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Garg, Sanjay*
Kandarapu, R.#, Vermani, K.#, Tambwekar, K#, Garg, A.*, Anderson, R.A.$., Waller, D.P@., Zaneveld, L.J.D.$
*School of Pharmacy, University of Auckland, Auckland, New Zealand.; #Niper, Punjab, India; $Topcad, Rush Medical Center, Chicago, Il, USA; @School of Pharmacy, University of Illinois, Chicago, Il, USA.
Maintenance of acidic environment in presence of infections and after intercourse may be an effective mechanism for microbicides. ACIDFORM and BufferGel act by this mechanism and are in advanced stages of clinical development. Solid unit dose formulations such as tablets and films are more preferred due to user convenience and higher stability as compared to gels. The present paper reports acid-buffering vaginal films as novel microbicide with performance characteristics similar to ACIDFORM gel. All ingredients used are either GRAS-listed or reported for vaginal use. Films of 2.5¥2.5 inch2 were prepared using glass casting technique. Dissolution time, pH, osmolality of film were evaluated in normal saline (10 ml) at 37oC. Buffering capacity of film was determined by titrating with standard alkali (1N NaOH) and human semen samples. Bioadhesive properties and tensile strength of film were evaluated using a texture analyzer. Films dissolved in 3 minutes, yielding a smooth dispersion with osmotic pressure of 540 mosmol/kg (for 5% w/w gel, 390 mosmol/kg). 1.23 meq of NaOH and 6 ml of semen was required to raise the pH of film from 3.52-4.98 as compared to 1.32 and 7 ml for 4 g of gel. Bioadhesive strength of film (sheep vagina model) was higher (21.3 g) as compared to gel (16.1 g). Tensile strength of film (22 g) was similar to vaginal film, VCF (25 g). In conclusion, acid-buffering films were found to possess similar performance characteristics as that of ACIDFORM gel.
Dr. Sanjay Garg
School of Pharmacy, FMHS, University of Auckland, Building 504, LGF, 85 Park Road, Grafton, Auckland, New Zealand
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