Potential combination topical therapy of anal fissure: development, evaluation, and clinical study†

Figures & data

Figure 1. (a–e) DSC thermograms of LDH, NIF and BMV as (a) drug–drug mixtures where (I) LDH (II) NIF (III) BMV (IV) LDH-NIF (V) LDH-BMV (VI) NIF-BMV (b) tertiary drug mixture, (c) LDH-excipient mixtures, (d) NIF-excipient mixtures, and (e) BMV-excipient mixtures; where I) drug alone, II) drug-CP940, III) drug-P407, IV) drug-methylparaben, V) drug-propylparaben, and VI) drug-titanium-dioxide. (f–h) FT-IR spectra of (f) LDH-P407, (g) LDH-methylparaben, (h) LDH-propylparaben, as control sample (I) and sample subjected to isothermal stress (II).

Table 1. (a) Peak temperature (T_peak) values of drugs, drug–drug and drug-excipient mixtures (1:1 w/w). (b) IST results of drugs, drug–drug, and drug-excipient mixtures (1:1 w/w) after 4 weeks of storage at stressed conditions.

(a)
Sample	Tpeak (°C)
	NIF		LDH		BMV
Drug or drug–drug	–		–		–
NIF	169.94		–		–
LDH	–		77.15		–
BMV	–		–		194.5
NIF + LDH	Disappeared		73.49		–
NIF + BMV	150.8		–		Disappeared
LDH + BMV	–		75.3		Disappeared
NIF + LDH + BMV	167.2		73.8		180
Drug-excipient
CP940	171.33		77.16		190.54
P407	Disappeared		75.788		Disappeared
Methylparaben	Disappeared		50		Disappeared
Propylparaben	Disappeared		50.95		Disappeared
Titanium dioxide	171.93		73.117		192
(b)
	Drug remained (%), mean ± SD
	NIF		LDH		BMV
Sample	Control	Test	Control	Test	Control	Test
Drug or drug-drug	–	–	–	–	–	–
NIF	100.00 ± 1.00	103.23 ± 0.76	–	–	–	–
LDH	–	–	99.39 ± 1.82	101.19 ± 1.10	–	–
BMV	–	–	–	–	99.80 ± 0.75	97.90 ± 0.50
NIF + LDH	102.00 ± 0.20	101.40 ± 2.50	102.60 ± 2.00	102.10 ± 7.70	–	–
NIF + BMV	103.00 ± 0.10	103.70 ± 1.00	–	–	103.20 ± 0.90	98.14 ± 1.00
LDH + BMV	–	–	101.36 ± 2.57	102.40 ± 0.60	102.10 ± 7.70	99.20 ± 0.50
Drug-excipient
CP940	103.60 ± 1.22	101.00 ± 1.35	104.30 ± 1.57	104.38 ± 0.90	101.00 ± 0.80	97.00 ± 0.50
P407	104.00 ± 1.60	98.50 ± 1.50	104.60 ± 2.00	105.80 ± 7.00	99.97 ± 0.48	93.40 ± 1.50
Methylparaben	102.62 ± 2.50	94.10 ± 2.40	104.40 ± 0.70	100.69 ± 1.10	100.10 ± 0.34	94.23 ± 0.03
Propylparaben	104.00 ± 1.29	100.50 ± 1.59	99.98 ± 10.40	102.59 ± 10.3	100.50 ± 0.60	95.32 ± 3.90
Titanium dioxide	104.00 ± 0.80	103.20 ± 2.20	106.40 ± 2.57	103.69 ± 6.30	99.23 ± 0.76	99.19 ± 1.97
Transcutol^®	103.53 ± 1.90	103.00 ± 0.86	103.40 ± 6.28	105.55 ± 2.00	100.65 ± 0.98	99.16 ± 4.40
Benzyl alcohol	109.90 ± 1.04	109.10 ± 7.45	108.63 ± 6.63	106.06 ± 8.84	108.18 ± 1.23	105.80 ± 1.40
Tween^® 20	106.60 ± 7.60	110.21 ± 2.53	102.86 ± 6.41	106.94 ± 6.91	104.58 ± 7.53	104.80 ± 2.60

Figure 2. (a) Effects of irradiation on NIF photostability in gel formulations containing different concentrations of titanium dioxide. (b–d) In vitro release of (b) NIF, (c) LDH, and (d) BMV in phosphate buffer pH 7.4.

