Transdermal Drug Delivery System of Salbutamol Sulphate: Formulation and Evaluation

Vaseeha Banu T. S.¹*, Sukhen Som², Mohamed Khaleel² and Nirmal T. Havannavar²

¹Department of Pharmaceutics, M.M.U College of Pharmacy, K. K. Doddi, Dist- Ramanagara- 571511, Karnataka (India)

²Department of Pharmaceutical Chemistry, M.M.U College of Pharmacy, K. K. Doddi, Dist. Ramanagara- 571511, Karnataka (India)

ABSTRACT:

Salbutamol Sulphate (SS) is a selective β2 adrenergic receptor agonist having oral bioavailability of 50%. The transdermal films of SS were formulated using solvent casting technique. Solutions containing polymers i.e. Hydroxy Propyl Methyl Cellulose (HPMC) and Ethyl Cellulose (EC) at different concentrations (1%, 1.5%, 2%, 2.5%, and 3%) were prepared. These solutions were then used to prepare films. Prepared films were then evaluated for their different physicochemical parameters like physical appearance, weight variation, thickness, drug content, folding endurance, tensile strength, percent elongation and finally in vitro release study across rat abdominal skin. Between the two polymers used results revealed that the films prepared by using 2% HPMC with 30% propylene glycol(PG) was very flexible with high folding endurance and uniform drug content, further release study showed 88.68% release across the rat abdominal skin for 24 hours.

KEYWORDS: Salbutamol, Asthma, Bronchitis

INTRODUCTION:

The controlled drug delivery is rather a more recent approach on the era of new drug delivery system which is meant to deliver the drug into systemic circulation at a predetermined rate. Such system helps to overcome the unwanted effects associated with conventional systems of medication which requires multiple dosing ¹. Using skin as a port of entry of the drug into systemic circulation is increasingly becoming popular day by day for various reasons ². For such an approach that is the Transdermal Drug Delivery System (TDDS) the goal and design of dosage simultaneously minimizes the retention and metabolism of the drug ³. It represents numerous advantages like a) variation of absorption which in turn leads to difference in metabolism associated with oral administration can be avoided, b) permits the use of drugs with short biological half life, c) increase in bioavailability and efficacy of the drug because hepatic first pass metabolism can be avoided and finally d) provide a simple therapeutic regimen leading to good patient compliance. Despite all these advantages the TDDS is still limited to a certain number of drugs with suitable profile ⁴.

Salbutamol Sulphate (SS) is one of the most widely used drugs for the treatment of bronchial asthma, bronchitis and emphysema ⁵. Injectable and aerosols dosage forms of SS are recommended for instant relief in severe asthmatic attacks. The dose in adults and children is 2 to 3 inhalations of aerosol with strength of 100-200 µg every 4-6 hours. The drug undergoes extensive first pass metabolism and thus requires frequent oral administration ⁶. On the contrary frequent administration of this drug is not recommended as reported in literature ⁷. Thus there is a need to develop such a system which can maintain the required therapeutic concentration for a long period of time without frequent dosing. Hence reliancing the available literatures, the suitability of SS with respect to dose, solubility, molecular weight and half life and with a hope that TDDS can vie with the conventional dosage forms (like tablet, capsule, parenterals etc.) in near future, here in our present study an effort has been made to prepare the transdermal films of SS and to evaluate different physicochemical properties associated with it.

MATERIALS AND METHODS:

SS was obtained as a gift sample from Astrazeneca Ltd., Bangalore, HPMC from NR chemicals, Mumbai, EC from BPRL Bangalore, Propylene Glycol (PG) from Rankem, New Delhi and all other ingredients used were of highly pure analytical grade.

Preparation of transdermal film

Method used for the preparation of film was solvent casting technique ⁸. Table 1 and 2 Shows composition of transdermal films of SS with HPMC and EC alone and in combination respectively. Polymer was dissolved in 50% alcohol. Drug was separately dissolved in 50% alcohol. PG was added to this solution and stirred for 30 minutes on a magnetic stirrer for uniform mixing. Then the solution containing drug and PG was added to the polymer solution and the resulting solution was stirred for 30min. The prepared solution was poured into petridish and dried at room temperature for 48 hours. The petridish was covered by inverted funnel, to avoid rapid evaporation of the solvent.

