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SIDE BY SIDE CELL - PowerPoint PPT Presentation

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SIDE BY SIDE CELL

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  1. SIDE BY SIDE CELL spectrophotometer surge chamber computer pump Thermostatic unit Thermostatic unit Teflon adapter Donor Receiver membrane jacket jacket solid drug stirrer Magnetic engine Magnetic engine

  2. 2 - DRUG DIFFUSION MEASUREMENT TEFLON ADAPTER DONOR CHAMBER RECEIVER CHAMBER THERMOSTATIC JACKET MAGNETIC STIRRERS

  3. 2 - MODELING POWDER DISSOLUTION DRUG PERMEATION DONOR RECEIVER jacket jacket DRUG CONCENTRATION INCREASE STIRRER

  4. MATHEMATICALL MODELING

  5. SOLID SURFACE VARIATION: MONODISPERSED PARTICLES SYSTEM SOLID DRUG Particles initial surface area

  6. FICK LAW 1st stagnant layer membrane 2nd stagnant layer

  7. BOUNDARY CONDITIONS

  8. BOUNDARY CONDITIONS

  9. BOUNDARY CONDITIONS

  10. SIMULATION: NO DISSOLUTION Vr = Vd H = Stagnant layer thickness *hm Dm = 5.3*10-6 cm2/s *hm *hm D1 = 8.8*10-6 cm2/s *hm D1 = D2 Kp = 0.8 hm = 100 mm S = 10 cm2

  11. SIMULATION: PROFILE CONCENTRATION S = 10 cm2 Vr = Vd Dm = 5.3*10-6 cm2/s D1 = 8.8*10-6 cm2/s D1 = D2 Kp = 0.8 hm = 100 mm h1 = h2 = 0.5*hm

  12. SIMULATION: DISSOLUTION Vd = 100 cm3 Vr = 800 cm3 h1 = h2 = hm=100mm Kp = 0.8 Dm = 5.3*10-6 cm2/s D1 = 8.8*10-6 cm2/s D1 = D2 Kd = 10-6cm/s A = 5000 g/cm2 Cs = 12495 mg/cm3 S = 10 cm2

  13. SIMULATION: STEADY STATE APPROXIMATION For t ∞ Cd = Cd0 (constant drug concentration in the donor) Cr = 0 (sink conditions in the receiver) FICK eq. solution (only membrane) is: Membrane Permeability

  14. For t ∞ For a trilaminate system the solution is:

  15. SIMULATION: LINEAR PROFILES (THIN MEMBRANES)

  16. SIMULATION: LINEAR PROFILES (THIN MEMBRANES) EMPIRICAL APPROACH

  17. 3 - DRUG DIFFUSION COEFFICIENT MEASUREMENT REQUIRES THE DETERMINATION OF: 1 2 3 4 5 DRUG SOLUBILITY CS IN THE RELEASE ENVIRONMEMT DRUG DIFFUSION COEFFICIENT DW IN THE RELEASE ENVIRONMEMT DRUG POWDER DISSOLUTION CONSTANT KDP DRUG PARTITION COEFFICIENT Kp(MEMBRANE/RELEASE ENVIRONMENT) THICKNESS OF STAGNANT LAYERSSANDWICHING THE MEMBRANE

  18. CASE STUDY: THEOPHYLLINE AND ALGINATES THEOPHYLLINE MONOHYDRATED - Carlo Erba , Milano - (C7H8N4O2*H2O); MW 198, WHITE CRYSTALLINE POWDER - DENSITY 1.49 ±01 g/ cm3 (Helium picnometer) - SURFACE AREA = 2941 cm2/g (mercury porosimeter) - U.V. PEAK ABSORBANCE 271 nm ALGINATE: - Protanal LF 20/ 60, Pronova Biopolymer, Drammen, Norway - THEY ARE EXTRACTED FROM BROWN SEAWEED - SEQUENCE OF GULURONATE AND MANNURONATE (LF 20/60: 70% GULURONATE) - THEY FORM STRONG PHYSICAL GELS IN PRESENCE OF DIVALENT IONS (TYPICALLY Ca++)

  19. Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ EGG BOX CONFIGURATION

  20. DRUG SOLUBILITY CS IN THE RELEASE ENVIRONMEMT Cs = 12945± 104 mg/cm3 (DISTILLED WATER 37°C) 1 2 DRUG DIFFUSION COEFFICIENT DW IN THE RELEASE ENVIRONMEMT DW= (8.2 ± 0.6)*10-6 cm2/s (DISTILLED WATER 37°C) IDR IDR Kd = 0.62*DW2/3w1/2 *n-1/6

  21. SEALING TAPE 3 DRUG POWDER DISSOLUTION CONSTANT KDP Donor jacket solid drug Magnetic engine

  22. t = 0 t > 0 DISSOLUTION Rp Rp0 PARTICLES SURFACE Md = drug amount in the donor (soluble) Mp = solid particle mass - SINK CONDITIONS - Np MONOSIZED SPHERICAL PARTICLES (Rp0 INITIAL RADIUS)

  23. A = Particles initial surface area Mp0 = initial particles mass

  24. KDP = 1.2*10-3 cm/s

  25. 4 C∞ 24 h M0 = V*C∞+Vg* Cg∞ Kp = Cg∞/C∞ DRUG PARTITION COEFFICIENT Kp(MEMBRANE/RELEASE ENVIRONMENT) Cylindrical gel V IDR Vg (DISTILLED WATER 37°C) C0 = 20 mg/cm3

  26. 5 THICKNESS OF STAGNANT LAYERSSANDWICHING THE MEMBRANE MEMBRANE Donor Receiver STAGNANT LAYER STAGNANT LAYER jacket jacket stirrer stirrer

  27. DRUG Donor jacket stirrer hss = 60.7 mm STAGNANT LAYER

  28. 4 - RESULTS - Model - Linear approximation Experimental data Vd = 100 cm3 Dm = (5.1± 0.64)*10-6 cm2/s Vr = 100 cm3 S = 10 cm2 %P = 4

  29. T = 25°C 2% 4% 1%

  30. T = 37°C 2% 4% 1%

  31. MEMBRANES CHARACTERISTICS

  32. DIFFUSION COEFFICIENTS