The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Chang-koo Shim - One of the best experts on this subject based on the ideXlab platform.
-
Rectal Absorption of omeprazole from suppositories in rabbits
Archives of Pharmacal Research, 1995Co-Authors: Kyong-hoon Eun, Yong-hee Lee, Chang-koo ShimAbstract:Rectal Absorption of omeprazole, a proton pump inhibitor, from suppositories was studied in rabbits. The suppositories were prepared by the conventional melting method with two types of bases, water-soluble polyethylene glycol (PEG) 4000 and oil-soluble Witepsol H15 bases, and administered intraRectally (ir) to rabbits at a dose of 10 mg omeprazole/kg. The plasma omeprazole concentration-time profiles of the two suppositories were compared with those following intravenous (iv) administration of the same dose. There were no significant differences between the two suppositories in bioavailabilities and peak plasma concentrations (C_max). Bioavailabilities and C_max of PEG- and Witepsol suppositories were 30.3 and 33.9%, and 7.0 and 5.6 μg/ml, respectively. However, PEG suppository showed significantly (P
-
Rectal Absorption of omeprazole from suppositories in rabbits
Archives of Pharmacal Research, 1995Co-Authors: Kyong-hoon Eun, Yong-hee Lee, Chang-koo ShimAbstract:Rectal Absorption of omeprazole, a proton pump inhibitor, from suppositories was studied in rabbits. The suppositories were prepared by the conventional melting method with two types of bases, water-soluble polyethylene glycol (PEG) 4000 and oil-soluble Witepsol H15 bases, and administered intraRectally (ir) to rabbits at a dose of 10 mg omeprazole/kg. The plasma omeprazole concentration-time profiles of the two suppositories were compared with those following intravenous (iv) administration of the same dose. There were no significant differences between the two suppositories in bioavailabilities and peak plasma concentrations (Cmax). Bioavailabilities and Cmax of PEG- and Witepsol suppositories were 30.3 and 33.9%, and 7.0 and 5.6 μg/ml, respectively. However, PEG suppository showed significantly (P<0.05) shorter time to reach peak plasma concentration (Tmax), mean Absorption time (MAT) and mean residence time in the plasma (MRT) than Witepsol suppository. The Tmax MRT and MAT were 25.0, 83.0 and 38.5 min for PEG suppository, but were 90.0, 122.5 and 78.0 min for Witepsol suppository, respectively. These differences between the two suppositories could be explained by the difference in the in vitro dissolution rates between the suppositories. The dissolution of omeprazole from PEG suppository was reportedly much faster than that from Witepsol suppository. It suggests that plasma profiles of omeprazole, especially Cmax, MAT and MRT, could be controlled by modifying thein vitro dissolution rate of the drug from the suppositories. Above results suggest that Rectal suppository is worth developing as an alternative dosage form of omeprazole to the conventional oral preparations which need sophisticated treatments, such as enteric coating, to prevent acid degradation of the drug in the stomach fluid.
Toshiaki Nishihata - One of the best experts on this subject based on the ideXlab platform.
-
Absorption-promoting adjuvants: enhancing action on Rectal Absorption
Advanced Drug Delivery Reviews, 1997Co-Authors: Toshiaki Nishihata, J. Howard RyttingAbstract:Abstract Studies of Absorption-promoting adjuvants used for the modification of the barrier function of the Rectal membrane are interesting for biochemical research as well as providing a basis for the development of new formulations of poorly absorbed drugs such as some moderately large water soluble drugs and peptides. Compounds such as chelating agents and sulfhydryl depleters increase the Rectal Absorption of drugs through the paracellular route and transcellular route, respectively, by modifying the barrier function of each route. Salicylate, its derivatives and fatty acids also increase Rectal drug Absorption through both routes. Lectin increases Rectal Absorption of drugs by inducing microvillous infusion. With respect to formulation development, ampicillin suppositories incorporating sodium caprylate as an Absorption promoting adjuvant were confirmed clinically to be an effective formulation, and are a marketed product in Japan. In human trials, administration of insulin in a combination with salicylate inhibited postprandial hyperglycemia in diabetic patients.
-
Enhanced Rectal Absorption of itazigrel formulated with polysorbate 80 micelle vehicle in rat: role of co-administered esterase.
The Journal of pharmacy and pharmacology, 1994Co-Authors: Ken Yamamoto, Ashok C. Shah, Toshiaki NishihataAbstract:— We investigated the effect of esterase on Rectal Absorption in the rat of itazigrel using polysorbate 80 (PS-80) micelle as a vehicle to overcome the poor aqueous solubility of itazigrel. The itazigrel formulation prepared with PS-80 increased the Absorption compared with a 0·25% carmellose sodium suspension, probably by supplying the itazigrel solute to keep a high concentration at the epithelial surface. When esterase was co-administered with the formulations containing PS-80, the Absorption of itazigrel from rat rectum was accelerated further, by rapid release of itazigrel from the micelle vehicle after enzymatic degradation of the PS-80 micelle.
Kyong-hoon Eun - One of the best experts on this subject based on the ideXlab platform.
