The effect of propane-diols on the intestinal uptake of nutrients and brush border membrane enzymes in the rat

Re-evaluation of propane-1,2-diol (E 1520) as a food additive

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of propane-1,2-diol (E 1520) when used as a food additive. In 1996, the Scientific Committee on Food (SCF) established an acceptable daily intake (ADI) of 25 mg/kg body weight (bw) per day for propane-1,2-diol. Propane-1,2-diol is readily absorbed from the gastrointestinal and is expected to be widely distributed to organs and tissues. The major route of metabolism is oxidation to lactic acid and pyruvic acid. At high concentrations, free propane-1,2-diol is excreted in the urine. No treatment-related effects were observed in subchronic toxicity studies. The available data did not raise concern with respect to genotoxicity. Haematological changes suggestive of an increased red blood cell destruction with a compensatory increased rate of haematopoiesis were observed at the highest dose level (5,000 mg/kg bw per day) in a 2-year study in dogs. No adverse effects were reported in a 2-year chronic study in rats with propane-1,2-diol (up to 2,500 mg/kg bw per day). The SCF used this study to derive the ADI. No adverse effects were observed in the available reproductive and developmental toxicity studies. Propane-1,2-diol (E 1520) is authorised according to Annex III in some food additives, food flavourings, enzymes and nutrients and it is then carried over to the final food. Dietary exposure to E 1520 was assessed based on the use levels and analytical data. The Panel considered that for the food categories for which information was available, the exposure was likely to be overestimated. Considering the toxicity database, the Panel concluded that there was no reason to revise the current ADI of 25 mg/kg bw per day. The Panel also concluded that the mean and the high exposure levels (P95) of the brand-loyal refined exposure scenario did not exceed the ADI in any of the population groups from the use of propane-1,2-diol (E 1520) at the reported use levels and analytical results.

Effectiveness and Safety of a Probiotic-Mixture for the Treatment of Infantile Colic: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial with Fecal Real-Time PCR and NMR-Based Metabolomics Analysis

Introduction: To investigate the effectiveness and the safety of a probiotic-mixture (Vivomixx^®, Visbiome^®, DeSimone Formulation^®; Danisco-DuPont, Madison, WI, USA) for the treatment of infantile colic in breastfed infants, compared with a placebo. Methods: A randomized, double-blind, placebo-controlled trial was conducted in exclusively breastfed infants with colic, randomly assigned to receive a probiotic-mixture or a placebo for 21 days. A structured diary of gastrointestinal events of the infants was given to the parents to complete. Samples of feces were also collected to evaluate microbial content and metabolome using fecal real-time polymerase chain reaction (qPCR) and Nuclear magnetic resonance (NMR)-based analysis. Study registered at ClinicalTrials.gov (NCT01869426). Results: Fifty-three exclusively-breastfed infants completed three weeks of treatment with a probiotic-mixture (n = 27) or a placebo (n = 26). Infants receiving the probiotic-mixture had less minutes of crying per day throughout the study by the end of treatment period (68.4 min/day vs. 98.7 min/day; p = 0.001). A higher rate of infants from the probiotic-mixture group responded to treatment (defined by reduction of crying times of ≥50% from baseline), on day 14, 12 vs. 5 (p = 0.04) and on day 21, 26 vs. 17 (p = 0.001). A higher quality of life, assessed by a 10-cm visual analogue scale, was reported by parents of the probiotic-mixture group on day 14, 7.1 ± 1.2 vs. 7.7 ± 0.9 (p = 0.02); and on day 21, 6.7 ± 1.6 vs. 5.9 ± 1.0 (p = 0.001). No differences between groups were found regarding anthropometric data, bowel movements, stool consistency or microbiota composition. Probiotics were found to affect the fecal molecular profile. No adverse events were reported. Conclusions: Administration of a probiotic-mixture appears safe and reduces inconsolable crying in exclusively breastfed infants.

Safety assessment of propylene glycol, tripropylene glycol, and PPGs as used in cosmetics

Propylene glycol is an aliphatic alcohol that functions as a skin conditioning agent, viscosity decreasing agent, solvent, and fragrance ingredient in cosmetics. Tripropylene glycol functions as a humectant, antioxidant, and emulsion stabilizer. Polypropylene glycols (PPGs), including PPG-3, PPG-7, PPG-9, PPG-12, PPG-13, PPG-15, PPG-16, PPG-17, PPG-20, PPG-26, PPG-30, PPG-33, PPG-34, PPG-51, PPG-52, and PPG-69, function primarily as skin conditioning agents, with some solvent use. The majority of the safety and toxicity information presented is for propylene glycol (PG). Propylene glycol is generally nontoxic and is noncarcinogenic. Clinical studies demonstrated an absence of dermal sensitization at use concentrations, although concerns about irritation remained. The CIR Expert Panel determined that the available information support the safety of tripropylene glycol as well as all the PPGs. The Expert Panel concluded that PG, tripropylene glycol, and PPGs ≥3 are safe as used in cosmetic formulations when formulated to be nonirritating.

