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This work focused on a new technique for the preparation of doxorubicin (DOX) loaded chitosan (CS) nanoparticles (DOX-CS) - formation by electrospray ionization in the presence of tripolyphosphate (TPP) as the stabilizer. The working distance, needle gauge, flow rate, stirring rate, electrospraying voltage and DOX to CS molar ratio were sequentially and individually optimized and found to be a 26 gauge needle, an applied voltage of 13 kV, a flow rate of 0.5 mL/h, a working distance of 8 cm and a stirring rate of 400 rpm. The incorporation of chemically unchanged DOX with the CS into the particles was ascertained by Fourier transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Under these optimized conditions, the DOX-CS particles were found to be nanoparticles of approximately 300-570 (dry particles) or 530-870 nm diameter (hydrated particles), with a PDI and SPAN polydispersity indices of 0.97-0.82 and 0.62-0.64, respectively, for initial DOX loading levels of 0.25-1%, as determined by SEM and particle size analyzer, respectively. Moreover, a high encapsulation efficiency (EE) of DOX into the nanoparticles was attained, ranging from 63.4 to 67.9% EE at 1 to 0.25% DOX loading. Finally, the in vitro DOX release behaviors of the DOX-CS particles revealed a prolonged release of DOX over at least seven hours.

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The purpose of this study was to design and characterise an oral mucoadhesive micellar drug carrier. In this regard, a mucoadhesive hydrophobic cationic aminocellulose was easily synthesised under mild homogeneous conditions with high yield. The cellulose derivative resulted in strongly improved mucoadhesive properties but was pH dependent. Furthermore, the hydrophobic anticancer drug camptothecin was successfully encapsulated into the mucoadhesive cellulose derivative micelles with spherical shape stability of 233 nm in diameter and low particle size distribution. The CPT-loaded nanocarriers provided high encapsulation efficiency about 86.4%. In vitro release, CPT-loaded cellulose derivative micelles showed a reduction in release rate compared with physically pure CPT solution. The release results also indicated that a sustained release of CPT to >80% over 4 d for pH 6.8 and 7.4. Therefore, mucoadhesive hydrophobic cationic aminocellulose micelles seem to be a promising carrier for various pharmaceutical applications especially for poorly water-soluble drug delivery system.

The structure determination of diclofenac embedded in a diclofenac‐containing chitosan matrix using conventional X‐ray powder diffraction data is demonstrated. It reveals that sodium diclofenac, the starting material in the preparation of a controlled‐release diclofenac‐containing chitosan matrix, changes to diclofenac acid in space group C2/c in the matrix. Simple methods were employed for handling the sample to obtain X‐ray powder diffraction data of sufficiently high quality for the determination of the crystal structure of diclofenac embedded in chitosan. These involved grinding and sieving several times through a micro‐mesh sieve to obtain a suitable particle size and a uniformly spherical particle shape. A traditional technique for structure solution from X‐ray powder diffraction data was applied. The X‐ray diffraction intensities were extracted using Le Bail's method. The structure was solved by direct methods from the extracted powder data and refined using the Rietveld method. For comparison, the single‐crystal structure of the same drug was also determined. The result shows that the crystal structure solved from conventional X‐ray powder diffraction data is in good agreement with that of the single crystal. The deviations of the differences in bond lengths and angles are of the order of 0.030 Å and 0.639°, respectively.