PEGylated rosin derivatives: Novel microencapsulating materials for sustained drug delivery

The aim of this study was to investigate PEGylated rosin derivatives (PRDs) as microencapsulating materials for sustained drug delivery. PRDs (D1, D2, and D3) composed of a constant weight of rosin and varied amounts of polyethylene glycol (PEG) 400 and maleic anhydride were synthesized in the laboratory. Microparticles were prepared by the O/O solvent evaporation technique using the acetone/paraffin system. Diclofenac sodium (DFS) and diltiazem hydrochloride (DLTZ) were used as model drugs. The effect of the type of PRD, drug, PRD:drug ratio, viscosity of external phase, stirring speed, concentration of magnesium stearate (droplet stabilizer), and method of preparation on particle size, drug loading, and drug release profiles of microparticles was investigated. PRDs could produce discrete and spherical microspheres (with DFS) and microcapsules (with DLTZ). The drug loading value for microparticles was found to be in the range of 37.21% to 87.90%. The microparticle size range was 14 to 36 μm. The particle size and drug loadings of microparticles were substantially affected by the concentration of magnesium stearate and the type of drug, respectively. Most of the formulations could sustain the DFS and DLTZ release for 20 hours. DFS and DLTZ release from PRD microparticles followed Hixson-Crowell and first-order kinetics, respectively. The results suggest that PRDs can be used successfully to prepare discrete and spherical microparticles with DFS and DLTZ for sustained drug delivery

Immunohistochemical testing for <it>Helicobacter Pylori</it> existence in neoplasms of the colon

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori</it> is a common pathogen, and its prevalence varies with socioeconomic conditions (10–80%). It has recently been recognized as a class I carcinogen in relation to gastric cancer. The aim of this study was to investigate the presence of <it>Helicobacter pylori</it> in neoplasms of the colon by immunohistochemical methods.</p> <p>Methods</p> <p>The polypectomy materials of 51 patients (19 male and 32 female) who had undergone colonoscopic polypectomy were retrieved for retrospective examination. The endoscopic size and colonic localization of the polyps were recorded. Hematoxylin and eosin stains were evaluated according to histological type and grade of dysplasia. Biopsy stains were immunohistochemically treated with <it>Helicobacter pylori</it> antibodies by the streptavidine-biotin immunoperoxidase technique. <it>Helicobacter pylori</it> staining in the gastric mucosa was used as the control for the immunohistochemical method. Specimens were classified according to the presence of <it>Helicobacter pylori</it> under an optical microscope, and <it>Helicobacter pylori</it> positive specimens were stratified according to the respective staining pattern.</p> <p>Results</p> <p>Mean age was 61.88 ± 10.62 (40–82) years. Polyp sizes were 1.45 ± 0.92 (1–4) cm; and 25.5% of polyps were localized in the right colon, 68.6% in the left colon and 5.9% in the transverse colon. Presence of <it>Helicobacter pylori</it> was not correlated with localization (p > 0.05) or size of the polyps (p > 0.05).</p> <p>Eleven (21.6%) of all specimens included in the study were <it>Helicobacter pylori</it> positive by immunohistochemical methods. Of the <it>Helicobacter pylori</it> positive specimens, the staining pattern was diffuse: Equivocal in 90.9%, nonspecific with a finely granular type concentrated on the luminal surface in 90.9%, dot-like granular in 54.5%, and spiral in 9.1%. Of the tubular polyps, 17.9% were <it>H. pylori</it> positive, and the staining pattern was equivocal in 100%, luminal in 85.7%, and dot-like granular in 57.1%. Of the villous polyps, 60% were <it>H. pylori</it> positive, and the staining pattern was inconclusive in 66.7%, luminal in 100%, dot-like granular in 33.3%, and spiral in 33.3%. Of the cancerous cases, 25% were <it>H. pylori</it> positive and showed an equivocal, luminal, and dot-like granular staining pattern. No significant correlation was determined between histologic types and prevalence of <it>H. pylori</it> (p > 0.05).</p> <p>Conclusion</p> <p>The presence of <it>H. pylori</it> in colon polyps did not yield any correlation with polyp size, colonic localization or histopathologic type. The higher rate of <it>H. pylori</it> positivity in villous polyps does not present a causal relationship. We were able to determine <it>H. pylori</it> existence in colon polyps by immunohistochemical methods, albeit with no statistical significance.</p