Reference

A study of correlations between the release of drugs from petrolatum-based gels containing nonionic surfactants and some physical and physicochemical characteristics of the gel systems

A study of correlations between the release of drugs from petrolatum-based gels containing nonionic surfactants and some physical and physicochemical characteristics of the gel systems. Di Colo, G.; Nannipieri, E.; Serafini, M. F.; Vitale, D. (Ist. Chim. Farm., Univ. Pisa, Pisa 56100, Italy). Int. J. Cosmet. Sci., 8(3), 105-13 (English) 1986. CODEN: IJCMDW. ISSN: 0142-5463. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) The in vitro release of benzocaine (I) [94-09-7] and 2-ethylhexyl p-dimethylaminobenzoate (II) [21245-02-3] from petrolatum-based gels either contg. 2 nonionic surfactants, or not, was compared with some phys. and/or physicochem. characteristics of the drugs, the gels and the drug-gel systems. The surfactants had no effect on the release of II, the less polar drug, whereas they decreased the release of I. Moreover, the release data show a complex dependence of diffusive properties of I on drug and surfactant concn. I appears to form mixed micelles with each of the two surfactants and/or undergoes self-aggregation phenomena within surfactant micelles. Thus, drug diffusion is affected by gel porosity, drug mol. size and polarity, and mol. interactions.

Occurrence of para-aminobenzoic acid and benzocaine as contaminants in sunscreens containing para-aminobenzoic acid esters

Occurrence of para-aminobenzoic acid and benzocaine as contaminants in sunscreens containing para-aminobenzoic acid esters. Bruze, Magnus; Fregert, Sigfrid; Gruvberger, Birgitta (Dep. Occup. Dermatol., Univ. Hosp., Lund, Swed.). Photodermatology, 1(6), 277-85 (English) 1984. CODEN: PHTDEI. DOCUMENT TYPE: Journal CA Section: 62 (Essential Oils and Cosmetics) p-Aminobenzoic acid (PABA) [150-13-0] and its Et (benzocaine) [94-09-7], amyl [6521-29-5], and glyceryl [136-44-7] esters, Et 4-bis(hydroxypropyl)aminobenzoate [58882-17-0], and 2-ethylhexyl p-dimethylaminobenzoate [21245-02-3] were sepd. and detd. by chromatog. on silica gel F-254 plates with CHCl3-MeCN-MeOH-HOAc (:). The limit of detection (fluorescence at 254 nm) for PABA and benzocaine was 0.2 mg. For detn. by high-pressure liq. chromatog., the compds. were eluted from a Nucleosil C18 column with 0.015 M H3PO4-MeCN (, or ) with eluate monitoring at 290 nm. The limit of detection was 0.005 mg for PABA with the eluent and 0.005 mg for benzocaine with the eluent. The levels of PABA and benzocaine ester in different batches and brands of the 4 esters used in sunscreens were batch dependent. Both compds. were present at >0.1% in the glyceryl ester, and benzocaine levels of 0.3 and 0.6% were found in Et 4-bis(hydroxypropyl)aminobenzoate. PABA levels were low in the other samples. The significance of these contaminants in sunscreen dermatitis or photocontact allergy is discussed.