Table 2. In vitro evaluation of the prepared combination gels (F1 and F2) and the market products (a) Viscosity, pH, drug content (%), and steady-state flux (J_ss). (b) Kinetic modeling of release data. (c) Stability study data of the optimized combination gel (F2) after storage for three months at different temperatures.

(a)
Formula	Viscosity (mPa.s)	pH Mean ± SD	Drug content (%), Mean ± SD			Jss (µg/cm^2.h), Mean ± SD
			NIF	LDH	BMV	NIF	LDH	BMV
F1	1858 ± 22	5.95 ± 0.03	102.9 ± 2.6	97.8 ± 1.8	99.21 ± 3.1	5.31 ± 0.22	1161 ± 103	4.00 ± 0.20
F2	2043 ± 34	5.88 ± 0.02	102.6 ± 1.12	99.9 ± 1.8	104.3 ± 1.3	29.97 ± 0.5	1045 ± 71	3.27 ± 0.079
Lignocaine^® 5% gel	1479 ± 26	6.05 ± 0.008	–	101.5 ± 3.1	–	–	1518 ± 99	–
Betaderm^® cream	2237 ± 34	4.76 ± 0.04	–	–	99.27 ± 1.0	–	–	1.03 ± 0.10
(b)
		The correlation coefficient (r^2)				Korsmeyer		Main transport mechanism
Drug	Formula	Zero-order	First order	Higuchi model	Release order	r^2	n
NIF	F1	0.9712	0.8798	0.9171	Zero order	0.9850	0.97	Non-Fickian
	F2	0.9952	0.9299	0.9119	Zero order	0.9964	0.98	Non-Fickian
LDH	F1	0.8873	0.8705	0.9907	Diffusion	0.9838	0.51	Non-Fickian
	F2	0.9314	0.9327	0.9944	Diffusion	0.9917	0.53	Non-Fickian
	Lignocaine^® 5% gel	0.9363	0.8533	0.9622	Diffusion	0.9656	0.68	Non-Fickian
BMV	F1	0.9589	0.8752	0.9032	Zero order	0.9640	0.95	Non-Fickian
	F2	0.9907	0.9092	0.9120	Zero order	0.9846	0.99	Non-Fickian
	Betaderm^® cream	0.8617	0.7317	0.8864	Diffusion	0.8573	0.75	Non-Fickian
(c)
Storage Temp.	NIF			LDH			BMV
	t90	t50	% Drug remained	t90	t50	% Drug remained	t90	t50	% Drug remained
(°C)	(days)	(days)	Mean ± SD	(days)	(days)	Mean ± SD	(days)	(days)	Mean ± SD
8 ± 1	910	3920	101.77 ± 1.16	1141	5084	101.42 ± 2.77	845	3664	100.77 ± 0.86
25 ± 1	691	2917	100.66 ± 2.96	806	3546	100.61 ± 4.42	78	320	89.77 ± 2.02
40 ± 1	434	1821	100.29 ± 2.42	331	1371	101.26 ± 4.27	5	66	43.37 ± 4.33

Table 3. Clinical study (a) Baseline characteristics of the study population. (b) Prevalence of fissure healing, pain, bleeding, discharge, and itching among patients with AAF and CAF at first, third, and sixth week post-treatment.

