Biomedical subjects

Stanley L Hem

Publications and source records attributed to Stanley L Hem.

20 records · Page 2Linked to original sources

PubMedDate not supplied

Determination of methylparaben in o/w emulsions by solid-phase extraction and high-performance liquid chromatography.

A simple, fast, and accurate solid-phase extraction (SPE) using a 1-cc Oasis HLB cartridge for sample clean-up followed by an HPLC analysis for the assay of methylparaben (MP) in an o/w emulsion is described. One milliliter of methanol followed by 1 ml of 10% methanol in water was used to activate the cartridge sorbent. The sample was loaded into the cartridge and MP was then separated from oil-soluble excipients by washing the cartridge with 1 ml of 10% CH(3)CN in water. MP was finally eluted from the cartridge with mobile phase, acetonitrile and water (60:40), and quantified by HPLC analysis on a Nova-pak(R) C-18 column at 254 nm.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

Potentiometric/turbidometric titration of antiperspirant actives.

A titration procedure that simultaneously monitors the pH and turbidity of an antiperspirant solution during neutralization with sodium hydroxide was developed to characterize antiperspirant actives. Aluminum chloride, aluminum chlorohydrate (ACH), and aluminum zirconium glycine complex (AZG) gave distinctive pH/turbidity profiles. The activated forms of aluminum chlorohydrate (ACH') and aluminum zirconium glycine complex (AZG') produced more turbidity than the non-activated forms. On an equimolar basis, AZG' produced more turbidity than any of the antiperspirant actives tested.

Deodorants↗