Gastrointestinal transit time

JL Madsen. Effects of gender, age, and body mass index on gastrointestinal transit times. Digest Dis Sci 37 1548-1553, 1992. 

JMC Price, SS Davis, IR Wilding. The effect of fibre on gastrointestinal transit times in vegetarians and omnivores. Int J Pharmaceut 76 123-141, 1991. 

SY Choe, E Lipka, LX Yu, JR Crison, GL Amidon. Optimization of dosage form release parameters based on pharmacokinetic and gastrointestinal transit time considerations. Pharm Res 13 S292, 1996. 

A. M., Lanteri, E., Cataiano, F., Influence of aging on gastrointestinal transit time - An ultrasonographic and radiologic study, Invest. Radiol. 1999, 34, 357-359. 

Di Lorenzo C, Dooley CP, Valenzula JE Role of fasting gastrointestinal motility in the variability of gastrointestinal transit time assessed by hydrogen breath test. Gut 1991 32 1127-1130. 

Since ferrets eat only their caloric requirements, and since their gastrointestinal transit time is short (3-5 h), it is recommended that they receive diet ad libitum. Dry cat food was previously recommended for ferrets however, there are now at least two standardized ferret chows commercially available. The most important dietary variable is the quality of the protein, and ferrets appear to do best with a high percentage of animal protein in their diet (Morton and Morton, 1985). Feed consumption will be higher in the fall and winter and lower in the spring and... 

The expected Cmax and AUC for each of the profiles are listed in Table 3. The profiles are predicted to show an acceptable range of Cmax values with around 20% difference between the fast and medium formulations and between the medium and slow formulations. The predicted differences in AUC are only related to the slightly different content of the three formulations, reflected in the Finf values (100% for the fast formulation and 102% for the other formulations). Normally, AUC is not expected to be rate-dependent unless there is some non-linear process involved in the disposition of the drug or drug release or absorption is very slow compared to gastrointestinal transit time. Given the predicted Cmax differences, these three formulations are appropriate choices for an IVIVC study as they show acceptable in vitro and predicted in vivo differences. 

Gastrointestinal transit time by hydrogen breath test and radio-opaque markers Gastrointestinal motiUty agents... 

Pearson, R.A. and Merritt, J.B. (1991) Intake, digestion and gastrointestinal transit time... 

Krenzelok EP, KeUer R, Stewart RD. Gastrointestinal transit times of cathartics combined with charcoal. Ann Emerg Med 1985 14 1152-5. 

R. Schwarz, A. Kaspar, J. Seelig, B. Kunnecke, Gastrointestinal transit times in mice and humans measured with Al and F nuclear magnetic resonance, Magn. Reson. Med. 48 (2002) 255-261. 

Robinson. Barley bran flour accelerates gastrointestinal transit time. J Amer HV062 Diet Ass 1993 93(8) 881-885. 

Cockcroft A. E., M. McDermott, J. H. Edwards, and P. McCarthy. Grain exposure— symptoms and lung function. Eur JRespirDis 1983 64(3) 189-196. Lupton J. R., J. L. Morin, and M. C. Robinson. Barley bran flour accelerates gastrointestinal transit time. J Am Diet Assoc 1993 93(8) 881-885. Thorbum A., J. Muir], and]. Proietto. Carbohydrate fermentation decreases hepatic glucose output in healthy subjects. Metabolism 1993 42(6) 780-785. 

Methyinaltrexone is a quaternary derivative of the opioid antagonist, naltrexone. The addition of the methyl group forms a compound with greater polarity and lower lipid solubility, so that it is poorly absorbed, and does not cross the blood-brain barrier. Methyinaltrexone distributes selectively (>200-fold selectivity) to peripheral receptors. In human trials it prevented morphine-induced delay in gastrointestinal transit time, while sparing centrally mediated analgesic effects. 

Mebendazole probably acts by inhibiting microtubule synthesis the parent drug appears to be the active form. Efficacy of the drug varies with gastrointestinal transit time, with intensity of infection, and perhaps with the strain of parasite. The drug kills hookworm, ascaris, and trichuris eggs. 

Sugimoto, K., et al. 1998. Evaluation of poly(vinyl alcohol)-gel spheres containing chitosan as dosage form to control gastrointestinal transit time of drugs. Biol Pharm Bull 21 1202. 

H. Bechgaard, K. Ladefoged, Gastrointestinal transit time of single-unit tablets, J Pharm Pharmacol 33 791-792 (1981). 

Most peptides and proteins are currently formulated as parenteral formulations because of their poor oral bioavailability. Nevertheless, oral delivery of peptides and proteins would be the preferred route of administration if bioavailability issues could be overcome, as it offers the advantages of convenient, pain-free administration. Although various factors such as permeability, chemical and metabolic stability and gastrointestinal transit time can affect the rate and extent of absorption of orally administered peptides and proteins, molecular size is generally considered the ultimate obstacle [36]. 

Patients with liver disease may have an increased gastrointestinal transit time [3]. These patients may benefit from taking a pro-kinetic agent, as normalisation of gastrointestinal motility will reduce the time available for the absorption of nitrogenous compounds that may precipitate encephalopathy. The use of pro-kinetic agents has also been shown to reduce intestinal bacterial overgrowth in patients with cirrhosis [4-6]. 

Constipation is commonly encountered with cyclizine, owing to its anticholinergic effect. It is also a problem with the SHTj-receptor antagonists as a result of increased gastrointestinal transit time, although the incidence appears to be greater with ondansetron. Dry mouth is seen with cyclizine, prochlorperazine and promethazine. Metoclopramide has been documented as causing diarrhoea. 

The relative concentration of the pharmacologically active S enantiomer of ibuprofen (S R ratio) increases with prolongation of the gastrointestinal transit time of racemic formulations due to a corresponding increase in chiral inversion of the R to S enantiomer in the gut (25). Administration of S-ibuprofen, therefore, reduces the formulation-dependent variability in the concentration of the active enantiomer in the body. 

Oral absorption may be decreased as a percentage of administered dose at high doses. This can occur if the gastrointestinal transit time is less than the time required for complete absorption. This is sometimes the case with poorly absorbed drugs and drugs with poor solubility. 

Certain other patients are especially sensitive to the gastrointestinal effects of sorbitol for example, diabetics can be prone to sorbitol intolerance, because of altered gastrointestinal transit time and motility. Some of them also have a higher consumption of sorbitol-containing dietary foods. Patients on chronic hemodialysis can be predisposed to sorbitol intolerance as a result of carbohydrate malabsorption (25). 

Thumshirn M, Coulie B, Camilleri M, Zinsmeister AR, Burton DD, Van Dyke C. Effects of alosetron on gastrointestinal transit time and rectal sensation in patients with irritable bowel syndrome. Ahment Pharmacol Ther 2000 14(7) 869-78. 

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