Formulation optimization and Evaluation of Transdermal patch of losartan potassium containing DMSO as permeation enhancer

Sachin B. Jadhav*, Ankita R. Koshti, Mr. M. M. Bari, Dr. S. D. Barhate

Shree Sureshdada Jain Institute of Pharmaceutical Education and Research, Jamner

*Corresponding Author E-mail: jsachin399@gmail.com

ABSTRACT:

The present investigation focused on the formulation optimization and evaluation of transdermal patch of losartan potassium containing DMSO as permeation enhancer. Transdermal patches were prepared by solvent evaporation method by taking different ratios of polymers such as HPMC K100M and Eudragit RS 100, along with the DMSO as permeation enhancer and PEG-400 as plasticizer. Two factor three levels central composite design applied to optimize the formulation variables. In this study, amount of HPMC K100 M (X1) and amount of Eudragit RS 100 (X2) were selected as independent variables. The percentage losartan potassium permeated at 3 hrs (Y1), percentage losartan potassium permeated at 6 hrs (Y2) and permeation flux (Y3) were selected as dependent variables. The FTIR studies confirmed that there is no interaction between losartan potassium and the polymers. Nine formulations were formulated according to design. The prepared formulations were evaluated for various physical and chemical parameters. In-vitro drug permeation study was carried out for 6 hrs. The formulation OLP-4 was given as best batch by the design expert software. The formulation OLP-4 showed the 34.47 % permeation in 6 hrs and permeation flux435.74 µg/cm²/hr. The best fit model for optimized batch OLP-4 is zero order model with highest r² value of (r² = 0.9641) and the mechanism of release was fickian diffusion mediated. Statistical optimization proved to be very useful in the subsequent formulation development work following preliminary evaluations. Thus, the design of experiment with response surface method is an efficient tool to determine and optimize formulation conditions within experimental conditions.

KEYWORDS: Losartan potassium, HPMC K100M, Eudragit RS 100, Transdermal patch, Controlled release, Central composite design.

INTRODUCTION^{(1,2,3,4,5,6,7)}:

Controlled Drug Delivery System:

Controlled release system refers to use of delivery device with the objective of releasing the drug into patient’s body at a predermined rate, or at specific times or with specific release profiles. The term controlled release has a meaning that goes beyond the scope of sustained release.

It also implies a predictability and reproducibility in the drug release kinetics, which means that the release of drug ingredients from a controlled drug delivery system proceeds at a rate profile that is not only predictable kinetically, but also reproducible from one unit to another.

Transdermal Drug Delivery System:

The system of drug delivery that employs a skin portal to the systemic circulation at a predermined rate and maintains clinically effective concentrations over a prolonged period of times is known as a transdermal drug delivery system (TDDS).

The word transdermal has been derived from the root ‘trans’ meaning through, across or beyond and ‘derma’ meaning skin. Transdermal drug delivery system was introduced to overcome the difficulties of drug delivery through oral route. Transdermal systems are a desirable form of drug delivery because of the obvious advantages over other routes of delivery. Transdermal delivery provides convenient and pain-free self-administration for patients. Transdermal delivery provides a leading edge over injectables and oral routes by increasing patient compliance and avoiding first pass metabolism.

Losartan potassium is the potassium salt of losartan, a non-peptide angiotensin II receptor antagonist with antihypertensive activity. Losartan potassium is readily absorbed from the gastrointestinal tract following oral administration, but undergoes substantial first pass metabolism resulting in a systemic bioavailability of about 33%. Elimination half-life of losartan potassium about 1.5 to 2.5 hours.

MATERIAL AND METHODS:

Materials:

Losartan potassium was obtained as gift sample from Medley Pharma Ltd., Daman. HPMC K100 M was obtained from Molychem, Mumbai. Eudragit RS 100 was obtained from Loba Chemie Pvt. Ltd., Mumbai, India. Polyethylene glycol 400, Dimethyl sulfoxide, Methanol and Dichloromethane were obtained from Jinendra Scientific, Jalgaon.