(a)
	Total (n = 71)	AAF (n = 37)		CAF (n = 34)
		Group A	Group B	Group C	Group D
		(n = 20)	(n = 17)	(n = 18)	(n = 16)
Age (years)	33.50 ± 8.80	37.40 ± 10.10	31.50 ± 6.10	33.70 ± 9.60	30.60 ± 7.30
Gender
Male n (%)	22 (31.0%)	7 (35.0%)	5 (29.4%)	6 (33.3%)	4 (25.0%)
Female n (%)	49 (69.0%)	13 (65.0%)	12 (70.6%)	12 (66.7%)	12 (75.0%)
Duration of symptoms (weeks)	8 (1–55)	4 (1–8)	4 (1–8)	18 (11–55)	25.5 (12–55)
Pain scale	90 (50–100)	90 (80–100)	90 (80–100)	80 (50–100)	80 (60–100)
Patients have bleeding (%)	15 (21.1%)	1 (5.0%)	2 (11.7%)	6 (33.30)	6 (37.0%)
Bleeding, discharge, and itching	8 (6–9)	9 (6–9)	9 (6–9)	6 (6–9)	6 (6–9)
(b)
No of weeks Symptoms	AAF				CAF
	Total	Group A	Group B		Total	Group C	Group D
	(n = 37)	(n = 20)	(n = 17)	p Value	(n = 34)	(n = 18)	(n = 16)	p Value
First week
Healing n (%)
Complete	0 (0.0%)	0 (0.0%)	0 (0.0%)	0.1^a	0 (0.0%)	0 (0.0%)	0 (0.0%)	0.004^a
Partial	32 (86.5%)	19 (95.0%)	13 (76.5%)		28 (82.4%)	18 (100.0%)	10 (62.5%)
No	5 (13.5%)	1 (5.0%)	4 (23.5%)		6 (17.6%)	0 (0.0%)	6 (37.5%)
pain	50 (40–70)	50 (40–70)	60 (40–70)	0.115^b	60 (30–90)	50 (30–70)	60 (30–90)	0.223^b
Bleeding discharge/itching	6 (3–8)	4.5 (3–8)	6 (3–6)	0.728^b	6 (3–6)	6 (3–6)	6 (3–6)	0.436^b
Third week
Healing n (%)
Complete	27 (73.0%)	18 (90.0%)	9 (52.9%)	0.024^a	24 (70.6%)	15 (83.3%)	9 (56.3%)	0.015^a
Partial	6 (16.2%)	2 (10.0%)	4 (23.5%)		4 (11.8%)	3 (16.7%)	1 (6.3%)
No	4 (10.8%)	0 (0.0%)	4 (23.5%)		6 (17.6%)	0 (0.0%)	6 (37.5%)
pain	20 (10–80)	20 (10–50)	40 (10–80)	0.007^b	20 (10–80)	20 (10–60)	40 (10–80)	0.053^b
Bleeding discharge/itching	3 (0–7)	3 (0–7)	3 (0–6)	0.249^b	3 (0–6)	3 (0–6)	4.5 (3–6)	0.031^b
Sixth week
Healing n (%)
Complete	28 (75.7%)	19 (95.0%)	9 (52.9%)	0.01^a	24 (70.6%)	15 (83.3%)	9 (56.3%)	0.015^a
Partial	4 (10.8%)	0 (0.0%)	4 (23.5%)		4 (11.8%)	3 (16.7%)	1 (6.3%)
No	5 (13.5%)	1 (5.0%)	4 (23.5%)		6 (17.6%)	0 (0.0%)	6 (37.5%)
pain	20 (10–70)	10 (10–50)	20 (10–70)	0.001^b	15 (10–90)	10 (10–50)	20 (10–90)	0.023^b
Bleeding discharge/itching	1 (0–6)	0 (0–6)	2 (0–6)	0.004^b	1.5 (0–9)	0 (0–6)	3 (0–9)	0.042^b

^a Chi-square test.

^b Mann–Whitney U test.

Group A; with acute anal fissure (AAF) treated with the optimized combination gel (F2).

Group B; with acute anal fissure (AAF) treated with the market topical preparations.

Group C; with chronic anal fissure (CAF) treated with the optimized combination gel (F2).

Group D; with chronic anal fissure (CAF) treated with the market topical preparations.

Figure 3. Representative photographs of patients suffering from either AAF (a) before treatment (baseline), (b) after treatment for six weeks with the optimized combination gel (F2) or CAF, (c) before treatment (baseline), and (d) after treatment for six weeks with the optimized combination gel (F2).