Unitary-core osmotic pump tablet for controlled release of water-insoluble drug / 药学学报

<p><b>AIM</b>To study unitary-core osmotic pump tablet for delivering water-insoluble drug for 24 hours.</p><p><b>METHODS</b>Unitary-core osmotic pump tablet was prepared using nifedipine as the model drug. The effects of various core formulation variables on drug release were studied.</p><p><b>RESULTS</b>Polyethylene oxide and potassium chloride have comparable positive effects on drug release, whereas, nifedipine has markedly negative effect on drug release.</p><p><b>CONCLUSION</b>Unitary-core osmotic pump tablet is very easy in preparation and it can deliver water-insoluble drug in substantially constant rate for 24 hours.</p>

Sandwiched osmotic pump tablet for controlled release of water-insoluble drug / 药学学报

<p><b>AIM</b>To study sandwiched osmotic pump tablet for delivering water-insoluble drug for 24 hours.</p><p><b>METHODS</b>Sandwiched osmotic pump tablet was prepared using nifedipine as the model drug. The effects of various formulation variables and orifice size on drug release were studied. The mechanical properties of cellulose acetate membrane were also investigated.</p><p><b>RESULTS</b>Polyethylene oxide of drug layer and potassium chloride of push layer showed marked positive effects on drug release. In the range of 0.50 mm to 1.40 mm, orifice size hardly affects drug release. Cellulose acetate membrane is strong enough to assure the integrity of osmotic pump tablet and could sustain an internal pressure ranging from 0.34 MPa to 2.85 MPa.</p><p><b>CONCLUSION</b>Sandwiched osmotic pump tablet can deliver water-insoluble drug constantly for 24 hours. Release media and agitation rate scarcely affect drug release. Compared with the commercialized push-pull osmotic pump tablet, sandwiched osmotic pump tablet is easy in preparation with exempting identification of drug layer before drilling.</p>

Effect of Dexamethasone and 1,25(OH)2D3 on Proliferation and Osteogenic Differentiation of Cultured Human Bone Marrow Stromal Cells / 대한내분비학회지

BACKGROUND: It is crucial, in the case of regenerating bone by tissue-engineering technique, that osteoblast progenitors are proliferated and induced to differentiate to osteoblasts sequentially at the proper time. Osteoblasts can be obtained from bone itself or from osteoblast progenitors in bone marrow, even though the amount of human marrow stromal cells in marrow aspirate is usually scanty. These cells, however, have been known demonstrate the potential to easily proliferate and differentiate in osteoblasts, chondroblasts or adipocytes according to different microenvironmental factors. We evaluated the effect of dexamethasone and 1,25(OH)2D3 on the proliferation, differentiation, and mineralization of human marrow stromal cells in vitro. METHODS: We used twelve bone marrow aspirates obtained from different healthy bone marrow donors. Culture plates were randomly divided into the following four experimental groups; group 1 was cultured with control medium only, group 2 with control medium containing 1,25(OH)2D3, group 3 with control medium containing dexamethasone, and group 4 with control medium containing both 1,25(OH)2D3 and dexamethasone. 3H-thymidine uptake, protein content of cell lysates, alkaline phosphatase activities and alkaline phosphatase histochemistries were measured. Alizarin Red-S staining and quantification of dissolved dye were also performed. RESULTS: Combined stimulation of marrow stromal cells with both 1,25(OH)2D3 and dexamethasone was found to be effective to maintain stable long-term culture of the cells and to increased differentiation and mineralization of the cells. Synthesis and mineralization of matrix were highest when the cells were stimulated with 1,25(OH)2D3 alone during the early culture phase. However, 1,25(OH)2D3 shortened the lifespan of the cells. Interestingly, mineralization was higher in female donor cells than in male donor cells when stimulated with dexamethasone alone or with both dexamethasone and 1,25(OH)2D3. Neither 1,25(OH)2D3 nor dexamethasone affected cell proliferation. CONCLUSION: Our results suggest that the synergistic effect of dexamethasone and 1,25(OH)2D3 is important in maintaining long-term culture and differentiation of human marrow stromal cells. It is preferable to administer 1,25(OH)2D3 after the attachment of cultured osteoblasts to biomaterials has been established, since it could shorten cell survival despite the great increase of mineralization at the early culture phase.

Development of Gentamicin Loaded PLGA Microspheres for the Treatment of Musculoskeletal Infection: In Vivo Evaluation / 대한정형외과연구학회지

PURPOSE: We evaluate in vitro and in vivo efficacy of newly developed gentamicin loaded PLGA microspheres for the treatment of musculoskeletal infection. MATERIALS AND METHODS: Controlled gentamicin sulfate releasing microspheres manufactured from biodegradable PLGA were prepared with an Oil/Oil solvent evaporation method for the treatment of musculoskeletal infection. The in vitro release amount of GS was analyzed by high performance liquid chromatography (HPLC) and the released GS activity was determined by microbiological assay using staphylococcus (S) aureus, respectively. The results of inhibition zone test agree well with the HPLC results obtained from the in vitro release test. RESULTS: The microspheres of different size were obtained with varying the experimental conditions, and the shape of microspheres was smooth and spherical. The PLGA microspheres release gentamicin for 67 days in in vitro test. There was significant inhibition around microphere PLGA from 1 day to 7th week in inhibition zone test The inhibition was reduced after 8th week. and there was no inhibition at 9th week PLGA microspheres. CONCLUSION: It can be suggested that GS/PLGA MSs implantable system that provided a prolonged delivery of GS was found to be effective against S. aureus infection for desired period.