A 63-year-old woman was admitted due to right upper quadrant abdominal pain. She was going through hemodialysis due to end stage renal disease and taking calcium polystyrene sulfonate orally and rectally due to hyperkalemia. Colonoscopy showed a circular ulcerative mass on the proximal ascending colon. Biopsy specimen from the mass showed inflammation and necrotic debris. It also revealed basophilic angulated crystals which were adherent to the ulcer bed and normal mucosa. These crystals were morphologically consistent with calcium polystyrene sulfonate. She was diagnosed with calcium polystyrene phosphate induced colonic necrosis and improved with conservative treatment.
Colonic Diseases/chemically induced/complications/*pathology ; Colonoscopy ; Female ; Humans ; Kidney Failure, Chronic/complications/*diagnosis ; Middle Aged ; Necrosis ; Polystyrenes/*adverse effects

Colonic necrosis is known as a rare complication following the administration of Kayexalate (sodium polystryrene sulfonate) in sorbitol. We report a rare case of colonic mucosal necrosis following Kalimate (calcium polystryrene sulfonate), an analogue of Kayexalate without sorbitol in a 34-yr-old man. He had a history of hypertension and uremia. During the management of intracranial hemorrhage, hyperkalemia developed. Kalimate was administered orally and as an enema suspended in 20% dextrose water to treat hyperkalemia. Two days after administration of Kalimate enema, he had profuse hematochezia, and a sigmoidoscopy showed diffuse colonic mucosal necrosis in the rectum and sigmoid colon. Microscopic examination of random colonic biopsies by two consecutive sigmoidoscopies revealed angulated crystals with a characteristic crystalline mosaic pattern on the ulcerated mucosa, which were consistent with Kayexalate crystals. Hematochezia subsided with conservative treatment after a discontinuance of Kalimate administration.
Adult ; Colon/*pathology ; Gastrointestinal Hemorrhage/etiology ; Humans ; Hyperkalemia/drug therapy ; Intestinal Mucosa/*pathology ; Male ; Necrosis/*chemically induced/complications/pathology ; Polystyrenes/*adverse effects/therapeutic use ; Uremia/*physiopathology

The effect of surface charges on the cellular uptake rate and drug release profile of tetrandrine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPNs) was studied. Stabilizer-free nanoprecipitation method was used in this study for the synthesis of TPNs. A typical layer-by-layer approach was applied for multi-coating particles' surface with use of poly(styrene sulfonate) sodium salt (PSS) as anionic layer and poly(allylamine hydrochloride) (PAH) as cationic layer. The modified TPNs were characterized by different physicochemical techniques such as Zeta sizer, scanning electron microscopy and transmission electron microscopy. The drug loading efficiency, release profile and cellular uptake rate were evaluated by high performance liquid chromatography and confocal laser scanning microscopy, respectively. The resultant PSS/PAH/PSS/PAH/TPNs (4 layers) exhibited spherical-shaped morphology with the average size of 160.3±5.165 nm and zeta potential of-57.8 mV. The encapsulation efficiency and drug loading efficiency were 57.88% and 1.73%, respectively. Multi-layer coating of polymeric materials with different charges on particles' surface could dramatically influence the drug release profile of TPNs (4 layers vs. 3 layers). In addition, variable layers of surface coating could also greatly affect the cellular uptake rate of TPNs in A549 cells within 8 h. Overall, by coating particles' surface with those different charged polymers, precise control of drug release as well as cellular uptake rate can be achieved simultaneously. Thus, this approach provides a new strategy for controllable drug delivery.
Antineoplastic Agents, Phytogenic ; administration & dosage ; chemistry ; Benzylisoquinolines ; administration & dosage ; chemistry ; Cell Line, Tumor ; Drug Liberation ; Humans ; Lactic Acid ; chemistry ; Nanoparticles ; adverse effects ; chemistry ; metabolism ; Polyamines ; chemistry ; Polyglycolic Acid ; chemistry ; Polystyrenes ; chemistry ; Static Electricity