TABLE- 1: Formulation composition of transdermal films of HPMC and EC alone containing 5 mg of SS

Serial number	Formulation code	HPMC	EC	P G
1	H1	1%	-	20%
2	H2		-	30%
3	H3		-	40%
4	H4	1.5%	-	20%
5	H5		-	30%
6	H6		-	40%
7	H7	2%	-	20%
8	H8		-	30%
9	H9		-	40%
10	H10	2.5%	-	20%
11	H11		-	30%
12	H12		-	40%
13	H13	3%	-	20%
14	H14		-	30%
15	H15		-	40%
16	E1	-	1%	20%
17	E2	-		30%
18	E3	-		40%
19	E4	-	1.5%	20%
20	E5	-		30%
21	E6	-		40%
22	E7	-	2%	20%
23	E8	-		30%
24	E9	-		40%
25	E10	-	2.5%	20%
26	E11	-		30%
27	E12	-		40%
28	E13	-	3%	20%
29	E14	-		30%
30	E15	-		40%

Physicochemical evaluation

The prepared films were evaluated for their physical appearance, uniformity of thickness, weight variation, tensile strength, folding endurance, drug content, water vapour transmission rate (WVTR) and in vitro release studies across the rat abdominal skin.

Weight variation

A 2 cm² film was cut uniformly and weighed in digital balance and results are reported in table-3 and 4.

Thickness of the film

Screw gauge was used to determine thickness of the films. It was placed at three different positions by keeping the film in between two glass slides of known thickness and average thickness was calculated and the values are given in table-3 and 4.

Folding endurance ⁹

The folding endurance was measured manually. A strip of film having an area of 2cm² was cut evenly and repeatedly folded at the same place till it broken/cracked. The number of times the film could be folded at the same place without breaking/cracking give the exact value of folding endurance and the results are reported in table-3 and 4.

Tensile strength ¹⁰

Tensile strength was measured using analytical two-pan balance. A patch of 20 mm width and 50 mm length was cut and clamped between two clamps on one side. Weights were added to the pan on the other side until the patch is broken. The weight required for breaking the patch was taken as a measure of tensile strength of the patch and the results are reported in table-3 and 4.

Percentage elongation

Percentage elongation was calculated by measuring the increase in length of the film after tensile strength measurement by using the following formula.

Percentage elongation = (L_F- L_O) X 100 / L_O. Where L_F = final length, L_O= initial length.

Water vapor transmission studies ^{9, 10}

Previously washed and dried vials of equal diameter were used as transmission cells. About 1 gm of fused calcium chloride was taken in the cell and the polymeric patches were fixed over the brim with the help of an adhesive. Then the cells were weighed accurately and kept in a closed dessicator containing saturated solution of potassium chloride (200ml). The humidity inside the dessicator was measured by a Hygrometer and it was found to be 80-90% relative humidity. The cells were taken out and weighed after 2, 8, 12, 24, 48 and 72 h. From the increase in weights, the amount of water vapor transmitted and the rate of water vapor transmitted was calculated using the formula, Water Vapor Transmission Rate = W L /S. where W = Gm of water transmitted, L = Thickness of the patch and S = Exposed surface area of the patch.

Drug content ⁹

A 2cm² film was cut into small pieces and put in 100ml phosphate buffer (pH 7.4). This was then shaken in a mechanical shaker for 2 hrs to get a homogenous solution and filtered. Then sample solutions from this was prepared by diluting to different concentrations and determined spectroscopically. The determinations were carried out in triplicates and the average of three readings were recorded and reported in table 3 and 4.

In vitro release studies across the rat skin ^{8, 11}

The Franz diffusion cell assembly having 100 ml capacity in receptor chamber was used. The rat abdominal skin was washed with plenty of water and trimmed in to circular section of about 3 cm diameter. The patch was then placed over the skin facing the stratum corneum side and mounted with cap of the diffusion cell and clamped securely on to the receptor compartment with dermis side of the skin facing

TABLE- 2: Formulation composition of transdermal films with combination of polymers containing 5 mg of SS

