151
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Sakai M, Imai T, Ohtake H, Otagiri M. Cytotoxicity of absorption enhancers in Caco-2 cell monolayers. J Pharm Pharmacol 1998; 50:1101-8. [PMID: 9821655 DOI: 10.1111/j.2042-7158.1998.tb03319.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study was performed to evaluate the utility of absorption enhancers with reference to mucosal cell cytotoxicity. Overall assessment of the damage to plasma, lysosomal and nuclear membranes by three absorption enhancers, sodium deoxycholate, sodium caprate and dipotassium glycyrrhizinate, was performed on Caco-2 cell monolayers. The cytotoxicities of sodium deoxycholate (0.02-0.1% w/v), sodium caprate (0.1-0.5% w/v) and dipotassium glycyrrhizinate (0.5-2% w/v) were evaluated by the trypan blue-exclusion test, the protein-release test, the neutral-red assay, the DNA--propidium iodide staining test and the test for recovery of transepithelial electrical resistance (TEER) up to 24 h after treatment with each enhancer. Sodium dodecyl sulphate (SDS; 0.1% w/v), a potent surfactant, was used as positive control. SDS at this level was significantly cytotoxic whereas dipotassium glycyrrhizinate was not cytotoxic in any tests. Results from the trypan blue-exclusion and protein-release tests showed that high concentrations of sodium caprate (0.5% w/v) and sodium deoxycholate (0.1% w/v) were significantly cytotoxic to the plasma membrane. The neutral-red assay, an indicator of damage to lysosomal membranes, revealed that 0.5% (w/v) sodium caprate had no effect whereas the uptake of neutral red was slightly increased by treatment with 0.1% (w/v) sodium deoxycholate, implying that the compound had cell-growth-enhancing activity. Nuclear-membrane damage, as evaluated by the DNA--propidium iodide staining test, was severe in cell monolayers treated with 0.5% (w/v) sodium caprate compared with that induced by 0.1% (w/v) sodium deoxycholate. In the TEER recovery test, TEER failed to recover 24 h after treatment with 0.5% (w/v) sodium caprate and 0.1% (w/v) SDS, but recovered after treatment with 0.1% (w/v) sodium deoxycholate. The recovery of TEER might be related to nuclear membrane damage and cell-growth-enhancing activity. These results indicate that of the three classes of enhancer, dipotassium glycyrrhizinate was not cytotoxic and that high concentrations of sodium caprate and sodium deoxycholate could damage plasma and nuclear membranes.
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Affiliation(s)
- M Sakai
- Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kumamoto University, Japan
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152
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Bock U, Kolac C, Borchard G, Koch K, Fuchs R, Streichhan P, Lehr CM. Transport of proteolytic enzymes across Caco-2 cell monolayers. Pharm Res 1998; 15:1393-400. [PMID: 9755891 DOI: 10.1023/a:1011949521144] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To investigate the mechanisms by which proteolytic enzymes, such as trypsin, chymotrypsin, papain, and bromelain, are able to cross the intestinal mucosal barrier after oral administration to man. METHODS Filter-grown Caco-2 cell monolayers were incubated with proteolytic enzymes and then the transepithelial electrical resistance (TEER) and the transport of the paracellular marker fluorescein were monitored. The effects of the enzymes on the cells were investigated by light microscopy and by biochemical assays. Transport of intact proteases across the cells was verified by monitoring the proteolytic activity and MALDI-TOF mass spectroscopic identification of undegraded trypsin. RESULTS Depending on time, concentration, and side of exposure to Caco-2 cell monolayers, all proteases decreased the TEER and increased the transport of fluorescein. Some morphological and metabolic changes were observed. The effects were reversible, but until 24 hours after removal of the proteases. Under the conditions of this in-vitro model, approximately 10% of the apically applied dose reached the basolateral compartment as biologically active, non-degraded molecules. CONCLUSIONS Proteolytic enzymes were found to exert considerable effects on the barrier function of Caco-2 monolayers, facilitating the transport of normally non-absorbable compounds. This suggests the also reported, but so far unexplained, systemic absorption of proteolytic enzymes after oral administration in vivo may occur by self-enhanced paracellular transport.
