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(1) Background: The aim of the work was to investigate the influence of selected physico-chemical factors on the solubility and release rate of CT (cryptotanshinone) in alcohologels. (2) Methods: The alcohologels of methylcellulose (MC), hydroksyethylcellulose (HEC), polyacrylic acid (PA) and polyacrylic acid crosspolymer (PACP) with CT were prepared and/or doped with native potato starch (SN) and modified citrate starches (SM2.5 and SM10). The analytical methods included evaluation of CT release profiles, Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and electrospray ionization mass spectrometry (ESI-MS), and scanning electron microscope (SEM) images were performed. (3) Results: The release and decomposition kinetics of CT in relation to the phosphate buffer solution (PBS) and methanol were observed. The amount of cryptotanshinone (CT) released into PBS was significantly lower (2.5%) compared to its release into methanol, where 22.5% of the CT was released into the model medium. The addition of SM2.5 to the alcohologel significantly increased the CT content to 70% in the alcohologel preparation containing NaOH (40%), and this enhanced stability was maintained for up to two months. The ATR-FTIR exhibited interactions between PA and 2-amino-2-methyl-1,3-propanediol (AMPD) as well as between PA and NaOH in case of the alcohologels. Moreover, it indicated the interaction between CT and NaOH. PXRD diffractograms confirmed the FTIR study. (4) Conclusions: The study observed the influence of a number of factors on the solubility and release rate of CT, as: alkalizers and their concentration, SM2.5 addition. The transition of CT in the presence of NaOH to the tanshinone V sodium (T-V sodium) form was suspected.

Background and purpose: The aim of the work was to compare the interactions of three newly synthesized non-toxic starch derivatives, with varied anionic and non-ionic functional groups with methylene blue (MB) as a model cationic drug, and selection of starch derivative with highest affinity to the MB. Experimental approach: The native potato starch (SN), modified via acetylation (SM1), esterification and crosslinking (SM2) and crosslinking (SM3), was evaluated in MB adsorption studies and assessed by FTIR, PXRD, and DSC. Key results: The adsorption of MB on SM2 and SM3 matched the BET isotherm model, which confirmed physisorption on the low-porous surface. In the case of SM1, adsorption took place via electrostatic attraction between the heterogeneous adsorbent surface and the adsorbate, as demonstrated by the Freundlich plot. The FTIR confirmed vibrations assigned to N=C stretching bonds at 1600 cm-1 in the case of MB adsorbed on the SN and SM2. The most intense PXRD peaks belonged to SN and the least to SM2. In the DSC study, the thermal stability via ΔT was assessed, with SM2 of lowest ΔT value (179.8 °C). Conclusion: SM2 presented the best adsorption capacity, followed by SM3 and the weakest SM1. The interactions were confirmed in the adsorption studies and may reflect applications of the modified starches as drug carriers. In the FTIR study, a probable interaction between the OH- groups of SM2 and N+ of MB was revealed. The most amorphous struc­ture was shown for SM2, which was correlated with the lowest thermal stability provided by the DSC study.

The problem of drug delivery often concentrates on the prolongation of drug activity. Application of natural polymers which are biodegradable and inexpensive is in the interest of many researchers. The aim of this study was the application of newly synthesized starch derivatives as potential functional excipients proposed for hydrophilic gel with lidocaine hydrochloride (LH) to prolong drug release from the hydrogel matrix. In our study, we investigated the effect of starch modified with citric acid on the release kinetics of LH using UV-VIS and Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), as well as viscosity and pH measurements. We demonstrated the effectiveness of citric-acid-modified starch in prolonging the release of LH from methylcellulose gel.

The application of cryptotanshinone (CT), a diterpenoid obtained from the root of Salviae miltiorrhiza, is significantly hindered due to its poor aqueous solubility. The aim of the present research was to develop an optimal solvent for analytical and preparative procedures of prospective dermal hydrogel formulations with CT. The influence of pH, temperature, and cosolvent presence on the solubility of CT was examined. Various components were applied to increase CT solubility, i.e., ethanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-(hydroxymethyl)-1,3-propanediol, 2,2′,2″-nitrilotriethanol, and triisopropanoloamine. The concentration of CT was analyzed by spectral and chromatographic methods, including UV–vis and HPLC methods. The increased solubility of CT was demonstrated in alkaline solvents with ethanol as a cosolvent. CT solutions doped with alcoholamines are more stable compared to CT solutions doped with NaOH.

