In this review, an extensive analysis of dry powder inhalers (DPIs) is offered, focusing on their characteristics, formulation, stability, and manufacturing. The advantages of pulmonary delivery were investigated, as well as the significance of the particle size in drug deposition. The preparation of DPI formulations was also comprehensively explored, including physico-chemical characterization of powders, powder processing techniques, and formulation considerations. In addition to manufacturing procedures, testing methods were also discussed, providing insights into the development and evaluation of DPI formulations. This review also explores the design basics and critical attributes specific to DPIs, highlighting the significance of their optimization to achieve an effective inhalation therapy. Additionally, the morphology and stability of 3 DPI capsules (Spiriva, Braltus, and Onbrez) were investigated, offering valuable insights into the properties of these formulations. Altogether, these findings contribute to a deeper understanding of DPIs and their development, performance, and optimization of inhalation dosage forms.

Background/Objectives: To improve the therapeutic efficacy of albendazole (ABZ) for ileocolonic diseases, its low solubility at higher pH levels should be enhanced. Organic acids have been widely used as pH modifiers to improve the solubility of weakly basic drugs. To achieve an adequate effect of the acidic microenvironmental pH during the drug release, pH modifiers should not leach out from the formulation. In the present work, we aimed to demonstrate that 100% tartaric acid pellets (TAP) can be used as pH-modifier cores, providing an acidic microenvironmental pH to enhance the solubility of albendazole at a higher pH. Methods: This study develops multilayer-coated pellets using TAP as starter cores in a bottom-spray-configured fluidized bed apparatus. The drug-layered TAP were coated with time-dependent and pH-dependent layers. Results: The release of ABZ from tartaric acid-based coated pellets was enhanced compared to that from pellets with the same layering structure but with an inert core of sugar or microcrystalline cellulose (MCC). In vitro experiments showed that tartaric acid remained in the pellet core during the dissolution test at a pH 6.8 medium, which resulted in an enhanced release of albendazole at a higher pH. The application of a combination of time-dependent and pH-dependent polymers aimed not only to prevent the release of albendazole at lower pH levels but also to protect TAP from premature release from the formulation. Conclusions: The application of 100% ready-to-use tartaric acid pellets (TAP) with the applied combination of coatings enhanced the solubility of the weakly basic drug albendazole at higher intestinal pH.

Background/Objectives: Matrix pellet formulations enable homogeneous incorporation of the active ingredient and advanced control of release depending on the excipients added. The aim of this study was to develop, characterize, and assess the drug release profiles of microcrystalline cellulose (MCC) and isomalt-based matrix pellets with direct drug incorporation, advancing beyond the earlier concept of isomalt as a mere inert core with layered drug application, under simulated physiological conditions in vitro. Methods: Matrix pellets with varying MCC–isomalt ratios (90:10, 70:30, and 50:50) were produced by extrusion/spheronization and subsequently coated with film-forming polymers. Dissolution experiments were performed under varying osmolarity to characterize release profiles. The experimental design data were statistically evaluated. Results: The extrusion/spheronization technique yielded uniform, robust matrix pellets with acceptable sphericity and mechanical integrity, even at high isomalt levels. Release from coated pellets was significantly influenced by the polymer coating and osmolarity of the dissolution medium. However, with increasing isomalt content in the matrix, the dependence of drug release kinetics on medium osmolarity was substantially reduced. Conclusions: The production of MCC–isomalt matrix pellets in which isomalt acts as a functional matrix component reduced the effect of osmolarity of dissolution medium on the release of ibuprofen sodium salt in in vitro experiments.

Background/Objectives: To improve the potential therapeutic efficacy of albendazole (ABZ), its low solubility in alkaline environments should be addressed. Spray drying has been widely applied to increase the solubility of poorly soluble drugs. Eudragit^® E PO (EudE) has previously been used to increase the solubility of weakly basic drugs, alone and in combination with organic acids. In the present work, we aimed to demonstrate that EudE and tartaric acid (TA) significantly increase the solubility of ABZ via spray drying. Furthermore, a colon-delivery formulation was applied to deliver ABZ at pH 7.2. Methods: This study developed spray-dried formulations of ABZ-TA-EudE. The formulation with the best solubility profile was selected and loaded into the EUDRACAP^® colon to achieve colon-delivery of the ABZ formulation with enhanced solubility at basic pH. The physicochemical characteristics and in vitro drug release were evaluated and compared with those of the respective physical mixtures. Results: The addition of TA further enhanced the solubility of ABZ-EudE formulations. Both EudE and TA significantly increase ABZ solubility. The ternary ABZ-TA-EudE formulation with the best solubility, when delivered into the EUDRACAP^® colon, showed enhanced ABZ release at pH 7.2. Enhanced in vitro drug release at basic pH and physicochemical characteristics were observed for the spray-dried formulation of ABZ-TA-EudE compared with the corresponding physical mixture and the ABZ powder. Conclusions: TA and EudE significantly enhance the solubility of the weakly basic drug, ABZ, in a spray-dried formulation. Furthermore, the application of EUDRACAP^® colon is effective for colon-delivery of ABZ, as it ensures ABZ release at pH 7.2, thereby providing enhanced formulation’s solubility at its site of action.