Rectal delivery of antiinflammatory drugs. II. The influence of basic amino acid salts on rectal absorption of diclofenac.
作者:HIDEYA YAGINUMA、TOHRU NAKATA、HARUMASA TOYA、TERUO MURAKAMI、MASARU YAMAZAKI、AKIRA KAMADA、HAJIME SHIMAZU、ICHIRO MAKITA
DOI:10.1248/cpb.29.3326
日期:——
Rectal absorption of diclofenac (DC) and its salts with sodium (DCNa), L-arginine (DC-Arg), L-lysine (DC-Lys), and L-histidine (DC-His) was studied in dogs, rabbits and rats. Plasma levels of unchanged DC were measured by high performance liquid chromatography. Both the bioavailability and the plasma peak level of DC-Lys were the largest among the salts studied. The bioavailability of DCNa on oral administration in terms of plasma levels of DC was observed to be much larger than after rectal administration of DC but it was of the same order as those of rectal administration of DCNa, DC-Arg, and DC-His. The extents of bioavailabilty in rabbits and in rats were similar, but considerably better than that in dogs. The irritative effects of DC salts on the rectal mucosa in rats were studied by gross and light microscopic examinations following the administration of suspensions in 1% methyl cellulose solution. DC-Arg showed the weakest irritation of the rectal mucosa, and the irritation caused by 20% suspension was equivalent to that of 5% suspension of DCNa. The protective effects of counter ions against the histological damage caused by DC to the rectal mucosa increased in the order or sodium≥lysine≥arginine. From these results, it appears that the basic amino acid salts of DC may be useful as rectal delivery preparations for clinical use.
本研究在狗、兔和大鼠中探讨了双氯芬酸(DC)及其与钠盐(DCNa)、L-精氨酸(DC-Arg)、L-赖氨酸(DC-Lys)和L-组氨酸(DC-His)的直肠吸收。通过高效液相色谱法测定了未改变的DC的血浆水平。在所研究的盐类中,DC-Lys的生物利用度和血浆峰值水平最大。口服DCNa的生物利用度(以血浆DC水平计)明显大于直肠给药后的DC,但与DCNa、DC-Arg和DC-His的直肠给药结果在同一数量级上。兔子和大鼠的生物利用度相似,但明显优于狗。通过对在1%甲基纤维素溶液中悬浮液给药后的大鼠直肠粘膜进行肉眼和光镜检查,研究了DC盐对直肠粘膜的刺激作用。DC-Arg对直肠粘膜的刺激最弱,20%悬浮液所造成的刺激相当于5%悬浮液的DCNa所造成的刺激。对直肠粘膜造成的组织学损伤,反离子保护作用的强度依次为钠盐≥赖氨酸≥精氨酸。根据这些结果,看起来DC的基础氨基酸盐可能作为临床使用的直肠给药制剂是有用的。