The effects of pharmaceutical excipients on drug disposition

Many new chemical entities are poorly soluble, requiring the use of co-solvents or excipients to produce suitable intravenous formulations for early pre-clinical development studies. There is some evidence in the literature that these formulation components can have significant physiological and physicochemical effects which may alter the distribution and elimination of co-administered drugs. Such effects have the potential to influence the results of pre-clinical pharmacokinetic studies, giving a false impression of a compound's intrinsic pharmacokinetics and frustrating attempts to predict the drug's ultimate clinical pharmacokinetics. This review describes the reported effects of commonly used co-solvents and excipients on drug pharmacokinetics and on physiological systems which are likely to influence drug disposition. Such information will be useful in study design and evaluating data from pharmacokinetic experiments, so that the potential influence of formulation components can be minimised.

Effect of propane-1,2-diol ingestion on carbohydrate metabolism in female rat erythrocytes

This study was undertaken to assess the effect of propane-1,2-diol(PD) ingestion on carbohydrate metabolism in female rat erythrocytes. For this purpose, two different groups of adult albino female rats were treated orally with PD at two different dose levels of 73 and 294 mg 100 g-1 body wt. The blood samples drawn from the retro-orbital sinus prior to the treatment served as the controls, whereas the treated samples were collected at peak periods (1/2 and 2 h) 2 and 7 days after the treatment. A single dose of PD was found to elevate levels of blood glucose, lactate, pyruvate and the lactate/pyruvate ratio at the peak periods (P < 0.001) and after 2 days (P < 0.001) in both the groups. A significant (P < 0.05) increase in the contents of erythrocyte 2,3-diphosphoglycerate (2,3-DPG) was observed only at the peak periods. All these parameters returned to their base level after 7 days of treatment. The activities of hexokinase (HK), 2,3-diphosphoglycerate phosphatase (2,3-DPG Pase), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PD), 6-phosphogluconate dehydrogenase (6-PGD) and aldehyde reductase II (AR II) declined markedly, whereas those of pyruvate kinase (PK) and aldose reductase increased as a result of PD ingestion. The changes in the activities of 2,3-DPG Pase and LDH were persistent up to 8 days post-treatment. The [14C]glucose flux through glycolysis and the hexose monophosphate shunt pathway in erythrocytes was found to be lowered (P < 0.001) in response to PD treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of propylene glycol metabolism in lactatemia in the rabbit

Propylene glycol (1,2-propanediol PD) has been reported to significantly alter the blood parameters when administered as a drug vehicle. In this study, experiments were performed to estimate the pH, levels of PD, and its metabolites to determine the acute effect of PD in blood. PD was administered to rabbits orally in a single dose of 1 ml 28.4% aqueous solution per 100 g body weight equivalent to 38.66 mmol/kg. Whole blood pH and the levels of PD and metabolites were estimated at fast (O.O h, before feeding PD) and at 0.25, 1, and 3 h after the dose. PD elevated the concentrations of blood PD to its maximum (41.04 +/- 9.98 mmol/liter, n = 4) at 1 h; whereas blood PD is normally absent during fasting. PD significantly increased (P less than 0.01) the concentration of L-lactate in blood, which reached its plateau (2.55 +/- 0.62 mmol/liter, n = 4) at 0.25 h and was 2.45-fold higher than the observed fasted values (1.04 +/- 0.22 mmol/liter, n = 4). Production of D-lactate in blood was similarly increased significantly from 5.1 +/- 5.0 mumols/liter at fast to 150.0 +/- 30.4 mumols/liter at 3 h after oral PD (P less than 0.001, n = 4). As was observed in the fasted blood of PD treated rabbits, D-lactate levels at fast and after saline ingestion in the control animals was found either absent or too low. Despite this increase in lactate, blood pH did not alter significantly when appropriate anticoagulant, i.e., heparin + 4-methylpyrazole, was employed.(ABSTRACT TRUNCATED AT 250 WORDS)