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A simple, rapid, and precise RP-HPTLC method for analysis of Prednisolone acetate and Moxifloxacin hydrochloride in their eye drop dosage forms has been developed and validated. Chromatography was performed on silica gel 60 RP-18F254S plates with Methanol:Water:Triethylamine 7:3:0.3 (v/v) as mobile phase. Detection was performed at 274 nm. The Rfvalues for Prednisolone acetate and Moxifloxacin hydrochloride were found to be 0.50 ± 0.02 and 0.72 ± 0.02, respectively. Regression plots revealed good linear relationships in the concentration ranges 600–3600 ng/band for Prednisolone acetate and 300–1800 ng/band for Moxifloxacin hydrochloride. When accuracy was checked by conducting recovery studies the % recoveries were ranging from 100.97% to 102.03% (Prednisolone acetate) and 100.49% to 101.25% (Moxifloxacin hydrochloride), respectively. The amount of Prednisolone acetate and Moxifloxacin hydrochloride estimated in marketed formulation were 99.22% and 101.07%, respectively. [ABSTRACT FROM AUTHOR]

The selected steroid compounds (androsterone, epi-androsterone, dehydroepi-androsterone, testosterone, stigmasterol, β-sitosterol, estradiol, hydrocortisone, and cholesterol) were investigated with the use reversed phase high performance thin layer chromatography on RP18W plates (#1.14296, E. Merck), using methanol-water, acetonitrile-water in different volume compositions as a mobile phases. The chromatographic parameters of lipophilicity (RMW) of the studied steroids were determined. Topological indexes based on the adjacency matrix: Gutman (M, Mν), Randic (oχν, 1χν, oχν, and 1χν), based on distance matrix: Rouvray (R), Wiener (W), and Pyka (A, oB, and 1B), and also based on information theory (ISA and ISA) and theoretical partition coefficients (Alog Ps, IAlog P, Clog P, log PKowwin, xlog P, and miLog P) for investigated steroids were calculated. It was found that lipophilicity determined chromatographically (RMW) correlated best with topological indices oχν, 1χν, R, W, A, and 1B. However, theoretical partition coefficient values (Alog Ps, IAlog P, Clog P, log PKowwin, xlog P, and miLog P) correlated best with topological index ISA. [ABSTRACT FROM AUTHOR]

Acids from pentanoic to tricosanoic have been separated using RP-HPTLC, on RP-18 plates with and without a concentrating zone, using methanol-water, ethanol-water and n-propanol-water (90:10, 95:5, and 100:0, v/v) as mobile phases. RF values obtained have been converted into RM values. RM values have been used to calculate and predict the neutralization value, boiling point, melting point, and heat of crystallization of fatty acids investigated. Relationships between selected physiochemical properties of fatty acids and RM values obtained using RP-HPTLC have been described by polynomials of the second degree or linear functions. All described relationships have been characterized by high values of determination coefficients, which were in the range of 93.32÷99.94%. It suggests the possibility of using them to calculate and predict the values of neutralization value, boiling point, melting point, and heat of crystallization of acids investigated. [ABSTRACT FROM AUTHOR]

Nicotinic acid (1) and its derivatives, namely nicotinamide (8), 3-pyridinecarbaldehyde (11), 3-pyridinecarbonitrile (12), 3-pyridylmethanol (13), and methyl 3-pirydyl ketone (14) were investigated by NP-TLC, and RP-HPTLC. The RF values were obtained from the densitometric analysis. The separation factors ΔRF, RFα, and selectivity α were calculated from the RF values. The comparison and characteristic of chromatographic bands of the examined compounds were presented on the basis of calculated resolutions: RS(c), RS(b), RS(h), and RS(a). The resolutions of substances were determined by visual method (RS(c)) and densitometric method (RS(b), RS(h), and RS(a)). It was affirmed that the densitometric method is correct and the standard method to determine the above mentioned parameters. Furthermore, the RS parameter determined by the visual method for two adjacent substances is always larger than determined by the densitometric method. It was affirmed, that the best separation of the studied compounds was obtained by the RP-HPTLC technique on RP18WF254 plates, and by use of dioxane-water in a volume composition of 20:80. However, 3-pyridinecarbaldehyde (11) from 3-pryridinecarbonitrile (12) cannot be separated by the RP-HPTLC technique. It was also affirmed, that adsorption thin-layer chromatography (NP-TLC) in the system of a silica gel 60F254 and the acetone-n-hexane mobile phase in a volume composition of 80:20 provided the optimum conditions for the complete separation of 3-pyridinecarbaldehyde (11) from 3-pryridinecarbonitrile (12). [ABSTRACT FROM AUTHOR]

