Universita degli Studi di Milano Corso di Laurea Magistrale in Farmacia Tecnologia e Legislazione Farmaceutiche I - 9 CFU Prof. Andrea Gazzaniga Rilascio Modificato Orale Ritardato/Pulsatile Parte II
Swelling Controlled Release System (SCRS) film di EC e HPMC (75:25) nucleo (unità singole) contenente il farmaco ed un agente idrofilo rigonfiante (polivinilalcol) Morita R. et al., J. Control. Rel. 63, 297 (2000)
film semipermeabile di cellulosa acetato & nucleo (pellets) contenente il farmaco (paracetamolo) e un agente osmoattivo (NaCl) Schultz P. and Kleinebudde P., J. Control. Rel. 47, 181 (1997)
film di etilcellulosa (insolubile, permeabile) & nucleo (compresse o pellets) contenente il farmaco, agenti idrofili rigonfianti (Na carbossimetilcellulosa) e osmoattivi (NaCl, sorbitolo) Amidon G.L. and Leesman G.D., US Patent 5 229 131 (1993)
film di etilcellulosa & nucleo (compresse) contenente il farmaco ed una miscela di acido citrico e sodio bicarbonato Kroegel I. and Bodmeier R., Int. J. Pharm. 187, 175 (1999)
Sistemi orali a rilascio ritardato/pulsante (delayed/pulsatile release) - sistemi réservoir - nucleo contenente il principio attivo - rivestimento ritardante il rilascio lacerazione per aumento della pressione interna aumento della permeabilità dissoluzione e/o erosione
Sigmoidal Release System (SRS) Narisawa S. et al., Pharm. Res. 11(1),111 (1994) aumento della permeabilità
Sistemi orali a rilascio ritardato/pulsante (delayed/pulsatile release) - sistemi réservoir - nucleo contenente il principio attivo - rivestimento ritardante il rilascio lacerazione per aumento della pressione interna aumento della permeabilità dissoluzione e/o erosione
Time-Clock System Pozzi F. et al., J. Control. Rel., 31, 99 (1994) Wax mixture spray-coating in rotating pan or fluid bed at 80-90 C Core (tablet) Stage 1 - Erosion of the wax layer [surfactants/hydrophilic agents] Stage 2 - Rapid release of the active
Time-Clock System Pozzi F. et al., J. Control. Rel., 31, 99 (1994) Wax mixture spray-coating in rotating pan or fluid bed at 80-90 C Core (tablet) Stage 1 - Erosion of the wax layer [surfactants/hydrophilic agents] Stage 2 - Rapid release of the active
Plasma concentration (ng/ml) 20 15 10 5 Time-Clock System adapted from Pozzi F. et al., J. Control. Rel., 31, 99 (1994) conventional dosage form Time-Clock 0 0 120 240 360 480 600 Time (min) Salbutamol plasma profiles following oral administration of conventional dosage form and TIME CLOCK
Eur. J. Pharm. Biopharm., 40 (4) 246-250 (1994) Oral Chronotopic TM Drug Delivery Systems: Achievement of Time and / or Site Specificity Andrea Gazzaniga *,Maria Edvige Sangalli **,Ferdinando Giordano ** - * University of Milan, Institute for Pharmaceutical Chemistry, Milan, Italy - ** University of Pavia, Department of Pharmaceutical Chemistry, Pavia, Italy
Gazzaniga A. et al., Eur. J. Pharm. Biopharm. 40(4), 246 (1994) Hydrophilic swellable polymeric layer (HPMC, different viscosity grades) Stage 0 - Dissolution of gastric resistant film Stage 1 - Swelling/Erosion of polymeric layer Stage 2 - Rapid release of the active Drug-containing core [single/multiple unit]
amount released Chronotopic System The slow interaction polymer/fluid lead to the formation of a gel [glassy/rubbery] glassy drug particles rubbery time
amount released Chronotopic System Rapid or slow release depending on core characteristics glassy drug particles rubbery no release time
amount released Lag phase physical-chemical characteristics and coating level of the retarding polymer glassy drug particles rubbery lag phase no release time
How to prepare the retarding layer? spray-coating press-coating - polymers [high viscosity HPMC] never used before as coating agents. - technical obstacles to acceptable sprayability and reasonable processing time [hydroalcoholic dispersions/viscosity] - large-scale production implies use of special presses - difficult core centering with consequences on coating thickness uniformity
press-coating Methocel K100 LV
press-coating Methocel K100 LV limitations in the design flexibility owing to the large amount of coating needed
