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Results for “PYRETHRINS”

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PubMed1990

Toxicology of selected pesticides, drugs, and chemicals. Pyrethrin and pyrethroid insecticides.

Pyrethroids have a wide spectrum of insecticidal potency, vertebrate toxicity, and environmental stability. The exceptionally high selectivity ratios of pyrethrins and pyrethroids have resulted in their use for insect control in numerous formulations. A primary effect of pyrethroids is to slow the closing of the sodium activation gate in nerve cells. All pyrethroids have essentially the same basic mechanism of action on voltage-dependent sodium channels but differ in the magnitude of effect. Based on clinical signs, electrophysiologic responses, and chemical structure, pyrethroids can be classified as Type I or Type II. Inhibition of the GABAA receptor appears to be an additional mechanism of Type II pyrethroids. Clinical signs in small animals during a pyrethroid toxicosis vary but are generally attributable to neural dysfunction. Treatment consists of decontamination procedures and application of appropriate symptomatic care, including control of seizures if necessary.

Animals↗

PubMed2006

Quantitative determination of pyrethroids, pyrethrins, and piperonyl butoxide in surface water by high-resolution gas chromatography/high-resolution mass spectrometry.

A new method for determination of pyrethroids, pyrethrins, and piperonyl butoxide (PBO) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for surface water samples. The method is based on sampling 100 L of ambient surface water with a solid phase extraction (SPE) technique that uses both wound glass fiber filters for collecting the particulate-associated chemicals and XAD-2 resin for collecting the dissolved chemicals. The method detection limits of the analytes ranged from 0.58 to 8.16 ng/sample, which is equivalent to a detection limit range of 0.0058-0.082 ng/L for a 100 L water sample collected by the SPE technique. The SPE when coupled with HRGC/HRMS was a suitable match for detecting these chemicals at subnanogram per liter ranges that are toxicologically significant to aquatic organisms. To confirm the utility of this method for environmental applications, pyrethroids and PBO were found at subnanogram per liter concentrations in surface water samples collected from five tributaries (primarily urban creeks) of the San Francisco Bay, California.

Adsorption↗

PubMed2004

Pyrethrins and piperonyl butoxide adsorption to soil organic matter.

The adsorption and mobility of pyrethrins (Pys), the major insecticidal components obtained from the pyrethrum daisy Tanacetum cinerariifolium, and piperonyl butoxide (PBO), a pyrethrum synergist, were determined in soil using batch-equilibrium and reverse-phase thin-layer chromatographic techniques. Two soil management practices were used, soil mixed with yard waste compost (COM) at 50 t acre(-1) on dry weight basis and no-mulch (NM) bare soil. Adsorption isotherm experiments were carried out using known concentrations of Pys (Py-I and Py-II) and PBO mixed with known amounts of COM or NM soil at constant temperature and pressure until equilibrium was attained. Pys and PBO in soil extracts were purified and concentrated using solid-phase extraction cartridges containing C18-octadecyl bonded silica. Pys and PBO residues were quantified using a high-performance liquid chromatograph equipped with a UV detector. Adsorption studies showed that compost amended soil adsorbed more Pys and PBO than native (NM) soil. Py-I adsorption was greater than Py-II and PBO. Adsorption of Pys and PBO to humic and fulvic acids was also studied by reverse-phase thin layer chromatography (RPTLC). Results indicated that humic acid, a significant component of organic matter, reduced Pys and PBO mobility. Pys and PBO mobility decreased as the concentration of humic acid in the mobile phase increased.

Adsorption↗

PubMed1998

Comparative study of the clinical effectiveness of a pyrethrin-based pediculicide with combing versus a permethrin-based pediculicide with combing.

In a randomized, evaluator-blinded clinical trial, 190 patients were treated for Pediculus humanus capitis infestations with a pyrethrin-piperonyl-butoxide pediculicide (RID; Py-PB) and a permethrin pediculicide (NIX; PM). A total of 160 patients were evaluable for nit-combing speed, 156 patients were evaluable for efficacy at day 7, and 150 patients were evaluable for efficacy at day 14. Both Py-PB and PM showed 100% efficacy at day 7. At day 14, one patient in the PM group had an apparent reinfestation. The Py-PB group had significantly lower mean combing times (P=0.04), but because the PM group had more nits, the two groups were not significantly different in combing speed expressed as seconds per nit. Multiple regression and covariance analyses suggested that the greater speed of the Py-PB comb might have been masked by this baseline difference. Three patients had mild adverse experiences (Py-PB: erythema, PM: erythema and tingling sensation). No patients were removed from the study because of adverse events. In conclusion, this controlled clinical study demonstrated that both Py-PB and PM provided 100% efficacy following a single application. Differences attributable to comb design favored the Py-PB "rake" comb, but this requires additional evaluation and confirmation.

Child↗

PubMed1991

[Pyrethrin and pyrethroid (permethrin) in the treatment of scabies and pediculosis].

