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Ibopamine is an original dopamine analogue. The drug, instilled in the conjunctival sac, induces mydriasis and is well-tolerated. In the present study, we have investigated the pharmacokinetic and pharmacodynamic characteristics of ibopamine alter ocular application. Ibopamine produces a dose-dependent mydriasis endowed with very interesting characteristics: rapid onset, marked pupil dilation and rapid return to normal pupillary diameter. Ibopamine is well absorbed through the cornea, it is rapidly hydrolysed by esterases to epinine and the mydriatic effect is correlated with the concentration of epinine in the aqueous humor. The results of the experiments with the α1-antagonists bunazosin and thymoxamine, and with reserpine, suggest that the mydriatic effect of ibopamine is obtained by direct stimulation of the α1-adrenergic receptors; pretreatment with bunazosin almost completely inhibits the mydriatic activity of ibopamine: the mydriasis is also antagonized by thymoxamine. Pretreatment with reserpine has no effect on the extent of the mydriasis induced by ibopamine.

A crystalline substance with marked antimitotic activity on several biological systems (mitoses of ascites S 180, of the megaloblasts of chick embryo, of the tips of wheat radicles) has been isolated from the bulbs of several varieties of Narcissus and named Narciclasine. After reference to the tests that led to its discovery and isolation and to the work of others in the same field, the method of isolation is described together with the physical and chemical properties of the substance (identification, chromatographic behavior, UV, IR and fluorescence). The structural formula, established on the basis of work reported elsewhere, is given.

Levomoprolol is a β-blocking agent used in the topical treatment of glaucoma. The necessity for comparing the plasma levels of a drug administered by the ophthalmic route with those obtained following systemic treatment requires increasingly sensitive methods in order to determine the low plasma concentrations produced by the administration of eye drops. On-line high-performance liquid chromatography-gas chromatography and concurrent solvent evaporation proved to be advantageous in the determination of levomoprolol in human plasma. Levomoprolol was determined by capillary gas chromatography (GC) with electron-capture detection (ECD) after solid-phase extraction from plasma and derivatization. Quantitation was based on the internal standard method. The detection limit of 0.2 ng/ml is 50 times lower than that obtained with previous GC methods involving on-column injection and ECD.