Vaginal and reproductive system treatments using a bioadhesive polymer

• Published in: Journal of controlled release Vol. 28; no. 1; pp. 87 - 94
• Main Authors: Robinson, Joseph R., Bologna, William J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 1994; Elsevier
• Subjects: Biological and medical sciences; General pharmacology; Medical sciences; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Colloidal gel; Dosage form; Vagina; Polymer; Pharmaceutical technology; Formulation
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/0168-3659(94)90156-2

Polycarbophil, a lightly cross-linked polyacrylic acid, can remain on vaginal tissue for 3–4 days and hence serve as a platform for drug delivery. Intrinsic properties of the polymer such as acidic pKa and polyelectrolyte nature of the ionized form of the polymer can alter the local pH and hydration level of the tissue to effectively treat local pathologies. Clinical assessment of local tissue pH, in postmenopausal women, shows a reduction in pH from about 6 to 4 and maintenance of this acidic pH for about 3–4 days after the last dose. This acidic pH is an unfavorable environment for pathogens. In addition a low viscosity gel of the polymer is an effective treating agent for dry vagina, a common condition of postmenopausal females and those female cancer patients on estrogen blockers. Hydration of the vaginal tissue occurs through an increase in vaginal blood flow as determined by a laser Doppler study. In addition, the polymer appears to be an effective delivery system for the spermicidal/antiviral agent nonoxynol-9. By virtue of its ability to adhere to vaginal tissue while retaining nonoxynol-9 in its gel structure, it is an excellent extended effect spermicide. Moreover, the ability of the polymer to attach to lymphocytes, while carrying nonoxynol-9, makes it a targeted drug delivery system and useful as an AIDS prophylaxis, as well as a treating agent for other sexually transmitted diseases. Finally, employing the polymer gel with natural progesterone allows extended vaginal delivery ot the drug to achieve the clinical endpoint of a fully secretory endometrium with low serum levels of the drug. The lower serum drug levels translate into reduced side effects.