This study aimed to determine the effect of “annealing” acetylated potato starch with a homogenous granule size and various degrees of substitution on the thermal pasting characteristics (DSC), resistance to amylases, rheology of the prepared pastes, swelling power and dynamics of drug release. A fraction of large granules was separated from native starch with the sedimentation method and acetylated with various doses of acetic anhydride (6.5, 13.0 or 26.0 26 cm3/100 g starch). The starch acetates were then annealed at slightly lower temperatures than their pasting temperatures. The annealing process caused an almost twofold increase in the resistance to amylolysis and a threefold increase in the swelling power of the modified starch preparations. The heat of phase transition decreased almost two times and the range of starch pasting temperatures over two times, but the pasting temperature itself increased by ca. 10 °C. The 40 g/100 g addition of the modified starch preparation decreased the rate of drug release from a hydrogel by ca. one-fourth compared to the control sample.

Naturally sourced products introduced to human nutrition and rediscovered for therapy include polysaccharides from potatoes. The starch may obtain unique properties via acetylation with acetic anhydride at 13 cm3/100 g of starch as the basic dose of reagent used in industrial conditions. The hydrogel formulation was applied as a carrier for escin included in the dry extract of Aesculus hippocastanum. Six hydrogels were evaluated (methylcellulose, polyacrylic acid-Carbopol 980 NF and polyacrylate crosspolymer 11—Aristoflex Velvet) with various concentrations of the modified starch. The kinetic studies of in vitro β-escin release were carried out in purified water at 37 ± 0.5 °C using a paddle apparatus at 50 rpm and a time period of 7 h. The criterion for the most suitable model was based on a high correlation coefficient of evaluated release profiles. The addition of modified annealed acetylated potato starch resulted in prolongation of β-escin release.

Triterpenoid saponins complex of biological origin, escin, exhibits significant clinical activity in chronic venous insufficiency, skin inflammation, epidermal abrasions, allergic dermatitis, and acute impact injuries, especially in topical application. The aim of the study is the comparison of various hydrogel formulations, as carriers for a horse chestnut seed extract (EH). Methylcellulose (MC), two polyacrylic acid derivatives (PA1 and PA2), and polyacrylate crosspolymer 11 (PC-11) were employed. The release rates of EH were examined and a comparison with the Weibull model equation was performed. Application of MC as the carrier in the hydrogel preparation resulted in fast release rate of EH, whereas in the case of the hydrogel composed with PC-11 the release was rather prolonged. Applied Weibull function adhered best to the experimental data. Due to the evaluated shape parameter β, in the Weibull equation, the systems under study released the active compound according to the Fickian diffusion.

Nanospheres and microspheres are known as a multipurpose compounds and are used in various branches of science. Recent controlled delivery systems for drugs are also based on poly-micro and nanospheres. In our study we describe an investigation of the influence of thermosensitive polymer N-isopropylacrylamide (NIPA) on the release of the drug naproxen sodium (NS) with a hydrogel hydroxypropyl methylcellulose (HPMC) base. The hydrodynamic diameter (DH) of the obtained polymer was measured by using dynamic light scattering (DLS) at a wavelength of 678 nm. Hydrogel formulations of NS were prepared in a specific way ex tempore. NS was sprinkled on the surface of a distilled water, then polymer soluted in water was added. Afterward, HPMC was affixed to the solution. Prepared samples were stored at room temperature for 24 h. Release tests showed that modification of thevcross-linker type influenced the properties of synthesized polymeric particles. The NIPA derivatives obtained via surfactant free precipitation polymerization (SFPP) may be formulated as hydrogel preparations using HPMC. The obtained formulations presented varied half-release times, depending on the type of applied NIPA derivatives in hydrogel formulations. At 18 °C, the release rates were lower comparing to the reference HPMC hydrogel, whereas at 42 °C, the release rates were significantly higher. The synthesized thermosensitive polymers enabled temperature-triggered release of NS.