Compatibility Studies⁽⁸⁾:

Fourier Transform Infrared Spectroscopy:

Fourier Transformed Infra-Red Technique was one of the most powerful technique used to identify functional groups. Drug excipient compatibility studies were important in the drug development process, as the knowledge gained from excipient compatibility studies was used to select the dosage form components, delineate stability profile of the drug and identify degradation products. Excipient compatibility studies relate to the physical and chemical stability of the drug in solid dosage form.

UV Spectroscopy^(9,10,11):

Determination of UV Spectrum:

Losartan potassium solution (25 µg/ml) was prepared in phosphate buffer pH 7.4. These solution scanned under double beam UV Visible spectrophotometer 1800 and spectrum was recorded in the wavelength ranges between 400-200 nm.

Calibration Curve of Losartan Potassium:

From primary stock solution (100 µg/ml), prepared 5, 10, 15, 20 and 25 µg/ml solution by appropriate dilution of stock solution. The absorbance of these solutions was determined spectrophotometrically at wavelength 248.10 nm.

Design of Experiment^{(12, 13, 14)}:

Modern optimization techniques using experimental designs are a vital aid in formulation development as they help in developing the best possible formulation under a given set of conditions, thus saving considerable time, money and developmental effort. Current investigations aim at developing transdermal patch of losartan potassium by using two factor three levels central composite design optimization technique. This design involved three dependent variables, the percentage losartan potassium permeated at 3 hrs (Y1), percentage losartan potassium permeated at 6 hrs (Y2) and permeation flux (Y3). In this study, amount of HPMC K100 M (X1) and amount of Eudragit RS 100 (X2) were selected as two independent variables. The Design-Expert Software (version 7.1.5, Stat-Ease Inc., Minneapolis, USA) was used to design the experiment with 5 center points and one block. On the basis of preliminary trial batches the levels of HPMC K 100M were selected as 250, 300 and 350 mg whereas levels of Eudragit RS 100 were selected as 150, 200 and 250 mg. The software generated 13 model formulations. The composition of optimized batches of transdermal patches of losartan potassium showed in Table 1 which was used for the formulation of losartan potassium loaded transdermal patches. Upon the completion of statistical optimization experiments, regression equations and 3- dimensional response surface plots were generated to study the effect of independent variables to different response variables in order to identify the optimized batch.

Formulation of Transdermal Patch of Losartan Potassium by Central Composite Design⁽¹⁵⁾:

The matrix-type transdermal patches containing losartan potassium were prepared by solvent evaporation method using different ratios of hydroxy propyl methyl cellulose (HPMC K100 M) and Eudragit RS 100. The requisite ratios of polymers were weighed and dissolved in mixture of solvent such as methanol and dichloromethane (10ml:10ml) with continuous stirring on slow speed.

Polyethylene glycol 400 (20 % v/v) and dimethyl sulfoxide (15 % v/v) were added after one another as plasticizer and permeation enhancer respectively. Then, dissolved calculated amount of drug (losartan potassium) in the remaining quantity of solvents such as methanol and dichloromethane (3ml:3ml) and add this drug solution to the polymeric solution. Sonicate the resulting polymeric solution for 2 min to remove the air bubbles and until the solution becomes the clear. Poured the resulting solution into a petridish containing aluminium foil as backing. Then, funnel was placed over the petridish in inverted position to control the rate of evaporation.

Table 1: Composition of Optimized Batches of Transdermal Patches of Losartan Potassium

Ingredient	Batches
Ingredient	OLP-1	OLP-2	OLP-3	OLP-4	OLP-5	OLP-6	OLP-7	OLP-8	OLP-9
Losartan Potassium	452.125	452.125	452.125	452.125	452.125	452.125	452.125	452.125	452.125
HPMC K100 M	300	300	350	250	370.71	250	350	300	229.29
EudragitRS 100	129.29	200	250	250	200	150	150	270.71	200
PEG-400	0.089	0.089	0.089	0.089	0.089	0.089	0.089	0.089	0.089
DMSO	0.068	0.068	0.068	0.068	0.068	0.068	0.068	0.068	0.068
Methanol	13	13	13	13	13	13	13	13	13
Dichloro-methane	13	13	13	13	13	13	13	13	13

Casting solvent mixture was allowed to evaporate for 24 hrs.at room temperature. Then, the dried films were cutted into required size (2 x 2 cm²).

