The development of innovative forms of combination drugs is closely related to the invention of the multilayer tablet press, polymers for pharmaceutical applications, the hot-melt extrusion process, and 3D printing in the pharmaceutical industry. However, combining multiple drugs within the same dosage form can bring many physicochemical and pharmacodynamic interactions. More and more new forms of fixed-dose combinations (FDCs) have been developed due to work to overcome the incompatibility of active substances or to obtain different drug release profiles in the same dosage form. This review provides discussions of the application of various innovation formulation technologies of FDC drugs such as bilayer system, multilayer tablet, active film coating, hot-melt extrusion, and 3D printing, taking into account the characteristics of the key ingredients in the FDC formulation and presenting technological problems and challenges related to the development of combination drugs. Moreover, the article summarizes the range of dosage forms that have been made using these technologies over the past 30 years.

Cannabis leaves contain a diverse range of antioxidants, including cannabinoids, flavonoids, and phenolic compounds, which offer significant health benefits. Utilising cannabis leaves as a source of antioxidants presents a cost-effective approach because they are typically discarded during the cultivation of cannabis plants for their seeds or fibres. Therefore, this presented study aimed to assess the antioxidant activity of the leaves of selected hemp cultivars, such as Białobrzeska, Tygra, and Henola, based on the results obtained with the 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid, ferric reducing antioxidant power, cupric reducing antioxidant capacity, and 2,2-Diphenyl-1-picrylhydrazyl assays. The cannabinoid profile was analysed for the antioxidant activity to the contents of cannabidiol (CBD), cannabigerol (CBG), Δ⁹-tetrahydrocannabinol (Δ⁹-THC), and cannabichromene (CBC), determined based on chromatographic assays. The following variables were tested: the impact of various extractants (methanol, ethanol, and isopropanol), and their mixtures (50:50, v/v, as well as extraction methods (maceration and ultra-sound-assisted extraction) significant in obtaining hemp extracts characterised by different cannabinoid profiles. The results revealed that the selection of extractant and extraction conditions significantly influenced the active compounds’ extraction efficiency and antioxidant activity. Among the tested conditions, ultrasound-assisted extraction using methanol yielded the highest cannabinoid profile: CBD = 184.51 ± 5.61; CBG = 6.10 ± 0.21; Δ9-THC = 0.51 ± 0.01; and CBC = 0.71 ± 0.01 μg/g antioxidant potential in Białobrzeska leaf extracts.

Curcumin, a compound known for its antioxidant and neuroprotective properties, faces challenges due to its low water solubility, which can limit its effectiveness. One effective method to address this issue is through amorphization. Incorporating curcumin into a polymeric matrix to form amorphous solid dispersions is a common approach. Another strategy involves co-amorphous systems, where low-molecular-weight components act as co-formers. A recent innovative approach combines these strategies. This study used tryptophan as a co-former and prepared systems using supercritical fluid technology. The amorphous nature of two systems was confirmed through X-ray powder diffraction: one with 10% curcumin and a polymer, and another with 10% curcumin, a polymer, and tryptophan. Fourier-transform infrared analysis demonstrated molecular interactions among all components in the systems. Scanning electron microscopy revealed that the amorphization process significantly modified the morphology of the powder particles. The ternary system with tryptophan notably increased curcumin solubility by over 300-fold. The amorphous form of curcumin in both systems exhibited significantly higher dissolution rates compared to its crystalline form. The system with tryptophan showed more than a threefold improvement in permeability according to the PAMPA test. The enhanced solubility led to over a sixfold increase in antioxidant activity and a 25-fold improvement in the inhibition of the enzyme butyrylcholinesterase.

Chitosan is a valued excipient due to its biocompatibility properties and increasing solubility of poorly water-soluble drugs. The research presented in this paper concerns the preparation of binary combinations of chitosan (deacetylated chitin) with carvedilol (beta-blocker) to develop a formulation with a modified carvedilol release profile. As part of the research, six physical mixtures of chitosan with carvedilol were obtained and identified by spectral (PXRD, FT-IR, and Raman), thermal (DSC), and microscopic (SEM) methods. The next stage of the research estimated the profile changes and the dissolution rate for carvedilol in the obtained drug delivery systems; the reference sample was pure carvedilol. The studies were conducted at pH = 1.2 and 6.8, simulating the gastrointestinal tract conditions. Quantitative changes of carvedilol were determined using the developed isocratic UHPLC-DAD method. Established apparent permeability coefficients proved the changes in carvedilol’s permeability after introducing a drug delivery system through membranes simulating the gastrointestinal tract and skin walls. A bioadhesive potential of carvedilol–chitosan systems was confirmed using the in vitro model. The conducted research and the obtained results indicate a significant potential of using chitosan as an excipient in modern oral or epidermal drug delivery systems of carvedilol.

This review presents the most common disease entities in which combinations of NSAIDs and spasmolytic drugs are used to reduce pain. The benefits of fixed-dose combination products (FDCs) are that they improve the response in people with insufficient monotherapy. Using the synergy or additive effect of drugs, it is possible to obtain a significant therapeutic effect and faster action with the use of smaller doses of individual drugs. In addition, one active ingredient may counteract adverse reactions from the other. Another essential aspect of the use of FDCs is the improvement of medical adherence due to the reduction in the pill burden on patients. It is also possible to develop a fixed-dosed combination product de novo to address a new therapeutic claim and be protected by patents so that the manufacturer can obtain exclusive rights to sell a particular FDC or a formulation thereof. The proposed fixed-dose combinations should always be based on valid therapeutic principles and consider the combined safety profile of all active substances included in the medicinal product. This review aims to identify which combinations of NSAIDs and spasmolytics have been developed and tested and which combinations are still under development.

Hesperidin is a polyphenol derived from citrus fruits that has a broad potential for biological activity and the ability to positively modify the intestinal microbiome. However, its activity is limited by its low solubility and, thus, its bioavailability—this research aimed to develop a zein-based hesperidin system with increased solubility and a sustained release profile. The study used triple systems enriched with solubilizers to maximize solubility. The best system was the triple system hesperidin-zein-Hpβ-CD, for which the solubility improved by more than six times. A significant improvement in the antioxidant activity and the ability to inhibit α-glucosidase was also demonstrated, due to an improved solubility. A release profile analysis was performed in the subsequent part of the experiments, confirming the sustained release profile of hesperidin, while improving the solubility. Moreover, the ability of selected probiotic bacteria to metabolize hesperidin and the effect of this flavonoid compound on their growth were investigated.