PREPARATION AND CHARACTERIZATION OF SELF NANO EMULSIFYING DRUG DELIVERY SYSTEM CONTAINING ANTI-HYPERTENSIVE DRUG’’

The present work is to prepare and characterization of self nano emulsifying drug delivery system containing Anti-hypertensive drug. Losartan is a competitive antagonist and inverse agonist of angiotensin 2 receptor. The SNEDDS is prepared by Sonication method using a components of SPAN 60/Eudragit RS 100 as a surfactant, PVA as a Co-surfactant, Iso propyl alcohol as a solvent and DCM as a co-solvent. The prepared SNEDDS was evaluated for Fourier transform infrared spectroscopy, Surface morphology, particle size, zeta potential,  drug entrapment efficiency, visual assessment, self-emulsification time, Robustness to dilution, in-vitro drug release and short term stability studies. The in-vitro drug release data of all the formulations were found to be zero order over a period of 24 h and Formulation F7 shows good results for the drug release kinetics as controlled release. The stability studies data was found that there was no such difference in drug EE and in-vitro drug release.


INTRODUCTION
Oral delivery route is that the most convenient route for drug administration to attain desired therapeutic effects and also the greatest degree of patient compliance, particularly for chronic condition diseases. Super molecule primarily based formulations, as well as selfnanoemulsifying formulations, is that the promising technologies for PWSD delivery and has shown to boost the oral absorption of those medicine. Self-nanoemulsifying Drug Delivery system (SNEDDS) is isotropic mixture of oil, natural or synthetic surfactants and co-surfactants that have a ability of forming fine oil in water (O/W) nano-emulsions under mild Agitation followed by aqueous media. Self-Nano emulsifying Drug Delivery System having size vary of globules is a smaller amount than 100nm underneath dispersion of water. numerous strategies for choice of parts and methodology of preparation that square measure mentioned in review of literature, For to attain the SNEDDS the category II and sophistication III medicine square measure best suited.
Components of SNEDDS and their concentrations have an effect on drop size, emulsification potency and unharness property of fashioned nanoemulsion. SNEDDS square measure ready by trial and error basis to urge smart region forming nanoemulsion. But this can be time consuming and needs a bigger range of trails.
The objective of this study was to prepare and characterize the self nanoemulsifying drug delivery system containing Anti-hypertensive drug (Losartan potassium) by sonication methodology.

Materials:
Losartan potassium was procured from Nirupama K V, Dept. of pharmaceutics, Bharathi college of pharmacy, Mandya as a gift sample, SPAN 60, Eudragit RS 100, Eudragit RSPO was supplied from Yarrow chemicals, Polyvinyl alcohol (PVA) was supplied from Fisher scientifics, Iso propyl Alcohol, Dichloromethane, NaOH and Potassium Dihydrogen Orthophosphate was supplied from SD Fine chemicals.

Preparation of SNEDDS by Sonication Method
Solution of surfactant SPAN 60/ Eudragit RS 100 in Iso propyl alcohol was mixed with Cosurfactant polyvinyl alcohol by using controlled flow rate syringe pump 3ml/min rate. During this mixing the aqueous phase was sonicated using a probe sonicator set at 10 KHz of energy output (Labman Pro-500) to produce oil in water type of emulsion. place this preparation for magnetic stirrer at 1000 rpm until the organic phase is to evaporate. The obtained nanoparticles were recovered by centrifugation (Remi PR 24) at 10,000 rpm for 15-20 min and washed thrice with distilled water. The washing water was removed by a further centrifugation and nanoparticles were dried.

Drug -Excipient Compatibility Study
The compatibility of components and drug was evaluated by FT-IR study.

FTIR Study:
FTIR spectra of pure drugs, physical mixture of SPAN 60 and Eudragit RS 100, RSPO and drug loaded Nanoparticles were recorded on a BRUKER IR spectrophotometer and scanned in the spectral region between 4000 cm -1 and 600 cm -1 .

Surface morphology:
The surface morphology is most commonly measured by Scanning Electron microscopy. The surface morphology has been studied by using JEOL JSMT -330A Scanning electron microscopy (SEM).

Particle size:
The particle size and distribution is measured by Malvern Zeta sizer by Wet technique. The average particle sizes of the individual batch of Nanoparticles were reported.

Zeta potential:
The Zeta potential of a nanoparticle is commonly used to characterize the surface charge property of Nanoparticles. Zeta potential is measured by Malvern zeta analyzer.

Drug entrapment efficiency:
The self emulsifying Nanoparticles were separated from the aqueous medium by ultracentrifugation at 10,000 RPM for 15-20 min. Then the resulting supernatant solution was decanted and dispersed into phosphate buffer pH 7.4. Thus the procedure was repeated twice to remove the un-entrapped drug molecules completely. The amount of drug entrapped in the nanoparticle was determined as the difference between the total amount of drug used to prepare the Nanoparticles and the amount of drug present in the aqueous medium.

