Table 4. Comparative SAR, Physiochemical, and In Vitro ADME Data for Select Analogs.

						solubility (μM)g		aqueous stability (%)j,k
entry	analog	RSV CPE potency ± standard deviation EC50 (μM)a	HEp-2 cellular toxicity ± standard deviation CC50 (μM)d	selectivity index (CC50/ EC50)	viral titer reduction at 10 μM (log)	PBSh	mediai	PBS	1:1 PBS/ACN	Pe, PAMPA permeability (×10–6 cm/s)g,l	hepatocyte toxicity LC50 (μM)g,o
1	2	2.1 ± 0.5	>50.0	23.8	4.2	0.1	NT	88.1	94.0	NT	NT
2	15	0.5 ± 0.05b	>50.0b	>100	5.6f	1.3	2.8	83.4	94.9	364/349/356m	>50
3	19	0.3 ± 0.03c	>50.0c,e	>166.7	6.7	0.4	10.2	27.0	100	718/631/703n	>30
4	46	1.1 ± 0.2	44.7 ± 7.2	41.8	>6.2	11.2	18.5	90.2	100	780/686/514m	>50

^aData were an average of ≥3 experiments.

^bData were an average of outcomes from three separate lots of compound 15.

^cData were an average of outcomes from two separate lots of compound 19.

^dData are an average of ≥2 experiments.

^eData were obtained from a 3-day exposure experiment versus 5-day duration due to precipitation of compound after 3 days.

^fData were an average of outcomes from two separate lots of compound 15.

^gData collected by Ms. Arianna Mangravita-Novo at the Conrad Prebys Sanford Burnham Medical Research Institute.

^hKinetic solubility in 1× PBS, pH 7.4.

ⁱKinetic solubility in CPE assay media: (DMEM/F12(r) (Sigma, Cat # D6434)/1× Pen/Strep/Glutamine (Gibco, Cat # 10378)/2% Heat Inactivated FBS (Gibco Cat # 10082)).

^jData collected by Mr. Patrick Porubsky at the University of Kansas Analytical Chemistry Core, Specialized Chemistry Center.

^kResults are represented as percent parent remaining after 48 h; Stability assessment was done independently in PBS or with 1:1 PBS and acetonitrile; the latter was used to account for limitations in solubility affecting PBS results.

^lPAMPA donor pH: 5.0/6.2/7.4, acceptor pH: 7.4; controls: verapamil (222/1097/1936–highly permeable), metoprolol (14/60/472–moderately permeable), ranitidine (<10/<10/<10–poorly permeable).

^mPAMPA done in PBS, no additives.

ⁿPAMPA done with 20% acetontrile added to compensate for PBS solubility. Without acetonitrile, Pe was insignificant at each pH.

^oFa2N-4 immortalized human hepatocytes. Data were analyzed using Microsoft Excel 2010; NT = not tested.