Evaluation of the Safety of Drugs and Biological Products Used During Lactation: Workshop Summary.

This report serves as a summary of a 2-day public workshop sponsored by the US Food and Drug Administration (FDA) to discuss the safety of drugs and biological products used during lactation. The aim of the workshop was to provide a forum to discuss the collection of data to inform the potential risks to breastfed infants with maternal use of medications during lactation. Discussions included the review of current approaches to collect data on medications used during lactation, and the considerations for future approaches to design and guide clinical lactation studies. This workshop is part of continuing efforts to raise the awareness of the public for women who choose to breastfeed their infants.

Toxicity of free fatty acids for cultured rat heart muscle and endothelioid cells. I. Saturated long-chain fatty acids.

Capric (C10:0), lauric (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0) and arachidic (C20:0) acids were compared for their toxic effects upon cultured rat heart muscle and endothelioid cells. The free fatty acids (FFA) were found to albumin (6:1) and tested at 5 x 10(-5)M. Reduction of cell viability (51Cr release) and in situ mitochondrial and lysosomal labilization were used as indices of injury. Reduction in viability of both cell types was produced by palmitic, stearic or arachidic acids, but only after exposures of from 12 to 36 h. These FFA also produced needle-like cytoplasmic inclusions. Mitochondria and lysosomes were labilized after shorter exposures. Capric, lauric and myristic acids, were relatively non-toxic, and protected endothelioid cell lysosomes from labilization.

Toxicity of free fatty acids for cultured rat heart muscle and endothelioid cells. II. Unsaturated long-chain fatty acids.

Oleic (C18:1), linoleic (C18:2), linolenic (C18:3) and arachidonic (C20:4) acids were compared for their toxic effects upon cultured rat heart muscle and endothelioid cells. The free fatty acids (FFA) were bound to albumin (6:1) and tested at concentrations from 5 x 10(-5)M to 5 x 10(-4)M. Reduction of cell viability (51Cr release) and in situ mitochondrial and lysosomal labilization were used as indices of injury. Oleic acids was non-toxic at all times and concentrations tested while linoleic acid increased cell death only in muscle cells after 32 h. Arachidonic acid, by contrast, demonstrated significant toxicity as early as 2 h while both linolenic and arachidonic acids produced major injury at longer durations. A detergent effect was excluded as the injury mechanism because of marked differences in the toxicities of the individual FFA. The similarity in the effects of linolenic and arachidonic acids would appear to exclude prostaglandins as responsible toxic products.

Transfer of interferon alfa into human breast milk.

Originally assumed to be antiviral substances, the efficacy of interferons in a number of pathologies, including malignancies, multiple sclerosis, and other immune syndromes, is increasingly recognized. This study provides data on the transfer of interferon alfa (2B) into human milk of a patient receiving massive intravenous doses for the treatment of malignant melanoma. Following an intravenous dose of 30 million IU, the amount of interferon transferred into human milk was only slightly elevated (1551 IU/mL) when compared to control milk (1249 IU/mL). These data suggest that even following enormous doses, interferon is probably too large in molecular weight to transfer into human milk in clinically relevant amounts.

A quantitative method for measurement of lysosomal acid phosphatase latency in cultured rat heart cells with 210Pb.

A method is described for measuring the latency of lysosomal acid phosphatase in cultured rat heart endotheloid cells. 210Pb was added to a medium used to demonstrate acid phosphatase activity by the Gomori lead method, and the amount of lead deposited was measured with a liquid scintillation counter. Deposition rates were measured after enzyme activation pretreatments with acetate buffer (pH 5.0) at various osmolalities, and after formaldehyde fixation. Formaldehyde, alloxan, or fluoride in the Gomori medium were evaluated for their differential effects on lysosomal and non-lysosomal acid phosphatase. The method was found to provide a sensitive, rapid and quantitative evaluation of acid phosphatase latency and should be useful for studying the integrity of lysosomes within cells.

Quantitation of mitochondrial injury in cultured rat heart endothelioid cells with nitroblue tetrazolium.

A sensitive method is presented for measurement of changes in the permeability of mitchondria in cultured cells. Rat heart endothelioid cells were used to determine the penetration rate of nitroblue tetrazolium (NitroBT) or other reactants into mitochondria in situ. Nitroblue formazan, produced as a consequence of succinate dehydrogenase activity in the mitochondria, was eluted and measured with a spectrophotometer. Prior injury of cells with hypo-osmolar solutions increased the rate of formazan production. Several methods are described or suggested for the statistical analysis of the data.

Therapeutic drug monitoring in a pediatric laboratory.

