Histological toxicity study of subcutaneous in situ gel

Materials

Male Wistar rats, normal saline solution, gel formulation, hematoxylin-eosin stain, microtome, paraffin, compound microscope.

Procedure

• Twenty four male Wistar rats weighing between 190-225g are used as test animals. They are divided into two groups.

Group-I:Control Gr:Physiological saline 0.3ml

Group-II:Test Gr:In situ gel formulation 0.3ml

• The formulations are given subcutaneously. The rats are sacrificed at 1st, 7th and 14th day after the begining of the study.
• The subcutaneous tissue at the injection site is separated and fixed by 10% formalin solution for three days. The fixed subcutaneous tissue is embedded in paraffin and sliced into 3micron thin slices.
• To evaluate the inflammatory reaction at the site of injection, the comparison of the numbers of neutrophils, eosinophils and macrophages between Group-I and Group-II is performed. Neutrophils and eosinophils are counted in hematoxylin-eosin stained sections. Macrophages are counted in immunohistolchemical staining sections.

References 

Xin, C., Lihong, W., Qiuyuan, L., Hongzhuo, L., 2014. Injectable long-term control-released in situ gels of hydrochloric thiothixene for the treatment of schizophrenia: Preparation, in vitro and in vivo evaluation. International Journal of Pharmaceutics 469, 23–30.