Adapted from Gazzaniga A. et al.- Eur.J. Pharm. Biopharm. 40(4), 246 (1994) press-coating Methocel K100 LV limitations in the design flexibility owing to the large amount of coating needed % released 80 40 quite difficult to avoid the relatively and undesired long diffusion phase 0 time (min) 0 120 240 360 480 600 Release profile of Verapamil.HCl from Methocel K100 LV press-coated systems with 150% weight gain 177.6 mg/cm 2 coating polymer amount [tablet cores 60 mg]
Polymer 5 % W/W in Ethanol/Water mixture (84/6 w/w) spray-coating hydroalcoholic dispersions Methocel K15M Large scale production limitations due to the use of organic solvents
% released Chronotopic System Polymer 5 % W/W in Ethanol/Water mixture (84/6 w/w) spray-coating hydroalcoholic dispersions Methocel K15M Large scale production limitations due to the use of organic solvents 100 80 tablet core 7,6 mg/cm 2 60 40 20 15,2 mg/cm 2 22,8 mg/cm 2 30,4 mg/cm 2 0 0 100 200 300 400 time (min) Release profiles of indomethacin from uncoated cores (4 mm diameter, 20 mg model drug) and systems spray-coated [rotating pan] with increasing amounts, mg/cm 2, of high viscosity HPMC - [hydro-alcoholic dispersion of Methocel K15M - 5% w/w] Adapted from Gazzaniga A. et al.- Eur.J. Pharm. Biopharm. 40(4), 246 (1994)
Adapted from Gazzaniga A. et al.- Eur.J. Pharm. Biopharm. 40(4), 246 (1994) Chronotopic System Polymer 5 % W/W in Ethanol/Water mixture (84/6 w/w) spray-coating hydroalcoholic dispersions Methocel K15M Large scale production limitations due to the use of organic solvents 300 Lag time (min) 200 100 0 Applied polymer amount (mg/cm 2 ) 0 10 20 30 40 Relationship between applied polymer amount and lag time for high viscosity HPMC spray-coated units [rotating pan, hydro-alcoholic dispersion of Methocel K15M- 5% w/w]
Spray coating with aqueous solutions of different HPMC viscosity grade Comparative evaluation of different HPMC viscosity grades, Methocel E5, E50 and K4M, in terms of process feasibility and performances as coating agents in aqueous solution unsolved issue how to switch to aqueous solvents? systematic study to select the most convenient HPMC aqueous coating systems
Spray coating with aqueous solutions of different HPMC viscosity grade M.E. Sangalli et al., Eur. J. Pharm. Sci. 22, 469 (2004) SEM photomicrographs of cross-sectioned systems coated with Methocel E5 (top), E50 (middle) and K4M (bottom) aqueous solutions at 16, 8 and 2% w/v, respectively (magnification 47x)
drug released (%) Spray coating with aqueous solutions of different HPMC viscosity grade M.E. Sangalli et al., Eur. J. Pharm. Sci. 22, 469 (2004) 100 75 50 25 uncoated Methocel E5 Methocel E50 Methocel K4M 0 time (min) 0 30 60 90 120 150 Release profiles obtained from uncoated cores and systems coated (w.g. 20%) with Methocel E5, E50 and K4M aqueous solutions at 16, 8 and 2% w/v, respectively
Spray coating with aqueous solutions of different HPMC viscosity grade finally Methocel E50 was selected for further studies since it affords the best balance among: -process time necessary for spray-coating -ability to delay drug release -final dimensions of the coated units -possibility of finely tuning the lag phase duration
Spray coating with aqueous solutions of Methocel E 50 A. Gazzaniga et al., STP Pharma Sci., 5, 83 (1995) fine tuning of lag time 100 % released 80 60 40 20 core w.g. 22% w.g. 35% w.g. 50% w.g. 58% w.g. 73% w.g. 92% w.g. 115% w.g. 142% 0 0 30 60 90 120 150 180 210 time (min) 240 270 Release profiles of a tracer substance from uncoated cores (6.7 mm diameter, 180 mg weight, 2.3% methyl-4-hydroxybenzoate ) and cores coated with increasing amount of low viscosity HPMC (Methocel E50)
Spray coating with aqueous solutions of Methocel E 50 A. Gazzaniga et al., STP Pharma Sci., 5, 83 (1995) 210 Lag time (min) 180 150 120 90 60 30 0 0 20 40 60 80 100 120 weight gain (%) 140 Relationship between weight gain and lag time for low viscosity HPMC (Methocel E50)-coated units (fluid bed).
Spray coating with aqueous solutions of Methocel E 50 A. Gazzaniga et al., STP Pharma Sci., 5, 83 (1995) 1.2 thickness (mm) 0.8 0.4 weight gain (%) 0.0 0 50 100 150 Relationship between weight gain and layer thickness for Methocel E50 caoted-units.
