Properties of a new acid-buffering bioadhesive vaginal formulation (ACIDFORM).
Vaginal prophylactic methodology may prevent heterosexual transmission of the HIV and other sexually transmitted disease-causing organisms as well as unplanned pregnancies. A new delivery system (ACIDFORM) was designed with acid-buffering, bioadhesive, and viscosity-retaining properties to (1) maintain the acidic vaginal milieu (the low pH inactivates many pathogens and spermatozoa), (2) form a protective layer over the vaginal/cervical epithelium (minimizing contact with pathogenic organisms), and (3) provide long-term vaginal retention. A Phase I clinical study with ACIDFORM provided initial information about its safety and showed the formation of a layer over the vaginal/cervical epithelium [1; Amaral et al., Contraception 1999;60:361-6]. To study the properties of the gel (without active ingredient) in more detail, ACIDFORM's acid-buffering, bioadhesive, viscosity-retaining, and spermicidal properties were compared in vitro to marketed formulations, and its long-term stability was assessed. ACIDFORM, either when titrated with NaOH or when mixed directly with semen, is highly acid buffering and much more effective than Aci-Jel, a commercial acid-buffering vaginal product. ACIDFORM adheres well to two model membranes (excised sheep vagina and cellophane) and is more bioadhesive than Conceptrol, Advantage S, Replens, Aci-Jel, and K-Y jelly. On dilution, ACIDFORM also retains its viscosity better than these marketed products. ACIDFORM is spermicidal and is stable for at least 2 years. These results suggest that ACIDFORM has advantages over presently marketed vaginal delivery systems. The gel may either be useful by itself as an antimicrobial contraceptive product or as a formulation vehicle for an active ingredient with antimicrobial and/or contraceptive properties.
Garg
S
S
Section of Ob/Gyn Research, Rush University, Rush Presbyterian St. Luke's Medical Center, Chicago, IL, USA.
Anderson
R A
RA
Chany
C J
CJ
Waller
D P
DP
Diao
X H
XH
Vermani
K
K
Zaneveld
L J
LJ
D000180:Acrylic Resins; D002626:Chemistry, Pharmaceutical; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects*; D008297:Male; D012749:Sexually Transmitted Diseases / Q000517:prevention & control; D013089:Spermatocidal Agents / Q000627:therapeutic use*
D000180:Acrylic Resins; C420918:BufferGel; D013089:Spermatocidal Agents