-
Rectal Absorption of omeprazole from suppositories in rabbits
Archives of Pharmacal Research, 1995Co-Authors: Kyong-hoon Eun, Yong-hee Lee, Chang-koo ShimAbstract:Rectal Absorption of omeprazole, a proton pump inhibitor, from suppositories was studied in rabbits. The suppositories were prepared by the conventional melting method with two types of bases, water-soluble polyethylene glycol (PEG) 4000 and oil-soluble Witepsol H15 bases, and administered intraRectally (ir) to rabbits at a dose of 10 mg omeprazole/kg. The plasma omeprazole concentration-time profiles of the two suppositories were compared with those following intravenous (iv) administration of the same dose. There were no significant differences between the two suppositories in bioavailabilities and peak plasma concentrations (C_max). Bioavailabilities and C_max of PEG- and Witepsol suppositories were 30.3 and 33.9%, and 7.0 and 5.6 μg/ml, respectively. However, PEG suppository showed significantly (P
-
Rectal Absorption of omeprazole from suppositories in rabbits
Archives of Pharmacal Research, 1995Co-Authors: Kyong-hoon Eun, Yong-hee Lee, Chang-koo ShimAbstract:Rectal Absorption of omeprazole, a proton pump inhibitor, from suppositories was studied in rabbits. The suppositories were prepared by the conventional melting method with two types of bases, water-soluble polyethylene glycol (PEG) 4000 and oil-soluble Witepsol H15 bases, and administered intraRectally (ir) to rabbits at a dose of 10 mg omeprazole/kg. The plasma omeprazole concentration-time profiles of the two suppositories were compared with those following intravenous (iv) administration of the same dose. There were no significant differences between the two suppositories in bioavailabilities and peak plasma concentrations (Cmax). Bioavailabilities and Cmax of PEG- and Witepsol suppositories were 30.3 and 33.9%, and 7.0 and 5.6 μg/ml, respectively. However, PEG suppository showed significantly (P<0.05) shorter time to reach peak plasma concentration (Tmax), mean Absorption time (MAT) and mean residence time in the plasma (MRT) than Witepsol suppository. The Tmax MRT and MAT were 25.0, 83.0 and 38.5 min for PEG suppository, but were 90.0, 122.5 and 78.0 min for Witepsol suppository, respectively. These differences between the two suppositories could be explained by the difference in the in vitro dissolution rates between the suppositories. The dissolution of omeprazole from PEG suppository was reportedly much faster than that from Witepsol suppository. It suggests that plasma profiles of omeprazole, especially Cmax, MAT and MRT, could be controlled by modifying thein vitro dissolution rate of the drug from the suppositories. Above results suggest that Rectal suppository is worth developing as an alternative dosage form of omeprazole to the conventional oral preparations which need sophisticated treatments, such as enteric coating, to prevent acid degradation of the drug in the stomach fluid.
Noboru Yata - One of the best experts on this subject based on the ideXlab platform.
-
Decanoic Acid Induced Enhancement of Rectal Absorption of Hydrophilic Compounds in Rats
Pharmaceutical Research, 1994Co-Authors: Koji Takahashi, Teruo Murakami, Yutaka Higashi, Ryoko Yumoto, Tomomi Hattori, Noboru YataAbstract:The enhancing effect of decanoic acid (CIO) on the Rectal Absorption of phenolsulfonphtalein (PSP) was analyzed with a pharmacokinetic model. The transfer index of PSP from the Rectal lumen to the epithelial layer in the presence of C10 was proportional to the product of the C10 disappearance rate from the Rectal lumen and its calcium ion sequestration capacity. The enhancement of Rectal PSP Absorption by different doses of C10 was also predictable by using a permeability index, Pa, of PSP, which was defined as a proportionality constant relating transfer index and the product value described above. The Pa values of various hydrophilic compounds with different molecular weights were also estimated from their Rectal bioavailability in the presence of C10. A linear relationship was observed between Pa values and reciprocal values of the square root of individual molecular weight. These findings suggest that the Pa index is related to the permeant’s diffusion coefficient through paracellular aqueous openings formed by C10.
Shigeru Goto - One of the best experts on this subject based on the ideXlab platform.
-
Preparation and Evaluation of Eudragit Gels. VIII. Rectal Absorption of 5-Fluorouracil from Eudispert hv Gels in Rats
Journal of pharmaceutical sciences, 1995Co-Authors: Hiroyuki Umejima, Asako Kikuchi, Nak-seo Kim, Takahiro Uchida, Shigeru GotoAbstract:Abstract Rectal Absorption of the hydrophilic 5‐fluorouracil (5‐FU) in rats was studied with Eudispert hv gels with or without fatty acids as the Rectal bases. In the absence of fatty acids, absolute bioavailabilities of 5‐FU for Eudispert hv hydrogel and xerogel preparations increased ˜2.5 times compared with those of Witepsol H‐15 and PEG 2000 suppositories. When n ‐capric acid or linolenic acid was used as an Absorption enhancer, absolute bioavalabilities of 5‐FU were, respectively, 25.5 and 30.9% for Witepsol H‐15 and 64.4 and 66.1% for PEG 2000. Furthermore, the absolute bioavailabilities of 5‐FU for Eudispert hv hydrogel with n ‐capric acid or linolenic acid were 95.6% and 81.7%. The addition of capric acid or linolenic acid to the hydrogel was a useful method for increasing 5‐FU permeability through the Rectal membranes. These results are consistent with the observation that the total amounts of 5‐FU remaining in the lumenal contents of the rectum and that accumulated in the Rectal tissue decreased in relation to the increase in the bioavailabilities. Thus, the Eudispert hv hydrogel containing 5‐FU with capric acid may be a useful Rectal preparation for increasing the maximum plasma level and improving the absolute bioavailability of 5‐FU.