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Affiliation(s)
- U Bock
- Department of Biopharmaceutics and Pharmaceutical Technology, University of the Saarland, Saarbrücken, Germany
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153
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De Angelis I, Vincentini O, Brambilla G, Stammati A, Zucco F. Characterization of furazolidone apical-related effects to human polarized intestinal cells. Toxicol Appl Pharmacol 1998; 152:119-27. [PMID: 9772207 DOI: 10.1006/taap.1998.8445] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In studying the effects of furazolidone (FZ) on the human intestinal Caco-2 cell line grown on microporous membrane, we have previously demonstrated a higher toxicity when the compound was administered at the apical (AP) side than at the basolateral (BL) side. Moreover, we have also shown the production, in the intact cells, of a nitroanion radical from FZ by a cytochrome c P450 reductase. The aim of the present study was to investigate which specific cell structures and functions are involved in the observed domain-related toxicity. The relevance of alterations in integrity and selective properties of the intestinal barrier as first-pass site for ingested molecules is also discussed. We have confirmed that, as expected, the Caco-2 cells are protected from FZ injury by a specific inhibitor of the cytochrome c P450 reductase, and we have shown that this protection is more active on the apical side of the cells. In sublethal conditions, FZ causes increased permeability to 3H-mannitol and, to a different extent, to 3H-inulin. Again the effect is higher when the cells are apically exposed. We have thus examined the tight junctions morphology: a disruption of the apical perijunctional actin-bound cytoskeleton was detected by rhodamine-phalloidin staining and microtubule disorganization by antitubulin fluoresceinated antibodies. Again, the effect was more evident when the cells were apically treated with FZ. Preferential transport and accumulation of the compound by active transport mechanisms could be excluded, since transport of FZ was linear and no intracellular accumulation was detected either from the AP and or the BL sides. All together these results may suggest that the AP formation of the active metabolite and its possible reactivity with SH groups of perijunctional microfilaments could be responsible of the higher FZ apical toxicity. This study shows that polarized differentiated cells are very interesting in vitro models to investigate specific cellular domains as targets of toxic effects and to detect subtle changes that may be induced, in absence of cell death, in specialized epithelial layers.
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Affiliation(s)
- I De Angelis
- Laboratorio di Tossicologia Comparata ed Ecotossicologia, Istituto Superiore di Sanita', Rome, Italy
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154
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Sakai M, Imai T, Ohtake H, Azuma H, Otagiri M. Effects of absorption enhancers on cytoskeletal actin filaments in Caco-2 cell monolayers. Life Sci 1998; 63:45-54. [PMID: 9667764 DOI: 10.1016/s0024-3205(98)00235-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Histomorphological changes of actin filaments, intracellular levels of calcium ion, and amount of released lactate dehydrogenase (LDH) were examined, in order to elucidate the mechanism of action of three absorption enhancers, i.e., sodium caprate (Cap-Na), sodium deoxycholate (Deo-Na), and dipotassium glycyrrhizinate (Grz-K), using Caco-2 cell monolayers. The structure of actin filaments in microvilli was slightly modified by 0.5 %(w/v) Grz-K and was significantly changed by 0.2 %(w/v) Cap-Na, 0.05 %(w/v) Deo-Na, and 0.0015 %(w/v) ionomycin. All of the enhancers, except Grz-K, induced significantly histomorphological changes in the actin filaments on the middle depth and basal side of the cells. Furthermore, the altered structure of the actin filaments in the monolayers was restored after removal of the Cap-Na, Grz-K and ionomycin, but not Deo-Na. Intracellular levels of calcium ion increased in the following order: ionomycin = Cap-Na > Deo-Na. However, the intracellular calcium ion levels decreased by treatment with Grz-K. The changes in transepithelial electric resistance (TEER) at the initial stage of treatment with all enhancers correlated with intracellular calcium ion levels. These results suggest that one of the mechanisms by which these agents exert absorption-enhancing activity involves structural alterations in the cytoskeletal actin filaments which are provoked by changes in intracellular calcium ion levels. Only the monolayers which were treated with 0.05 %(w/v) Deo-Na released a significant amount of LDH and irreversibly altered the structure of actin filaments, thus indicating that Deo-Na might affect the actin filaments not only by increasing intracellular calcium ion level but also by other, presently unknown factors.