Evaluation of Formulated Transdermal Patches of Losartan Potassium:

Thickness⁽¹⁶⁾:

The thickness of the prepared patches were measured at 5 different points by using a digital vernier caliper. Standard deviation was determined by taking the average of three readings. The results were shown in Table No.2.

Weight Variation⁽¹⁷⁾:

Weight of three individual patches 2 x 2 cm² from each batch was determined and average weight was calculated with standard deviation. The results were shown in Table No.2.

Folding Endurance⁽¹⁸⁾:

The folding endurance was measured manually for the prepared transdermal patches. A patch of 2 x 2 cm² was cut and repeatedly folded at the same place until it broke. The number of times the patch could be folded at the same place without breaking or cracking was observed. The results were shown in Table No.2.

Flatness⁽¹⁹⁾:

For flatness determination, one strip of patch of 2 x 2 cm² was cut from the center and two from each side of patches. The length of each strip was measured and the difference in lengths was measured by determining percent constriction, with 0 % constriction equal to 100 % flatness. It was calculated by using following formula.

(L1-L2)

% Constriction =––––––––––––

L2×100

Where,

L1 = Initial length of each strip,

L2 = Final length of each strip

The results were given in Table No.2.

% Moisture Uptake⁽²⁰⁾

The percentage moisture uptake test was carried out to check the physical stability and integrity of the patches at high humid conditions. The films were weighed accurately and placed in the desiccator containing 100 ml of saturated solution of aluminium chloride which maintains 75 % RH. After 3 days the films were taken out and weighed. The percentage moisture uptake was calculated using the following formula.

Final Weight-Initial Weight

% Moisture Uptake = ––––––––––––––––––––––––––

(Initial Weight) × 100

The results were shown in Table No.3.

% Moisture Loss⁽²⁰⁾:

The percentage moisture loss test was carried out to check the physical stability during the storage of patch. The films were weighed accurately and kept in a desiccators containing anhydrous calcium chloride. After 3 days, the films were taken out and weighed. The percentage moisture loss was calculated using the following formula.

Initial Weight-Final Weight

% Moisture Loss = –––––––––––––––––––––––––––

(Final Weight) × 100

The results were shown in Table No.3.

% Drug Content^{(16, 21)}

A specified area of the patch 2 x 2 cm² was dissolved in a beaker containing 20 ml of phosphate buffer pH 7.4 solution. The content was placed on magnetic stirrer continuously for 24 hrs. Then the whole solution was sonicated. After sonication and subsequent filtration, the appropriate dilution was made with phosphate buffer pH 7.4. The absorbance of the diluted solution was measured at wavelength 248.10 nm using UV-Visible spectrophotometer and determined the % drug content.

Test Reading Standard Dilution

%Drug Content = ––––––––––– × ––––––––––––– ×100

Standard Reading Test Dilution

The results were shown in Table No.3.

In-Vitro Drug Permeation Study^{(14, 15, 22)}:

In-vitro permeation of losartan potassium from the transdermal patches through the artificial membrane was studied using 3 stages Franz diffusion cell apparatus. Franz diffusion cell has an exposed surface area of 3.14 cm² and receptor compartment contains 20 ml of phosphate buffer pH 7.4 solution. The jacketed diffusion cell with inlet and exit ports for the circulation of water was used in order to maintain temperature at 32⁰C ± 2⁰ C. The receptor compartment fluid was continuously stirred at 400 rpm with a teflon coated magnetic bead and 70 % magnetic induction. The artificial membrane 0.45 µ was placed on the receptor compartment. The prepared transdermal patches were placed on the artificial membranes 0.45 µ and both the receptor and donor compartments were clamped together with the help of Millipore type clamp.

The diffusion was carried out for 6 hours and 2 ml sample was withdrawn from each diffusion cell at intervals of 0.5, 1, 2, 3, 4, 5 and 6 hours. The same volume of phosphate buffer pH 7.4 was added to receptor compartment of each cell to maintain sink conditions. Finally, by doing the proper dilutions samples were analyzed by using UV-Visible spectrophotometer at 248.10 nm. The results were shown in Table No.4 and graphs were showed in Fig.