Serial number	Formulation code	HPMC : EC (1:1)	HPMC : EC (1:2)	HPMC : EC (1:3)	P G
1	HE1	1%	-	-	20%
2	HE2	1%	-	-	30%
3	HE3	1%	-	-	40%
4	HE4	1.5%	-	-	20%
5	HE5	1.5%	-	-	30%
6	HE6	1.5%	-	-	40%
7	HE7	2%	-	-	20%
8	HE8	2%	-	-	30%
9	HE9	2%	-	-	40%
10	HE10	2.5%	-	-	20%
11	HE11	2.5%	-	-	30%
12	HE12	2.5%	-	-	40%
13	HE13	3%	-	-	20%
14	HE14	3%	-	-	30%
15	HE15	3%	-	-	40%
16	HE16	-	1%	-	20%
17	HE17	-	1%	-	30%
18	HE18	-	1%		40%
19	HE19	-	1.5%	-	20%
20	HE20	-	1.5%	-	30%
21	HE21	-	1.5%	-	40%
22	HE22	-	2%	-	20%
23	HE23	-	2%	-	30%
24	HE24	-	2%	-	40%
25	HE25	-	2.5%	-	20%
26	HE26	-	2.5%	-	30%
27	HE27	-	2.5%	-	40%
28	HE28	-	3%	-	20%
29	HE29	-	3%	-	30%
30	HE30	-	3%	-	40%
31	HE31	-	-	1%	20%
32	HE32	-	-	1%	30%
33	HE33	-	-	1%	40%
34	HE34	-	-	1.5%	20%
35	HE35	-	-	1.5%	30%
36	HE36	-	-	1.5%	40%
37	HE37	-	-	2%	20%
38	HE38	-	-	2%	30%
39	HE39	-	-	2%	40%
40	HE40	-	-	2.5%	20%
41	HE41	-	-	2.5%	30%
42	HE42	-	-	2.5%	40%
43	HE43	-	-	3%	20%
44	HE44	-	-	3%	30%
45	HE45	-	-	3%	40%

the receptor solution containing 100 ml pH 7.4 phosphate buffer solution. The receptor solution was constantly stirred at 37 ± 1⁰C over magnetic stirrer. At hourly intervals, 1ml of the sample was withdrawn and replaced immediately with fresh media. Amount of drug in the withdrawn samples was determined spectrophotometrically and reported in table 3 and 4.

RESULTS AND DISCUSSION:

Prepared transdermal films were thin, flexible transparent and smooth. The solvent casting technique used to prepare the films was satisfactory. From the physicochemical evaluation data of the films (table 3 and 4) it is evident that there was no physical change like appearance, flexibility and colour when the films were stored at room temperature. The thickness found to be least for the films prepared with 1% w/v polymer alone and in combination with 20% PG. (table 3 and 4). Same observation was attributed for the weights measured of the films. When it comes to tensile strength measurements formulations H8 and E8 and HE8, HE23 and HE38 having the maximum value. It may be due to

the fact that at the ratio of 2% polymer with 30% PG provided the ideal tensile strength required for the films.

The drug content for all the formulations was determined by using calibration plot and it varies in the range of 94.27% to 98.83%. In case of folding endurance the formulation prepared with HPMC shown more values than the formulations prepared with EC, irrespective of the percentage of HPMC used. This fact can be explained by the elasticity of HPMC which is more than EC. Same observation was also seen in case of tensile strength, in turn percent elongation of the films.

The water vapour transmission (WVT) pattern was observed in the order of HPMC (H1 to H15) > HPMC: EC- 1:1 (HE1 to HE15)> HPMC: EC- 1:2 (HE16 to HE30)> EC (E1 to E15)> HPMC: EC- 1:3 (HE31 to HE45). Furthermore it was revealed that at 30% concentration of PG the WVT rate was maximum in case of polymers used alone as well as in combination. The above series of WVT rate may be justified by the hydrophilicity of HPMC which is more than EC.

