No abstract

In this paper, hot-melt extrusion was applied to prepare drug delivery systems using polylactide acid (PLA) as the matrix. Diclofenac sodium (DS) was used as a model drug. Polyethylene glycol (PEG, molecular weight is 6000) and sodium dodecyl sulfate (SDS) were used as the release rate modifiers. For the PLA/PEG/DS blends, the release of DS was enhanced with higher amounts of PEG and DS. After the addition of SDS to the PLA/PEG/DS blends, the dispersion of DS and PEG was significantly improved. Compared to the PLA/PEG/DS blends with the same drug loading, the drug release behavior of PLA/PEG/DS/SDS was remarkably suppressed due to the presence of SDS. And a controllable linear release of DS was achieved.

Poly(ε-caprolactone)/glycerol tristearate (PCL/C18) composites with excellent oxygen and water vapor barrier properties were developed through melt blending. After the addition of C18, a significant decrease of 81.4% in water vapor permeability (50% relative humidity) was obtained for the PCL/C18 blend (sample PCL-30) compared to that of pure PCL. Moreover, when the humidity increased from 50 to 90%, the barrier property of PCL/C18 blends only sacrificed a little, exhibiting noticeable humidity stability. C18 was evenly distributed in the PCL matrix with various particle sizes, and hydrophobic ″bulk barrier″ was formed. The PCL/C18 composites not only had the low surface solubility coefficient on the surface of the material but also had the tortuous diffusion path in the bulk material. Moreover, the addition of C18 with excellent hydrophobicity resisted the penetration of water vapor through the PCL/C18 blends and decreased the swelling and plasticization effects on PCL matrices, leading to the remarkable barrier stability in high humidity. The barrier performance of PCL-30 at 90% RH was only deteriorated by 0.63 × 10 −14 g•cm•cm −2 •s −1 •Pa −1 compared with that at 50% RH. Based on the excellent water barrier property and barrier stability in high humidity, especially considering the simple and effective manufacture processing, this method exhibited a great value in packaging applications.

Hot-melt blending has been widely used in the pharmaceutical industry to produce drug delivery systems, however, realizing the controlled drug release behavior of a hot-melt blended medicament it is still a tough challenge. In this study, we developed a simple and effective heat treatment method to adjust the drug release behavior, without the addition of any release modifiers. Thin metoprolol tartrate (MPT)/poly(ε-caprolactone) (PCL) tablets were prepared through hot-melt processing, and different morphologies of MPT were obtained by altering processing temperatures and the following heat treatment. MPT particles with different particle sizes were obtained under different processing temperatures, and fibrous crystals of MPT were fabricated during the following heat treatment. Different morphological structures of MPT adjusted the drug diffusion channel when immersed in phosphate-buffered saline (PBS), and various drug release behaviors were approached. After being immersed for 24 h, 7% of the MPT was released from the blend processed at 130 °C, while more than 95% of the MPT were released after the following heat treatment of the same sample. Thus, flexible drug release behaviors were achieved using this simple and effective processing manufacture, which is demonstrated to be of profound importance for biomedical applications.