full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and PharmacyVol. 5 (2) 1110-1122 April 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)1111blocking agent and widely used in the treatmentof mild to moderate hypertension and anginapectoris. It has antioxidant and anti proliferativeproperties which makes it suitable to combat thedeleterious effects of sympathetic nervous systemactivation in heart failure. It undergoes extensivefirst pass metabolism and its systemic bioavailability is only 25 to 35% (7). As perBiopharmaceutical classification it belongs toclass II compound and therefore it is insoluble inaqueous medium (8). Certain strategies such asfast dissolving tablets (9), muco adhesive drugdelivery systems (10), self emulsifying drugdelivery systems (11) and other controlled releasesystems (12, 13) were reported to improve theaqueous solubility, to overcome first passmetabolism and thereby increase the systemicbioavailability. But these technologies requireunique production processes and also have certaindisadvantages like limited formulation flexibilityand complexity in manufacturing, high productioncosts, low stability, low drug loading and fewchoices of dosage forms.The objectives of present study are toinvestigate the feasibility of development of o/wNEs loaded with carvedilol using sesame oil orolive oil by high energy homogenization technique,to study the effect of oil phase volume on thedrug loading efficiency, particle size and zetapotential, to study the effect of concentration andtype of surfactants on the globule size, zetapotential and in-vitro drug release characteristicsand to carry out the comparative pharmacokineticstudy of optimized nano emulsion with marketedtablet dosage-form in rats.Materials and MethodsMaterials: Carvedilol was a gift sample fromOrchid Pharmaceuticals, India. Brij-97, Tween-80, dialysis tubing cellulose membrane (size: 43mm × 27 mm) were purchased from SigmaAldrich, USA. Sesame oil was purchased fromThiagarajan Agro Products Pvt Ltd., Chennai,India. Olive oil was purchased from Figaro, SriRoda Foods Pvt Ltd., New Delhi India. All otherchemicals, water and solvents are of HPLCgrade and purchased from S.D. Fine Chemicals,India.Preparation of carvedilol nano emulsion :Various Carvedilol NEs were prepared by usinghigh energy emulsification technique. Prior toemulsification the oil phase and aqueous phasewere prepared separately.A specified quantity of oil was taken in abeaker and 6.3 mg of drug was added and thetotal weight of the oil phase was determined. Tothis 200 µl of chloroform was added to dissolvethe drug in oil. Then nitrogen gas was purged toevaporate the chloroform. This was confirmedby reweighing oil phase.Aqueous phase was prepared by dissolvingthe non-ionic surfactant in HPLC grade waterpH- 6.8±0.2. A volume of this surfactant solutionwas added and a coarse emulsion was preparedby using a high shear stirrer (RQ-127A, RemiMotors, India) for 25 min at 6000 rpm. Then thecoarse emulsion was subjected to high energyemulsification using a probe sonicator (BandelinSonoplus, Heinrichstrab 3-4 D-12207, Berlin,Germany) in a continuous mode at 37 to 40 HZ.NEs were prepared using 100 µl of sesameoil and non-ionic surfactants Brij-97 or tween-80.Then various formulation parameters such asoil phase volume (100, 150 and 200 µl) andconcentration of each surfactant (1.25, 1.5 and1.75) were optimized for particle size, zetapotential and drug loading efficiency. Theprocedure was repeated for the preparation andoptimization of carvedilol loaded olive oilnanoemulsions.Koteswari Poluri et al