TABLE- 3: Physicochemical data of transdermal films of HPMC and EC containing SS

Form code	Poly. Conc.	Plasticizer Conc.	Physical app.	Thickness (mm) n = 5	Weight (mg) n = 5	Drug content (%) n = 3	Tensile Strength Gm/10^2cm n = 5	Percent elongation n = 5	Folding endurance n = 5	WVTR g/cm^2 at 72hrs	In-vitro release studies
Films prepared only with HPMC
H1	1%	20%	Uniform	0.011 ± 0.005	6.253 ± 0.25	96.87 ± 0.79	32.34 ± 0.41	08 ± 0.082	155 ± 5.8	0.16752	84.48
H2		30%	Uniform	0.013 ± 0.008	6.325 ± 0.53	97.38 ± 0.82	34.52 ± 0.58	08 ± 0.053	158 ± 6.9	0.16784	85.52
H3		40%	Uniform	0.014 ± 0.006	6.401 ± 0.86	98.49 ± 0.56	34.90 ± 0.62	10 ± 0.079	162 ± 7.5	0.16754	84.83
H4	1.5%	20%	Uniform	0.012 ± 0.007	6.482 ± 0.42	94.27 ± 0.42	31.42 ± 0.78	10 ± 0.056	157 ± 3.4	0.16652	85.68
H5		30%	Uniform	0.014 ± 0.002	6.502 ± 0.38	96.32 ± 0.38	35.02 ± 0.52	11 ± 0.075	163 ± 6.3	0.16598	85.68
H6		40%	Uniform	0.015 ± 0.005	6.509 ± 0.52	97.39 ± 0.45	35.63 ± 0.38	12 ± 0.091	162 ± 7.8	0.16575	87.45
H7	2%	20%	Uniform	0.014 ± 0.008	6.602 ± 0.68	95.43 ± 0.68	37.80 ± 0.56	14 ± 0.056	175 ± 8.5	0.16983	86.98
H8		30%	Uniform	0.015 ± 0.001	6.621 ± 0.34	96.96 ± 0.63	37.86 ± 0.38	15 ± 0.085	189 ± 5.9	0.17256	88.68
H9		40%	Uniform	0.016 ± 0.005	6.628 ± 0.56	97.23 ± 0.42	37.05 ± 0.21	15 ± 0.062	180 ± 8.1	0.17005	87.64
H10	2.5%	20%	Uniform	0.017 ± 0.007	6.643 ± 0.45	97.02 ± 0.72	35.14 ± 0.45	15 ± 0.037	170 ± 7.5	0.16848	87.58
H11		30%	Uniform	0.017 ± 0.006	6.648 ± 0.62	96.52 ± 0.85	36.82 ± 0.57	16 ± 0.095	174 ± 6.9	0.16732	86.98
H12		40%	Uniform	0.018 ± 0.004	6.651 ± 0.78	96.29 ± 0.45	37.45 ± 0.88	16 ± 0.063	175 ± 7.6	0.16719	87.34
H13	3%	20%	Uniform	0.019 ± 0.001	6.683 ± 0.82	95.12 ± 0.28	34.54 ± 0.38	15 ± 0.025	174 ± 8.3	0.16695	87.86
H14		30%	Uniform	0.020 ± 0.003	6.685 ± 0.34	98.09 ± 0.76	35.92 ± 0.21	16 ± 0.096	178 ± 5.9	0.16654	86.59
H15		40%	Uniform	0.022 ± 0.006	6.701 ± 0.58	96.38 ± 0.38	36.0 ± 0.72	15 ± 0.025	180 ± 5.6	0.16627	86.63
Films prepared only with EC
E1	1%	20%	Uniform	0.013 ± 0.005	6.436 ± 0.86	98.28 ± 0.96	28.12 ± 0.48	07 ± 0.019	81 ± 7.6	0.13351	67.54
E2		30%	Uniform	0.015 ± 0.007	6.445 ± 0.53	96.54 ± 0.57	28.05 ± 0.26	07 ± 0.057	85 ± 8.5	0.13768	66.38
E3		40%	Uniform	0.015 ± 0.004	6.451 ± 0.39	97.28 ± 0.53	29.12 ± 0.34	08 ± 0.053	85 ± 9.6	0.14024	67.21
E4	1.5%	20%	Uniform	0.014 ± 0.005	6.502 ± 0.45	96.45 ± 0.76	28.83 ± 0.58	07 ± 0.089	88 ± 5.9	0.14345	69.45
E5		30%	Uniform	0.016 ± 0.008	6.529 ± 0.52	97.49 ± 0.58	29.18 ± 0.63	08 ± 0.025	87 ± 5.6	0.14728	68.68
E6		40%	Uniform	0.018 ± 0.003	6.537 ± 0.61	97.48 ± 0.19	29.09 ± 0.42	09 ± 0.045	88 ± 7.4	0.15023	68.54
E7	2%	20%	Uniform	0.017 ± 0.009	6.801 ± 0.78	98.19 ± 0.74	27.54 ± 0.86	07 ± 0.087	90 ± 2.6	0.15098	69.72
E8		30%	Uniform	0.020 ± 0.004	6.782 ± 0.96	96.31 ± 0.21	30.05 ± 0.34	08 ± 0.032	105 ± 8.5	0.15108	71.83
E9		40%	Uniform	0.021 ± 0.007	6.824 ± 0.48	97.38 ± 0.89	27.26 ± 0.48	08 ± 0.056	105 ± 4.7	0.14958	70.94
E10	2.5%	20%	Uniform	0.019 ± 0.008	6.901 ± 0.43	97.45 ± 0.39	26.02 ± 0.62	08 ± 0.074	95 ± 8.7	0.14563	68.58
E11		30%	Uniform	0.022 ± 0.004	6.905 ± 0.46	97.58 ± 0.42	27.14 ± 0.53	07 ± 0.025	89 ± 4.8	0.13805	68.32
E12		40%	Uniform	0.024 ± 0.008	6.915 ± 0.83	98.22 ± 0.88	27.46 ± 0.85	08 ± 0.056	85 ± 7.6	0.13782	66.67
E13	3%	20%	Uniform	0.021 ± 0.004	8.081 ± 0.27	98.76 ± 0.75	24.77 ± 0.52	07 ± 0.073	79 ± 8.6	0.13658	69.67
E14		30%	Uniform	0.023 ± 0.005	8.212 ± 0.59	95.33 ± 0.54	25.82 ± 0.61	08 ± 0.027	82 ± 2.9	0.12568	68.45
E15		40%	Uniform	0.023 ± 0.007	8.293 ± 0.73	96.45 ± 0.76	25.9 ± 0.38	08 ± 0.039	86 ± 3.7	0.12145	68.98