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Affiliation(s)
- M Sakai
- Hisamitsu Pharmaceutical Co., Inc. Tsukuba Laboratories, Ibaraki, Japan
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155
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Lindmark T, Schipper N, Lazorová L, de Boer AG, Artursson P. Absorption enhancement in intestinal epithelial Caco-2 monolayers by sodium caprate: assessment of molecular weight dependence and demonstration of transport routes. J Drug Target 1998; 5:215-23. [PMID: 9606011 DOI: 10.3109/10611869808995876] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sodium caprate (C10), a medium chain fatty acid, is used clinically to enhance rectal absorption of the low molecular weight (MW) drug ampicillin. The main aim of this study was to investigate whether C10 also enhances the permeability of high MW model drugs in a model of the intestinal epithelium. The second aim was to present visual evidence of the route of enhanced transport across the epithelial cell layer. The studies were performed in Caco-2 monolayers cultured on permeable supports. The effects of non-toxic concentrations (< or = 13 mM) of C10 on drug transport across the monolayers was studied using monodisperse 14C-polyethylene glycols (MW 238-502; 14C-PEGs), 125I-Arg5-vasopressin (MW 1,208), 125I-insulin (MW 6,000) and FITC-labelled dextrans (MW 4,400 and 19,600; FD4 and FD20 respectively) as model drugs. Electron and confocal laser scanning microscopy were used to demonstrate transport routes across the epithelium. 10 mM C10 increased the permeability of all 14C-PEGs to approximately the same extent. 13 mM C10 increased the permeability of 125I-Arg8-vasopressin 10-fold. Only small increases in FD4 and FD20 permeabilities were observed. After C10 exposure, both tight junctions with normal morphology and those with dilatations showed an increased permeability to ruthenium red, indicating that C10 enhanced the paracellular transport of molecules with a MW < 1,000. Confocal microscopy showed that C10 increased the transport of FD4 and FD20 by the paracellular route. In conclusion, non-toxic concentrations of C10 can be used to enhance the permeability of drugs of MW up to approximately 1,200. Enhancement of the absorption of molecules larger than 4,000 is quantitatively insignificant. The enhanced permeability occurred via the paracellular pathway.
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Affiliation(s)
- T Lindmark
- Department of Pharmacy, Uppsala University, Sweden
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156
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Barthe L, Woodley JF, Kenworthy S, Houin G. An improved everted gut sac as a simple and accurate technique to measure paracellular transport across the small intestine. Eur J Drug Metab Pharmacokinet 1998; 23:313-23. [PMID: 9725499 DOI: 10.1007/bf03189357] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
An improved everted gut sac system has been developed in which the sacs were carefully prepared from rat small intestine and incubated in tissue culture medium. Under these conditions, the tissue showed good morphology at the electron microscope level, and was metabolically active for up to 2 h at 37 degrees C. Mannitol, an established probe of paracellular transport, was transported from the mucosal to the serosal side of the sac tissue. Excellent kinetic data showed that transport was linear up to 75 min and over a wide range of concentrations (0.025 - (10 mM). Mannitol was not detected in the tissue and transport was enhanced by EGTA, confirming the paracellular route of passage. Sacs prepared from colon also showed mannitol transport, but at a slower rate. Comparisons with Caco-2 cell monolayers showed that the everted sacs exhibited higher levels of paracellular transport than the cultured cell line. The improved everted gut sac system is an inexpensive and relatively simple technique with considerable potential as an in vitro tool to study the mechanisms, kinetics and enhancement of drug absorption across the small intestine at different sites and in the colon.
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Affiliation(s)
- L Barthe
- Equipe Cinétique des Xénobiotiques, Facultá des Sciences Pharmaceutiques, Toulouse, France
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157
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Shimazaki T, Tomita M, Sadahiro S, Hayashi M, Awazu S. Absorption-enhancing effects of sodium caprate and palmitoyl carnitine in rat and human colons. Dig Dis Sci 1998; 43:641-5. [PMID: 9539662 DOI: 10.1023/a:1018835829643] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We examined the enhancing action of sodium caprate and palmitoylcarnitine on the permeability of fluorescein isothiocyanate dextran 4000 as a paracellular permeant compound in isolated rat and human colon samples using the Ussing-type chamber method. In the absence of an enhancer, the permeation clearance of fluorescein isothiocyanate dextran 4000 was not significantly different in the rat and human colons, but the electric membrane resistance was smaller in the rat colon than in the human colon. Sodium caprate and palmitoylcarnitine increased permeation clearance and decreased electric membrane resistance in both types of colonic membrane, showing that the rat colon can be used as a model of the human colon for studies of enhancer effects. A calmodulin antagonist significantly inhibited the action of sodium caprate in both colonic membranes. However, it tended to promote the effects of palmitoylcarnitine on permeation clearance and electric membrane resistance. These results suggest that sodium caprate induces the contraction of the perijunctional actomyosin ring to widen the tight junction and that the mechanism of palmitoylcarnitine is different from that of sodium caprate in the human colon, as reported previously for Caco-2 cell monolayers.
