SONOPHORETIC TRANSDERMAL DELIVERY OF LOSARTAN POTASSIUM PRONIOSOMAL GEL

SONOPHORETIC TRANSDERMAL DELIVERY OF LOSARTAN POTASSIUM PRONIOSOMAL GEL

R. Rao ¹ and S. Nanda ^{* 2}

Department of Pharmaceutical Sciences ¹, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India-125001

Department of Pharmaceutical Sciences ², Maharishi Dayanand University, Rohtak, Haryana- 124001, India

ABSTRACT: Proniosomes based drug delivery systems have potential as a significant drug carrier in a variety of therapeutic applications. The objective of the present study was to investigate in vitro sonophoretic transdermal delivery of Losartan Potassium (LP) across albino rat skin using proniosomal gel and its comparison with aquasonic gel. Proniosomes of LP were fabricated with L-a-lecithin (egg yolk), cholesterol and a non-ionic surfactant and confirmed using optical microscopy. Permeation experiments were performed using modified Franz Diffusion Cell along with ultrasound treatment (Frequency-1MHz; Intensity- 2.5 W/cm²; Duration of application- 30 min; Mode of application - Continuous and Pulsed). An in vitro skin permeation of LP with aquasonic gel was found superior than proniosomal gel using sonophoretic delivery. Using proniosomal gel, when ultrasound was applied in pulsed mode, LP transdermal flux and enhancement factor were 60.88 ± 6.2 μg/cm²/h and 5.31, respectively, 115.41 ± 5.01 μg/cm²/h and 10.07 those achieved using aquasonic ultrasound gel, respectively. Similar results were observed (better flux with aquasonic gel than proniosomal gel) using continuous mode of ultrasound application. These findings suggested that aquasonic gel could act better means of delivery for LP instead of proniosomal gel, when used in combination with ultrasound treatment.

Sonophoresis, Ultrasound, Proniosomes, Transdermal, Losartan Potassium

INTRODUCTION: Transdermal systems are generally designed aiming for systemic delivery of therapeutic agents to the intact skin surface. It has offered great advantages including prolonged therapeutic effect, non-invasiveness, improved bioavailability, reduced side effects, easy termination of drug therapy, and better patient compliance ¹.

Hypertension is most common cardiovascular disorder. Management of hypertension needs long term treatment with a greater frequency of drug administration resulting in poor patient compliance with conventional therapy.

Although, a plethora of therapeutically effective categories of antihypertensive agents are available including single doses or associations of diuretics, calcium channel blockers, beta-blockers, angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor (AT1) antagonist (ARA) ^2-3. Problem associated with these therapeutic moieties and conventional delivery systems affect their utility and patient compliance.

An orally active angiotensin II receptor antagonist indicated for hypertension is LP (Biopharmaceutics classification system class 3 drugs). The normal daily dose of LP is 50 mg and 100 mg dose is given in severe cases. The drug possesses extensive hepatic first pass metabolism (67%) and short biological half-life (2 h) ^4-5. Therefore, in order to bypass hepatic first pass metabolism, and reduce its dose, a transdermal formulation can be explored. All these properties, such as extensive hepatic first pass metabolism (67%), short biological half-life (2 h), low dose (25-50 mg), low oral bioavailability (33%), and low molecular weight (461.01 Da), make it good candidate for transdermal drug delivery system ^6-9. However, TDD is limited by low skin permeability due to the barrier properties of the stratum corneum (SC), the outermost layer of the skin.

Very low permeability of SC to foreign molecules is the main hindrance of TDD. A number of technologies have been proposed to overcome the natural barrier function of the skin, such as use of chemical enhancers ¹⁰, iontophoresis ¹¹ and sonophoresis ^12-13. Sonophoresis refers to a technique that temporarily enhances skin permeability such that various molecules can be delivered non-invasively. For the past several decades, various sonophoretic transdermal studies have been carried out focusing on delivery mechanism, parameter optimisation, transport pathway or delivery of several categories of drugs including and high molecular weight and hydrophilic compounds ¹⁴. Sonophoresis can be combined with other TDD techniques to enhance drug delivery routes ¹⁵.  However, a TDD system and proniosomes is yet to be studied.

