                  8 - 1 , Page 1 . Pharmaceutical Sciences, 2012, Vol. 18, No Study of anti-microbial effects of Clarithromycin nanosuspensions against Staphylococcus aureus and Salmonella typhi Lotfipour F. 1,2* , Valizadeh H. 1 , Azhdarzadeh M. 1 , Zakeri-Milani P. 1 1 Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran. 2 Gastrointestinal and Liver Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Received: 26 Nov. 2011, Accepted: 19 Jan. 2012 Objectives: Clarithromycin is a semi synthetic antibiotic from macrolid group that bind to 50 S ribosomal subunit of susceptible bacteria and inhibit essential bacterial protein synthesis. The purpose of this study is to prepare Clarithromycin-PLGA nanoparticles and to evaluate their antibacterial properties. Methods: Modified Quasi Emulsion Solvent Diffusion (MQESD) method was applied to prepare the Clarithromycin nanoparticles. Clarithromycin and PLGA were dissolved in acetone as a water miscible solvent and added to aqueous phase containing PVA2% as emulsifier and stabilizer agent, under homogenization. This led to formation of a quasi emulsion that contains Clarithromycin and PLGA and acetone in the inner phase. The microbial culture method was used to compare the effectiveness of nanosuspensions with untreated drug. Staphylococcus aureus PTCC 1112 and Salmonella typhi PTCC 1609 were used in this method. Minimum inhibitory concentration of clarithromycin nanosuspension was compared to those of clarithromycin solution. Results: Minimum inhibitory concentration of nanosuspensions in comparison with those of drug solution was significantly higher. This increased potency of formulated nanosuspensions is perhaps related to increased drug adsorption as well as lower drug degradation and modified surface characteristics. Conclusion: Our results indicate that clarithromycin in the form of nanosuspension has better antibacterial effect in comparison with untreated drug in the same drug concentration. Keywords: Clarithromycin, Poly (lactic-co-glycolic acid), Modified Quasi Emulsion Solvent Diffusion, nanosuspensions, Minimum inhibitory concentration            !" #$      !" #$    % &’(   )"( #*+ ,   - !.’ !.’ /!  01 #2 3/1 4  - !.’ !.’ /!  01 3.*  56 78"89’ !*( 4 : ;’ < = >  > ? 5@ ;’  <  > ? > ? %  &’ ( A"’"B CD A ,"E(C)* F!G B HI’ JK   B $ 3"*( C2  A"CCL2 " S =? M.2 #C*B . #C*B #N #$ ,"O’ !CL2 P( ( 6  4 ,  Q3$ R(  C2 B ,"E(C)* -"ES22 TK  " 3"2 A"/"6* A"C*U V PLGA W  2B X YT #$ -"ES22 B/"(3N #$ 2 " Z[ Z**"C2  "’ )2 3B ( 4  ) ( 5 Modified Quasi Emulsion Solvent Diffusion (MQESD) "P’ #B #$ -"ES22 ,"E(C)* 36 C2 4 -C2  "   V @ \)C] H)T ^D B W 3LL* -"E( #T BD  B  36 _T V PVA 95000 W H)T  " ,"E(C)* ]  B -"E( . A * 36 N 3 (  ‘$ B !%$ a2’ * T  6 ( _"/1’ 4 -"ES22 1bBX 2B cL( B Z[ Z**"C2 #$ #C*B  PTCC 1112 "’ )2  PTCC 1609 B/"( :1* 5 C2 * 36  3 #P( :cd _e3T #B 3(D :23B -"ES22 #$ -"2U( 36 E8( -D H9( B ,"E(C)* 4   ( 3 #P( :cd _e3T C* S22  H9( B E8(  -"E LR( B  f! * 3B ( 7+ 1bBX  Mb’ f$*  C1"B :cd [""/!" 7"YI] -3 L"PB  H2 g2  7+ 7+ 3B ( , _U  3’ ( 4 * + ( (C)* -* ( * :2 , 0"B hC -"ES22 7Y B ,"E 3$ ( f!   , 1bBX 4  ,-  < -"ES22 ,"E(C)* 3"2 A"/"6 * A"C*U  Modified Quasi Emulsion Solvent Diffusion  3 #P( :cd _e3T  HOE( 3LE <  01 #2 3/1 C2    !.’ /! - !.’  4 ,’ < =?  ?i B  < iij  ?i Email: lotfipoor@tbzmed.ac.ir * Corresponding Author: Farzaneh Lotfipour, Assistant Professor, Faculty of Pharmacy, Tabriz University of medical sciences, Tabriz, Iran.Email: lotfipoor@tbzmed.ac.ir Tel: +98-411-3392580 Fax: +98-411-3344798