Studies on gynaecological hydrophilic lactic acid preparations. Part 3: Effects of chitosan on the properties of methylcellulose gels.

Methylcellulose gels comprising lactic acid, similarly to its water solutions, have pH values between 2.0 and 2.6, i.e. out of the physiological range. Addition of Chitosan enables preparation of gels with pH values from 2.2 to 4.9 similar to the natural vagina pH range, 3.8-4.4. The absolute viscosity of the gels, ranging from 27 up to 700 mPa.s, depends on chemical composition and on excess of lactic acid used. Measurement of adhesion enabled the selection of gels which remain located at the point of application under simulated biopharmaceutical conditions. The behavior of those preparations in the true environment of the vagina needs to be verified in vivo.