Transdermal drug delivery (TDD) is an increasingly important non-invasive method for administering active pharmaceutical ingredients (APIs) through the skin barrier, offering advantages such as improved therapeutic efficacy and reduced systemic side effects. As demand increases for patient-friendly and minimally invasive treatment options, TDD has attracted substantial attention in research and clinical practice. This review summarizes recent advances enhancing skin permeability through chemical enhancers (e.g., ethanol, fatty acids, terpenes), physical (e.g., iontophoresis, microneedles, sonophoresis), and nanotechnological methods (e.g., liposomes, ethosomes, solid lipid nanoparticles, and transferosomes). A comprehensive literature analysis, including scientific publications, regulatory guidelines, and patents, was conducted to identify innovative methods and materials used to overcome the barrier properties of the stratum corneum. Special emphasis was placed on in vitro, ex vivo, and in vivo evaluation techniques for such as Franz diffusion cells for assessing drug permeation and skin interactions. The findings highlight the importance of active physical methods, passive nanostructured systems, and chemical penetration enhancers. In conclusion, integrating multiple analytical techniques is essential for the rational design and optimization of effective transdermal drug delivery systems.

Thermosensitive systems based on poloxamer 407 are widely used in targeted drug delivery; however, the stability of the phase transition temperature remains insufficiently studied. This article presents the results of a study on the effect of adding polyethylene glycols (PEG) with different molecular weights and some classical gel-forming polymers on the gelation temperature of thermoreversible compositions based on poloxamer 407 in a long-term experiment. The study showed a positive effect of PEG addition with average molecular weights at concentrations of 1.5–2.0%, as well as gelling agents at a concentration below the critical gelation concentration. The proposed rheological test for studying the samples’ adhesion can give an indirect forecast of the composition adhesive rate. Based on the conducted studies, three experimental binary systems based on poloxamer 407 were selected, with the addition of HPMC 0.5%, sodium alginate 0.5%, and PEG 1500 1.5%. These systems are the most promising for the further development of in situ targeted drug delivery systems.

Introduction. Intranasal delivery of in situ gel-forming systems is a complex but promising direction. Due to the high cost of developing a new chemical object or genetically engineered modification of biological molecules, pharmaceutical companies are focusing on developing technologies for new delivery systems for existing active pharmaceutical ingredients to improve their effectiveness and bioavailability. In situ systems for intranasal delivery, due to increased viscosity and mucoadhesion to the nasal mucosa, allow overcoming mucociliary clearance and ensuring complete absorption and prolonged release of drugs.Text. The article discusses the main advantages of intranasal in situ delivery systems shown in preclinical studies, as well as approaches to the technology of obtaining and standardization of these systems. The results of scientific research in this field over the past 15 years are summarized, the most promising polymers for creating thermoreversible and pH-sensitive compositions are identified, and modern methods for evaluating the sol-gel transition in situ are analyzed.Conclusion. The use of in situ systems for intranasal administration allows providing a high targeting of the delivery of synthetic and biological molecules to the brain. Currently, numerous pharmacokinetic and pharmacodynamic preclinical studies confirm the effectiveness of such systems, as well as their safety. Thermoreversible commercially available and directionally synthesized polymers (poloxamer 407, PLGA, NIPAAm, etc.), as well as chitosan, remain the most popular for the design of in situ delivery systems. In vitro and ex vivo methods with mucosa and artificial nasal fluid are widely used to assess the parameters of in situ gelation, but to increase the reproducibility of the methods and improve the correlation in vitro/in vivo, it is recommended to conduct modeling of the nasal cavity. Developing the technology and methods of screening of intranasal reversible systems will help to get closer to clinical trials and the entry of these delivery systems into the global pharmaceutical market.

