Sufficient penetration of peracetic acid into drilled human femoral heads.

Chemical sterilisation methods for musculoskeletal transplants have the problem of penetration into all tissue strata. The present study examined if a peracetic acid/ethanol solution penetrated to a sufficient extent into specifically prepared femoral heads. To this effect, 10 femoral heads have been provided with drillings (diameter 2 mm, depth 10 mm) at a distance of 15 mm (series B) and placed in a diffusion chamber with sterilisation solution. From an additional central drilling at the femoral neck junction, the sample drawing was made after 30 min each over a period of 4 h for the iodometric determination of peracetic acid (PAA) concentration. Ten femoral heads, which did contain only the central drilling, served as controls (series A). In 9 of the examined femoral heads of series A the defined minimum concentration of PAA of 0.2% (inactivation of bacteria, spores, fungi) has been clearly exceeded over the complete period of measurement. About 0.8% PAA (inactivation of viruses) was achieved within 4 h only with six femoral heads. Nine out of the 10 examined femoral heads in series B show a clearly improved penetration behaviour which was expressed in smaller standard deviations, a faster increase in concentration, as well as in higher starting and final concentrations (approx. 0.9%) of PAA. Previous drying in air leads to a faster penetration into the centre of the bone. Standardised drilling of de-cartilaged femoral heads creates favourable conditions for the penetration of the PAA sterilisation solution into the whole tissue and guarantees a sufficient inactivation of microorganisms.

[Biological testing of biomaterials in the framework of permitted procedures. 2]. / Zur biologischen Prüfung von Biomaterialien im Rahmen des Zulassungsverfahrens. 2. Mitteilung.

Submitted is the revised version of a proposal for a guideline for biological testing of materials (biomaterials) which remain temporarily or permanently, resp., at or in the human body or have contact with drugs or body fluids outside the human body.

[The toxicologic evaluation of biomaterials. 1. Results of biomaterial tests in cultures of human amnion epithelial cells and human fibroblasts]. / Beiträge zur toxikologischen Bewertung von Biomaterialien. 1. Mitteilung: Ergebnisse von Biomaterial-Prüfungen an Kulturen von Human-Amnionepithelzellen und Human-Fibroblasten.

Cell cultures are a highly sensitive toxicological model used also for the testing of biomaterials. Beside the safety tests provided in the Pharmacopoeia of GDR cultures from human amnionepithelial cells and fibroblasts are used. The paper reports the results of some methodical investigations concerning the procedure of extraction of biomaterials, the evaluation of test results and the comparison with the results of other biological tests.

Remarks about some pharmacopoieal safety tests for plastics and elastomers.

A survey of the biological methods for quality control of plastics and elastomers included in pharmacopoeias is given. The value of some of these methods (test for pyrogen-like substances, test for acute systemic toxicity in mice, tests on frog hearts, on Daphnia magna and on rat sperm, mode of extraction) is discussed.

[Resistance of yeast cells to plastics and elastics]. / Beitrag zur Verträglichkeitsprüfung von Gegenständen aus Plasten und Elasten unter Verwendung von Hefezellen.

For the investigation of plastics and elastics several sensitive biological methods are in use. In the Pharmacopeia of GDR, 2nd edition, a safety-test on isolated frogheart is prescribed for plastics and a safety-test on daphnia magna for elastics. Ionescu-Stoian had recommended a test using saccharomyces cerevisiae. We found a good conformity of the result given by this test with the results of the daphnia-test. On the other hand, the saccharomyces cerevisiae-test is much more sensitive than the test with isolated frogheart.