full issue - Association of Biotechnology and Pharmacy

Current Trends in Biotechnology and PharmacyVol. 5 (2) 1173-1182 April 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)1174alternative mode of delivery system is desirable,to deliver the drug at effective concentrations totreat hypertension. LCDP was selected as amodel drug because; its oral dose is low (2-8 mg),low molecular mass 455.5 g mol -1 and low oralbioavailability.The system designs for transdermal patchesinclude matrix, microreservoir, reservoir, adhesiveand membrane moderated matrix hybrid. Matrixtype transdermal patches remain the most popularas they are easy to manufacture (5).Microemulsion based reservoir system wasdeveloped with the enhancement of bioavailabilityfrom our laboratory (6). The developed systemsuffers from poor mechanical properties.Transdermal system with suitable mechanicalproperties would be desired to withstand duringwear and tear. Therefore a matrix type systemfor prolonged release of LCDP having suitablemechanical properties to withstand wear and tearis developed.The present paper describes thedevelopment of matrix type patches for LCDP.The developed patches were also evaluated forphysicochemical, in vitro, ex vivo and mechanicalproperties.Materials and MethodsMaterials: Lacidipine, Eudragit RL100, ethylcellulose and poly vinyl pyorrolidone 30 K wereobtained as gift samples from Dr Reddy’sLaboratories, Hyderabad, India. All otherchemicals and solvents used were of analyticalreagent grade.Preparation of patches: Matrix type transdermalpatches containing LCDP were prepared by filmcasting technique using different ratios of ethylcellulose/Eudragit RL 100 and poly vinylpyrrolidone (Table 1). Weighed quantity ofpolymers was dissolved in 20 mL of solventmixture consisting of 1:1 ratio of dichloromethaneand methanol. Weighed quantity of LCDP wasdissolved in 5 mL of solvent system. Thepolymeric solution is kept for swelling for 6 hr.Then drug solution, d-limonene as permeationenhancer and dibutyl pthalate as plasticizer areadded to the polymeric solution and vortexed for5 min then transferred into Anumbra petri plate.Drying of these patches is carried out at roomtemperature for overnight and then in vacuumoven at room temperature for 8 to 12 hrs. Theprepared patches were removed, cut to size eachhaving 3.56 cm 2 and stored in desiccator.Weight and thickness variation test: Eachformulated film was prepared in triplicate and tencircular films having an area of 3.56 cm 2 werecut from each plate. Their weight was measuredusing digital balance (Shimadzu, Japan). Thethickness of films was measured using digitalscrew gauge (Digimatic micrometer, Mitutoyo,Japan).Estimation of LCDP in polymeric films: Theformulated polymeric films were assayed for drugcontent. Three patches from each formulationseries were taken, cut into small pieces and wasallowed to dissolve in a 100 mL of 0.5% of w/vTween 80 solution. The solution was dilutedsuitably filtered through membrane filter (0.45 µ)and LCDP content was measured using HPLC(7).In vitro release studies: Drug release from thetransdermal patch was studied using dissolutionapparatus (Disso 2000, Labindia, India) equippedwith an auto sampler and fraction collector forcollection and replenishment of samples anddissolution medium respectively. Waterimpermeable back up membrane was placed onone side of the patch and further was adhered toUSP-V (Paddle over disc). It was placed indissolution vessel containing 500 mL of 0.5 % w/v Tween 80 solution as in vitro release medium.The study was conducted at 50 rpm as stirringRamesh Gannu et al