Topotecan hydrochloride

Topotecan HCl（SKF104864）is an inhibitor of topoisomerase 1 and semisynthetic analogue of camptothecin [1].

Topotecan HCl（SKF104864）has been reported to have a potent antitumor activity against tumors in murine models. In addition, Topotecan HCl has also shown the potent effect against intravenously implanted P388 leukemia and both intravenously and subcutaneously implanted Lewis lung carcinoma. Topotecan HCl has noted the activity against subcutaneously implanted solid tumors including chemorefractory tumors and human colon carcinoma xenograft HT-29. Topotecan HCl has been found to induce regressions in the lung tumor model (Lewis lung carcinoma and B16 melanoma), compared to camptothecin and 9-amino-camptothecin. In the preclinical toxicology studies, Topotecan HCl has been revealed to have a concentration-dependent, reversible and limited toxoicity to rapidly proliferation tissues such as bone marrow and gastro-intestinal epithelium [1].

References:
[1] Creemers GJ1, Lund B, Verweij J. Topoisomerase I inhibitors: topotecan and irenotecan. Cancer Treat Rev. 1994 Jan;20(1):73-96.

Topotecan hydrochloride effects on retinal vessels in newborn rats.[Pubmed:22374727]

Histol Histopathol. 2012 Apr;27(4):497-506.

A physiological system, i.e. rodent retina during vessel formation and hierarchical organization, was utilised for assaying antiangiogenic properties of Topotecan, a topoisomerase I inhibitor, capable of inhibiting tumoral growth in animal models of retinoblastoma. In particular we analysed possible differences in effectiveness and side effects among different drug dosages and ways of administration. In the present research only qualitative analyses were undertaken. After preliminary experiments, in which suckling animals subcutaneously treated with Topotecan dosages comprised between 9 and 3 mg/kg underwent high lethality and extremely severe systemic damages, 7 day-old rats were subcutaneously, intravenously or peribulbary injected with a single dose of 1 mg/kg; retinal vessels were visualized in retinal fluorangio-graphies taken 1 and 2 weeks after treatment. The most important and frequent alterations were found to affect radial vessels, which showed non-perfused and/or regionally mislocated segments, together with abnormal branching and enlargements in retinal periphery; persistence of capillary-free periarteriolar regions, non-vascularised regions and spots of extravascular FITC were also detected. Despite the high individual variability the alterations were substantially similar among the different ways of drug administration, while they appeared milder in 21 day-old rats, with respect to younger ones. The extensive vascular remodelling found after Topotecan administration, besides demonstrating the antiangiogenic properties of this chemioterapic drug, confirms the rodent retina as a highly valuable model system for studying angiogenesis modulation.

Topotecan hydrochloride liposomes incorporated into thermosensitive hydrogel for sustained and efficient in situ therapy of H22 tumor in Kunming mice.[Pubmed:24909735]

Pharm Dev Technol. 2015 Nov;20(7):812-819.

Topotecan hydrochloride (TPT) has potential for the treatment of ovarian cancer, but the activity of TPT tends to decrease due to the ring-opening at physiological pH. In this study, we proposed to incorporate TPT liposomes into injectable thermosensitive in situ hydrogel, consisting of chitosan (CS) and beta-glycerophosphate (beta-GP), for sustained release and preservation of active lactone form of TPT. The rheology studies were carried out to investigate the sol-gel temperature, flow behavior and viscosity of these CS/beta-GP systems. The optimized formulation exhibited sol-gel transition at 40.2 +/- 0.4 degrees C, with pseudoplastic flow behavior. The drug release rate of TPT liposomes loaded CS/beta-GP hydrogel in phosphate buffer saline (pH = 7.4) was found to be slowed down, and the lactone fraction of TPT in the hydrogel matrix was maintaining 40% after 50 h. In addition, the antitumor efficacy in Kunming mice bearing Hepatoma-22 tumor, after intratumoral injection of TPT liposomes loaded CS/beta-GP hydrogel, was higher than that of TPT in saline and TPT in CS/beta-GP hydrogel. Those results demonstrated that TPT liposomes loaded CS/beta-GP hydrogel could become a potential formulation for improving the antitumor efficacy of TPT and suggested an important technology platform for intratumoral administration of derivative of camptothecin-family drugs.