In vitro release study (table 3 and 4) shows that HPMC when used alone has the maximum in vitro release through rat abdominal skin which is followed by the formulations prepared with HPMC : EC- 1:1. In this row the third entity is the formulation developed by using

HPMC : EC- 1:2 followed by HPMC : EC- 1:3 and lastly only with EC. As SS is water soluble and HPMC is hydrophilic in nature the drug release was facilitated and found to be the best through HPMC based films which further declined as the concentration of HPMC and EC

TABLE- 4: Physicochemical data of transdermal films of HPMC and EC in combination

Form code	Poly. Conc	Plasticizer Conc.	Physical app.	Thickness (mm) n = 5	Weight (mg) n = 5	Drug content (%) n = 3	Tensile Strength Gm/10^2cm n = 5	Percent elongation n = 5	Folding endurance n = 5	WVTR g/cm^2 at 72hrs	In-vitro release studies
HPMC : EC = 1 : 1
H1	1%	20%	Uniform	0.013 ± 0.002	6.308 ± 0.31	98.68 ± 0.42	30.96 ± 0.24	08 ± 0.082	146 ± 4.5	0.15982	85.62
H2		30%	Uniform	0.014 ± 0.008	6.315 ± 0.38	97.87 ± 0.52	30.54 ± 0.58	09 ± 0.034	148 ± 6.3	0.16054	84.32
H3		40%	Uniform	0.015 ± 0.007	6.324 ± 0.52	96.23 ± 0.67	30.86 ± 0.54	09 ± 0.026	148 ± 7.2	0.16024	86.53
H4	1.5%	20%	Uniform	0.015 ± 0.004	6.338 ± 0.58	97.85 ± 0.83	29.84 ±0.24	10 ± 0.052	146 ± 5.6	0.15871	86.12
H5		30%	Uniform	0.015 ± 0.006	6.339 ± 0.32	96.67 ± 0.75	30.12 ± 0.29	08 ± 0.045	138 ± 5.3	0.15865	85.98
H6		40%	Uniform	0.016 ± 0.008	6.341 ± 0.65	96.84 ± 0.38	30.23 ± 0.58	08 ± 0.032	132 ± 3.8	0.15845	85.38
H7	2%	20%	Uniform	0.018 ± 0.005	6.349 ±0.21	98.23 ±0.84	30.05 ± 0.75	09 ± 0.018	132 ± 4.5	0.16055	86.82
H8		30%	Uniform	0.019 ± 0.006	6.349 ± 0.58	96.45 ± 0.45	31.12 ± 0.45	11 ± 0.028	124 ± 2.1	0.17087	88.37
H9		40%	Uniform	0.019 ± 0.008	6.350 ± 0.29	98.28 ± 0.55	30.15 ± 0.28	08 ± 0.075	124 ± 5.6	0.16982	87.93
H10	2.5%	20%	Uniform	0.021 ± 0.002	6.357 ± 0.72	97.54 ± 0.28	28.92 ± 0.51	07 ± 0.028	118 ± 7.8	0.16754	85.24
H11		30%	Uniform	0.021 ± 0.005	6.355 ± 0.28	98.73 ± 0.59	29.05 ± 0.26	08 ± 0.043	116 ± 8.6	0.16732	86.54
H12		40%	Uniform	0.023 ± 0.003	6.356 ± 0.45	98.45 ± 0.43	29.12 ± 0.65	09 ± 0.037	119 ± 9.1	0.16741	87.21
H13	3%	20%	Uniform	0.023 ± 0.008	6.364 ± 0.61	97.68 ± 0.27	28.24 ± 0.72	10 ± 0.028	119 ± 7.5	0.16708	86.74
H14		30%	Uniform	0.022 ± 0.005	6.365 ± 0.83	97.68 ± 0.77	28.36 ± 0.52	10 ± 0.064	109 ± 4.2	0.16578	86.68
H15		40%	Uniform	0.024 ± 0.009	6.368 ± 0.19	97.45 ± 0.28	28.38 ± 0.14	08 ± 0.053	113 ± 5.3	0.16676	85.32
HPMC : EC = 1 : 2
HE16	1%	20%	Uniform	0.017 ± 0.006	6.310 ± 0.45	98.23 ± 0.22	28.85 ± 0.18	09 ± 0.025	124 ± 4.5	0.14872	76.24
HE17		30%	Uniform	0.017 ± 0.003	6.312 ±0.38	96.68 ± 0.27	28.96 ± 0.27	08 ± 0.044	126 ± 4.8	0.14905	76.58
HE18		40%	Uniform	0.019 ± 0.009	6.311 ± 0.61	97.38 ± 0.88	27.05 ± 0.85	10 ± 0.038	130 ± 6.2	0.15132	77.13
