The Advanced Sol-Gel Silica Matrix for Drugs SNU MSE 2004-12200 Yeon, Jung In

Contents Introducing The Relation Drugs and Sol-Gel matrixes 1 Introducing The Relation Drugs and Sol-Gel matrixes 2 Summing up The Article New Sol-Gel Silica Matrix by HPGG 3 Further Reading and Questioning How to make this study more reliable Jung IN

Introducing(1) Jung IN

Introducing(1) As an entrapped strawberry… Sol-gel matrix Therapeutic window Sol-gel matrix [D] Time Tc Time interval between taking drugs Jung IN

Introducing(2) Drug delivery system ! Sustained-Release As a gelatin part… Containing a large number of small aqueous pools Holding tightly these aqueous phases in a gelatin The sol-gel skeleton does not only have to be Silica!! Sustained-Release Drug delivery system ! Jung IN

Summing up(1) A rough explanation of the basic idea 1 H-bonding Condensation Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10668 Jung IN

Summing up(2) Preparation of the experiment The entrapped Drug In the sol-gel Silica matrix Produced with HPGG Vitamin B12 : The water-soluble model drug THEOS : The water-soluble Silica precursor HPGG : Hydroxypropyl Guar Gum Jung IN

Summing up(3) THEOS : Tetrakis(2-hydroxyethyl)orthosileates EtO OEt HO + Si OH EtO OEt 4 Glycols TEOS EtO OEt HO OH Si HO OH EtO OEt THEOS Jung IN

Summing up(4) HPGG : Hydroxypropyl Guar Gum Jung IN Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10666 Jung IN

Summing up(5) Aqueous HPGG! Well-matched ionic conc. with human bodies The model drug and the buffer solution First mixed with Aqueous HPGG! Well-matched ionic conc. with human bodies Vitamin B12 PBS (Phosphate-buffered saline) Drug Entrapment And release Jung IN

Summing up(6) 1 2 3 4 Dynamic moduli Gelation Time The Critical Strain Data and result 10 wt% THEOS + 0.2 / 0.5 / 1.0 / 1.5 wt% HPGG Dynamic moduli ( G’ and G’’ ) 1 Gelation Time (From The 1st result) The Critical Strain ( In Linear Viscoelastic) Drug release behavior ( Into the PBS ) 2 3 4 Jung IN

Summing up(7) Dynamic moduli Gelation time (Tgel ) Fig.2 The storage modulus(G’) and loss modulus(G’’) as a Function of time for pure THEOS system and THEOS/HPGG hybrid system Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10666 Jung IN

Summing up(8) ☞ Hydrogen bonds with (Si-OH) Gelation time /Effect of HPGG amount “ HPGG ” - nonionic polyhydroxy compound ☞ Hydrogen bonds with (Si-OH) (HOㅡ)nSi(ㅡOR)4-n + HO-HPGG → (HO)n-1(ROㅡ)4-nSiㅡOㅡHPGG + H2O Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10667 Jung IN

☞ The more HPGG, The faster process!! Summing up(9) Rate-determinant stage : Condensation H-bonding Condensation ☞ The more HPGG, The faster process!! Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10668 Jung IN

Summing up(10) Critical strain / Microstructure of silica gel matrix Critical strain - separating the linear and nonlinear viscoelastic responses. Q. Changed factors? Ans. Interactions b/w particles , delicate microstructures Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10667 Jung IN

Summing up(11) Microstructure of THEOS/HPGG hybrid and pure THEOS system Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10668 Jung IN

Summing up(12) The denser network structure The slower (by increasing wt% HPGG) Drug release behavior The slower drug-releasing behavior as increasing wt%HPGG Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10669 Jung IN

Further R &Q(1) Sol-Gel Matrix Gel Matrix In situ formation of Gel matrix vs. Sol-gel matrix Sol-Gel Matrix Gel Matrix Producing first a drug loaded gel matrix → PBS test Q. Nothing to do with sol??? In situ formation of Silica gel matrix and Short gelation time Ans. Subcutaneous injection as a sol type!! Jung IN

? Further R &Q(2) Randomly Biodegradable Assurance positioned How dense is the gel matrix? And, is the gel matrix biodegradable? Biodegradable two starting materials Assurance of bio- degradability Randomly positioned and densely condensed ? Jung IN

Further R &Q(3) Q. Continuously decreasing slopes? Ans. Not sure! 2 Slopes of the G’ and G’’ curves in Region lll Q. Continuously decreasing slopes? Ans. Not sure! 1st) not enough time interval 2nd) one more region for steady state Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10666 Jung IN

Further R &Q(4) Suggestion Add one experimental step more for this Comparing all Also, compare this result with the G’ &G’’ curves After 450 min Taking SEM pictures of silica gel After 200 min Taking SEM pictures of silica gel Jung IN

Summary Introducing The Relation Drugs and Sol-Gel matrixes 1 Introducing The Relation Drugs and Sol-Gel matrixes 2 Summing Up The Article New Sol-Gel Silica Matrix by HPGG 3 Further Reading and Questioning How to make this study more reliable Jung IN

Reference “ Manipulating Formation and Drug-release Behavior of New Sol-Gel Silica Matrix by Hydroxypropyl Guar Gum” Title Guan-Hai Wang, Li-Ming Zhang, J. Phys. Chem. B. 111 (2007), 10665-10670 Jung IN

Questions? SNU MSE YEON JUNG IN