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Affiliation(s)
- T Shimazaki
- Department of Biopharmaceutics, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan
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158
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Abstract
The high aqueous solubility of ionic compounds can be attributed to the ease of solvation of the counter ions. Replacement of the counter ions with ionic detergents dramatically alters the solubility properties of the molecule. Not only does the aqueous solubility drop precipitously, but the solubility in organic phases increases as well. Consequently, the partition coefficient changes by orders of magnitude. This ion pairing phenomenon, which we term hydrophobic ion pairing (HIP), has been extended to polyelectrolytes, such as proteins and polynucleotides. These materials form HIP complexes that dissolve in a range of organic solvents, often with retention of native structure and enzymatic activity. The HIP process has been used to purify protein mixtures, conduct enzymatic reactions in nonaqueous environments, increase structural stability, enhance bioavailability, and prepare new dosage forms.
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Affiliation(s)
- J D Meyer
- Center for Pharmaceutical Biotechnology, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA
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159
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Hayashi M, Tomita M, Awazu S. Transcellular and paracellular contribution to transport processes in the colorectal route. Adv Drug Deliv Rev 1997. [DOI: 10.1016/s0169-409x(97)00072-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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160
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Lutz KL, Siahaan TJ. Molecular structure of the apical junction complex and its contribution to the paracellular barrier. J Pharm Sci 1997; 86:977-84. [PMID: 9294808 DOI: 10.1021/js970134j] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- K L Lutz
- Department of Pharmacetutical Chemistry, University of Kansas, Lawrence 66047, USA
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161
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Lindmark T, Söderholm JD, Olaison G, Alván G, Ocklind G, Artursson P. Mechanism of absorption enhancement in humans after rectal administration of ampicillin in suppositories containing sodium caprate. Pharm Res 1997; 14:930-5. [PMID: 9244152 DOI: 10.1023/a:1012112219578] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE The medium chain fatty acid sodium caprate (C10) is approved as an absorption enhancer but its mechanism of action has not been studied in humans. The aim of this study was to investigate the mechanism of action of C10 in human subjects after rectal administration. METHODS Twelve healthy human subjects were randomised to receive ampicillin suppositories with (AM-C10) or without (AM) C10. Serum and urine samples were collected and analysed for ampicillin by HPLC. Rectal biopsies were taken before and 25 min (approximate time of maximum serum concentration, Cmax, for ampicillin) and 185 min (during the final part of the elimination phase) after rectal administration of the suppositories. The osmolality of the rectal fluid was also measured. RESULTS AM-C10 administration increased Cmax, area under the serum concentration-time curve (AUC) and urinary recovery of ampicillin 2.6-, 2.3- and 1.8-fold, respectively, compared to AM. Histological examination of the biopsies showed that AM-C10 exposure resulted in reversible mucosal damage that occurred at the same time as the Cmax for ampicillin while AM prolonged mucosal damage. A reversible increase in rectal fluid osmolality was observed with both treatments. CONCLUSIONS AM-C10-enhanced absorption of ampicillin coincides with non-specific damage to the rectal mucosa. C10 itself as well as the suppository base and the hyperosmolality of the rectal fluid contributed to this effect. However, the histological damage was reversible with AM-C10, suggesting that C10 also has a protective effect on the rectal mucosa.
