Salt Effect on the Cloud Point Phenomenon of Amphiphilic Drug-Hydroxypropylmethyl Cellulose System

Table 1

Cloud point (CP) and energetic parameters for clouding in different weight percent of HPMC solutions in the presence of NORT (50 mM) and IBF (50 mM) in presence and absence of various salts. The uncertainties in the CP values lie within ±0.1 degree.

HPMC; % w/v	CP; K	Δ𝐺𝑐^0; kJ/mol	Δ𝐻𝑐^0; kJ/mol	𝑇Δ𝑆𝑐^0; kJ/mol	HPMC; % w/v	CP; K	Δ𝐺𝑐^0; kJ/mol	Δ𝐻𝑐^0; kJ/mol	𝑇Δ𝑆𝑐^0; kJ/mol
NORT					IBF
Pure water
0.10	353.15	−50.63	186.02	236.65	0.10	353.15	−50.63	133.38	184.01
0.20	351.15	−48.32		234.34	0.20	349.15	−48.04		181.42
0.50	347.15	−45.12		231.15	0.50	343.15	−44.60		177.98
1.00	341.15	−42.38		228.40	1.00	336.15	−41.75		175.14
10 mM NaCl
0.10	359.15	−51.49	154.12	205.61	0.10	354.15	−50.77	146.34	197.11
0.20	356.15	−49.01		203.13	0.20	349.15	−48.04		194.38
0.50	352.15	−45.77		199.89	0.50	344.15	−44.73		191.08
1.00	344.15	−42.75		196.87	1.00	338.15	−42.01		188.35
100 mM NaCl
0.10	343.15	−49.20	85.16	134.36	0.10	342.15	−49.05	147.02	196.07
0.20	338.15	−46.53		131.69	0.20	337.15	−46.39		193.41
0.50	332.15	−43.18		128.34	0.50	333.15	−43.30		190.32
1.00	319.15	−39.65		124.81	1.00	327.15	−40.63		187.65
200 mM NaCl
0.10	341.15	−48.91	93.86	142.77	0.10	341.15	−48.91	144.74	193.64
0.20	336.15	−46.26		140.11	0.20	336.15	−46.25		190.99
0.50	330.15	−42.92		136.77	0.50	331.15	−43.04		187.78
1.00	319.15	−39.65		133.50	1.00	326.15	−40.51		185.25