Investigation of in-vitro release characteristics of NSAID-loaded polylactic acid microspheres.

The intra-pulmonary delivery of non-steroidal anti-inflammatory drug-loaded PLA microspheres has potential utility in the treatment of inflammatory lung conditions such as asthma. Drug encapsulation efficiency and release kinetics depend upon a variety of parameters in the production process, all of which affect the properties of the microspheres produced. The release of piroxicam from PLA microspheres followed an apparently biphasic release profile. PLA microspheres containing indomethacin, however, exhibited kinetics which approached more closely to zero order release. The effect of microsphere production parameters upon these release profiles has been investigated. Results indicate that factors affecting the nature of the microsphere matrix have the greatest influence on release profiles. The use of halothane as organic solvent in the microsphere production increases the burst release effect. Residual halothane is known to be present in the microspheres, producing a less stable matrix, thus allowing much faster release of the drug. The nature of drug incorporated also appears to affect the nature of the microspheres matrix. Piroxicam-loaded microspheres possess a much more porous matrix than indomethacin-loaded microspheres, as evidenced by washing procedures. This difference could explain the difference in release profiles between the two types of microspheres.

[Septic leg fractures. Value of cancellous bone grafting without skin closure, aligned on the fibula]. / Fractures infectées de jambe. Intérêt de la greffe spongieuse à ciel ouvert appuyée sur le péroné.

The authors have treated 63 septic fractures of the tibia, 29 of whom were seen less than four months after the injury; the remainder were more long-standing. In both series the surgeon faced three problems--curing of the septic drainage, skin cover and bone union. In 46 cases bone excision was considered necessary: in 18 diaphyseal resection was performed. Immobilisation of the fracture was obtained by plaster cast in 14 cases, an external fixator in 48 cases, and medullary nailing in one. Reconstruction was needed in 11 cases after closed grafting, 9 of them being tibio-fibular, and in 46 after cancellous graft without skin closure. The results in 63 cases were 61 unions: 43 primary unions, 19 additional procedures to reinforce callus and 1 amputation. In two patients union remained particularly tenuous. Two patients are still showing discharge and 9 have poor skin cover. The average time to bone union was nine months and was twelve months in cases of resections greater than 3 cms. The authors are in favour of a technique of massive cancellous bone grafting of the tibia, aligned towards the fibula with partial skin closure. This procedure leads to a firmer and more rapid bone union than the Papineau technique. Secondary bone or skin procedures were needed less often. Tibio-fibular grafting was indicated in cases of limited infection and when the main tibial fragments were still uniting postero laterally.