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Investigation of tricyclic heterocycles related to the 2-arylpyrazolo[4,3-c]quinolin-3(5H)-ones, structures with high affinity for the benzodiazepine (BZ) receptor, led to the synthesis of 2-phenyl-[1,2,4]triazolo[1,5-c]quinazolin-5(6H)-one, a compound with 4 nM binding affinity to the BZ receptor. Analogues were prepared to assess the importance of the 2-substituent and ring substitution in modifying activity. Several novel synthetic routes were designed to prepare the target compounds, including a two-step synthesis beginning with an anthranilonitrile and a hydrazide. Of the 34 compounds screened in this series, three compounds were found to be potent BZ antagonists in rat models. The leading compound, 9-chloro-2-(2-fluorophenyl) [1,2,4]triazolo[1,5- c]quinazolin-5(6H)-one (CGS 16228), showed activity comparable to that of CGS 8216 from the pyrazolo[4,3-c]quinoline series.

For a series of bases, which penetrate through human skin in vitro at similar rates (0.056-0.49 microM/cm2/hr), penetrant pKa is shown to correlate with erythema, edema, and color meter readings. As estimates of irritation, erythema, edema, and redness measurements are highly linearly correlated. For the selected series, irritation becomes significant for bases with a pKa greater than 8. The irritation potential of acids with pKa less than or equal to 4 has been previously reported; pKa appears highly predictive of acute skin irritation for acids and bases in man.

Sorption of ethanol and water into stratum corneum, delipidized stratum corneum, and triolein as a simple model lipid was investigated. Optima in ethanol sorption and flux are related to dehydration of keratins. There was no optimum for solubility in triolein; a linear cosolvency is observed with ethanol:triolein mixtures. A model is proposed which qualitatively predicts the key features of ethanol-enhanced skin permeation on the basis of these solubility phenomena and a constant diffusion coefficient.

The solution properties of aqueous ethanol donor solutions were characterized for the particular case of an increased flux nitroglycerin transdermal system. Permeation through porous and nonporous polymer membranes was investigated and modelled. While the permeation of ethanol through the porous membranes is adequately described by theory, clogging of pores occurs in the presence of lactose. Permeation through ethylene vinyl acetate membranes reflects interactions of the solute and solvent with the polymer.

The relationship between pKa and skin irritation in man is studied for a homologous series of benzoic acid derivatives, which permeate through human skin at comparable rates (15-88 micrograms/cm2/hr). Skin irritation and pKa are correlated for pKa less than or equal to 4. Laser Doppler velocimetric assessment of skin blood flow, color meter readings, erythema, edema, and the primary irritation index are all linearly correlated and related to pKa; erythema at 24 hr appears to be the most sensitive parameter to variation in pKa when pKa less than or equal to 4.

An optimal concentration range of aqueous ethanol produces 5-10-fold increases in nitroglycerin flux across skin and ethanol skin permeation that are far greater than reported previously. For aqueous ethanol solutions saturated with nitroglycerin with an ethanol volume fraction less than or equal to 0.7, the flux of nitroglycerin across skin is linear with the ethanol flux and is traced to a linear solubility relationship and a constant diffusion coefficient.

The synthesis of chiral 1,5-benzothiazepines 2a-c, 14a-c, 15c, and 16a prepared from cysteine is described. In vitro inhibition of angiotensin converting enzyme (ACE) is reported for each compound. Compound 2c was the most potent in vitro having an IC50 of 2.95 nM. The ester of 2c, i.e. 14c, was found to inhibit the AI pressor response by 75% at a dose of 0.05 mg/kg iv and by 39% at 1.0 mg/kg po. Additionally, 14c lowered blood pressure in the spontaneous hypertensive rat (SHR) by 35 mmHg, at a dose of 10 mg/kg po.