The history and development of pyrethrum, the natural pyrethrins and synthetic pyrethroids and their insecticidal properties, chemical structure and toxic and allergic side-effects are reported. Permethrin is stressed as a photostable insecticide that is very effective against a large variety of insects and mites with low mammalian toxicity and virtually no allergic side-effects. Only 10-20 min after application, permethrin (1% cream rinse or 0.5% in ethanol) proved to be safe, reliable and cosmetically acceptable in the treatment of infestations with head lice and the prevention of reinfestations, and also in failures with lindane owing to the development of tolerance in the lice. The same was true of 5% permethrin cream (2.5% in children below 5 years of age) used in the treatment of scabies. Permethrin is absorbed percutaneously in only small amounts, is metabolized rapidly in the skin and excreted in the urine. A single "head to toe" application is ideal for eradication programmes allowing lice to be targetted and the prevalence of secondary bacterial infections decreased at the same time. Benzyl benzoate has an irritant potential, and lindane has been reported to exert CNS toxicity in a few anecdotal cases, in particular in small children or after repeated applications in patients with scabies crustosa, and permethrin was distinctly superior to both of these. This is documented by the results obtained in the treatment of 48 children and 56 adults suffering from scabies. Permethrin is recommended in scabies therapy in premature infants, small children, patients with seizures and neurological complications, in treatment failures with lindane entailing the need to repeat the therapy, in scabies crustosa and in pregnant women and nursing mothers.

Adolescent↗

PubMed1987

Comparison of pediculicidal and ovicidal effects of two pyrethrin-piperonyl-butoxide agents.

A pyrethrin-piperonyl-butoxide shampoo was compared with a similarly formulated lotion for their pediculicidal and ovicidal effects against head lice. Forty children with active Pediculus humanus capitis infestation were randomly assigned to one of two groups for a single treatment with either the shampoo or the lotion. An average of ten nits were taken from each patient both before and after treatment. These eggs were incubated for 14 days, the resulting lice counted, and their conditions noted. Lice recovered from the rinse water after treatment were also counted and observed. Although both products proved to be effective in killing lice, the shampoo had greater ovicidal efficacy, 50% versus 25% for the lotion, after adjustment for natural mortality of the ova.

Administration, Topical↗

PubMed1987

Clinical evaluation of pediculicidal and ovicidal efficacy of two pyrethrin-piperonyl-butoxide formulations.

The pediculicidal and ovicidal efficacy of two pyrethrin-piperonyl-butoxide agents was evaluated in 40 children infested with head lice. Both commercial products, a lotion and a shampoo, had similar formulations. Specifically, the shampoo vehicle was tested to determine whether its surface-tension-lowering action made it more effective as an ovicidal agent than the lotion. Results of the study indicate that the shampoo is 49% more effective than the lotion as an ovicide.

Administration, Topical↗

PubMed2003

Direct on-line continuous supercritical fluid extraction and HPLC of aqueous pyrethrins solutions.

A new method, employing supercritical fluid extraction (SFE) connected on-line with high-performance liquid chromatography, was developed for the determination of pyrethrins and piperonyl butoxide in aqueous solutions. The principle of the laboratory-made device for SFE is based on the low mutual solubility of water and supercritical (liquid) CO2. This device works in continuous mode that offers extraction of unlimited sample volumes. Different extraction temperatures and pressures were tested to find optimum extraction conditions. The addition of organic modifier and inorganic salt to the water sample to increase extraction recovery was investigated. The method was evaluated, and it was applied for the extraction of aqueous samples spiked with commercial insecticides. The working concentration range of the method was from the limit of quantification (0.1 microg L(-1)) to the solubility of the analytes in water.

Journal Article↗

PubMedDate not supplied

Efficacy and tolerability of natural synergised pyrethrins in a new thermo labile foam formulation in topical treatment of scabies: a prospective, randomised, investigator-blinded, comparative trial vs. permethrin cream.

We compared in a prospective, randomised, investigator-blinded trial, the efficacy and tolerability of a new synergised-pyrethrins thermo-labile foam (F) formulation with permethrin 5 % cream (P) in 40 patients with scabies. Clinical evolution of scabetic lesions (Clinical grading = CG) and itching intensity (IS) were assessed, using a 5-point semi-quantitative score, at baseline, at week 2 and 4. F and P were equally effective in the clinical resolution of scabetic lesions. As compared to baseline, P reduced CG and IS from 3.4 0.7 and 3.1 0.4 to 0.2 0.6 and 1.4 1, at week 2, and to 0.0 0.0 and 0.1 0.3 at week 4, respectively (P < 0.001). F reduced CG and IS from 3.3 0.5 and 3.2 0.4 to 0.05 0.2 and 0.4 0.6 (week 2) and to 0.0 0.0 and 0.0 0.0 (week 4), respectively (P < 0.0001). As compared to P group, the IS in F group, at week 2, was significantly lower (0.4 0.6 vs. 1.4 1.1) (P < 0.0013). This foam formulation was at least as effective as permethrin 5 % cream in the treatment of scabies. In comparison with permethrin the foam induced a more rapid and complete resolution of itching.

Administration, Topical↗

PubMed1952