Comparative in vitro spermicidal activity of chelating agents and synergistic effect with nonoxynol-9 on human sperm functionality.

Nonoxynol-9 (N-9), a nonionic surfactant, exerts both spermicidal and anti-viral activities and is the most widely used spermicide. Although N-9 has been regarded as an efficient spermicidal agent for barrier contraception, it has been reported to cause vaginal irritation and allergic vaginitis, and its spermicidal action in the vaginal mucus may be limited. To address these problems, the spermicidal activity of several chelating agents against human semen and their synergistic effect on the spermicidal activity of N-9 were evaluated using computer-assisted semen analysis and a cervical mucus penetration test.

Risk assessment of the allergic dermatitis potential of environmental exposure to hexavalent chromium.

Although hexavalent chromium, Cr(VI), is a potent sensitizer and inducer of allergic contact dermatitis and is found in many common materials, no standard or guideline currently exists for protection against these effects in environmental exposure. There appears to be a generalized allergenic potential among the various compounds of Cr(VI). Estimates of the prevalence of Cr sensitivity in the population are uncertain, but range from about 2% of the total population in Finland to as high as 20% in U.

Skin permeation and cutaneous hypersensitivity as a basis for making risk assessments of chromium as a soil contaminant.

A literature review of experimental and human exposure studies of skin permeation and cutaneous hypersensitivity reactions evoked by chromium was carried out to provide a basis for making a risk assessment of chromium as a soil contaminant. In vitro and in vivo studies demonstrated that 1 to 4% of the applied dose of hexavalent and trivalent chromium to guinea pig skin penetrated skin within 5 to 24 hr after application. Ultrastructural investigations showed that hexavalent chromium localized intracellularly and extracellularly in the upper layers of guinea pig epidermis.

Transdermal dual-controlled delivery of contraceptive drugs: formulation development, in vitro and in vivo evaluations, and clinical performance.

Several transdermal contraceptive device (TCD) formulations were developed to provide a dual-controlled transdermal delivery of levonorgestrel (LN), a potent progestin, and 17 beta-estradiol (E2), a natural estrogen. Using a sensitive HPLC method, the in vitro release and skin permeation profiles of LN and E2 from various TCD formulations were simultaneously characterized in the hydrodynamically well-calibrated Valia-Chien skin permeation cells and both were found to follow zero-order kinetics. The rates of drug release and skin permeation were observed to vary significantly depending upon some formulation parameters.

Tests for local toxicity of intramuscular drug preparations: comparison of in vivo and in vitro methods.

Different concentrations of aqueous preparations of metoclopramide, gaboxadol, cis(Z)-clopenthixol, digoxin and chlorpromazine and of cis(Z)-clopenthixol acetate in Viscoleo have been tested for local toxicity after intramuscular injection in rabbits. The weight of macroscopically changed muscle tissue isolated 3 days after injection was determined. In addition, homogenized injection site muscle tissue was analysed for creatine kinase (CK) activity and by comparison with the CK activity of contralateral muscle tissue, the amount of injection site muscle tissue totally depleted for CK activity was calculated.