Validation of a Rapid and Easy-to-Apply Method to Simultaneously Quantify Co-Loaded Dexamethasone and Melatonin PLGA Microspheres by HPLC-UV: Encapsulation Efficiency and In Vitro Release

Ketorolac, melatonin and latanoprost tri-loaded PLGA microspheres for neuroprotection in glaucoma

Glaucoma is a multifactorial neurodegenerative disease that affects the retina and optic nerve. The aim of this work was to reach different therapeutics targets by co-encapsulating three neuroprotective substances with hypotensive (latanoprost), antioxidant (melatonin) and anti-inflammatory (ketorolac) activity in biodegradable poly (lactic-co-glycolic acid) (PLGA) microspheres (MSs) capable of releasing the drugs for months after intravitreal injection, avoiding the need for repeated administrations. Multi-loaded PLGA MSs were prepared using the oil-in-water emulsion solvent extraction-evaporation technique and physicochemically characterized. PLGA 85:15 was the polymer ratio selected for the selected formulation. Tri-loaded MSs including vitamin E as additive showed good tolerance in retinal pigment epithelium cells after 24 h exposure (>90% cell viability). The final formulation (KMLVE) resulted in 33.58 ± 5.44 µm particle size and drug content (µg/mg MSs) of 39.70 ± 5.89, 67.28 ± 4.17 and 7.51 ± 0.58 for melatonin, ketorolac and latanoprost respectively. KMLVE were able to release in a sustained manner the three drugs over 70 days. KMLVE were injected at 2 and 12 weeks in Long-Evans rats (n = 20) after the induction of chronic glaucoma. Ophthalmological tests were performed and compared to not treated glaucomatous (n = 45) and healthy (n = 17) animals. Treated glaucomatous rats reached the lowest intraocular pressure, enhanced functionality of bipolar and retinal ganglion cells and showed greater neuroretinal thickness by optical coherence tomography (p < 0.05) compared to not treated glaucomatous rats at 24 weeks follow-up. According to the results, the tri-loaded microspheres can be considered as promising controlled-release system for the treatment of glaucoma.

Novel Indole-Thiazole Derivative Containing a p-Nitro Substituent (CS03): Validation of an HPLC-UV Quantification Method

The validation of an analytical method enables the identification of the physicochemical characteristics of a molecule, aiding in the development of new drugs and allowing for its dosage in pharmaceutical forms. This is a crucial step in the creation of new pharmaceutical products. This article aims to validate a method for quantifying a novel indole-thiazole derivative with a p-nitro substituent (CS03) encapsulated in nanoparticles. The CS03 quantification method was evaluated using HPLC-UV techniques based on selectivity, linearity, accuracy, precision, detection and quantification limits, and robustness. Additionally, the stability of CS03 in various simulated pH environments and its encapsulation in polysaccharide-coated nanoparticles were assessed. The method proved effective in quantifying CS03, demonstrating selectivity, linearity, precision, and accuracy, with detection and quantification limits appropriate for measuring the molecule postencapsulation in nanoparticles. The validated method is suitable for determining CS03, facilitating studies focused on the clinical application of this molecule for new drug development.

QbD driven targeted pulmonary delivery of dexamethasone-loaded chitosan microspheres: Biodistribution and pharmacokinetic study

Inhaling drugs, on the other hand, is limited mainly by the natural mechanisms of the respiratory system, which push drug particles out of the lungs or make them inefficient once they are there. Because of this, many ways have been found to work around the problems with drug transport through the lungs. Researchers have made polymeric microparticles (MP) and nanoparticles as a possible way to get drugs into the lungs. They showed that the drug could be trapped in large amounts and retained in the lungs for a long time, with as little contact as possible with the bloodstream. MP were formulated in this study to get dexamethasone (DMC) into the pulmonary area. The Box-Behnken design optimized microspheres preparation to meet the pulmonary delivery prerequisites. Optimized formulation was figured out based on the desirability approach. The mass median aerodynamic diameter (MMAD) of the optimized formula (O-DMC-MP) was 8.46 ± 1.45 µm, and the fine particle fraction (FPF) was 77.69 ± 1.26%. This showed that it made suitable drug delivery system, which could make it possible for MP to settle deeply in the lung space after being breathed in. With the first burst of drug release, it was seen that drug release could last up to 16 h. Also, there was no clear sign that the optimized formulation was toxic to the alveoli basal epithelial cells in the lungs, as supported by cytotoxic studies in HUVEC, A549, and H1299 cell lines. Most importantly, loading DMC inside MP cuts the amount of drug into the bloodstream compared to plain DMC, as evident from biodistribution studies. Stability tests have shown that the product can stay the same over time at both the storage conditions. Using chitosan DMC-MP can be a better therapeutic formulation to treat acute respiratory distress syndrome (ARDS).

