Influence of selected tensides on the hydrocortisone concentration equilibrium balance in micelles and the dispersing center.

The degree of hydrocortisone binding, was investigated by means of equilibrium dialysis in the presence of 1% or 3% micellar solutions of polysorbate 20 and 80. Stabilization of the concentration equilibrium was found in all the cases investigated. The degree of hydrocortisone binding in micelles depends on the concentration and type of tenside used.

Influence of tensides on the release of medical agents from hydrophilic gels, part 2: The influence of selected tensides on hydrocortisone release from xerogels.

With the increase of polysorbates 20 and 21 concentration in xerogels, in the presence of 1,2-propylene glycol and PEG 200, hydrocortisone half-release periods from these preparations become longer while the half-release periods for polysorbate 80 and propylene glycol, and polysorbate 21 and PEG 200 are proportionally shortened. The concentration of tensides has no significant impact on the half-release periods of hydrocortisone with polysorbate 81 added to xerogels in the presence of propylene glycol and polysorbate 20 and 80 with PEG 200.

Studies on gynaecological hydrophilic lactic acid preparations, part 6: use of Eudragit E-100 as lactic acid carrier in intravaginal tablets.

Hydrophilic intravaginal tablets based on methylcellulose and containing lactic acid component with Eudragit E-100 undergo swelling in standard conditions. A high flow-limit of the gel that originates from the tablets as well as its dynamic viscosity should allow for the durable dosage form in the vagina. By choosing a 1:1 ratio of lactic acid to Eudragit E-100, it is possible to obtain tablets disintegrating into a gelform at physiological range of 3.8-4.4. An increase in the amount of lactic acid in the complex in relation to the polymer up to 2:1 and 3:1 ratios results in gels with a lower pH. These gels possess an acid reserve that might be ableto neutralise the excess of alkali present in severe vaginal infections.

Studies on gynaecological hydrophilic lactic acid preparations. Part 5: The use of Eudragit E-100 as lactic acid carrier in intravaginal tablets.

Intravaginal tablets based on hydrophilic methylcellulose and containing lactic acid complexed with Eudragit E-100 undergo deformation under standard conditions. The high flow--limit of gel originating from the tablets as well as its dynamic viscosity should enable durability of this dosage form on the vaginal mucosa. By selecting either 1 : 1 or 2 : 1 ratios of lactic acid to Eudragit E-100 it is possible to obtain tablets that disintegrate into a gelform at pH 3.8-4.4, i.e. the pH remains within the physiological range. Increasing the amount of lactic acid in the complex in relation to the polymer to a 4:1 ratio results in gels with a lower pH while possessing an acid reserve that can neutralize the excess of alkali present in severe vaginal infections.

Influence of some polysorbates on hydrocortisone release from hydrophilic gels considered as two-compartment models.

Hydrocortisone release from hydrogels containing of 1% and 3% polysorbate 20 or polysorbate 80, in the presence of 1,2-propylene glycol or PEG 200 has two stages. In the first one the release rates are higher than those of the second stage. Half-release times in the first stage are in the range 0.31 h to 0.48 h and in the second stage 16.65 h to 23.22 h. Hydrocortisone release from the gels containing of 1% to 3% of polysorbate 21 or 81, in the presence of 1,2-propylene glycol or PEG 200 conform to second order kinetics. Release rates in this stage are in the range from 3.80 x 10(-4)%.h-1 to 5.97 x 10(-4)%.h-1.

Studies on gynaecological hydrophilic lactic acid preparations. Part 4: Effects of polyvinyl pyrrolidone K-90 on properties of methylcellulose gels.

In continuing the investigation of the binding of lactic acid with basic polymers polyvinyl pyrrolidone K-90 (PVP) was used. Use of PVP in mixtures with lactic acid in experimentally determined and calculated proportions allowed the preparation of gels with pH 3.8-4.4, i.e. maintaining the physiological conditions in the vagina. The viscosity of the methylcellulose gels increases proportionally to the amount of the PVP--lactic acid complex added. Examination of the gels in the biopharmaceutical model, which simulated the physiological conditions of the vagina, allowed determination of the mobility of the preparations in patients.

Studies on dressings for oral cavity mucosa. Part 5: Properties of xerogel stomatological dressings with one-side antiadhesive coating.

The adhesion of xerogel dressings based on Eudragit (E), and methylcellulose (Mc) is in within the range of 143-270 g, and dissolution time of xerogel dressings in water is 3.4 h, and in artifical gastric juice 2.8 h. The 50% release time for Kunitz protease inhibitor ranges from 3.2-11.5 h.

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.

Studies on dressings for mucosa of the oral cavity. Part 4: Influence of technology used in the preparation of dental xerogel dressings in the presence of acetone on their properties.

Adhesion of xerogel dressings prepared on Eudragit-E 100, methylcellulose and glycerol compositions in acetone/water mixtures, remains within the range of 317-967 g, after addition of polyvinylpyrrolidone (PVP), it increases to 633-1200 g. Dissolution time of dressings in water amounts to 6 h, in artificial gastric juice to 3 h. Addition of PVP results in decrease of the elution rate, dissolution time amounts to 2.5 h. The Kunitz protease inhibitor semi-liberation times amount to 3.3-7.6 h.