IN AN ATTEMPT to develop a long-acting repository form of pencillin various modifications of ordinary benzyl penicillin have been prepared in an effort to maintain suitable therapeutic concentrations in the body. Jensen and his co-workers* in 1948 successfully developed a diethylaminoethyl ester hydriodide of penicillin G which, although it was found in low cencentrations in the plasma after intramuscular injection, did appear in high concentrations in sputum and lung tissue. This was ascribed to a specific organ affinity of the unhydrolyzed ester, which on hydrolysis in lung tissue liberated free penicillin and diethylaminoethyl alcohol. Comparison studies † in patients with equal amounts of penicillin procaine, penicillin sodium, and the diethylaminoethyl ester hydriodide of penicillin G revealed a five to eight times greater sputum concentration with the latter drug.
Animal studies have shown6 unusually high penicillin concentrations in the brain tissue of those treated with this ester. More important, Wellman
SMITH CN, DAVIS JS. MENINGITIS TREATED WITH DIETHYLAMINOETHYL ESTER HYDRIODIDE OF PENICILLIN G (NEO-PENIL)Report of Two Cases. AMA Arch Intern Med. 1954;93(4):629–632. doi:10.1001/archinte.1954.00240280149011