Study of Kinetics and Mechanism of Drug Release^[24]:

To understand the drug release kinetics and mechanism of drug release, all the in-vitro release data were fitted to various kinetic models such as zero order, first order and Higuchi and Korsmeyer- Peppas models. Different models expressing drug release kinetics were shown in Table No.5.

Stability Studies ^{(22, 23)}:

The stability studies of the formulated batches of the transdermal patches were conducted according to the ICH guidelines by storing the patches at 40°C ± 2°C and 75 % ± 5 % RH for 3 months. The samples were withdrawn at 30, 60 and 90 days and evaluated for physical appearance, thickness, % cumulative losartan potassium permeated in 6 hrs and drug content. The In-vitro permeation study was performed after 90 days and compared with fresh batch. The results were given in Table No.6.

RESULTS AND DISCUSSION:

FTIR- All the major peaks of drug were found in overlay FTIR spectra. Hence, it was concluded that there were no drug- excipient interaction; drug and excipient were compatible with each other.

Fig.: FTIR Spectrum of Losartan Potassium

Fig.: FTIR Spectrum of Losartan Potassium + HPMC K100 M + Eudragit RS100

Fig. UV Spectrum of Losartan Potassium in Phosphate Buffer pH 7.4

Fig. Calibration Curve of Losartan Potassium in Phosphate Buffer pH 7.4

Table 2 Results for Thickness, Weight Variation, Folding Endurance and Flatness of Optimized Batches of Losartan Potassium

Formulation Code	Physicochemical Parameters
Formulation Code	Thickness (mm) ± S. D	Weight Variation (gm) ± S. D	Folding Endurance	Flatness
OLP-1	0.086 ± 0.009428	0.069 ± 0.002055	142	100
OLP-2	0.103 ± 0.004714	0.067 ± 0.001633	147	100
OLP-3	0.104 ± 0.004899	0.062 ± 0.002055	141	100
OLP-4	0.103 ± 0.004714	0.059 ± 0.001886	144	100
OLP-5	0.102 ± 0.002828	0.061 ± 0.000816	146	100
OLP-6	0.103 ± 0.000943	0.055 ± 0.002494	142	100
OLP-7	0.104 ± 0.000943	0.060 ± 0.001886	145	100
OLP-8	0.096 ± 0.000943	0.062 ± 0.001247	148	100
OLP-9	0.102 ± 0.003399	0.056 ± 0.002055	143	100

In the present study, nine formulations were prepared by varying the concentration of polymers. The thickness of the patches ranges from 0.086 ± 0.009428 to 0.104 ± 0.004899. While the weight of the patches ranges from 0.055 ± 0.002494 to 0.069 ± 0.002055. The results indicate the physical uniformity of prepared patches. The low standard deviation values showed that the process used for preparing the patches is capable of formulating patches with minimum intra batch variability.

The folding endurance of the prepared patches was found maximum upto 148. These indicate that the patches have good flexibility, tensile strength, capable to withstand the mechanical pressure and able to maintain the integrity with general skin folding when applied. All the patches showed the 100 % flatness.

Table 3: Results for % Moisture Uptake, % Moisture Loss and % Drug Content of Optimized Batches of Losartan Potassium

Formulation Code	Physicochemical Parameters
Formulation Code	% Moisture Uptake	% Moisture Loss	% Drug Content
OLP-1	3.52	2.49	92.30 ± 0.1
OLP-2	3.12	2.05	94.32 ± 0.2
OLP-3	2.95	1.47	92.97 ± 0.2
OLP-4	2.79	1.25	93.65 ± 0.1
OLP-5	3.26	2.76	94.66 ± 0.3
OLP-6	3.10	2.02	91.63 ± 0.4
OLP-7	2.94	1.92	92.50 ± 0.2
OLP-8	3.09	1.98	93.65 ± 0.5
OLP-9	3.14	2.15	95.33 ± 0.1

