Medicated chewing gums (MCGs) represent a beneficial platform for realizing drugs intended for dental prophylaxis and treatment. The present study aimed to investigate the impact of compression force on the mechanical, textural, release, and chewing perception characteristics of compressible MCGs with the combination of lysozyme hydrochloride (LH) and ascorbic acid (AsA). Four batches of MCGs were obtained on a laboratory single-punch tablet machine applying different forces, i.e., 5, 7, 10, and 15 kN, and evaluated by their geometrical parameters, mechanical resistance, surface and internal structure characteristics, texture profile, release behavior, and perception attributes during mastication. It was found that increasing compression force slightly affected resistance to crushing and friability of MCGs, but resulted in surface smoothing and formation of a thicker layer with highly compacted particle arrangement. According to the texture analysis, increasing compression force led to harder and more adhesive gums, indicating possible difficulties in chewing and, therefore, impairment of their consumer properties. Lower compression forces were also found to be preferable in terms of better drug release from the obtained chewing gums. The volunteers’ assessment showed that an increase of compression force led to significantly raising the initial hardness and crumbliness as well as to decreasing the rate of the integral gum mass formation during mastication, which may negatively affect perceptive sensations when using MCGs. Based on the results obtained, the optimal compressing force was selected to be 7 kN, which allows obtaining MCGs with good organoleptic, mechanical, textural, and release properties.

The study of validation parameters of the quantitative determination method of riboflavin by specific absorbance and their assessment have been conducted in order to standardize procedures for analysis by the specific absorbance and the stage-by-stage control of correctness of the results obtained during the validation experiment. According to the requirements of the State Pharmacopoeia of Ukraine (SPhU) the qualification of the spectrophotometer has been performed. The control of the cells (δ dif ≤ 0.002), absorbance accuracy, absorbance convergence with removing the cells (RSD 0 0.0007% ≤ 0.25%), as well as the study of the limit of stray light (absorbance of the solution at the wavelength of 198 nm is 2.56 ≥ 2.0, which meets the requirements of SphU) have been carried out. Characteristics and acceptance criteria of the assay method for riboflavin such as the nominal concentration of the substance in solution by the method, the nominal absorbance and requirements for its minimum value, the maximum uncertainty of the analysis procedure have been theoretically calculated. The linearity parameter has been studied at 9 points. The linear dependence plot has been constructed in the normalized coordinates. The values of b, s b , a, s a , RSD 0 and r calculated comply with the requirements to parameters of the linear dependence. When studying the parameter of accuracy the systematic error is δ = 0.72%, which meets δ ≤ 1.00%. According to the results of the convergence study the relative confidence interval Δ As = 0.83% does not exceed the critical value for convergence of the results Δ As = 0.96%. The validation parameters of the method meet the requirements of the SPhU and are characterized by qualitative analytical indicators.

Adaptation and validation of the analytical method of photocolorimetric determination of prednisolone using the reaction with phenylhydrazine by the standard method have been carried out in the scien 86 = 4.7, Δas% ≤ 3.20 = 2.86, δ ≤ 1.0240 = 0.92Prednisolone (Prednisolonum) -(11-β)-11,17,21-trihydroxypregna-1,4-diene-3,20-dione -is a dehydrated drug of the group of corticosteroids with an average therapeutic effectiveness that is widely used in medical practice in the form of injections, tablets, ointments, sprays, aerosols, creams, etc. However, injectable dosage forms and ointment are the most common. The latter is used to treat most of skin diseases [5].For the quantitative determination of prednisolone in the substance the SPhU, EPh and a number of other pharmacopoeias recommend spectrophotometry as the variant of the absorbance method with preliminary purity control by HPLC [3,6,7, 10]. In soft dosage forms it is most frequently determined chromatographically (HPLC, TLC, etc.) [8]. The spectrophotometric method is uncommon because of the lower specificity, but it is much cheaper and easier to perform [9].The aim of this research was the study and further adaptation of the method for quantitative determination of prednisolone in the ointment using the photocolorimetric method by the reaction of phenylhydrazine. Materials and MethodsFor our research a pharmacopoeial standard sample of prednisolone PSS SPhU No.11/1-2143 (the shelf-life from 01/13/2014 to 01.2015, the content of prednisolone is 99.8%) and "0.5% Prednisolone" ointment Nizhpharm, RN UA/4949/01/01 batch 80414 were used.In the experiment the following analytical equipment was used: a CPK-2 photocolorimeter, cuvettes with the thickness of 10 mm, an AB 204 S/A METTLER TOLEDO analytical balance, a TS-80 M-2 thermostat, reagents and measuring glassware of class A meeting the requirements of the SPhU.The method of the quantitative spectrophotometric determination of prednisolone in the ointment by the reaction with phenylhydrazine:Test solution: To the accurately weighed quantity of the ointment equivalent to 10.0 mg of prednisolone add 25 ml of 96% alcohol R. Heat on a water heater to dissolution of the base, then cool in ice. Filter the resulting mixture through a paper filter previously soaked in ethanol to a 100.0 ml volumetric flask.Standard solution: Dissolve the accurately weighed quantity of the standard powder in 96% alcohol R preparing the solution with the accurate concentration of prednisolone equivalent to 0.1 mg/ml. Sulfuric acid reagent (SAR):Prepare the solution of concentrated sulfuric acid, 96% alcohol R and purified water in the ratio of 4: 3: 3.Modified phenylhydrazine sulfuric acid reagent (MPSAR): dissolve 65 mg of phenylhydrazine hydrochloride in 100 ml of SAR.Procedure: Pipet 2.0 ml of the Test solution into each of two 50 ml conical flasks (identified as Test solution and Blank Test solution). Add 2.0 ml of the Standard solution into each of two 50 ml conical flasks (identified as Standard solution and Blank Standard solution)...

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