The main method of treatment and prevention of endophthalmitis is a combination of intravitreal and topical administration of antibiotics, such as cefuroxime moxifloxacin or vancomycin. However, this method is ineffective due to the rapid elimination of the drug. This problem can be solved with the help of intravitreal in situ injection systems, which are injected with a syringe into the vitreous body and provide prolonged action of the drug at the focus of inflammation. Under the influence of temperature, the liquid drug undergoes a phase transition and turns into a gel after injection. This ensures its prolonged action. The study aimed to develop an intravitreal in situ cefuroxime delivery system for the treatment of endophthalmitis based on a thermosensitive biodegradable composition of poloxamer 407 and hyaluronic acid. A combination of poloxamer Kolliphor^® P407, Kolliphor^® P188, and PrincipHYAL^® hyaluronic acids of different molecular weights was used as a delivery system. The potency of cefuroxime solid dispersion with polyvinylpyrrolidone-10000, polyethylene glycol-400, and polyethylene glycol-1500 in a 1:2 ratio was studied for prolonged action compared to cefuroxime substance. The experimental formulations were studied for the parameters of gelation temperature in a long-term test (4 months), pH, and release of cefuroxime using dialysis bags. To study the distribution parameter in the vitreous body, an in vitro model (1/13) was developed, which was a hollow agar sphere filled with 1% (w/v) polyacrylate gel. For the superior formulations, a HET-CAM test (chorioallantoic membrane test) was performed to determine the absence of irritant effects. According to the study results, a formulation containing a solid dispersion of cefuroxime:PEG-400 (1:2), the matrix of which contained 18% (w/v) Kolliphor^® P407 poloxamer, 3% (w/v) Kolliphor^® P188 poloxamer, and 0.5% (w/v) hyaluronic acid (1400–1800), was selected. This sample had an average gelation temperature of 34.6 °C, pH 6.7 ± 0.5, and a pronounced prolonged effect. Only 7.6% was released in 3 h of the experiment, whereas about 38% of cefuroxime was released in 72 h. No irritant effect on the chorioallantoic membrane was observed for any formulations studied.

Abiraterone acetate is one of the effective therapies in castration-resistant prostate cancer. There is only one dosage form in the form of film-coated tablets. Abiraterone has proven effective but has disadvantages and contraindications that complicate therapy. One of them is a positive food effect affecting the bioavailability and side effects of the drug. Abiraterone is taken strictly on an empty stomach, and the bioavailability of the drug, in this case, reaches only 10%. In addition, the drug is contraindicated in people with hepatic insufficiency since the main metabolism is in the liver. These and other disadvantages can be eliminated by obtaining targeted delivery systems - liposomes and nanocrystals. Another dosage form could be considered for the active pharmaceutical agent that would be cost-effective, accessible and have higher bioavailability for effective treatment. An intratumoral polymeric in situ implant is chosen as an excellent dosage form, the matrix of which will contain an optimized form of abiraterone, which can stably target a tumor.

Objective: To develop a stable composition with the substance of PEGylated interferon alfa-2b, to study technological and biopharmaceutical characteristics of the dosage form, and to conduct preclinical studies on the chronic toxicity and local irritating effect. Methods: Solid fats Witepsol® H15, Witepsol® W 35, Suppocire® BS2X, and Suppocire® BM brands were used as the suppository bases. Polysorbate 80 was used as an emulsifier. Citric acid, ascorbic acid, sodium tetraborate, lactic acid, ethylenediaminetetetraacetic acid, tocopherol acetate was also introduced into the experimental samples. Fourteen experimental samples were screened for biological and technological indicators. Preclinical studies were performed for the optimal composition on the indicators of chronic toxicity and local irritant effect. Results: The study examined the cytotoxic effects on the Vero cell line of selected suppository bases and excipients, namely, pH regulators and antioxidants. With excipients that did not have cytotoxicity we obtained suppository compositions with the following quality indicators: cytotoxicity, specific activity of interferon, time of complete deformation of suppositories and their melting temperature. A total of 14 compositions were studied, of which 5 were selected on the basis of the results for the study of stability. Only one composition turned out to be stable for the time studied. Conclusion: The most stable in terms of “specific activity” was sample 7, its composition: Witepsol® H15/W35 70/30, polysorbate-80 0.15%, ethylenediaminetetraacetic acid (EDTA) 0.15%, sodium tetraborate 0.15%, tocopherol acetate 3.0%. Preclinical studies, that showed the absence of chronic toxicity and local irritant effect, were performed for this composition.