Implants are readily applied as a convenient method of therapy. There is great interest in the prolonged release of active substances from implants. The objective of this work was to evaluate the dissolution kinetics of steroidal anti-inflammatory preparation (SAP) released from novel implants, and to test the influence of the technology on SAP release kinetics. The proposed long-acting preparations may overcome difficulties resulting from repeated injections and often visits to ambulatory clinic, as the stabilizing function of the artificial ligament would be enriched with pharmacological activity. The potential advantages provided by the new coatings of knee implants include the continuous, sustained, and prolonged release of an active substance. The study was carried out using a modified United States Pharmacopoeia (USP) apparatus 4. The amount of SAP was measured spectroscopically. It was revealed that the transport of the drug was mainly a diffusion process. The drug release kinetics was analyzed using zero-, first-, and second-order kinetics as well as Korsmeyer-Peppas, Higuchi, and Hixon-Crowell models. The highest values of the release rate constants were k₀ = (7.49 ± 0.05) × 10⁻⁵ mg × min⁻¹, k₁ = (6.93 ± 0.05) × 10⁻⁶ min⁻¹, and k₂ = (7.70 ± 0.05) × 10⁻⁷ mg⁻¹ × min⁻¹ as calculated according to zero-, first-, and second-order kinetics equations, respectively. The values of the rate constants obtained for the slowest process were k₀ = (3.63 ± 0.06) × 10⁻⁵ mg × min⁻¹, k₁ = (2.50 ± 0.03) × 10⁻⁶ min⁻¹, and k₂ = (2.80 ± 0.03) × 10⁻⁷ mg⁻¹ × min⁻¹. They may suggest the possibility of sustained release of betamethasone from the system. Due to the statistical analysis, differences were observed between most of the studied implants. Incubation, temperature, time of stabilization of layers, and the method of SAP deposition on the matrix affected the drug release.

The aim of this study was to verify the effect of the formulation on the release kinetics of active substances from preparations containing iron ions using in-line conductivity measurements. A simple, fast method was developed and may be applied for detailed evaluation of some kinetics factors obtained from the release data. Four different equations were used: zero-order equation, first-order equation, models: Korsmeyer–Peppas and Hixson–Crowell. Values of the determined half-time release for zero and first-order kinetic models ranged from 11.56 to 89.97 min. In the case of analysis according to these typical models, the values of the square root of the correlation coefficients were included between 0.9916 and 0.9995. The results transformed for the Hixson–Crowell model as constant release Ks, ranged between 0.0160 and 0.0437. The values of the respective calculated squares of the correlation coefficient ranged from 0.9933 to 0.9959. The determined release rate constants according to the Korsmeyer–Peppas model were between 0.0023 and 0.1630. The coefficients ‘n’ of the Korsmeyer–Peppas equation did not exceed 1.2 with the corresponding r² values 0.9408–0.9960. Obtained results confirmed that the method is applicable for evaluation of selected drug compositions containing iron ions.

Liposomes containing a certain amount of ethanol are often referred to in the literature as ethosomes. Liposomes vary in size from 25 nm to 25,000 nm. Ethosomes are defined as lipids composed of phospholipids, ethanol, or isopropyl alcohol in quite high concentrations, and water. They enable active substances to reach the deep skin layers or even the general circulation. The structure of ethosomes allows for an increased penetration of the drug through two effects: the ethanolic effect and the ethosomal effect. Ethosomes can be obtained using three methods: the hot method, the cold method, and the classic method of mechanical dispersion. The literature describes many of the therapeutic groups of drugs that can be enclosed in ethosomal formulations. These include anti-viral drugs, antineoplastic drugs, antifungal drugs, hypnotic drugs, hormones, and many others. Ethosomes show important practical advantages compared to classic liposomes. It is necessary to conduct research with regard to real pharmaceutical systems using advanced physicochemical techniques.

The aim of this study was to assess the photostability of quercetin in the presence of anionic and nonionic polymeric gels with varied compositions of an added component—glycerol. The samples were irradiated continuously at constant temperature. The stability of quercetin in solution and incorporated into the gels was evaluated by an UV-Vis spectrophotometer. FTIR spectroscopy (Fourier-transform infrared spectroscopy) was used to detect the changes in the structure of quercetin depending on the polymer used in the gel, and on the exposure time. Photostabilization is an important aspect of quality assurance in photosensitive compounds. The decomposition rate of quercetin in the ionic preparation of polyacrylic acid (PAA) with glycerol was 1.952·10⁻³ min⁻¹, whereas the absence of glycerol resulted in a decay rate of 5.032·10⁻⁴ min⁻¹. The formulation containing non-ionic methylcellulose resulted in a decomposition rate of quercetin in the range of 1.679·10⁻³ min⁻¹. The decay rate of quercetin under light influence depended on the composition of the gel. It was found that the cross-linked PAA stabilized quercetin and the addition of glycerol accelerated the photodegradation.

Stimuli-responsive carriers of pharmaceutical agents have been extensively researched in recent decades due to the possibility of distinctively precise targeted drug delivery. One of the potentially beneficial strategies is based on the response of the medical device to changes in the ionic environment. Fluctuations in ionic strength and ionic composition associated with pathological processes may provide triggers sufficient to induce an advantageous carrier response. This review is focused on recent developments and novel strategies in the design of ion-responsive drug delivery systems. A variety of structures i.e., polymeric matrices, lipid carriers, nucleoside constructs, and metal-organic frameworks, were included in the scope of the summary. Recently proposed strategies aim to induce different pharmaceutically beneficial effects: localized drug release in the desired manner, mucoadhesive properties, increased residence time, or diagnostic signal emission. The current state of development of ion-sensitive drug delivery systems enabled the marketing of some responsive topical formulations. Concurrently, ongoing research is focused on more selective and complex systems for different administration routes. The potential benefits in therapeutic efficacy and safety associated with the employment of multi-responsive systems will prospectively result in further research and applicable solutions.

The size of active pharmaceutical ingredient carrier is one of the key properties considered during design of submicron drug delivery systems. Particle diameter may determine drug biodistribution, cellular uptake, and elimination path. Solvent evaporation technique is a flexible method of particle preparation, in which various macromolecules and drugs may be employed. Parameters of emulsion obtained as first step of particle preparation are crucial in terms of particle size, drug loading, and morphology. The aim of the study was to investigate the influence of emulsion preparation parameters on diameter of resulting particles. Impact of surfactant type and concentration, homogenization time, homogenization rate, phase ratio, and conjugate concentration were evaluated. Model drug lamivudine was covalently bound to polymer and applied in solvent evaporation method in order to overcome issues related to drug loading and provide method-independent incorporation. Synthesized drug–polymer conjugate and obtained particles were evaluated via dynamic light scattering, chromatography, scanning electron microscopy, and spectroscopic methods. Covalent bonding between drug and polymeric chain was confirmed, estimated drug content per milligram of conjugate was 19 μg. Among employed colloid stabilizer, poly(vinyl alcohol) was proven to be most effective. Homogenization rate and surfactant concentration were identified as crucial parameters in terms of particle diameter control.