Improvement of photostability and dissolution profile of isradipine using inclusion complex

Development and Optimization of Dipyridamole- and Roflumilast-Loaded Nanoemulsion and Nanoemulgel for Enhanced Skin Permeation: Formulation, Characterization, and In Vitro Assessment

This study explores developing and optimizing a nanoemulsion (NE) system loaded with dipyridamole and roflumilast, aiming to improve skin penetration and retention. The NE formulation was further transformed into a nanoemulgel to enhance its application as a topical treatment for psoriasis. Solubility studies were conducted to select the oil, surfactant, and co-surfactant. Phase diagrams were constructed using the aqueous phase titration method. All the formulations were in nanoscale, and Formula (F2) (which contains oleic acid oil as the oil phase, a mixture of Surfactant Tween 80 and co-surfactant (ethanol) at a ratio of 1:2 in addition to distilled water as an aqueous phase in a ratio of 1:5:4, respectively) was the selected formula depending on the particle size, PDI, and zeta potential. Formula (F2) has the best ratio because it gives the smallest nanoemulsion globule size (particle size average of 167.1 nm), the best homogenicity (lowest PDI of 0.195), and the highest stability (higher zeta potential of -32.22). The selected formula was converted into a nanoemulgel by the addition of 0.5% (w/w) xanthan gum (average particle size of 172.7 nm) and the best homogenicity (lowest PDI of 0.121%) and highest stability (higher zeta potential of -28.31). In conclusion, the selected formula has accepted physical and chemical properties, which enhanced skin penetration.

Clays as Vehicles for Drug Photostability

Clay minerals are often used due to their high adsorption capacity, which has sparked interest in their biological applications to stabilize drugs and pharmaceutical products. This research aims to summarize information about the stability of drugs, cosmetics, dermocosmetics, and pharmaceutical compounds incorporated in the structure of different clay minerals. The databases used to search the articles were Web of Science, Scopus, PubMed, and Science Direct. Photostabilization of these compounds is reviewed and its importance demonstrated. For biological applications, the increase in solubility and bioavailability of clay minerals has proven useful for them as drug carriers. While their natural abundance, low toxicity, and accessible cost have contributed to classical applications of clay minerals, a wide range of interesting new applications may be facilitated, mainly through incorporating different organic molecules. The search for new functional materials is promising to challenge research on clay minerals in biological or biotechnological approaches.

1,4-Dihydropyridine Antihypertensive Drugs: Recent Advances in Photostabilization Strategies

The 1,4-dihydropyridine (DHP) drugs are nowadays the most used drugs in the treatment of hypertension. However, all the structures in this series present a significant sensitivity to light, leading to the complete loss of pharmacological activity. This degradation is particularly evident in aqueous solution, so much so that almost all DHP drugs on the market are formulated in solid preparations, especially tablets. The first and main process of photodegradation consists in the aromatization of the dihydropyridine ring, after which secondary processes can take place on the various substituents. A potential danger can result from the formation of single oxygen and superoxide species that can in turn trigger phototoxic reactions. Several strategies for the photostabilisation of DHP drugs have been proposed in recent years, in particular with the aim to formulate these drugs in liquid preparations, as well as to limit any toxicity problems related to light degradation. This review summarizes and describes the main aspects of the studies conducted in recent years to obtain photostable formulations of DHP drugs.