Table 4: Results for In-Vitro % Drug Permeation, Permeation Flux and Permeability Coefficient of Optimized Batches of Transdermal Patches of Losartan Potassium

Formulation Code	% Cumulative Losartan Potassium Permeated at 6 hrs.	Permeation Flux (µg/cm²/h.)	Permeability Coefficient (K_p)
OLP-1	41.76	514.98	0.0205
OLP-2	35.86	469.7	0.0187
OLP-3	31.56	401.21	0.0160
OLP-4	34.47	435.74	0.0174
OLP-5	30.78	392.64	0.0157
OLP-6	37.89	472.68	0.0189
OLP-7	33.67	428.23	0.0171
OLP-8	32.35	410.37	0.0164
OLP-9	43.29	519.36	0.0207

The formulated patches showed lowest % moisture uptake rate of 2.79 %. Overall moisture uptakes of all the formulations were low, which could protect the formulations from microbial contamination and reduce the bulkiness. Among all the formulations, the OLP-4 formulation shows lowest % moisture loss of 1.25 % which prevents the drying of patches.

The drug content for all the batches was found within specified limit.

Fig.: In-Vitro Permeation of Optimized Batches of Transdermal Patches of Losartan Potassium [OLP-1 to OLP-3] in Phosphate Buffer pH 7.4

Fig.: In-Vitro Permeation of Optimized Batches of Transdermal Patches of Losartan Potassium [OLP-4 to OLP-6] in Phosphate Buffer pH 7.4

Fig.: In-Vitro Permeation of Optimized Batches of Transdermal Patches of Losartan Potassium [OLP-7 to OLP-9] in Phosphate Buffer pH 7.4

In-Vitro drug permeation study was conducted to investigate the controlled release performance. The percentage cumulative losartan potassium permeated in 6 hrs for formulation OLP-4 was found to be 34.47 %, followed zero order kinetics (r²= 0.9641) with the permeation flux 435.74 µg/cm²/hr.

Table 5: Results of Drug Release Kinetics Model

Formulation

Code

r²

Zero Order

First Order

Higuchi

Korsmeyer- Peppas

OLP-4

0.9641

0.8818

0.9384

0.9165

0.4979

Stability Studies:

Data Analysis and Optimization:

The experimental values for the responses were curve fitted to quadratic, linear model. The generated data indicates that percentage losartan potassium permeated in 3 hrs (Y1), percentage losartan potassium permeated in 6 hrs (Y2) and permeation flux (Y3) were highly depend upon the selected independent variables HPMC K100M and Eudragit RS 100. The regression equations for the responses fitted in quadratic and linear model was generated. Only statistically significant (p < 0.05) coefficients were included in the regression equations.

Table 6: Results for Stability Studies of the Optimized Batch OLP-4

Parameters		40 ± 2⁰C / 75 % ± 5 % RH
Parameters		Initial	1 Month	2 Month	3 Month
Physical	Physical Appearance	Smooth and flexible	Smooth and flexible	Smooth and flexible	Smooth and flexible
Physical	Thickness (mm)	0.103	0.103	0.103	0.100
Chemical	% Cumulative Losartan Potassium Permeated in 6hrs.	34.47	34.42	33.95	33.89
Chemical	%Drug Content	93.65	92.02	91.89	91.76

Regression equations for the quadratic and linear models:

Percentage losartan potassium permeated in 3 hrs:

Final equation in coded form

% losartan potassium permeated in 3 hrs (Y1) =

+ 24.35 - 0.19X₁- 2.03X₂+ 1.84X1.X₂+ 2.00X₁²+ 1.48X₂²

The results of multiple linear regression analysis showed that the coefficient X1 bear negative sign and X2 bear negative sign. Therefore, increasing the concentration of film forming agents decreases the % permeation of drug in 3 hrs. A negative sign stands for an antagonistic effect.

Percentage losartan potassium permeated in 6 hrs:

Final equation in coded form

% losartan potassium permeated in 6 hrs (Y2) =

+ 35.85 - 3.10X₁- 2.19X₂

The results of multiple linear regression analysis showed that the coefficient X1 bear negative sign and X2 bear negative sign. Therefore, increasing the concentration of film forming agents decreases the % permeation of drug in 6 hrs. A negative sign stands for an antagonistic effect.

