of the shell wall, of prime interest would be the construction of an acacia-gelatin film for diffusion studies. Apparent optimal conditions for production of the coacervate film were developed. The conditions were similar to those used to produce microcapsules by various researchers. These conditions produced a coacervate film which could be cut into two square centimeter sections apparently suitable for diffusion studies. Films produced by complex coacervation appeared free from structural defects when observed with a stereo-microscope.

Dissolution of Suppositories IV: Effect of Crospovidone on Aspirin Release from Peg Bases

AbstractPrevious reports from this laboratory have described a suppository dissolution test apparatus as wall as the use of crospovidone to increase rate of release of acetaminophen from PEG suppositories. Also in previous reports from this lab, aspirin has been shown to give slow release from PEG bases and it was posited that addition of crospovidone to aspirin suppositories would also increase the rate of release. To test this hypothesis, four PEG blends were used as bases as in the previous studies. Each contained 350 mg of aspirin and 0.5%, 1%, or 5% of crospovidone (Polyplasdone XL, GAF). One thousand milliliters of phosphate buffer of pH 8.0 to approximately rectal pH was used as the dissolution media and maintained at 37.5°. A constant agitation rates of 25, and 50 rpm were used. Aspirin was assayed spectrophotometrically at 265 nm after appropriate dilution. Comparative dissolution profiles of the various agitation rates and with the concentrations of crospovidone were developed. Addition of crosp...

Dissolution of Suppositories III: Effect of Insoluble Polyvinylpyrrolidone on Acetaminophen Release

AbstractPreviously reported studies from this laboratory have demonstrated the usefulness of a new apparatus for suppository dissolution study. Acetaminophen suppositories gave slow release and it was posited that addition of a disintegrating agent commonly used in tablet manufacture would increase this release rate. To test the hypothesis, four PEG blends were used as bases as in the previous studies. Each contained 320 mg acetaminophen and 1%, 5%, or 10% of insoluble polyvinylpyrrolidone (Polyplasdone XLR). One thousand milliliters of phosphate buffer, pH 8.0 to approximate rectal pH was employed as the dissolution media and maintained at 37.5°. A constant agitation rate of 2 5 and 50 rpm was used. Acetaminophen was assayed spectrophotometrically at 243 nm. Comparative dissolution profiles at the various agitation rates and with the concentrations of polyvinylpyrrolidone were developed. Addition of insoluble polyvinylpyrrolidone increased the dissolution rate constant and dissolution half-times at the t...