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Affiliation(s)
- T Lindmark
- Dept. of Pharmacy, Uppsala University, Sweden
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162
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Sakai M, Imai T, Ohtake H, Azuma H, Otagiri M. Effects of absorption enhancers on the transport of model compounds in Caco-2 cell monolayers: assessment by confocal laser scanning microscopy. J Pharm Sci 1997; 86:779-85. [PMID: 9232516 DOI: 10.1021/js960529n] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Three typical absorption enhancers, i.e., sodium caprate (Cap-Na), sodium deoxycholate (Deo-Na), and dipotassium glycyrrhizinate (Grz-K), were compared in terms of their permeability-enhancing effects on hydrophilic and hydrophobic model compounds in Caco-2 cell monolayers. The transepithelial electrical resistance (TEER) of the monolayers was reduced concentration-dependently by treatment with Cap-Na and Deo-Na, while treatment with Grz-K increased the TEER. Two patterns of TEER reduction were observed: one pattern indicated that Cap-Na had a rapid reducing effect, and another indicated that Deo-Na had a delayed reducing effect. These reductions in the TEER were accompanied by the increased transepithelial transport of two hydrophilic model compounds, sodium fluorescein (Flu-Na; MW = 376, log P = -1.52) and fluorescein isothiocyanate-dextran 4000 (FD-4; MW = 4400, log P = -2.0), and one hydrophobic model compound, rhodamine 123 hydrate (Rh123; MW = 381, log P = 1.13). The transport-enhancing effects of Cap-Na and Deo-Na on these model compounds decreased in the following order: FD-4 > Rh123 > Flu-Na, while Grz-K was found to have no effect on the transport of any of these model compounds. Confocal laser scanning microscopy (CLSM) of Caco-2 cell monolayers revealed that Cap-Na and Deo-Na enhanced the transepithelial transport of the hydrophilic model compounds via the paracellular route and that of the hydrophobic model compound via both paracellular and transcellular routes. Semiquantitative visual information obtained from CLSM images reflected the results of the transport experiment.
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Affiliation(s)
- M Sakai
- Tsukuba Laboratories, Hisamitsu Pharmaceutical Company, Inc., Ibaraki, Japan
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163
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Dimitrijevic D, Lamandin C, Uchegbu IF, Shaw AJ, Florence AT. The effect of monomers and of micellar and vesicular forms of non-ionic surfactants (Solulan C24 and Solulan 16) on Caco-2 cell monolayers. J Pharm Pharmacol 1997; 49:611-6. [PMID: 9330201 DOI: 10.1111/j.2042-7158.1997.tb06854.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Measurements of transepithelial electrical resistance (TEER), the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) test and monitoring of poly(ethylene glycol) (PEG) transport have been used to study the effects of the non-ionic surfactants Solulan C24 and Solulan 16, either free in solution or as an integral part of niosome bi-layers, on intestinal epithelial cells from man (Caco-2 cell monolayers). The effects on epithelial integrity and on the transport of the hydrophilic drug metformin depend on the concentration of the surfactants. At concentrations above 1% the effect on TEER of the surfactant in niosomal form and free in solution were equivalent whereas cell viability was preserved to a higher concentration of Solulans when the Solulans were present in the niosomal form. It was concluded that the toxic effect of niosomes arises from free surfactant present in the niosome suspension.
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Affiliation(s)
- D Dimitrijevic
- Centre for Drug Delivery Research, School of Pharmacy, University of London, UK
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164
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Humberstone AJ, Charman WN. Lipid-based vehicles for the oral delivery of poorly water soluble drugs. Adv Drug Deliv Rev 1997. [DOI: 10.1016/s0169-409x(96)00494-2] [Citation(s) in RCA: 331] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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165
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Charman WN, Porter CJ, Mithani S, Dressman JB. Physiochemical and physiological mechanisms for the effects of food on drug absorption: the role of lipids and pH. J Pharm Sci 1997; 86:269-82. [PMID: 9050793 DOI: 10.1021/js960085v] [Citation(s) in RCA: 399] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Drugs are absorbed after oral administration as a consequence of a complex array of interactions between the drug, its formulation, and the gastrointestinal (GI) tract. The presence of food within the GI tract impacts significantly on transit profiles, pH, and its solubilization capacity. Consequently, food would be expected to affect the absorption of co-administered drugs when their physicochemical properties are sensitive to these changes. The physicochemical basis by which ingested food/lipids induce changes in the GI tract and influence drug absorption are reviewed. The process of lipid digestion is briefly reviewed and considered in the context of the absorption of poorly water-soluble drugs. The effect of food on GI pH is reviewed in terms of location (stomach, upper and lower small intestine) and the temporal relationship between pH and drug absorption. Case studies are presented in which postprandial changes in bioavailability are rationalized in terms of the sensitivity of the physicochemical properties of the administered drug to the altered GI environment.