Permeation flux:

Final equation in coded form

Permeation flux (Y3) = + 455.67 - 32.27X₁- 26.49X₂

The results of multiple linear regression analysis showed that the coefficient X1 bear negative sign and X2 bear negative sign. Therefore, increasing the concentration of film forming agents decreases the permeation flux. A negative sign stands for an antagonistic effect. These suggest that permeation rate of losartan potassium was appropriately controlled by HPMC K100 M (X1) and Eudragit RS 100 (X2).

Fig.: 3D- Contour Plot Showing Influence of HPMC K100M and Eudragit RS 100 On the Percentage Permeation of Losartan Potassium in 3 hrs, Percentage Permeation of Losartan Potassium in 6hrs and Permeation flux and Overlay Plot.

Table 7: Results of Analysis of Variance for Optimized Batches of Transdermal Patch of Losartan Potassium

Y1= % Losartan Potassium Permeated in 3 hrs

Model

Residual

Total

S. S

D.F

M.S

F-value

P-value Prob.> F

85.29

24.05

109.34

17.06

3.49

---

4.96

---

0.0293 -Significant

---

Y2= % Losartan Potassium Permeated in 6 hrs

Model

Residual

Total

115.21

36.45

151.66

57.50

3.65

---

75.80

---

0.0008 -Significant

---

Y3= Permeation Flux

Model

Residual

Total

13945.45

5043.11

18988.56

6972.73

504.31

---

13.83

---

0.0013 -Significant

---

*S. S= Sum of Squares, D. F= Degree of Freedom, M. S= Mean Square, F= Fischer’s Ratio.

CONCLUSION:

In the present study, an attempt was made to formulate, optimize and evaluate transdermal patch of losartan potassium containing DMSO as permeation enhancer. Statistical optimization proved to be very useful in the subsequent formulation development work following preliminary evaluations. Thus, the design of experiment with response surface method is an efficient tool to determine and optimize formulation conditions within experimental conditions. Overall, an optimized batch OLP-4 of transdermal patch of losartan potassium was successfully formulated and study proved that the formulated transdermal patches of losartan potassium exhibited good controlled release as well as permeation of losartan potassium upto 24 hrs. The best fit model for optimized batch OLP-4 is zero order model with highest r² value of (r² = 0.9641) and the mechanism of release found to be fickian diffusion mediated.

ACKNOWLEDGEMENTS:

Authors specially wish to express their sincere thanks to Department of Pharmaceutics, Shree Sureshdada Jain Institute of Pharmaceutical Education and Research Jamner, Dist. Jalgaon, Maharashtra for providing the laboratory facilities to carry out this research work.

REFERENCES:

1. Chien Y. W., Novel Drug Delivery Systems. 2^nd edition, revised and expanded, Drugs and the Pharmaceutical Sciences, Vol.50, Informa healthcare USA, Inc.; 2009: 301-380.

2. Jain N. K., Controlled and Novel Drug Delivery. 1^st edition, CBS publishers and distributors, New Delhi, 1997: 100-127.

3. Vyas S. P., Khar R. K., Controlled Drug Delivery: Concepts and Advances. Vallabh Prakashan, 1^st edition, 2002: 411-447.

4. Nag Ahindra and Dey Baishakhi. Computer Aided Drug Design and Delivery Systems. Mc Graw Hill, 2011: 22-37.

5. Kamal Saroha, Rohini Rana, Uditi Handa, Ajay Kumar and Sanju Nanda. Transdermal Patches as a Tool for Permeation of Drug through Skin. Journal of Chemical and Pharmaceutical Research, 2016, 8(5): 471-481.

6. Government of India, Ministry of Health and Family Welfare. The Indian Pharmacopoeia. Published by The Indian Pharmacopoeia Commission, Ghaziabad, 7^th edition, Vol-II, 2014, Pg.no. 2122-2123.

