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

Table 2

Effect of drug on the cloud point (CP) and energetic parameters for clouding in 1.0 weight percent of hydroxypropylmethyl cellulose (HPMC) solutions in the presence of various salts. The uncertainties in the CP values lie within ±0.1 degree.

10^4𝑋NORT	CP; K	Δ𝐺𝑐^0; kJ/mol	Δ𝐻𝑐^0; kJ/mol	𝑇Δ𝑆𝑐^0; kJ/mol	10^4𝑋IBF	CP; K	Δ𝐺𝑐^0; kJ·mol	Δ𝐻𝑐^0; kJ·mol	𝑇Δ𝑆𝑐^0; kJ·mol
NORT					IBF
Pure water
1.16	336.15	−25.31	−195.49	−170.17	2.91	334.15	−22.62	−70.16	−47.54
2.25	337.15	−23.54		−171.95	5.63	335.15	−20.85		−49.32
3.28	338.15	−22.55		−172.93	10.60	336.15	−19.14		−51.03
5.15	339.15	−21.34		−174.14	20.79	338.15	−17.36		−52.81
6.82	340.15	−20.61		−174.87	28.67	341.15	−16.61		−53.56
10.30	342.15	−19.56		−175.92	34.93	351.15	−16.52		−53.65
13.03	344.15	−19.01		−176.48	37.10	355.15	−16.53		−53.64
15.24	346.15	−18.66		−176.82	39.10	359.15	−16.56		−53.61
18.60	349.15	−18.25		−177.24	40.10	363.15	−16.6		−53.57
21.02	352.15	−18.05		−177.44
10 mM NaCl
1.16	336.15	−25.32	−171.51	−146.19	2.91	336.15	−22.76	121.82	−99.06
2.25	338.15	−23.61		−147.90	5.63	337.15	−20.97		−100.85
4.24	340.15	−21.96		−149.55	10.60	338.15	−19.26		−102.57
6.01	342.15	−21.10		−150.42	15.02	339.15	−18.33		−103.49
9.67	344.15	−19.86		−151.65	18.97	340.15	−17.73		−104.10
12.53	345.15	−19.17		−152.34	27.24	342.15	−16.80		−105.02
16.73	348.15	−18.50		−153.01	33.78	346.15	−16.38		−105.45
19.66	350.15	−18.14		−153.37	39.10	354.15	−16.32		−105.50
21.81	353.15	−17.99		−153.52
100 mM NaCl
1.16	330.15	−24.87	109.28	134.15	2.91	331.15	−22.42	210.20	232.628
2.25	327.15	−22.84		132.13	5.63	329.15	−20.48		230.682
3.28	324.15	−21.62		130.91	10.60	327.15	−18.63		228.837
4.24	321.15	−20.74		130.02	15.02	325.15	−17.57		227.782
5.15	319.15	−20.09		129.38	18.97	323.15	−16.84		227.046
6.01	318.15	−19.62		128.91	22.52	324.15	−16.43	−19.93	−3.5059
6.82	317.15	−19.22		128.51	25.74	327.15	−16.22		−3.717
10.30	321.15	−18.37	−72.74	−54.38	32.59	338.15	−16.1		−3.8347
13.03	323.15	−17.85		−54.9	38.12	348.15	−16.12		−3.8123
15.25	325.15	−17.53		−55.21
17.07	327.15	−17.33		−55.41
19.90	330.15	−17.07		−55.68
200 mM NaCl
1.16	326.15	−24.57	114.86	139.43	2.91	329.15	−22.29	163.87	186.157
2.25	322.15	−22.49		137.35	8.19	326.15	−19.27		183.145
3.28	319.15	−21.29		136.15	12.87	324.15	−17.94		181.808
5.15	315.15	−19.84		134.7	17.04	321.15	−17.02		180.892
6.82	316.15	−19.16	71.64	−52.47	20.79	319.15	−16.39		180.259
8.32	318.15	−18.76		−52.88	24.17	321.15	−16.09	19.13	−3.0444
11.47	321.15	−18.08		−53.56	27.24	323.15	−15.87		−3.2651
13.97	324.15	−17.71		−53.92	33.78	333.15	−15.76		−3.3708
16.02	327.15	−17.51		−54.13	39.10	343.15	−15.82		−3.3143
19.14	329.15	−17.13		−54.51
21.43	331.15	−16.92		−54.72