The rationale for using vesicles in dermal and transdermal drug delivery is many folds. Vesicles might a) act as drug carriers to deliver drugs into skin; b) act as penetration enhancers due to the penetration of the individual lipid components into the stratum corneum and subsequently the alteration of the intercellular lipid lamellae within the skin c) act as a depot for sustained release of dermally active moieties; d) serve as a rate-limiting membrane barrier for the modification of systemic absorption, hence, resulting a controlled transdermal delivery system ^16-17.

Today, lipid and non-ionic surfactant based drug delivery systems have drawn much attention from researchers as potential carriers of various bioactive molecules that could be used for therapeutic applications ¹⁸.

One such delivery system consists of proniosomes, prepared from non-ionic surfactants (spans and tweens) by dissolving these surfactants in a minimal amount of an acceptable solvent (ethanol, methanol, isopropyl alcohol) and least amount of water, proniosomes can be easily fabricated ¹⁹. Previously, we had investigated in vitro studies of LP to observe the effect of different ultrasound variables on the release of drug from the aquasonic gel, across the skin into the receptor solution ²⁰. The aim of present work is to study the effect ultrasonic waves over LP proniosomal vesicular system.

Combined approach proniosomes and ultrasound mediated delivery is used for transdermal delivery of LP. Safety may also be anticipated to improve, if the synergistic effect on transdermal permeability occurs. Further, this combination may allow a less severe ultrasound protocol/concentration. In addition, effect of ultrasound application on permeation of LP from proniosomal gel was compared in the present work with drug loaded in aquasonic jelly using male albino rat skin. There are many reports on the combined use of sonophoresis with other physical and chemical enhancers ²¹, however, till date no study have been published concerning the sonophoretic delivery of drugs formulated in proniosomes.

MATERIALS AND METHODS: Losartan Potassium was received as a gift sample from Jubiliant Organo Sys Ltd. (Noida, India). Ultrasound gel was procured from Survive Pharma, India. Sodium hydroxide and potassium dihydrogen phosphate were purchased from E-merk (Mumbai, India). Cholesterol, Span 60 and n-octanol, were purchased from Central Drug Pvt. Ltd., New Delhi, India. L-α- lecithin (from egg yolk) was provided as gift sample from Ind Swift Labs (Baddi, India). All other chemicals and reagents used were of analytical grade. Double distilled water was used throughout the study.

Ultrasound Equipment: Sonophoretic treatment was given using ultrasound generator (Supreme Surgical Ltd.) operating at a frequency of 1 MHz and intensity 2.5 W/cm². Probe diameter was 1 cm. Ultrasound treatments were carried out either in a continuous mode or pulsed mode (1:1) for 30 min duration.

Formulation of LP proniosomes: LP proniosomes formulated in present study were reported in literature by Thakur et al.⁶. Briefly, proniosomes were prepared by mixing the drug with weighed quantities of non-ionic surfactant (Span-60), L-α- lecithin from egg yolk and cholesterol in a wide mouth glass tube (Table 1). Then, 0.5 ml of absolute ethanol was added. The mouth of glass tube was covered with a lid and was warmed in a water bath at 65±3^°C for 5 min. Subsequently, 0.28 ml of phosphate buffer (PB) pH 7.4 was added and the mixture was further warmed in a water bath for 2 min. and finally allowed to cool down at room temperature till the dispersion was converted to proniosomal gel (PNG). Control formulations were prepared using same quantities of all ingredients without drug.

TABLE: 1 FORMULATION OF LP PRONIOSOMAL GEL

Characterization of LP Proniosomes:

Proniosomes formulated were confirmed by optical microscopy at different magnifications (Fig.1-3). A small quantity of PNG was taken and suspended in 10 ml of PB (pH 7.4). The dispersion of proniosomes was manually shaken for few seconds so that lumps of proniosomes are distinguished into individual proniosomes. A drop of the dispersion was placed onto the slide and examined under microscope. At 10, 20 and 50 X magnification, small size circular vesicle bodies were observed.