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Affiliation(s)
- W N Charman
- Department of Pharmaceutics, Victorian College of Pharmacy, Monash University (Parkville Campus), Victoria, Australia
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166
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In vitro models for selection of development candidates. Permeability studies to define mechanisms of absorption enhancement. Adv Drug Deliv Rev 1997. [DOI: 10.1016/s0169-409x(96)00434-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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167
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Tötterman AM, Schipper NG, Thompson DO, Mannermaa JP. Intestinal safety of water-soluble beta-cyclodextrins in paediatric oral solutions of spironolactone: effects on human intestinal epithelial Caco-2 cells. J Pharm Pharmacol 1997; 49:43-8. [PMID: 9120769 DOI: 10.1111/j.2042-7158.1997.tb06750.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Effects of water-soluble beta-cyclodextrins (beta CDs) on intestinal epithelial integrity were investigated, to establish the safe use of these beta CDs as solubilizers of spironolactone in paediatric enteral solutions. Mannitol permeability and transepithelial resistance (TER) of human intestinal epithelial Caco-2 cell monolayers during exposure to dimethyl-beta-cyclodextrin (DM beta CD), hydroxypropyl-beta-cyclodextrin (HP beta CD) and sulphobutyl ether beta-cyclodextrin (SBE beta CD) were followed. Staining methods were used to discern cells with damaged membranes and to study the integrity of cytoskeletal actin and tight junctions. Cytotoxicity of the beta CDs was tested by effects on intracellular dehydrogenase activity. Exposure to HP beta CD and SBE beta CD solutions had only minor effects on the integrity of Caco-2 cell monolayers. In contrast, DM beta CD clearly increased the epithelial permeability for the hydrophilic marker [14C]mannitol across Caco-2 monolayers, decreased TER and showed a dose-dependent cytotoxicity. According to staining, DM beta CD increased the permeability of the apical cell membrane without discernable effects on cytoskeletal actin. HP beta CD and SBE beta CD appear to be safe additives for use in enteral spironolactone preparations with respect to their acute local effects on epithelial integrity.
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Affiliation(s)
- A M Tötterman
- Department of Pharmacy, University of Helsinki, Finland
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168
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Yamamoto A, Uchiyama T, Nishikawa R, Fujita T, Muranishi S. Effectiveness and toxicity screening of various absorption enhancers in the rat small intestine: effects of absorption enhancers on the intestinal absorption of phenol red and the release of protein and phospholipids from the intestinal membrane. J Pharm Pharmacol 1996; 48:1285-9. [PMID: 9004192 DOI: 10.1111/j.2042-7158.1996.tb03937.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sodium glycocholate, sodium taurocholate, sodium deoxycholate, EDTA, sodium salicylate, sodium caprate, diethyl maleate, N-lauryl-beta-D-maltopyranoside, linoleic acid polyoxyethylated (60 mol) mixed micelles (all 20 mM) have been ranked in order of their effectiveness as enhancers of the absorption of drugs in the rat small intestine, by use of an in-situ loop model with phenol red as a model drug. Local toxicity in rats was examined by assessing protein and phospholipid release as biological markers. Of the absorption enhancers, sodium deoxycholate, EDTA and N-lauryl-beta-D-maltopyranoside were the most effective; sodium deoxycholate and EDTA, however, caused significant release of protein and phospholipids. N-lauryl-beta-D-maltopyranoside, on the other hand, did not damage the small intestinal membrane. Sodium taurocholate enhanced phenol red absorption from the small intestine and resulted in little or no protein and phospholipids release. Sodium salicylate, diethyl maleate and the mixed micelles had no absorption-promoting effects on phenol red. There was good correlation between the area under the plasma concentration-time curve for phenol red and the amounts of protein and phospholipid released in the presence of absorption enhancers. From these results it might be concluded that N-lauryl-beta-D-maltopyranoside and sodium taurocholate are effective absorption enhancers which have low toxicity levels at a concentration of 20 mM.