Spray coating with aqueous solutions of Methocel E 50 M.E. Sangalli et al., Eur. J. Pharm. Sci. 22, 469 (2004) 100 80 % released 100 % released 80 60 60 40 20 0 ph=1.5 time (min) 0 20 40 60 80 40 20 0 ph=11.5 time (min) 0 15 30 45 60 75 90 100 % released 80 60 40 20 0 ph=7.5 time (min) 0 20 40 60 80 Release profiles of acetaminophen obtained from Methocel E50-coated systems at different ph (weight gain: 20% - coating thickness 277 µm).
Spray coating with aqueous solutions of Methocel E 50 M.E. Sangalli et al., Eur. J. Pharm. Sci. 22, 469 (2004) 120 Lag timet 10 % (min) 80 40 0 ionic strength-independent lag phase in the physiological range 0.01-0.166 ionic strength 0 0.1 0.2 0.3 0.4 t 10% as a function of the medium ionic strength for Methocel E50-coated systems (weight gain 20%, coating thickness 277 µm) - bars represent s.d.
Spray coating with aqueous solutions of Methocel E 50 M.E. Sangalli et al., Eur. J. Pharm. Sci. 22, 469 (2004) 120 Lag timet 10 % (min) 80 40 0 ionic strength-independent lag phase in the physiological range 0.01-0.166 ionic strength 0 0.1 0.2 0.3 0.4 t 10% as a function of the medium ionic strength for Methocel E50-coated systems (weight gain 20%, coating thickness 277 µm) - bars represent s.d.
there was still room for improvement in process time spray-coating top spray fluid bed equipment tangential spray-coating powder layering rotor insert progressive decrease in process time
Tablets coated by spray-coating, top-spray fluid bed (thickness 475 µm, amount 49 mg/cm 2 ) Tablets coated by spray-coating, rotary tangential fluid bed (thickness 375 µm, amount 48 mg/cm 2 ) Tablets coated by powder layering, rotary tangential fluid bed (thickness 1020 µm, amount 48 mg/cm 2 ) 60 Lag time (min) <2 hours 13 hours 6 hours 40 20 0 layer thickness ~ 450 µm, ~ 50 mg/cm 2 ) Weight gain (%) 0 10 20 30 40 50 60 progressive decrease in process time
pellets large units design flexibility
Chronotopic System in vivo study on Antipyrine-containing units Model drug: Disintegrating core: Retarding layer: Spraying equipment: Volunteers: Sampling Antipyrine (50 mg) 6 mm, 158 mg Methocel E50 (thickness 325, 575 and 1020 µm) Fluid bed (Uniglatt, Glatt GmbH) 4 healthy male (age 36-45, weight 70-80Kg) Antipyrine was quantified in saliva by HPLC saliva and blood concentrations of Antipyrine are known to be consistent
Adapted from Sangalli M.E. et al., J. Control. Release 73, 103 (2001) HPMC coated units drug released (%) 100 80 60 40 20 0 F F25 F50 F100 time (h) 0 2 4 6 8 10 12 14 In vitro release profiles of antipyrine from uncoated cores (formulation F) and units coated with different amounts of HPMC (formulations F25, F50 and F100, coating thickness 325, 575 and 1020 µm); paddle, SIF, 37 0.5 C, 100 rpm, mean of 6 replicates.
Adapted from Sangalli M.E. et al., J. Control. Release 73, 103 (2001) 1.8 saliva concentration (µg/ml) HPMC coated units 1.5 1.2 0.9 0.6 1.8 1.5 saliva concentration (µg/ml) 0.3 0.0 0 8 16 24 32 40 48 time (h) 1.2 0.9 0.6 F F25 F50 F100 0.3 0.0 0 2 4 6 time (h) Average antipyrine saliva levels after oral administration of uncoated cores (formulation F) and units coated with differing amounts of HPMC (formulations F25, F50 and F100, coating thickness 325, 575 and 1020 µm).
Adapted from Sangalli M.E. et al., J. Control. Release 73, 103 (2001) Relationship between in vivo t 10% (time to 10% C max ) and coating thickness for formulations F25, F50 and F100 [coating thickness 325, 575 and 1020 µm] HPMC coated units 360 300 in vivo lag time T 10% (min) 240 180 120 60 0 y = 0,2812x - 58,195 R 2 = 0,9993 coating thickness (µm) 0 200 400 600 800 1000 1200
Adapted from Sangalli M.E. et al., J. Control. Release 73, 103 (2001) HPMC coated units 4 in vivo lag time T 10% (hours) 2 0 in vitro lag time T 10% (hours) 0 2 4 Relationship between in vivo and in vitro lag time for systems coated with Methocel E50 up to 325, 575 and 1020 µm layer thickness.