ABSTRACT
Poly(lactide-co-glycolide acid) (PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used materials for drug delivery and biomedical systems, also being present in several US Food and Drug Administration-approved carrier systems and therapeutic devices. For both applications, the quantification of the polymer is inalienable. During the development of a production process, parameters like yield or loading efficacy are essential to be determined. Although PLGA is a well-defined biomaterial, it still lacks a sensitive and convenient quantification approach for PLGA-based systems. Thus, we present a novel method for the fast and precise quantification of PLGA by RP-HPLC. The polymer is hydrolyzed into its monomers, glycolic acid and lactic acid. Afterwards, the monomers are derivatized with the absorption-enhancing molecule 2,4′-dibromoacetophenone. Furthermore, the wavelength of the deri-vatized monomers is shifted to higher wavelengths, where the used solvents show a lower absorption, increasing the sensitivity and detectability. The developed method has a detection limit of 0.1 μg/mL, enabling the quantification of low amounts of PLGA. By quantifying both monomers separately, in-formation about the PLGA monomer ratio can be also directly obtained, being relevant for degradation behavior. Compared to existing approaches, like gravimetric or nuclear magnetic resonance measure-ments, which are tedious or expensive, the developed method is fast, ideal for routine screening, and it is selective since no stabilizer or excipient is interfering. Due to the high sensitivity and rapidity of the method, it is suitable for both laboratory and industrial uses.
ABSTRACT
Objective: To prepare a self-designed three-dimensional woven scaffold using poly lactide-co-glycolide acid (PLGA), and to observe the influence of the prepared scaffold on the growth of Schwann cells in vitro and its in vivo degradation. Methods: The 3D scaffolds were prepared by means of melt spinning, extension, weaving, and other procedures. The alignment of micro-tubules was observed under the scanning electronic microscope (SEM). The size of the micropores was also measured. Primary cultured Schwann cells were seeded on the 3D scaffolds, and the growth, adherence, proliferation, and apoptosis of Schwann cells were observed under inverted phase contrast microscopy and SEM; the results were compared between Schwann cells cultured in collagen sponge and culture dish. The scaffold carrying Schwann cells was implanted into the paraspinal muscle in rats, and H-E staining was used to observe the in vivo degradation and the inflammation responses. Results: The external diameters of the scaffold and micro-tubules were 3 mm and 100 μm, respectively, and the micro-tubules were arranged in an even and parallel manner. The adherence rates and proliferation rates of Schwann cells were similar between scaffold group and collagen sponge group, but both groups were significantly lower than the culture dish group (P<0.05). The 3D scaffold degraded completely within 12 weeks, with no visible inflammatory cells around. Conclusion: The self-designed 3D scaffold has no harmful effect on the growth of Schwann cells, and it can degrade in vivo, showing a satisfactory biocompatibility.
ABSTRACT
Objective To prepare Paracetamol (APP) multiloculated implant loaded with poly-lactide-co-glycolide acid (PLGA) and to study the drug release profile in vitro. Methods APP multiloculated implant was fabricated by micro-electro-mechanical system (MEMS), and high-performance liquid chromato graphy (HPLC) measurement was used to investigate in vitro drug release profile. HPLC analysis was carried out by employing C18 column and a mixture of methanol-water (15∶85) as mobile phase. The detection wavelength was 215nm and flow rate was 0.8mL/min. Results With different multiloculated shape, the rate of the drug release in vitro was varied significantly. Moreover, the releasing of APP multiloculated implant with ecto-tetragonum ento-hexagon in vitro conformed to Higuchi equation. Conclusion The technology of the preparations is feasible, and the structural and morphological characteristics of the multiloculated implant have a significant impact on the release speed of the drug delivery system.