betadex and Diarrhea

This study was conducted to assess the safety and tolerability of the alternative formulation vehicles polysorbate 80 (PS80), propylene glycol (PG), and hydroxypropyl-beta-cyclodextrin (HPβCD) in general toxicology studies in the mouse, rat, dog, and monkey. Twenty (20) mg/kg of hydroxypropyl methylcellulose (MC, control), 10 mg/kg PS80, 1000 mg/kg PG, 500 mg/kg HPβCD, or 1000 mg/kg HPβCD were administered by oral gavage to mice, rats, dogs, and cynomolgus monkeys for approximately 90 days. The effects of these formulations on clinical observations, body weight and food consumption parameters, clinical pathology, and histopathology were evaluated across all species. The suitability of formulations containing up to 20 mg/kg MC, 10 mg/kg PS80, and 1000 mg/kg PG for use in preclinical safety studies was confirmed by a lack of effects on all parameters examined. However, formulations containing HPβCD produced elevated transaminase (aspartate and alanine aminotransferase) levels in rats and mice and fecal changes (loose and soft stool) in large animals. Although the etiology and toxicological significance of the transaminase elevations in rats and mice is uncertain, this finding could represent a significant liability for a preclinical formulation because of the critical importance of these biomarkers in the risk assessment of novel therapeutic agents. Based on these data, PS80 and PG are considered to be practical alternatives to MC in preclinical toxicology studies. However, formulations containing HPβCD should be used with caution because of the elevations in rodent transaminase levels.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Administration, Oral; Alanine Transaminase; Animals; Aspartate Aminotransferases; beta-Cyclodextrins; Diarrhea; Dogs; Female; Hypromellose Derivatives; Liver; Liver Function Tests; Macaca fascicularis; Male; Methylcellulose; Mice; Pharmaceutical Vehicles; Polysorbates; Propylene Glycol; Rats; Toxicity Tests

Enteropathogenic Escherichia coli (EPEC) is a significant cause of paediatric diarrhoea worldwide. Virulence requires adherence to intestinal epithelial cells, mediated in part through type IV bundle-forming pili (BFP), and the EPEC protein Tir. Tir is inserted into the enterocyte plasma membrane (PM), resulting in the formation of actin-rich pedestals. Tir is translocated by the type III secretion system (TTSS), through a pore comprised of EPEC proteins inserted into the PM. Here, we demonstrate that in the absence of BFP, EPEC adherence, effector translocation and pedestal formation are dependent on lipid rafts. Lipid raft disruption using methyl-beta-cyclodextrin (MbetaCD) decreased adherence by an EPEC BFP-deficient strain from 85% to 1%. Translocation of the effectors Tir and EspF was blocked by MbetaCD treatment, although the TTSS pore still formed. MbetaCD treatment after Tir delivery decreased pedestal formation by EPEC from 40% to 5%, but not by the related pathogen E. coli O157:H7 which uses a different Tir-based mechanism. In contrast, EPEC expressing the BFP can circumvent the requirement for membrane cholesterol. This suggests that lipid rafts play a role in virulence of this medically important pathogen.

Topics: Bacterial Adhesion; beta-Cyclodextrins; Carrier Proteins; Cell Membrane; Cholesterol; Diarrhea; Enterocytes; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Fimbriae, Bacterial; Humans; Intracellular Signaling Peptides and Proteins; Membrane Microdomains; Protein Transport; Receptors, Cell Surface

Following the unexpected activity of the excipient beta-cyclodextrin against experimental infection by Cryptosporidium parvum in suckling mice, its efficacy in the prevention and treatment of natural infections in lambs was evaluated under field conditions. Fifty-three crossbred neonatal lambs were randomly selected for the study. Treatment consisted of oral administration of an aqueous suspension of beta-cyclodextrin at a dose of 500 mg/kg of body weight. To test prophylactic efficacy, the suspension was administered at 1, 2 and 3 days of age. To evaluate therapeutic efficacy, the suspension was administered on each of the 3 days following onset of diarrhoea. Infection was monitored by daily examination of faecal samples, from birth to 30 days. The criteria studied in evaluating efficacy were: oocyst shedding, the presence of diarrhoea, and weight gain at 15 and 30 days. In the group that received prophylactic treatment with beta-cyclodextrin, there were no mortalities and, compared with control lambs, there was a decrease in the number of animals infected, a longer prepatent period and notable reduction in the patent period and the duration of diarrhoea. Therapeutic treatment also reduced the patent period and the severity of diarrhoea. beta-cyclodextrin was well tolerated by all of the treated animals.

Topics: Animals; Animals, Newborn; beta-Cyclodextrins; Cryptosporidiosis; Cryptosporidium parvum; Cyclodextrins; Diarrhea; Feces; Female; Male; Parasite Egg Count; Sheep; Sheep Diseases; Spain; Statistics, Nonparametric; Weight Gain

The effectiveness of beta-cyclodextrin, excipient used in pharmaceutical industry, in the treatment of natural infection by Cryptosporidium parvum in suckling calves, was evaluated. Administration of the drug at a dose of 500 mg/kg body weight for 3 consecutive days from birth (prophylactically) or following confirmation of the infection (therapeutically) decreased the severity of diarrhoea and shortened the duration of oocyst shedding.

Topics: Animals; Animals, Suckling; beta-Cyclodextrins; Cattle; Cattle Diseases; Coccidiostats; Cryptosporidiosis; Cryptosporidium parvum; Cyclodextrins; Diarrhea; Feces; Female; Male; Parasitic Sensitivity Tests