Krishnaiah Y S R, Satyanarayana S, Prasad Y V Rama, Rao S Narasimha
Department of Pharmaceutical Sciences, College of Engineering, Andhra University, Visakhapatnam, A.P., India.
J Pharm Pharm Sci. 2002 Jan-Apr;5(1):24-8.
The suitability of 99mTc-diethylenetriaminepenta- acetic acid (DTPA) and 99mTc-sulphur colloid (99mTc-SC) as tracers in gamma scintigraphy for the evaluation of colon-specific drug delivery systems was assessed in healthy volunteers.
Sodium chloride core tablets containing either 99mTc-DTPA or 99mTc-SC were prepared and compression coated with two different quantities of guar gum. The compression-coated tablets were subjected to gamma scintigraphic studies for colonic drug delivery in healthy human volunteers.
The tablets containing 99mTc-DTPA did not release the tracer in stomach and small intestine, and on entering the colon disintegrated completely whereas the tablets containing 99mTc-SC remained intact in stomach, small intestine and in colon as well. The study showed that DTPA is a suitable tagging agent for 99mTc in the evaluation of guar gum based colonic drug delivery systems containing water-soluble drugs.
In the present investigation guar gum was applied externally as a compression coat over the radiolabelled core. Since the core consisted of water-soluble material (sodium chloride), it is possible that the release of the tracer from the 99mTc-DTPA containing formulations is a combined effect of enzymatic action and diffusion of the salt. The failure of disintegration of 99mTc-SC containing formulations might be due to its interference with the disintegration or the part diffusion observed with 99mTc-DTPA cores. The results of the study showed that DTPA is a suitable tagging agent for 99mTc in the evaluation of colonic drug delivery systems containing water-soluble drugs by gamma scintigraphy.
在健康志愿者中评估99m锝-二乙烯三胺五乙酸（DTPA）和99m锝-硫胶体（99mTc-SC）作为γ闪烁显像示踪剂用于评价结肠特异性给药系统的适用性。
制备含有99mTc-DTPA或99mTc-SC的氯化钠核心片，并分别用两种不同量的瓜尔胶进行压制包衣。对压制包衣片在健康人类志愿者中进行结肠给药的γ闪烁显像研究。
含99mTc-DTPA的片剂在胃和小肠中不释出示踪剂，进入结肠后完全崩解，而含99mTc-SC的片剂在胃、小肠和结肠中均保持完整。研究表明，在评价含水溶性药物的瓜尔胶基结肠给药系统时，DTPA是99mTc合适的标记剂。
在本研究中，瓜尔胶作为压制包衣剂外用在放射性标记的核心片上。由于核心片由水溶性物质（氯化钠）组成，含99mTc-DTPA制剂中示踪剂的释放可能是酶作用和盐扩散的综合效应。含99mTc-SC制剂不崩解可能是由于其干扰了含99mTc-DTPA核心片的崩解或部分扩散。研究结果表明，在通过γ闪烁显像评价含水溶性药物的结肠给药系统时，DTPA是99mTc合适的标记剂。