HE19	1.5%	20%	Uniform	0.018 ± 0.008	6.316 ± 0.32	98.45 ± 0.86	28.05 ± 0.76	11 ± 0.043	126 ± 4.8	0.15097	75.93
HE20		30%	Uniform	0.020 ± 0.005	6.319 ± 0.28	97.98 ± 0.81	28.16 ± 0.52	09 ± 0.072	128 ± 7.3	0.14903	76.12
HE21		40%	Uniform	0.021 ± 0.004	6.18 ± 0.15	98.25 ± 0.49	28.18 ± 0.91	08 ± 0.052	130 ± 3.5	0.15136	76.58
HE22	2%	20%	Uniform	0.021 ± 0.002	6.322 ± 0.56	98.28 ± 0.44	28.12 ± 0.43	09 ± 0.031	125 ± 6.4	0.15745	77.28
HE23		30%	Uniform	0.024 ± 0.008	6.324 ± 0.62	97.67 ± 0.73	28.15 ± 0.78	11 ± 0.018	118 ± 8.2	0.15848	78.88
HE24		40%	Uniform	0.024 ± 0.004	6.324 ± 0.28	97.83 ± 0.84	28.21 ± 0.83	09 ± 0.012	119 ± 9.1	0.15752	78.83
HE25	2.5%	20%	Uniform	0.026 ± 0.003	6.330 ± 0.81	98.45 ± 0.43	27.36 ± 0.34	10 ± 0.034	125 ± 5.8	0.15648	77.54
HE26		30%	Uniform	0.026 ± 0.006	6.328 ± 0.41	96.36 ± 0.72	27.86 ± 0.45	11 ± 0.026	117 ± 5.6	0.15552	77.01
HE27		40%	Uniform	0.027 ± 0.007	6.339 ± 0.45	97.55 ± 0.85	27.42 ± 0.56	08 ± 0.037	113 ± 4.7	0.15638	76.98
HE28	3%	20%	Uniform	0.030 ± 0.004	6.379 ± 0.58	97.62 ± 0.25	26.54 ± 0.68	10 ± 0.068	118 ± 2.8	0.14956	77.12
HE29		30%	Uniform	0.032 ± 0.006	6.340 ± 0.68	98.83 ± 0.62	26.60 ± 0.87	09 ± 0.048	118 ± 3.4	0.15023	76.98
HE30		40%	Uniform	0.031 ± 0.008	6.339 ± 0.83	97.86 ± 0.71	26.61 ± 0.72	08 ± 0.037	117 ± 7.2	0.15056	76.94
HPMC : EC = 1 : 3
HE31	1%	20%	Uniform	0.019 ± 0.004	6.318 ± 0.55	97.38 ± 0.55	27.46 ± 0.24	08 ± 0.021	116 ± 4.5	0.13462	72.38
HE32		30%	Uniform	0.021 ± 0.009	6.319 ± 0.42	97.45 ± 0.76	27.48 ± 0.53	07 ± 0.018	120 ± 5.6	0.13578	72.56
HE33		40%	Uniform	0.022 ± 0.008	6.320 ± 0.36	98.21 ± 0.76	27.49 ± 0.37	07 ± 0.033	120 ± 6.8	0.13609	71.34
HE34	1.5%	20%	Uniform	0.024 ± 0.004	6.323 ±0.75	97.68 ± 0.49	27.28 ± 0.78	08 ± 0.045	114 ± 7.4	0.13845	72.83
HE35		30%	Uniform	0.024 ± 0.005	6.325 ± 0.28	98.22 ± 0.78	27.31 ± 0.45	08 ± 0.055	112 ± 4.8	0.13926	73.54
HE36		40%	Uniform	0.025 ± 0.003	6.327 ±0.46	98.35 ± 0.28	27.52 ± 0.26	09 ± 0.028	116 ± 8.6	0.13918	73.86
HE37	2%	20%	Uniform	0.026 ± 0.008	6.329 ± 0.23	97.91 ± 0.82	27.42 ± 0.64	08 ± 0.063	108 ± 5.8	0.14256	74.12
HE38		30%	Uniform	0.028 ±0.007	6.329 ±0.85	98.45 ± 0.62	27.68 ± 0.56	09 ± 0.043	109 ± 3.7	0.14548	75.32
HE39		40%	Uniform	0.029 ±0.005	6.331 ±0.27	98.56 ±0.54	27.55 ± 0.72	07 ± 0.029	107 ± 7.5	0.14537	74.84
HE40	2.5%	20%	Uniform	0.028 ± 0.009	6.334 ±0.53	97.81 ±0.28	26.98 ± 0.48	08 ± 0.082	100 ± 6.5	0.14138	72.34
HE41		30%	Uniform	0.030 ± 0.005	6.337 ± 0.96	97.46 ±0.38	27.01 ± 0.67	07 ± 0.077	99 ± 2.8	0.14145	72.58
HE42		40%	Uniform	0.031 ± 0.006	6.335 ± 0.48	97.57 ±0.55	26.85 ± 0.18	09 ± 0.049	102 ± 4.3	0.14362	71.63
HE43	3%	20%	Uniform	0.031 ± 0.007	6.338 ± 0.67	98.45 ±0.85	26.76 ± 0.17	09 ± 0.037	95 ± 5.6	0.14345	70.34
HE44		30%	Uniform	0.032 ± 0.006	6.339 ± 0.92	98.12 ± 0.56	26.87 ± 0.74	08 ± 0.076	97 ± 7.4	0.14297	70.54
HE45		40%	Uniform	0.032 ± 0.008	6.341 ±0.46	97.45 ± 0.65	2688 ± 0.43	08 ± 0.032	98 ± 8.3	0.14283	70.92

