Errors in Toxicology
David Woolley, Adam Woolley in Practical Toxicology, 2017
The evolution of such errors in a particular example is illustrated by methylene chloride, which emerged as a replacement for lye (a caustic alkaline solution) as a paint stripper. The perception was that lye was unsafe (caustic) and that methylene chloride was characterized as very safe. Understanding of the toxicity of methylene chloride diluted this assumption of safety and eventually ran full circle to the proposition that lye is safe. This is covered in more detail in Chapter 16, Case Study 18.1; however, the take-home message from this history is that it is not sensible to substitute a supposedly toxic material with another for which the illusion of safety is based on ignorance of effect or lack of understanding. The substitution of benzene by toluene is another example of this type of substitution; benzene is certainly more toxic than toluene, but the latter has its own effects and problems.
Ethnic Hair Care Products
Dale H. Johnson in Hair and Hair Care, 2018
When the active ingredient (sodium hydroxide) present in lye relaxers is replaced by freshly prepared guanidine hydroxide, these relaxers are called “no-lye relaxers.” The irritation potential of no-lye relaxers is significantly lower than lye relaxers containing sodium hydroxide. No-lye relaxers are generally available in two components. Component A is usually a cream containing calcium hydroxide, water, oils, emulsifiers, and thickeners. Component B is a concentrated solution of guanidine carbonate. Upon mixing Component A and Component B, guanidine hydroxide is produced according to the chemical equation shown below:
Manufacture of Glycerine from Natural Fats and Oils
Eric Jungermann, Norman O.V. Sonntag in Glycerine, 2018
Figures 3.3 and 3.4 are representative depictions of modern glycerine pre-treatment plants for the processing of sweetwater from high-pressure hydrolysis. Treatment of soap-lye crudes can be quite different, as seen in Figure 3.5. The unit operations involved in these processes include decantation, centrifuging, chemical treatment, filtration, and concentration. Numerous references are found in the literature [2,3,6,8] for the use of these types of unit operations for the recovery of glycerol from a variety of natural sources.
Acute chemical skin injuries in the United States: a review
Published in Critical Reviews in Toxicology, 2018
Alan H. Hall, Laurence Mathieu, Howard I. Maibach
“Lye” is a liquid metal hydroxide, most often sodium or potassium hydroxide. It is a strong alkali chemical. Wolfort et al (1970) reported on skin injuries in 416 patients treated at two hospitals in Baltimore from 1952 to 1968, or approximately 25 such patients annually. Among these, 42 had lye injuries involving 5–60% of the TBSA, with only 9 resulting from workplace accidents. The majority were deliberate chemical assaults. The mean hospital admission duration was 32 days. The one death that occurred was attributed to an anesthetic accident. Noted complications were tympanic membrane perforations (from liquid lye running into the external auditory canal), parotid fistulas, more potential for formation of keloids than usually seen with thermal burns, and early development of Marjolin's malignant ulcers in injury scars (noted at 3–9 years following lye injuries as opposed to an average of 34 years following thermal burns). In these 2 hospitals, treatment protocols were early water flushing and then 12–24 h of continuous flushing with water in a shower (Wolfort et al. 1970). Despite this, all 42 lye-exposed patients developed chemical skin injuries requiring debridement and skin grafting (Wolfort et al. 1970).
Pharmacokinetics and pharmacodynamics of dextromethorphan: clinical and forensic aspects
Published in Drug Metabolism Reviews, 2020
Ana Rita Silva, Ricardo Jorge Dinis-Oliveira
Experienced DXM abusers extract the DXM from the sirup and offer it as a powder in capsules. Two extraction techniques are widely described in the internet aiming to purify the DXM and therefore to avoid co-ingestant toxicity (e.g. ethanol, guaifenesin, saccharin, propylene glycol, coloring agents, sweeteners) present in combination cold preparations (Hendrickson and Cloutier 2007): (i) a single-phase acid–base extraction with sodium hydroxide that yields a freebase crystalline powder (i.e. ‘crystal dex’) and (ii) a two-phase acid–base extraction with ammonia resulting in a liquid (i.e. ‘DXemon juice’ or ‘agent lemon’). This last technique has become more popular because it yields a more palatable liquid product, it avoids the use of lye, and it eliminates the hazards of heating flammable solvents in enclosed spaces.
Related Knowledge Centers
- Alkali
- Corrosion
- Potassium Hydroxide
- Alkali Hydroxide
- Sodium Hydroxide
- Membrane
- Chloralkali Process
- Solution
- Curing
- Olive