FIG. 1: PHOTOMICROGRAPH OF LP PRONIOSOME FORMULATION AT 10 X

FIG. 2: PHOTOMICROGRAPH OF LP PRONIOSOME FORMULATION AT 20 X

FIG. 3: PHOTOMICROGRAPH OF LP PRONIOSOME FORMULATION AT 50 X

In vitro Permeation Studies using Ultrasound Gel: Permeation experiments were performed with modified Franz diffusion cells which allowed the introduction of an ultrasound probe into the donor compartment. The treatment procedure involves the application of an unmedicated coupling agent (usually gel) which transmit the ultrasound energy from the ultrasound transducer to treatment site (the donor compartment was filled with LP dispersed in ultrasound coupling gel). Ultrasound treatments were given as discussed earlier (section) and in vitro experimental conditions in Table 2.

A stationary technique was used because it was not possible to move the transducer in a reproducible fashion on diffusion cell without causing damage to the membrane. The receiver medium was phosphate buffer (pH 7.4). The top of donor was covered with aluminium foil after ultrasound exposure. The available diffusion area between cells was 6.21 cm². The receptor was kept at a constant temperature of 37°C and stirred by a magnetic stirrer at 500 rpm.

Each diffusion experiment was carried over 8 hrs and repeated with three skin samples obtained from three different bodies. At appropriate intervals, 5 ml aliquots of the receptor medium were withdrawn and immediately replaced by an equal volume of fresh receptor solution. Samples were analyzed spectrophotometrically using (UV-1601PC, Shimadzu, Japan), UV-Visible spectrophotometer at 254 nm. Similarly, in vitro permeation studies were performed using LP proniosomal gel in both continuous and pulsed mode of ultrasound application.

TABLE 2: EXPERIMENTAL CONDITIONS USED IN PERMEATION STUDY (IN VITRO)

Permeation Data Analysis: Cumulative amount of drug permeated through the skin (µg/cm²) was plotted as a function of time for each treatment group. The diffusion rate or flux (J_ss) was determined from the linear portion of slope of cumulative amount –time profile graphs and expressed as the amount of drug transported through a unit of area of skin membrane per hour ²². Enhancement factor was calculated by dividing J_ss of each variable by J_ss of the control i.e. passive delivery. Data are expressed as the mean ± S.D. of three experiments.

Statistical Analysis: Statistical analysis was performed using a one-way analysis of variance (P<0.05) using Graphpad Version 2.01, San Diego, CA.

RESULTS AND DISCUSSION: As the aim of our study here, was to study the effect of ultrasonic waves over proniosomal vesicular systems. LP proniosomes were formulated by method reported by Thakur et al. ⁶. Optical microscopy photographs confirmed the successful fabrication of LP proniosomes. Ultrasound treatment was given (Frequency-1MHz; Intensity- 2.5 W/cm²; Duration of application- 30 min; Mode of application - Continuous and Pulsed) to LP proniosomes and drug dispersed in aquasonic gel and evaluated for transdermal permeation parameters.

In the passive skin transport study, the permeated amounts and flux value (J_ss) of LP in proniosomes were significantly higher than those obtained with the control (drug dispersed in ultrasound gel) (Fig. 4 and Table 3). Hence, proniosomes improved LP penetration in comparison with drug dispersed in ultrasonic gel.

Proniosomes should be hydrated to form niosomal vesicles before the drug is released and permeated across the skin. As observed in the in vitro permeation experiments using proniosomes, the cumulative amount of LP was detected in the first sampling time (1h). This indicated that all the procedures of LP permeation including water penetration from the receptor compartment to skin, conversion of proniosomes to niosomal vesicles, LP release from niosomes, and permeation of drug across skin occur rapidly. Several mechanisms can be used to explain the ability of niosomes to modulate drug transfer across skin ²³, including: 1) the effect of vesicles as penetration enhancers to reduce the barrier properties of stratum corneum; and 2) the lipid bilayers of niosomes as rate-limiting membrane barrier for drugs.

One of the possible reasons for niosomes to enhance the permeability of drugs is structure modification of stratum corneum. It has been reported that the intercellular lipid barrier in stratum corneum would be dramatically changed to looser and more permeable by treatment with niosomes. Non- ionic surfactants in proniosomes can act as penetration enhancers that are useful in increasing the permeation of many drugs ²³.