FIGURE- 1: Comparative in vitro release study of the formulations H8 and E8

FIGURE 2: Comparative in vitro release study of the formulations HE8, HE23 and HE38

simultaneously reduces and increases respectively. It was also observed that 2% polymer alone and in combination with 30% plasticizer shown to have the maximum in vitro release irrespective of any other films prepare with any percentage of polymer and plasticizer.

Thus in this respect it can be stated that 2% polymer along with 30% plasticizer may contribute to the optimum ratio to formulate the transdermal films.

CONCLUSION:

The study demonstrates the feasibility of formulating the Transdermal Drug Delivery of SS. The various parameters that were evaluated helps to understand the suitability and usefulness of SS to be formulated as a transdermal film with different concentration of polymers. The transdermal formulations were found to safe and non reactive. Based on the physical appearance, folding endurance, weight variation, thickness, tensile strength, drug content and release pattern 2% polymer with 30% plasticizer (PG) was found to be the best.

Transdermal delivery of SS may appear to be relatively a better route to treat Bronchial Asthma. In the light of the results of the present work further attempt can be done to deliver the drug for duration up to several days.

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Received on 17.09.2009

Accepted on 15.11.2009

© A&V Publication all right reserved

Research Journal of Pharmaceutical Dosage Forms and Technology. 2(1): Jan. – Feb. 2010, 56-61