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)1114for 10 minutes and centrifuged for 10 minutes at4000 rpm at 20°C and supernatant wastransferred in to pre-labeled ria vial andevaporated under a stream of nitrogen at 35°Cuntil dryness, reconstituted the dried residue with400µl of mobile phase and vortexed. Samples wereloaded in to pre-labeled auto-injector vials and 10µl of samples were injected onto LC-MS/MSsystem containing HPLC (AGILENT 1200 series(VLS-UTL/HPLC/01) and Massspectrophotometer (AB MDS Sciex 4000,VLS-UTL/MASS/01) with a Column of HypurityAdvance, 100 X 4.6mm, 5µ.The column oventemperature was maintained at 40°C and themobile phase was 0.1% Formic acid: Acetonitrile(25:75 v/v) with a flow rate of 0.6ml/min and aninjection volume of 10µl. The separation wasconducted under isocratic conditions, and the totalrun time was within 4minutes. The electron sprayionization was performed in the selected ionmonitoring mode. The detection ions were atmass-to-charge ratios m/z of 407.3 amu (parent)to 222.1 amu (product) and 384.1 amu (parent)to 338.1 amu (product) for carvedilol and internalstandard felodipine respectively. Thechromatograms were evaluated by analyst 1.4.2version software and the concentration ofcarvedilol was calculated. Then the pharmacokinetic parameters were calculated by noncompartmentalanalysis by winn online (R) 5.2 software.Statistical analysis: The pharmacokineticparameters of the olive oil nano emulsion andmarketed tablet suspension were compared bythe student t-test. A p-value of less than 0.05 wasconsidered as statistically significant.ResultsNano emulsions loaded with carvedilolwere successfully prepared by using high energyemulsification technique.Optimization of oil phase volume andsurfactant concentration: Based on literaturesurvey and oil water partition coefficient studiessesame oil and olive oil were selected as solelipid phase. To determine the optimum content ofoil for the preparation of stable and high drugloaded NEs, different volumes of (100,150 and200 µl) sesame or olive oil with 6.3 mg ofcarvedilol were taken. Brij 97 and Tween 80 wereused as surfactants. In order to determine theoptimum surfactant type and concentration NEswere prepared with 1, 1.25, 1.5 and 1.75% w/vof each surfactant. Globule size, ZP and PDIwere measured for all the NEs as describedabove. The composition of all the NEs was givenin the Table 1.Characterization of carvedilol nano emulsions:The physical properties such as globule size, PDIand zeta potential are essential parameters inpredicting the physical stability of nano emulsions.The mean globule sizes of nano emulsions werein the range of 33.4±3.9to 183.56±1.78nm andthe PDI of nano emulsions were in the range of0.07±0.08to 0.35±0.026 which shows a narrowglobule size range and size distribution in allformulations. All the carvedilol loaded nanoemulsion formulations had zeta potentials between-2.87±0.65 to-14.18±0.72mv. These results werelower than the reported value of above 30 mV instable parenteral emulsions, which suggests thatthe prepared formulations were more stable. Allthe characterization parameters were shown inthe Table 2 and the effect of oil phase volumewas shown in Fig.1.Determination of drug content and In-vitrodrug release studies: Drug content wasdetermined in the formulations which showednarrow particle size and polydispersity and foundto be in the range of 43.81±2.68 to 98.93±1.31.In - vitro drug release studies were carried out inphosphate buffer saline pH 7.4 (PBS) containingFormulation, characterization and Pharmacokinetic studies