Table 4. Nominal Individual UWL Thicknesses Calculated Using the Flux Plateau Method^a.

model drug	receiver buffer	stirring rate (rpm)	particle size (nm)	a	UWL thickness (μm)
					donor UWL for the free drug (hfUWLd)	receiver UWL for the free drug (hfUWLr)	donor UWL for particles (hpUWLd)
atazanavir	no BSA	150b	460	NA	NA	NA	NA
		300	460	0.80	1471.7	365.8	4.8
		500	460	0.78	994.7	282.1	3.7
		1000	460	0.81	999.0	240.3	4.4
	3% BSA in receiver	150	460	0.72	892.6	339.6	9.0
		300	460	0.73	562.1	209.0	5.9
		300	193	0.74	524.6	187.2	6.5
clotrimazole	3% BSA in receiver	150	276	0.97	1937.6	54.7	7.5
lopinavir	3% BSA in receiver	300	254	0.74	1132.3	165.4	23.8
		300	454	NA	1132.3c	165.4c	19.8d
		300	839	NA	1132.3c	165.4c	13.5d

^aHere, p and f describe drug in the particle and free drug form; d and r denote donor and receiver, respectively; a is the UWL asymmetry coefficient; and h_UWL is the UWL thickness. NA: not applicable.

^bFlux plateau not clear due to the low diffusional flux and high experimental error.

^ch_fUWL was assumed to remain the same as the LPV 254 nm system since the same stirring rate was used.

^dh_pUWLd was calculated using eq 1 using the LPV 254 nm system as a reference.