Characterisation of hydroxypropyl methylcellulose-bile salts aggregation and its impact on poorly water-soluble drug solubilisation in the gut.

Transcription

1 Characterisation of hydroxypropyl methylcellulose-bile salts aggregation and its impact on poorly water-soluble drug solubilisation in the gut. Claudia Pigliacelli School of Pharmacy, University of East Anglia UKPharmSci 2012

2 Oral delivery of poorly water soluble drugs Bioavailability of poorly water soluble drugs: Challenge for formulation scientists! Salt formation Soluble pro-drugs Lipid based drug delivery systems Particles size reduction Nanosuspensions Solid dispersions

3 Solid dispersion A dispersion of one or more active ingredients in an inert carrier or matrix at solid state prepared by the melting (fusion), solvent or melting-solvent method (Chiou & Riegelman, 1971) Solid solution Solid dispersion Amorphous solid dispersion

4 Solid dispersions IDEAL CARRIER Amorphous drug Increase drug wettability Drug stability: avoid drug recrystallization Good release profile What happens in the GUT T.Vascocelos, B.Sarmento and P.Costa, Drug Discovery Today, 12, 23/24, 2007.

5 Polymeric carrier-bile salts interaction BILE SALTS Bio-surfactant derived from cholesterol metabolism Primary role in lipid solubilisation in the intestine Different structure from classical surfactant Hydrophilic polymers interact with anionic surfactant forming polymer-surfactant nanocomplexes. Polymer Bile salts complexes can play a role in poorly water soluble drug solubilisation in the GUT Madenci, D. and S. U. Egelhaaf. Current Opinion in Colloid & Interface Science 2010,15(1-2): Hoff, E., B. Nyström, and B. Lindman, Langmuir, (1): p Qi, S., S. Roser, K.J. Edler, C. Pigliacelli, M. Rogerson, F. Van Dycke, S. Stokbroekx, Pharmaceutical Research, submitted.

6 HPMC/Piroxicam solid dispersions 2 drug:polymer ratios 1:2 and 1:4 Microparticles 2-10 µm 10 Intensity (a.u.) Fasted state (FaSSIF) ph Osmolarity NaTC concentration 5 Lecithin concentration mM 0.75mM -10 Fed state mM 3.75mM (FeSSIF) Theta (degrees) Piroxicam Formulation HPMC/Piroxicam 2:1 Formulation HPMC/Piroxicam 4:1 Heat Flow (W/g) 0-5 HPMC/Piroxicam 4:1 DLS Piroxicam NANOSIGHT TEM and CRYO-TEM DISSOLUTION STUDIES HPMC/Piroxicam 2: Exo Up Temperature ( C) Universal V4.5A TA Instruments

7 Self-Assembly of Sodium Taurocholate NANOSIGHT TECHNIQUE Primary micelle FASTED STATE Monomer Secondary Micelle FED STATE Primary micelle

8 HPMC-NaTC Complexation FASTED STATE

9 HPMC-NaTC Complexation FED STATE

10 HPMC-NaTC Complexation MULTI-ANGLE DLS Form1_3 ph6.5 DExp Decay Fast Mode g 1(q,t)*ß Form1_3pH6.5_DExp Decay Θ ' Form 1_3pH6.5_100_sqrt' 'fit_ Form 1_3pH6.5_100_sqrt' ' Form 1_3pH6.5_90_sqrt' 'fit_ Form 1_3pH6.5_90_sqrt' ' Form 1_3pH6.5_70_sqrt' ' Form 1_3pH6.5_50_sqrt' 'fit_ Form 1_3pH6.5_70_sqrt' 'fit_ Form 1_3pH6.5_50_sqrt' ' Form 1_3pH6.5_60_sqrt' 'fit_ Form 1_3pH6.5_60_sqrt' Г 1 [ s-1] E+10 2E+10 3E+10 4E+10 5E+10 6E+10 7E+10 q 2 [cm -2 ] Form1_3pH6.5 DExp Fitting Slow Mode Г 1(s -1 ) t[µs] 0 0 1E+10 2E+10 3E+10 4E+10 5E+10 6E+10 7E+10 q 2 (cm -2 )

11 HPMC/NaTC Complexes particle-sizing Simulating Fluid HPMC Formulation 2:1 Formulation 4:1 Population 1 Population 2 Population 1 Population 2 Population 1 Population 2 FaSSIF 52±14 435±19 85±8 412±15 46±9 313±10 FaSSIF + lecithin 257±16 27±3 256±9 259±6 FeSSIF 52±11 230±15 42±9 280±12 90±12 377±18 FeSSIF + lecithin 300±20 48±7 340±6 240±11

12 Cryo-TEM

13 Dissolution studies Buffer ph 6.5 and FaSSIF Buffer ph 5 and FeSSIF

14 What happens in the GUT? FASTED STATE HIGHER HPMC CONCENTRATION FED STATE HIGHER HPMC CONCENTRATION

15 Conclusions The interaction between HPMC and sodium taurocholate resulted in the formation of polymer-natc nanocomplexes. In both fed and fasted states simulating intestinal fluids the presence of HPMC-NaTC nanocomplexes increased the dissolution rate and the drug release from the solid formulation. The interactions between polymeric carriers and bile salts in the intestinal tract may have an important effect on absorption of orally administered poorly water soluble drugs and play an important role in formulations design clinical outcomes.

16 Future Work AGGREGATES CHARACTERISATION: SELF DIFFUSION NMR:HPMC-NaTC aggregation SANS:Aggregates local structure HYDROPHOBIC MODIFICATION IMPACT ON INTERACTION: HPMC-AS BIOLOGICAL STUDIES: MUCIN UPTAKE STUDIES

17 Aknowledgements Dr. Sheng Qi Prof. Duncan Craig Dr. Francesca Baldelli Bombelli Dr. Patrick Gunning, Andrew Kirby (IFR) Dr.Debora Berti and Prof.Piero Baglioni(University of Florence) Dr. Jonny Eriksson(University of Uppsala) THANK YOU