Impact of shielding parenteral nutrition from light on routine monitoring of blood glucose and triglyceride levels in preterm neonates.

BACKGROUND: Premature infants are vulnerable to complications related to oxidative stress. Exposure to light increases oxidation products in solutions of total parenteral nutrition (TPN) such as lipid peroxides and hydrogen peroxide. Oxidative stress impairs glucose uptake and affects lipid metabolism. HYPOTHESIS: products of photo-oxidation contaminating TPN affect lipid metabolism. OBJECTIVE: Evaluate the effect of photoprotection of TPN in preterm infants on plasma glucose and triglyceride (TG) concentrations. DESIGN: Secondary analysis of a prospective study allocating preterm infants to light-exposed (LE, n = 32) or light-protected (LP, n = 27) TPN. SETTING: Level III NICU referral centre for patients of British Columbia. PATIENTS: Preterm infants requiring TPN. INTERVENTIONS AND OUTCOME MEASURES: TG and blood glucose measured during routine monitoring while on full TPN were compared between LE and LP. RESULTS: Clinical characteristics were similar between the two groups (gestational age 28+/-1 wk; birth weight: 1.0+/-0.1 kg). Nutrient intakes from TPN and from minimal enteral nutrition were comparable between LE and LP. Blood glucose was higher in preterm infants receiving LE (p<0.001). The accumulation of TG with increasing lipid intake was twice as high with LE accounting for significantly higher TG levels on days 8 and 9 (p<0.05). CONCLUSIONS: Failure to photoprotect TPN may cause alterations in intermediary metabolism. Shielding TPN from light provides a potential benefit for preterm infants by avoiding hypertriglyceridaemia allowing for increased substrate delivery.

Stability of imidacloprid (Premise 75) in a tank-mixed aqueous solution when stored in shade or sunlight.

Polyethylene tanks are commonly used by pest management professionals to mix and apply termiticides. These termiticides are susceptible to rapid photolysis and the ability of application tanks to filter sunlight has been questioned. We investigated the stability of imidacloprid (Premise 75) in aqueous solutions stored in polyethylene tanks under shade or sunlight. Chemical analysis of aqueous solutions sampled at 0, 24, 48, 72, 168 and 336 h revealed that imidacloprid was relatively stable. Our results indicate that polyethylene tanks are adequate to protect imidacloprid from photo degradation.

Photodegradation studies on lacidipine in solution: basic experiments with a cis-trans reversible photoequilibrium under UV-A radiation exposure.

The photostability of Lacidipine, a dihydropyridine drug used in the treatment of mild and moderate hypertension, was studied in solutions exposed to UV-A radiations. The effects of the solvent (ethanol, acetone, dichloromethane), drug concentration and radiation wavelength on the drug photostability were evaluated. Lacidipine and its photoproducts were separated by a selective liquid chromatographic (HPLC) method, under normal phase conditions (CN-column), using n-hexane:ethanol 97:3 (v/v) as mobile phase, at a flow rate of 2.0 ml/min. The main photodegradation products were isolated and characterised and a photodegradation pathway was proposed for Lacidipine in solution. The cis-isomer and a photocyclic isomer proved to be the main photodegradation products.

Photooxidation of papaverine, papaverinol and papaveraldine in their chloroform solutions.

Papaverine hydrochloride, papaverinol, and papaveraldine chloroform solutions were exposed to UV light of 254 nm in atmospheric, aerobic and anaerobic (helium) conditions. The same degradation products appear (TLC) in the above papaverine hydrochloride chloroform solutions. However, the rate of papaverine hydrochloride degradation processes is enhanced as a function of oxygen pressure. Papaverinol and papaveraldine photooxidation products are essentially not different from those observed in the above papaverine hydrochloride solutions. However, the amount of an unknown brown degradation product (X) is the greatest in the papaverinol chloroform solution degraded. That brown compound was previously observed in papaverine either hydrochloride or sulfate injection solutions on their storage even when protected from daylight. The preliminary X product structure development was undertaken (TLC, molecular weight, elemental analysis, UV/VIS, IR and 13C MAS NMR spectroscopy).