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Affiliation(s)
- A Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Japan
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169
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170
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Werner U, Kissel T. In-vitro cell culture models of the nasal epithelium: a comparative histochemical investigation of their suitability for drug transport studies. Pharm Res 1996; 13:978-88. [PMID: 8842033 DOI: 10.1023/a:1016038119909] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE To evaluate different in-vitro cell culture models for their suitability to study drug transport through cell monolayers. METHODS Bovine turbinate cells (BT; ATCC CRL 1390), human nasal septum tumor cells (RPMI, 2650; ATCC CCL 30), and primary cell cultures of human nasal epithelium were characterized morphologically and histochemically by their lectin binding properties. The development of tight junctions in culture was monitored by actin staining and transepithelial electrical resistance measurements. RESULTS The binding pattern of thin-sections of excised human nasal respiratory epithelium was characterized using a pannel of fluorescently-labelled lectins. Mucus in goblet cells was stained by PNA, WGA and SBA, demonstrating the presence of terminal N-acetylglucosamine, N-acetylgalactosamine and galactose residues respectively in the mucus of human nasal cells. Ciliated cells revealed binding sites for N-acetylglucosamine, stained by WGA, whereas Con A, characteristic for mannose moieties, labelled the apical cytoplasm of epithelial cells. Binding sites for DBA were not present in this tissue. Comparing three different cell culture models: BT, RPMI 2650, and human nasal cells in primary culture using three lectins (PNA, WGA, Con A) as well as intracellular actin staining and transepithelial electrical resistance measurements we found, that only human nasal epithelial cells in primary culture showed differentiated epithelial cells, ciliated nasal cells and mucus producing goblet cells, which developed confluent cell monolayers with tight junctions. CONCLUSIONS Of the in-vitro cell culture models studied, only human nasal cells in primary culture appears to be suitable for drug transport studies.
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Affiliation(s)
- U Werner
- Department of Pharmaceutics and Biopharmacy, University of Marburg, Germany
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171
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Tomita M, Hayashi M, Awazu S. Absorption-enhancing mechanism of EDTA, caprate, and decanoylcarnitine in Caco-2 cells. J Pharm Sci 1996; 85:608-11. [PMID: 8773957 DOI: 10.1021/js9504604] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The mechanism of paracellular expansion by absorption enhancers, e.g., EDTA, sodium caprate (C10), and decanoylcarnitine (DC), was studied, the focus being on the process of actin microfilament contraction in the tight junction. The effects of various inhibitors such as KN-62 (a specific inhibitor of Ca2+/calmodulin dependent protein kinase), H7 (a protein kinase C (PKC) inhibitor), and W7 (a calmodulin antagonist) were examined on the paracellular expansion by the enhancers in Caco-2 cells. From the experimental results, the following mechanisms were suggested. EDTA activates PKC by depletion of extracellular calcium via chelation resulting in expansion of the paracellular route. C10 increases the intracellular calcium level by an interaction with the cell membrane independent of cell polarity resulting in contraction with actin microfilament. DC interacts specifically with the apical membrane to increase the intracellular calcium level, but the mechanistic details subsequent to the increase of calcium are not clear.
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Affiliation(s)
- M Tomita
- Department of Biopharmaceutics, Tokyo University of Pharmacy and Life Science, Japan
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172
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Walter E, Kissel T. Heterogeneity in the human intestinal cell line Caco-2 leads to differences in transepithelial transport. Eur J Pharm Sci 1995. [DOI: 10.1016/0928-0987(95)00010-b] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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173
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Boulenc X, Breul T, Gautier JC, Saudemon P, Joyeux H, Roques C, Berger Y, Fabre G. Sodium lauryl sulphate increases tiludronate paracellular transport using human epithelial caco-2 monolayers. Int J Pharm 1995. [DOI: 10.1016/0378-5173(95)00041-g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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174
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Werner U, Kissel T. Development of a human nasal epithelial cell culture model and its suitability for transport and metabolism studies under in vitro conditions. Pharm Res 1995; 12:565-71. [PMID: 7596993 DOI: 10.1023/a:1016210231121] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A human nasal epithelial cell culture model has been adapted to observe transport and metabolism of drugs, e.g., peptides. Human nasal epithelial cells, isolated by protease treatment of human nasal conchae, grew to confluency after 6-8 days using DMEM supplemented with 1% nonessential amino acids, 1% glutamine, 10% FCS and 1% antibiotics. These cultures expressed microvilli and actively beating cilia as documented by light microscopy and scanning electron microscopy (SEM). Tight junctions were confirmed by dome formation and positive actin staining using FITC-labelled phalloidin. Preliminary transport studies, carried out with FITC-labelled Dextran (FD 4, MW 4400) and Sulforhodamine (SR 101, MW 607), demonstrated the intact barrier function of the cultured monolayer, grown on filter membranes. In addition, the cultured cells metabolized Leu-Enkephalin to Des-Tyr-Leu-Enkephalin demonstrating the presence of aminopeptidase, a naturally occurring enzyme in the human nasal mucosa.