Acids, from octanoic to octadecanoic, have been separated using RP‐HPTLC, on RP‐18 plates without and with a concentrating zone, using methanol‐water and ethanol‐water (90∶10 and 95∶5, v/v) as mobile phases. RF values obtained have been converted to RM values. RM values have been used to calculate the solubilities in water of fatty acids investigated at different temperatures. Relationships between solubility in water of fatty acids at different temperatures and RM values obtained using RP‐HPTLC have been described by polynomials of third degree or expotential functions. All described relationships have been characterized by high values of determination coefficients, which were in the range of 96.65÷99.97%. This suggests the possibility of using them to calculate and predict the values of solubilities in water of acids investigated. [ABSTRACT FROM AUTHOR]

The selected steroid compounds (androsterone, epi‐androsterone, dehydro‐epi‐androsterone, testosterone, stigmasterol, β‐sitosterol, estradiol, hydrocortisone, and cholesterol) were investigated with the use reversed‐phase high performance thin layer chromatography on RP18W plates (#1.14296, E. Merck), using methanol‐water, acetonitrile‐water in different volume compositions as a mobile phase. The chromatographic parameters of lipophilicity (RMW and ϕ0) of the studied steroids were determined. Lipophilic parameters (RMW and ϕ0) were compared both, with measured (logPexp), and calculated partition coefficients (AlogPS, IAlogP, logPKOWIN, xlogP, ClogP, miLogP). Comparing all calculation procedures, generally ClogP and IAlogP are more appropriate for chromatographic parameters of lipophilicity and experimental n‐octanol‐water partition coefficients of studied steroid compounds. The results indicate that chromatographic parameters of lipophilicity may be used as a measure of lipophilicity of the investigated steroid compounds. [ABSTRACT FROM AUTHOR]

The following bile acids: cholic acid (C), glycocholic acid (GC), glycodeoxycholic acid (GDC), chenodeoxycholic (CDC), deoxycholic acid (DC), lithocholic acid (LC), and glycolithocholic acid (GLC) were investigated with the use of reversed phase thin-layer chromatography on RP2 plates (E. Merck, # 1.13726) using methanol-water, organic mixture (acetonitrile-methanol 50:50, v/v)-water, acetone-water, dioxane-water in different volume compositions as mobile phases. The chromatographic parameters of lipophilicity (R MW and f 0 ) of studied bile acids were determined. Lipophilic parameters (R MW and f 0 ) were compared, both with measured partition coefficients (logP exp ) and calculated ones (AlogP S , IAlogP, logP KOWIN , xlogP, clogP, logP Rekker ). The most significant correlation was found between R MW and f 0 lipophilic parameters and logP KOWIN values. IAlogP correlates with the a/m lipophilic parameters slightly more poorly than logP KOWIN does. The values of R MW and f 0 lipophilic parameters obtained on both, RP2 and RP18W plates with the use of the a/m mobile phases, indicate that the investigated bile acids may be listed in order of decreasing lipophilicity as follows: LC>DC˜CDC˜GLC>C˜GDC>GC. [ABSTRACT FROM AUTHOR]

Selected bile acids: cholic acid (C), glycocholic acid (GC), glycodeoxycholic acid (GDC), chenodeoxycholic acid (CDC), deoxycholic acid (DC), lithocholic acid (LC), and glycolithocholic acid (GLC) were investigated with the use of reversed phase high performance thin-layer chromatography on RP18W (E. Merck, #1.14296), RP18 (E. Merck, #1.05914), RP2 (E. Merck, #1.13726), and CNF 254 (E. Merck, #1.12571) plates using methanol–water, organic mixture (acetonitrile–methanol 50:50, v/v)–water, acetone–water, dioxane–water, and acetonitrile–phosphate buffer (pH 4.60) as mobile phases, in different volume compositions. The obtained separations were carried out on the basis of separation factors values ?R F and R S . None of the applied chromatographic conditions enabled completion of the separation of all examined bile acids. Five neighboring bile acids, i.e., LC/DC, CDC/GLC, GLC/C, C/GDC, GDC/GC, were separated only when CNF 254 plates and the mobile phase acetone–water, 50:50; v/v were used. The biggest problem was to separate DC from CDC. These bile acids were separated only on RP2 plates by using methanol–water, 65:35, v/v as a mobile phase. [ABSTRACT FROM AUTHOR]

Fatty acids from octanoic acid to octadecanoic acid have been separated on RP-18 plates with and without a concentrating zone using methanol–water, ethanol–water, and n-propanol–water as mobile phases. The cluster analysis for comparison of RM parameters of investigated acids for chromatographic conditions used was proposed. Comparison of differences between RF values showed that acids from nonanoic to octadecanoic are separated on the longest distance, using as mobile phase methanol–water in a volume ratio of 95 + 5 and on RP-18 plates with and without concentrating zone. Moreover, resolution factor values (RS) calculated suggest that better separations of acids from octanoic to octadecanoic were obtained on RP-18 plates with a concentrating zone and methanol–water (95 + 5, v/v) as mobile phase. [ABSTRACT FROM AUTHOR]