Papers by Keyword: Poly-DL-Lactide-co-Glycolide)

Abstract: Copolymer poly(D,L-lactide-co-glycolide) is used for obtaining the systems for controlled delivery of medicaments. Its specific characteristics make it suitable for various researches where its synthesis is performed in different ways. Using the system for controlled delivery of medicaments, an equal concentration of the medicament is achieved in the body throughout an extended period of time and it has advantages over the conventional methods. In this paper we present a new solvent/non-solvent chemical method for obtaining DLPLG nanospheres. In the experiment various stabilizers were used in order to examine their influence on morphological characteristics of DLPLG particles. The samples were characterized by Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Stereological analysis.

Abstract: Supercritical carbon dioxide (scCO2) was used as a processing medium for the fabrication of drug encapsulated poly(DL-lactide-co-glycolide) (PLGA) monoliths for their potential application in the controlled release of water soluble drugs. Exposure of PLGA to scCO2 leads to effective plasticization and liquefaction due to the high solubility and interaction of the scCO2 in the copolymer. By exploiting this property, it was demonstrated that prolonged release formulations of molsidomine, a peripheral nitrovasodilator used to treat angina pectoris, can be prepared by chemical solvent-free, scCO2 assisted drug impregnation method. The in-vitro dissolution studies revealed that the release rates of drug from the porous polymer monoliths containing different amount of the drug samples were significantly retarded due to encapsulation of molsidomine into the PLGA matrix.

Abstract: Composite biomaterials based on calcium phosphate ceramic due to their high bioactivity are of interest for biological application and bone tissue repair. Structural and microstructural parameters of inorganic constituent of these materials are very important for the synthesis and characterization of composites. Quantitative and qualitative content, crystallite size of phases, as well as the degree of crystallinity have a great influence on the quality of composites, their application and bone tissue repair. X-ray diffractometry was employed to investigate the components of biocomposite materials, calcium phosphate (CaP) ceramic and poly-DL-lactide-coglycolide (DLPLG) polymer, as well as the biocomposite obtained from the mentioned components. Composite biomaterial was obtained by modified emulsion process. Using the Rietveld refinement, we analyzed CaP as an inorganic component of the composite, whence we have determined structural and microstructural properties of ceramic component of the investigated composite. The results obtained by structure refinement show that calcium phosphate ceramic materials synthesized at room temperature contain hydroxyapatite HAp as a predominant phase. The calculated Ca/P ratio is 1.667. The Rietveld analysis revealed lattice parameters a(Å)=9.4324(7) and c(Å)=6.8785(6) that are in agreement with the theoretical values.

Abstract: In this paper we report the results on synthesis of a composite biomaterial based on biphasic calcium phosphate (BCP) and poly-(DL-lactide-co-glycolide) (DLPLG). Besides, we have investigated the influence of new synthesis method on the structure and characteristics of the composite. The synthesis of biphasic calcium phosphate from Ca(NO3)2 x 4H2O and (NH4)3 PO4 in alkali environment was performed by means of precipitation technique. Composite material BCP/DLPLG was first prepared from commercial granules using chemical methods. Powdered polymer DLPLG was then homogenized at appropriate ratio with addition of biphasic calcium phosphate into the suspension. All samples were characterized by DSC, IR, X-Ray and SEM techniques.

Abstract: A different range of vancomycin was incorporated into a poly dl-lactide-co-glycolide) [PLGA] disc matrix using the hot compression method. The disc was placed in phosphate buffered saline (PBS) and incubated at 37oC. The PBS was changed periodically, and the removed solution was analyzed using high performance liquid chromatography. The sensitivity of the antibiotic-polymer matrix was evaluated using cultured-human-ear methicillin-resistant staphylococcus aureus (MRSA). The MRSA growth was inhibited proportionally to the incorporated vancomycin concentration in the disc matrix. A disc incorporating 400 µg of antibiotics inhibited the growth of MRSA 10 times longer than the disc containing 30 µg as a control. It was found that the biodegradable polymer matrix enabled the control-release of an antibiotic, and the release profile was observed as zero order.