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Affiliation(s)
- U Werner
- Department of Pharmaceutics and Biopharmacy, University of Marburg, Germany
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175
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Drug delivery studies in Caco-2 monolayers. II. Absorption enhancer effects of lysophosphatidylcholines. Int J Pharm 1995. [DOI: 10.1016/0378-5173(94)00232-t] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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176
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Drug delivery studies in Caco-2 monolayers. III. Intestinal transport of various vasopressin analogues in the presence of lysophosphatidylcholine. Int J Pharm 1995. [DOI: 10.1016/0378-5173(94)00233-u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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177
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Björk E, Isaksson U, Edman P, Artursson P. Starch microspheres induce pulsatile delivery of drugs and peptides across the epithelial barrier by reversible separation of the tight junctions. J Drug Target 1995; 2:501-7. [PMID: 7773612 DOI: 10.3109/10611869509015920] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Non-parenteral administration of peptide drugs is prevented by the limited permeability of the epithelia lining the mucosal tissues. As a new approach to non-parenteral delivery, degradable starch microspheres (dsm) were coated with insulin and administered to the mucosal side of monolayers of human intestinal epithelial (Caco-2) cells in vitro. The microspheres induced a pulsed delivery of insulin across the epithelium that lasted for 1-2 h. The pulsed delivery correlated with a reversible appearance of focal dilatations in the tight junctions between the epithelial cells, indicating that dsm enhance the delivery of insulin by the paracellular route. These results provide an explanation for the previously observed absorption enhancing properties of dsm.
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Affiliation(s)
- E Björk
- Dept. of Pharmaceutics, Uppsala University, Sweden
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178
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Adson A, Raub TJ, Burton PS, Barsuhn CL, Hilgers AR, Audus KL, Ho NF. Quantitative approaches to delineate paracellular diffusion in cultured epithelial cell monolayers. J Pharm Sci 1994; 83:1529-36. [PMID: 7891269 DOI: 10.1002/jps.2600831103] [Citation(s) in RCA: 217] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
When using cultured cell monolayers to determine the mechanism of transcellular diffusion of molecules, it may be important to identify the fraction that moves through the paracellular route or passively diffuses through tight junctions. We characterized the apparent diameter of the junctional pore in a variety of epithelial cell monolayers (Caco-2, MDCK, alveolar). Using hydrophilic extracellular permeants varying in molecular radii and charge (neutral, anionic, cationic, zwitterionic), rate-determining steps and factors of the paracellular route were quantitatively delineated by the model for molecular size-restricted diffusion within a negative electrostatic field of force. Protonated amines permeated the pores faster than their neutral images while organic anions were slower. With increasing molecular size the influence of charge diminished. This approach was used to quantify the relationship between permeant radius and transepithelial electrical resistance and to analyze changes in junctional pore size as a function of pharmacological perturbation, such as in the use of absorption promoters or adjuvants.
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Affiliation(s)
- A Adson
- Pharmaceutical Chemistry Department, University of Kansas, Lawrence 66045
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179
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P49 Paracellular absorption enhancement in intestinal CACO-2 monolayers by sodium caprate. Eur J Pharm Sci 1994. [DOI: 10.1016/0928-0987(94)90222-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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180
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Relative contribution of phosphatidylcholine and monoglyceride to absorption enhancement of low molecular weight heparin (Fragmin) by a new lipid-based drug delivery system in monolayers of human intestinal epithelial Caco-2 cells and after rectal administration to rabbits. Eur J Pharm Sci 1994. [DOI: 10.1016/0928-0987(94)90039-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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181
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Effects of a new lipid-based drug delivery system on the absorption of low molecular weight heparin (Fragmin) through monolayers of human intestinal epithelial Caco-2 cells and after rectal administration to rabbits. Eur J Pharm Sci 1994. [DOI: 10.1016/0928-0987(94)90038-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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182
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Hochman J, Artursson P. Mechanisms of absorption enhancement and tight junction regulation. J Control Release 1994. [DOI: 10.1016/0168-3659(94)90072-8] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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183
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Wan-Ching Y, Lee VH. Paracellular transport of a proteolytically labile pentapeptide across the colonic and other intestinal segments of the albino rabbit: implications for peptide drug design. J Control Release 1994. [DOI: 10.1016/0168-3659(94)90157-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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184
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Jørgensen L, Artursson P, Bechgaard E. Toxicological and absorption enhancing effects of glycofurol 75 and sodium glycocholate in monolayers of human intestinal epithelial (Caco-2) cells. Int J Pharm 1993. [DOI: 10.1016/0378-5173(93)90408-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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