Henry F. Smyth

Bio: Henry F. Smyth is an academic researcher from Mellon Institute of Industrial Research. The author has contributed to research in topics: Occupational hygiene & Toxicity. The author has an hindex of 12, co-authored 20 publications receiving 474 citations.

The toxicology of the polyethylene glycols

Abstract: Information developed during recent years upon the toxicological actions of the fluid and solid polyethylene glycols is summarized. This information has been re-interpreted and supplemented. Evidence presented in this report confirms the earlier work indicating that acute oral toxicity, dermal toxicity, and irritating properties of the polyethylene glycols are very low. The safe rat dose of “Carbowax” 1500 is now known to be substantially greater than originally reported, and of “Carbowax” 4000, slightly greater.

The chronic oral toxicology of the polyethylene glycols

Abstract: Polyethylene glycols were fed in the diet to rats for two years and to dogs for one year.Apparently a compound with a mean molecular weight of 6,000 is definitely less toxicby mouth than those of lower molecular weights.This work supports the view that the polyethylene glycols may be considered inert when taken by mouth.

Improved Communication—Hygienic Standards for Daily Inhalation—

Abstract: (1956). Improved Communication—Hygienic Standards for Daily Inhalation— American Industrial Hygiene Association Quarterly: Vol. 17, No. 2, pp. 129-185.

The toxicity of high molecular weight polyethylene glycols; chronic oral and parenteral administration.

Abstract: Results of administering oral doses of high molecular weight polyethylene glycols to rats over a two‐year period are reported. The single dose toxicity for several of these compounds by intraperitoneal administration to rats and intravenously to rabbits was also determined.

Effect of repeated inhalation of vapors of industrial solvents on animal behavior. i. evaluation of nine solvent vapors on pole-climb performance in rats.

Abstract: Repeated inhalation of vapors of nine industrial solvents has been investigated by study of rats selected on the basis of successful training to climb to a safety area of a chamber when activated by a conditioned stimulus. A wide behavioral spectrum of possible activity within the limited series of chemicals studied was obtained. Effects ranged from specific through nonspecific to no observable action on behavior, with or without concomitant changes in growth rate. No well-defined generalization of altered behavior occurring before other parameters of injury was consistently obtained with the inhalation schedules and behavioral method employed.

Poly(ethylene glycol) in Drug Delivery: Pros and Cons as Well as Potential Alternatives

Abstract: Poly(ethylene glycol) (PEG) is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery. The properties that account for the overwhelming use of PEG in biomedical applications are outlined in this Review. The first approved PEGylated products have already been on the market for 20 years. A vast amount of clinical experience has since been gained with this polymer--not only benefits, but possible side effects and complications have also been found. The areas that might need consideration and more intensive and careful examination can be divided into the following categories: hypersensitivity, unexpected changes in pharmacokinetic behavior, toxic side products, and an antagonism arising from the easy degradation of the polymer under mechanical stress as a result of its ether structure and its non-biodegradability, as well as the resulting possible accumulation in the body. These possible side effects will be discussed in this Review and alternative polymers will be evaluated.

A Critical Review of the Literature on Hydrogen Sulfide Toxicity

Abstract: The information available on the biological activity of hydrogen sulfide has been examined for present status of critical results pertaining to the toxicity of hydrogen sulfide. This review of the literature is intended as an evaluative report rather than an annotated bibliography of all the source material examined on hydrogen sulfide. The information was selected as it might relate to potential toxic effects of hydrogen sulfide to man and summarized, noting information gaps that may require further investigation. Several recommendations are listed for possible consideration for either toxicological research or additional short- and long-term tests. Two bibliographies have been provided to assist in locating references considered in this report: (1) literature examined but not cited and (2) reference citations. The majority of the references in the first bibliography were considered peripheral information and less appropriate for inclusion in this report.

The sources, fate, and toxicity of chemical warfare agent degradation products.

Abstract: We include in this review an assessment of the formation, environmental fate, and mammalian and ecotoxicity of CW agent degradation products relevant to environmental and occupational health. These parent CW agents include several vesicants: sulfur mustards [undistilled sulfur mustard (H), sulfur mustard (HD), and an HD/agent T mixture (HT)]; nitrogen mustards [ethylbis(2-chloroethyl)amine (HN1), methylbis(2-chloroethyl)amine (HN2), tris(2-chloroethyl)amine (HN3)], and Lewisite; four nerve agents (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), tabun (GA), sarin (GB), and soman (GD)); and the blood agent cyanogen chloride. The degradation processes considered here include hydrolysis, microbial degradation, oxidation, and photolysis. We also briefly address decontamination but not combustion processes. Because CW agents are generally not considered very persistent, certain degradation products of significant persistence, even those that are not particularly toxic, may indicate previous CW agent presence or that degradation has occurred. Of those products for which there are data on both environmental fate and toxicity, only a few are both environmentally persistent and highly toxic. Major degradation products estimated to be of significant persistence (weeks to years) include thiodiglycol for HD; Lewisite oxide for Lewisite; and ethyl methyl phosphonic acid, methyl phosphonic acid, and possibly S-(2-diisopropylaminoethyl) methylphosphonothioic acid (EA 2192) for VX. Methyl phosphonic acid is also the ultimate hydrolysis product of both GB and GD. The GB product, isopropyl methylphosphonic acid, and a closely related contaminant of GB, diisopropyl methylphosphonate, are also persistent. Of all of these compounds, only Lewisite oxide and EA 2192 possess high mammalian toxicity. Unlike other CW agents, sulfur mustard agents (e.g., HD) are somewhat persistent; therefore, sites or conditions involving potential HD contamination should include an evaluation of both the agent and thiodiglycol.

Introduction to Biotechnical and Biomedical Applications of Poly(Ethylene Glycol)

Abstract: At first glance, the polymer known as poly(ethylene glycol) or PEG appears to be a simple molecule. It is a linear or branched, neutral polyether, available in a variety of MWs, and soluble in water and most organic solvents. Despite its apparent simplicity, $${HO - {{\left( {C{H_2}C{H_2}O} \right)}_n} - C{H_2}C{H_2}OH} \hfill \\ {poly(ethylene\,glycol)}$$ this molecule is the focus of much interest in the biotechnical and biomedical communities. Primarily this is because PEG is unusually effective at excluding other polymers from its presence when in an aqueous environment. This property translates into protein rejection, formation of two-phase systems with other polymers, nonimmunogenicity, and nonantigenicity. In addition, the polymer is nontoxic and does not harm active proteins or cells although it interacts with cell membranes. It is subject to ready chemical modification and attachment to other molecules and surfaces, and when attached to other molecules it has little effect on their chemistry but controls their solubility and increases their size. These properties, which are described in more detail below, have led to a variety of important biotechnical and biomedical applications, a summary of which is also presented below.