Visual observation:
The formulation were diluted and made to stand for 24 hours at 37° C. They were observed for phase separation and turbidity.

Self-emulsification time:
1ml of formulations was added to 100 ml of distilled water at 37° C being agitated at 100 rpm. The time required for the formation of a milky emulsion was noted.

Robustness to dilution:
The formulations were diluted to 10 ml, 50 ml, and 100 ml were observed over a period of 24 hours for phase separation or signs of precipitation.

Dissolution Rate study on Self emulsifying Nanoparticles:
In-vitro drug release studies were performed in USP Type II dissolution apparatus at rotation speed of 50 rpm. The prepared Nanoparticles were immersed in 900ml of phosphate buffer solution in a vessel, and temperature was maintained at 37±0.20°C. Required quantity 5ml of the medium was withdrawn at specific time periods and the same volume of dissolution medium was replaced in the flask to maintain a constant volume. The withdrawn samples were analyzed using UV spectrophotometer (SHIMADZU 1700).

Stability studies
The prepared self emulsifying Nanoparticles were packed in screw capped HDPE bottles and were stored at 40± 20 C and 75 % RH for 45 days. After storage for 45 days, the products were tested for drug entrapment efficiency and drug release study as per the ICH guidelines.

RESULTS AND DISCUSSION
Pre-formulation studies:

I. Determination of λ max of Losartan potassium
The λ max of Losartan potassium was found to be 234 nm. The spectrum traced using UV spectrophotometer (UV1700, Shimadzu, Japan).

II. Standard plot of Losartan potassium
The standard plot was established for Losartan potassium in Phosphate buffer pH 7.4. Absorbance measured at 234 nm and a graph of concentration versus absorbance was plotted

Solubility analysis of drug (Losartan)
Practically completely soluble in Dichloromethane, Isopropyl alcohol, Ethanol, Methanol and Water.

Compatibility studies:
From the FTIR spectra of the pure drug and the combination of drug with the surfactant and co-surfactant was observed that all the characteristics peaks of Losartan is present in the combined spectra as well thus indicating the compatibility of the drug with the components . The individual FTIR spectra of the pure drug Losartan and physical mixture of SPAN 60, Eudragit RS100 and Eudragit RSPO as well as combination spectra of the drug and components (formulation F 7 ) are shown in Figure No. 13, 14 and 15. It was found that the drug was compatible with polymer in physical mixture.      Visual assessment: In nano-emulsion formulation only F2, F4, F5, F6 and F7 were clear. The rest of the formulations were showed precipitation.  IV  YES  2  F2  IV  NO  3  F3  III  YES  4  F4  III  NO  5  F5  III  NO  6  F6  III  NO  7 F7 III NO Self emulsification time 1 ml of formulation was a added to 100ml of distilled water at 37 0 C being agitated at 100 rpm. The time required for the formulation of a milky emulsion was noted for F2, F4, F5, F6 and F7 were 58 sec, 53 sec, 51 sec, 48 sec and 49 sec.

Robustness to dilution
The formulations were diluted in various ratios to assess the performance of the SNEDDS in the body. The diluted SNEDDS showed no precipitation or phase separation indicating the stability of the nanoemulsion.
In-vitro drug release study

Stability Study Report:
The prepared self emulsifying nanoparticles were tested for drug entrapment efficiency and drug release study as per the methods described earlier. The results are given in Table.

Conclusion
It can be concluded from the experimental study carried out that the formulation of a SNEDDS containing anti-hypertensive drug yields a formulation with spherical and smooth surface, nano size range & good percentage entrapment efficiency .
The particle size analysis indicated that the particles were in the size range of 320 nm to 520 nm, and showed good flow properties. The Nanoparticles were smooth, as shown by the scanning electron microscopic studies. In-vitro drug release showed that release from the SNEDDS gets successfully retarded for over 24h. The formulations were found to be stable in Short term stability studies. Pharmacokinetic studies indicate that the in-vitro drug release of the formulations fitted Peppas model and the mechanism follows non-Fickian drug release. By considering the results obtained from in-vitro and Stability studies, it can be suggested that there is further scope for the in-vivo and the Pharmacokinetic Study. Here we have selected F7 has an optimized formulation which shown good morphological features, drug entrapment efficiency and controlled drug release.

Acknowledgement
Very thankful to Dr. Bharathi DR, Principal, SJM College of Pharmacy, Chitradurga, Dr. T S Nagaraja Professor and HOD Dept. of Pharmaceutics, Dr. R Yogananda for providing the facilities of Library and literature source.