Controlled release of thyrotropin releasing hormone from microspheres: evaluation of release profiles and pharmacokinetics after subcutaneous administration.

The drug-release kinetics of thyrotropin releasing hormone (TRH) containing copoly(dl-lactic/glycolic acid) (PLGA) microspheres were evaluated both in vitro and in vivo. The drug was encapsulated in PLGA using an in-water drying method through a water in oil in water emulsion. The drug release from the PLGA microspheres in vitro correlated well with that in vivo, and pseudo-zero-order release kinetics were observed. The pharmacokinetics of TRH following administration of this controlled-release parenteral dosage form have been also examined in rats. Following a transient increase in the plasma level due to an initial burst, steady-state plasma levels were observed. The duration of drug release estimated from the plasma level was comparable with the results in the in vitro and in vivo release studies. The steady-state plasma levels correlated well with the levels predicted from the pharmacokinetic parameters following a single subcutaneous or intravenous injection of TRH solution. The results of this study confirm the previously reported in vivo sustained release of TRH achieved with this drug-delivery system.

Reduction in antiviral activity of human interferon-gamma in acidic media with reference to structural change.

The fluorescence intensity of a unique tryptophan 36 in human interferon-gamma was drastically decreased below pH 4 with a concomitant decrease of antiviral activity. The region of residues 32-42 of human interferon-gamma was found by calculation to have a low hydrophobicity together with a high helical hydrophobic moment, and the net electric charge of this region having an amphiphilic helical structure changed significantly near pH 4. These results suggest that the region of residues 32-42 plays an important role in exhibiting antiviral activity.

Partial resection of the discoid meniscus in the child's knee.

Seven children underwent partial meniscectomy for symptomatic discoid lateral meniscus. This procedure, modifying the discoid meniscus to the normal semilunar shape, was indicated only when degeneration or tear was minimal, when the meniscus was not abnormally thickened nor of Wrisberg type, when it was not hypermobile, when the capsular attachment was intact, and when the residual meniscus was free from abnormality. The results were excellent clinically, radiologically and arthroscopically, rehabilitation was shortened to half that required for total meniscectomy and the residual meniscus functioned entirely normally.