FIG. 4: LP TRANSPORT PASSES FROM PRONIOSOMAL GEL (PN GEL) AND US GEL ACROSS ALBINO RAT SKIN

FIG. 5: LP TRANSPORT FROM PRONIOSOMAL GEL (PN GEL + US, P, 2.5 W/cm²) AND US GEL (US GEL+ US, P, 2.5 W/cm²) ACROSS ALBINO RAT SKIN

Flux values were found decreased for LP proniosomal gels with US treatment when compared to LP in ultrasound gel both in continuous as well as pulsed mode as shown in Fig. 5-6 and Table 3.

TABLE 3: FLUX VALUES FOR PRONIOSOMAL GEL AND US GEL WITH AND WITHOUT SONOPHORETIC TREATMENT

FIG. 6: COMPARISONS OF FLUX VALUES FOR PRONIOSOMAL GEL AND US GEL WITH AND WITHOUT SONOPHORETIC TREATMENT

However, when permeation flux is compared to LP proniosomal gel without US treatment to PNG with US treatment (in both modes), latter showed higher flux values. Hence, it was found that application of US in both modes increases the permeation rate of drug from proniosomes but this increase was more significant from drug loaded in US jelly. It was deducted that combination of proniosomes with sonophoresis were found to increase drug permeation as hypothesized earlier.

However, permeation of drug from proniosomes (with US treatment) was lower, when compared to LP dispersed in aquasonic gel (with US treatment).

This may be due to skin repair caused by proniosomal gel application. It is hypothesized that the skin perturbation caused by sonication was repaired by permeation of proniosomal gel vesicles into sonicated skin. Many reports on decreased transdermal delivery were found in literature for combinations of electroporation ²⁴ and iontophoresis ²⁵. Earlier, Vyas et al., liposomally encapsulated diclofenac for sonophoresis induced systemic delivery and ultrasonic application produced a large increase in drug release²⁶. Therefore, it was hypothesized that ultrasound assisted delivery was enhanced by proniosomal encapsulation of LP due to their synergistic combination. Therapeutic US cause cavitation in skin and consequently enhance drug permeation. In addition, due to absorption of US waves in coupling media a thermal effect is caused which may be responsible for permeability changes in skin ²⁰.

CONCLUSION: Optical microscopy results confirmed successful formulation of LP proniosomes. Permeation parameters were determined using albino rat skin in modified Franz diffusion cell after sonophoretic treatment to both drug loaded proniosomes and aquasonic gel. Sonophoresis increased the permeation rate of LP in both gels over their passive counterparts (P<0.01), as well as synergistic effect was detected when used in conjunction with LP proniosomal gel. Higher steady-state flux and enhancement factor were obtained from aquasonic ultrasound gel and skin repair caused by proniosomal gel applicationis suggested to be the cause. Comparative studies (with US treatment) confirmed this finding. Hence, it is suggested LP from there preliminary studies loaded in ultrasound aqueous gel act as better delivery vehicle in sonophoretic mediated transdermal delivery and sonophoresis can be synergistically combined with proniosomal gel for better delivery.

REFERENCES:

1. Singh I and Morris PA: Performance of transdermal therapeutic systems: Effects of biological factors. International Journal of Pharmaceutical Investigation 2011; 1(1): 4-9.
2. Ladak N and Thompson J: Drugs acting on the heart: antihypertensive drugs. Anaesthesia and Intensive Care Medicine 2009; 10: 392-395.
3. Mahmud A and Feely J: Low-dose quadruple antihypertensive combination more efficacious than individual agents–a preliminary report. Hypertension 2007; 49: 272-275.
4. Goa KL and Wagstaff AJ: Losartan potassium: a review of its pharmacology, clinical efficacy and tolerability in the management of hypertension. Drugs 1996; 5:820-845.
5. Zaiken K, Hudd TR and Cheng JW: A review of the use of angiotensin receptor blockers for the prevention of cardiovascular events in patients with essential hypertension without compelling indications. Annals of Pharmacotherapy 2013; 47:686-693.
6. Thakur R, Anwer MK, Shams MS, Ali A, Khar RK, Shakeel F and Taha El: Proniosomal transdermal therapeutic system of losartan potassium: development and pharmacokinetic evaluation. Journal of Drug Target 2009; 17:442-449.
7. Shams MS, Alam MI, Ali A, Sultana Y, Aqil M and Shakeel F: Pharmacokinetics of a losartan potassium released from a transdermal therapeutic system for the treatment of hypertension. Pharmazie 2010; 65:679-682.
8. Baviskar DT, Parik VB, Gupta HN, Maniyar AH and Jain DK: Design and evaluation of patches for transdermal delivery of losartan potassium. PDA Journal of Pharmaceutical Science and Technology 2012; 66:126-135.
9. Vashisth I, Ahad A, Aqil M and Agarwal SP: Investigating the potential of essential oils as penetration enhancer for transdermal losartan delivery: Effectiveness and mechanism of action. Asian journal of pharmaceutical sciences 2014; 9:260-267.
10. Williams AC and Barry BW: Penetration enhancers. Advanced Drug Delivery Reviews 2012; 64: 128-137.
11. Ita K: Transdermal iontophoretic drug delivery: Advances and challenges. Journal of Drug Target 2015.
12. Rao R and Nanda S: Sonophoresis: recent advancements & future challenges. Journal of Pharmacy & Pharmacology 2009; 61: 89-705.
13. Rao R, Nanda S, and Anand S: Use of Factorial design in Sonophoretic Transdermal Delivery of Propanolol Hydrochloride. Indian Pharmacist 2010; 9:49-54
14. Park D, Park H, Seo J and Lee S: Sonophoresis in transdermal drug deliverys. Ultrasonics 2014; 54(1):56-65.
15. Kost J, Pliquett U, Mitragotri S, Yamamoto A, Weaver J, Langer R. Enhanced transdermal delivery: Synergistic effect of ultrasound and electroporation. Pharmaceutocal Research. 1996; 13: 633-638.
16. Schreier H and Bouwstra JA: Liposomes and niosomes as topical drug carriers: dermal and transdermal drug delivery. Journal of Controlled Release 1994; 30:1-15
17. Mezei M and Gulasekharam V: Liposomes – a selective drug delivery system for the topical route of administration: gel dosage form. Journal of Pharmacy and Pharmacology 1982; 34: 473-474
18. Kumar ND, Rao R and Nanda S: Preparation and Characterization Techniques in Niosomal Vesicular Systems- A Review. Journal of Pharmaceutical and Biomedical Sciences 2011; 5(5): 1-8
19. Kakkar R, Rao R, Goswami A, Nanda S and Saroha K: Proniosomes: An emerging Vesicular system in drug Delivery and Cosmetics. Der Pharmacia Lettre 2010; 2(4): 227-239
20. Rao R. Nanda S. and Nair A: Influence of Ultrasound mediated Transdermal Delivery of Losartan Potassium. Drug delivery letters 2012; 2(1): 46-53
21. Mitragotri S, Blankschtein D and Langer R: Transdermal protein delivery or measurement using low-frequency sonophoresis. US Patent 6018678, 2000.
22. Ghosh TK, Adir J, Xiang SL and Onyilofur S: Transdermal delivery of metoprolol II: In vitro skin permeation and bioavailability in hairless rats. Journal of Pharmaceutical Sciences 1995; 84:158-160.
23. Uchegbu IF and Vyas SP:Non-ionic surfactant based vesicles (niosomes) in drug delivery. International Journal of Pharmaceutics 1998; 172(1-2):33-70.
24. Essa EA, Bonner MC and Barry BW: Electroporation and ultradeformable liposomes; human skin barrier repair by phospholipid. Journal of Controlled Release 2003; 92:163-172.
25. Vutla NB, Betageri GV and Banga AK: Transdermal iontophoretic delivery of enkephalin formulated in liposomes. Journal of Pharmaceutical Sciences 1995; 85: 5-8.
26. Vyas SP http://informahealthcare.com/action/ show Popup?citid=citart1&id=end-a1&doi=10.3109/0265204 9509015285, R. Singh http://informahealthcare.com/ action/showPopup?citid=citart1&id=end-a1&doi=10.3109/ 02652049509015285 and Asati RK: Liposomally encapsulated diclofenac for sonophoresis induced systemic delivery. 1995; 12(2): 149-154.

How to cite this article:

Rao R and Nanda S: Sonophoretic transdermal delivery of losartan potassium proniosomal gel. Int J Pharm Sci Res 2017; 8(1): 305-11.doi: 10.13040/IJPSR.0975-8232.8(1).305-11.

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