Therapeutic drug monitoring using a new and faster high pressure liquid chromatographic (HPLC) method is discussed. Analysis of chloramphenicol and succinate esters and a large number of anticonvulsive drugs can be carried out using the same buffer and reverse-phase HPLC column by changing the solvent concentration to reflect the choice of drugs. A buffer prepared from 0.02 M sodium acetate and trifluoroacetic acid provides an optimal mobile phase for separation of a wide variety of drugs commonly used in pediatric medicine. Sample preparation and the use of special internal standards without extensive extractions provides excellent accuracy, reliability and sensitivity, and requires a minimum of preparation.

Transfer of metformin into human milk.

AIMS/HYPOTHESIS: The aim of this study was to characterize the milk-to-plasma ratio and infant dose for metformin in breastfeeding women, and to measure plasma concentrations and assess any effects in their infants. We hypothesized that metformin used by mothers is safe for their breastfed infants. METHODS: Seven women taking metformin (median dose 1500 mg orally daily) and their infants were studied. Metformin concentrations in plasma and milk were measured by high performance liquid chromatography. Infant exposure was estimated as the product of estimated milk production rate and the average concentration of the drug in milk and also expressed as a percentage of the weight-normalized maternal dose. RESULTS: The mean milk-to-plasma ratio for metformin was 0.35 (95%CI 0.2-0.5). The mean of its average concentrations in milk over the dose interval was 0.27 mg/l (0.15-0.39 mg/l). The absolute infant dose averaged 0.04 mg x kg(-1) x day(-1) (0.02-0.06 mg x kg(-1) x day(-1)) and the mean relative infant dose was 0.28% (0.16-0.4%). Metformin was present in very low or undetectable concentrations in the plasma of four of the infants who were studied. No health problems were found in the six infants who were evaluated. CONCLUSIONS/INTERPRETATION: The concentrations of metformin in breast milk were generally low and the mean infant exposure to the drug was only 0.28% of the weight-normalized maternal dose. As this is well below the 10% level of concern for breastfeeding, and because the infants were healthy, we conclude that metformin use by breastfeeding mothers is safe. Nevertheless, each decision to breastfeed should be made after conducting a risk:benefit analysis for each mother and her infant.

N-Acetylcysteine therapy of acute heavy metal poisoning in mice.

Therapy of acute heavy metal poisoning is currently limited to a group of moderately toxic drugs containing sulfhydryl groups. N-Acetylcysteine (NAC) was used in these studies to determine if this sulfhydryl containing amino acid would reduce the overall mortality of a group of heavy metal compounds. D-Penicillamine and dimercaprol (BAL) were also used for comparison. Groups of at least 100 mice (28 g) were injected subcutaneously with 2-190 mg/kg of copper, arsenic, thallium or cadmium for LD50 determinations. Other groups were injected 30-60 min later with NAC (200 mg/kg), d-penicillamine (50 mg/kg), or BAL (10 mg/kg), and mortality was monitored for 2 weeks. The LD50 for each treatment group was determined by regression analysis of log-probit transformed data. In arsenite treatment group the survival time was lengthened in NAC-treated animals although the LD50 was not significantly changed. BAL was only slightly more effective than NAC. The mortality in animals given copper and treated with NAC was almost eliminated, except at the highest doses. BAL provided the greatest protection, whereas d-penicillamine produced the least. The LD50 of copper was significantly changed from 60.5 mg/kg in control groups to 139 mg/kg in NAC-treated groups, and to 150 mg/kg and 91 mg/kg in BAL and d-penicillamine-treated groups. NAC and BAL were totally ineffective in the treatment of thallium and cadmium poisoning.

Vitamin E toxicity in neonatal piglets.

Intravenous vitamin E was associated with the deaths of 38 infants in the US in 1984. Because the vitamin E preparation used contained both vitamin E and a high level of polysorbate detergent, the etiology of the syndrome remains unknown. In this study, we determined the tissue disposition of an intravenous preparation of vitamin E solubilized with polysorbate (E-Ferol) in neonatal piglets. One to two-day-old piglets were injected daily with 50 IU/kg/d of vitamin E for a period of 13 days. Other groups were injected intramuscularly, or with a slow, 7 h intravenous infusion with 50 IU/kg/d vitamin E for six days. Massive splenic accumulation of vitamin E (16,004 micrograms/g vs 73 micrograms/g in controls) occurred following rapid injection, with far lesser concentrations in the liver and lung. Levels of vitamin E in the kidney and heart were only slightly above control. Tissue changes correlated with dosage and duration of vitamin E administration and suggested massive accumulation of vitamin E in cells of the mononuclear phagocyte system. Following slow intravenous infusion the highest levels of vitamin E occurred in the liver rather than spleen. Intramuscular injections at similar doses produced slight, but insignificant changes in tissue levels of vitamin E. We speculate that rapid intravenous injection of vitamin E emulsions produces massive accumulation in phagocytic cells of the spleen and to a lesser extent liver and lung, possibly leading to increased susceptibility to sepsis and/or abnormal pulmonary function. Slow infusions of vitamin E produce major accumulations in the liver rather than spleen.(ABSTRACT TRUNCATED AT 250 WORDS)