7. https://pubchem.ncbi.nlm.nih.gov/compound/losartan_potassium

8. Lampman G. M., Pavia D. L., Kriz G. S and Vyvyan I. R., Spectroscopy. 4^th edition, Cengage Learning India Pvt. Ltd, 2014, Delhi: 15-104.

9. Government of India, Ministry of Health and Family Welfare. The Indian Pharmacopoeia.Published by The Indian Pharmacopoeia Commission, Ghaziabad, 7^th edition, Vol-II, 2014, Pg.no. 2122-2123.

10. Dr. Bhise S. B., Dr. Dias R. J., Dr. Dhawale S. C., Shri Mali K. K. Laboratory Manual of Biopharmaceutics and Pharmacokinetics. Trinity Publishing House, 2010: 64-65.

11. Dr. Yadav A. V, Yadav V. B and Shete A. S. Experimental Biopharmaceutics and Pharmacokinetics. Nirali Prakashan: 1.1-1.57.

12. Jain N. K. Pharmaceutical Product Development. 2^nd edition, CBS Publishers and Distributors Pvt. Ltd: 369-394.

13. Bolton Sanford. Pharmaceutical Statistics. 3^rd edition, James Swarbrick, North Carolina: 336-338.

14. Madan P. L., Lin. S. and Vora Namrata. Development and In-Vitro Evaluation of an Optimized Carvedilol Transdermal Therapeutic System Using Experimental Design Approach. Asian Journal of Pharmaceutical Sciences 8 (2013): 28-38.

15. Parhi Rabinarayan and Padilam Suresh. Transdermal Delivery of Diltiazem HCl from Matrix Film: Effect of Penetration Enhancers and Study of Antihypertensive Activity in Rabbit Model. Journal of Advanced Research, 2016, 7, 539-550.

16. Yadav Mamta, Nayak Satish and Banweer Jetendra. Development and Evaluation of Aceclofenac Transdermal Patches with Different Permeation Enhancers. Der Pharmacia Lettre, 2015, 7 (3): 141-148.

17. Pisipati Aparna and Satya Venkata Chavali S. Formulation and Characterization of Anti-Hypertensive Transdermal Delivery System. Journal of Pharmacy Research 6 (2013): 551-554.

18. Chauhan Sheetal, Dr. Bolmal Uday B., Dr. Dandagi Panchaxari Mallappa and Dr. Singh Ajit. Design and Evaluation of Transdermal Patch of Felodipine. Indo American Journal of Pharmaceutical Research, 2015, 5 (9): 3035-3043.

19. Solanke Prashant Narayan, Ambekar Abdul Wahid and Chemate Satyam. Formulation Development and Characterization of Transdermal Drug Delivery System for Antidiabetic Drug. Asian Journal of Pharmacy and Pharmacology, 2018, 4 (5): 668-672.

20. Dingwoke John Emeka Francis. Development and Evaluation of Matrix type Transdermal Patches of Pioglitazone Hydrochloride. Universal Journal of Pharmaceutical Research, 2016, 1 (1): 31-37.

21. Singh Vikas Kumar, Pokhariyal Tarun and Tiwari Ajay Kumar. Formulation Optimization and Characterization of Transdermal Patch of Mefenamic Acid. Indo American Journal of Pharmaceutical Research, 2013, 3 (2): 4269-4277.

22. Singh Dashrath and Chandra Amrish. Formulation and Development of Fluoxetine Transdermal Patches: In-Vitro and In-Vivo Evaluation. International Journal of Pharmaceutical Research and Innovation, Vol.9, 2016: 1-8.

23. Vijaya R, Maheshwari Uma S. and Jaya Bharathi S. Development and In-Vitro Evaluation of Eudragit E 100 and PVP Based Matrix Films for the Transdermal Delivery of Repaglinide. The Pharma Innovation Journal 2015, 3 (12): 16-23.

24. Brahmankar D. M and Jaiswal S. B. Biopharmaceutics and Pharmacokinetics- A Treatise, 3^rd Edition, 2015, Vallabh Prakashan, Delhi: 434-436.

Received on 14.06.2019 Accepted on 18.07.2019

Asian J. Pharm. Tech. 2019; 9(3):220-227.

DOI: 10.5958/2231-5713.2019.00037.0