full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
full issue - Association of Biotechnology and Pharmacy
- No tags were found...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Current Trends in <strong>Biotechnology</strong> <strong>and</strong> <strong>Pharmacy</strong>Vol. 5 (2) 1173-1182 April 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)1175speed <strong>and</strong> temperature <strong>of</strong> 32 o C. Samples werecollected at preset time intervals <strong>and</strong> analyzedusing UV-Vis spectrophotometer (Elico, India) at282 nm.Release kinetics <strong>and</strong> mechanisms <strong>of</strong> drugrelease: Different kinetic models, zero order, firstorder (8), Higuchi <strong>and</strong> Korsmeyer expressions(8, 9) were applied to interpret the drug releasekinetics to know the mechanism <strong>of</strong> drug releasefrom these matrix systems with the help <strong>of</strong>equations 1-4.M t=M 0+K 0t—————————(1)LnM t=LnM 0+K 1t—————(2)M t=K Ht 1/2 ——————————(3)M t/M =K kt n ————————(4)M tcumulative amount <strong>of</strong> drug release at time t;M 0, is the initial amount <strong>of</strong> drug K 0,K 1,K H<strong>and</strong>K Kare rate constants for zero order, first order,Higuchi <strong>and</strong> Korsemeyer model respectively; M t/M is the fraction <strong>of</strong> drug release at time t n,release exponent indicative <strong>of</strong> the operatingrelease mechanism. The correlation coefficientvalues (r 2 ) presented in table 288Moisture absorption studies: The films wereweighed accurately <strong>and</strong> placed in a dessicatorcontaining 100 mL <strong>of</strong> saturated solution <strong>of</strong>aluminium chloride (79.5 % RH). After 3 days,the films were taken out <strong>and</strong> weighed, thepercentage <strong>of</strong> moisture uptake was calculated asthe difference between final <strong>and</strong> initial weight withrespect to initial weight (10).Moisture content: The patches were weighed<strong>and</strong> kept in a desiccator containing calcium chlorideat 40 o C for 24 hr. The final weight was notedwhen there was no further change in the weight<strong>of</strong> patch. The percentage <strong>of</strong> moisture content wascalculated as a difference between initial <strong>and</strong> finalweight with respect to initial weight (11).Measurement <strong>of</strong> mechanical properties:Mechanical properties, elongation at break (E.B)<strong>and</strong> tensile strength (T.S) <strong>of</strong> the films wereevaluated using a microprocessor based advancedforce gauze equipped with a motorized test st<strong>and</strong>(Ultra Test, Mecmesin, West Sussex, UK),equipped with 25 kg load cell. Film strip (60x10Table 1. Composition <strong>of</strong> LCDP transdermal patchesFormulation Ingredient (mg)LCDP EC20 ERL100 PVPLE1 (10:0) 90 - 2500 -LE2 (7.5:2.5) 90 - 1875 625LE3 (5.0:5.0) 90 - 1250 1250LE4 (2.5:7.5) 90 - 625 1875LP1 (10:0) 90 2500 - -LP2 (7.5:2.5) 90 1875 - 625LP3 (5.0:5.0) 90 1250 - 1250LP4 (2.5:7.5) 90 625 - 1875LCDP, Lacidipine; EC20, Ethyl cellulose 20, ERL 100, Eudrgait RL 100; PVP, Polyvinyl pyrrolidoneSolvent system used is 25 mL <strong>of</strong> 50:50 <strong>of</strong> dichloromethane <strong>and</strong> methanolPlasticizer 20 % w/v <strong>of</strong> dibutylphathalated-limonene 8 % w/v was incorporatedDevelopment <strong>of</strong> matrix type transdermal patches <strong>of</strong> lacidipine