Weibull β value for the discernment of drug release mechanism of PLGA particles

Mathematical models are used to characterize and optimize drug release in drug delivery systems (DDS). One of the most widely used DDS is the poly(lactic-co-glycolic acid) (PLGA)-based polymeric matrix owing to its biodegradability, biocompatibility, and easy manipulation of its properties through the manipulation of synthesis processes. Over the years, the Korsmeyer-Peppas model has been the most widely used model for characterizing the release profiles of PLGA DDS. However, owing to the limitations of the Korsmeyer-Peppas model, the Weibull model has emerged as an alternative for the characterization of the release profiles of PLGA polymeric matrices. The purpose of this study was to establish a correlation between the n and β parameters of the Korsmeyer-Peppas and Weibull models and to use the Weibull model to discern the drug release mechanism. A total of 451 datasets describing the overtime drug release of PLGA-based formulations from 173 scientific articles were fitted to both models. The Korsmeyer-Peppas model had a mean Akaike Information Criteria (AIC) value of 54.52 and an n value of 0.42, while the Weibull model had a mean AIC of 51.99 and a β value of 0.55, and by using reduced major axis regression values, a high correlation was found between the n and β values. These results demonstrate the ability of the Weibull model to characterize the release profiles of PLGA-based matrices and the usefulness of the β parameter for determining the drug release mechanism.

Breaking Barriers in Eye Treatment: Polymeric Nano-Based Drug-Delivery System for Anterior Segment Diseases and Glaucoma

The eye has anatomical structures that function as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of medications administered topically. The development of polymeric nano-based drug-delivery systems (DDS) could be the solution to these challenges: it can pass through ocular barriers, offering higher bioavailability of administered drugs to targeted tissues that are otherwise inaccessible; it can stay in ocular tissues for longer periods of time, requiring fewer drug administrations; and it can be made up of polymers that are biodegradable and nano-sized, minimizing the undesirable effects of the administered molecules. Therefore, therapeutic innovations in polymeric nano-based DDS have been widely explored for ophthalmic drug-delivery applications. In this review, we will give a comprehensive overview of polymeric nano-based drug-delivery systems (DDS) used in the treatment of ocular diseases. We will then examine the current therapeutic challenges of various ocular diseases and analyze how different types of biopolymers can potentially enhance our therapeutic options. A literature review of the preclinical and clinical studies published between 2017 and 2022 was conducted. Thanks to the advances in polymer science, the ocular DDS has rapidly evolved, showing great promise to help clinicians better manage patients.

Unveiling the Collaborative Effect at the Cucurbit[8]uril-MoS2 Hybrid Interface for Electrochemical Melatonin Determination

Host-guest interactions are of paramount importance in supramolecular chemistry and in a wide range of applications. Particularly well known is the ability of cucurbit[n]urils (CB[n]) to selectively host small molecules. We show that the charge transfer and complexation capabilities of CB[n] are retained on the surface of 2D transition metal dichalcogenides (TMDs), allowing the development of efficient electrochemical sensing platforms. We unveil the mechanisms of host-guest recognition between the MoS₂ -CB[8] hybrid interface and melatonin (MLT), an important molecular regulator of vital constants in vertebrates. We find that CB[8] on MoS₂ organizes the receptor portals perpendicularly to the surface, facilitating MLT complexation. This advantageous adsorption geometry is specific to TMDs and favours MLT electro-oxidation, as opposed to other 2D platforms like graphene, where one receptor portal is closed. This study rationalises the cooperative interaction in 2D hybrid systems to improve the efficiency and selectivity of electrochemical sensing platforms.

Novel Osmoprotective DOPC-DMPC Liposomes Loaded with Antihypertensive Drugs as Potential Strategy for Glaucoma Treatment

Glaucoma is a group of chronic irreversible neuropathies that affect the retina and the optic nerve. It is considered one of the leading causes of blindness in the world. Although it can be due to various causes, the most important modifiable risk factor is the elevated intraocular pressure (IOP). In this case, the treatment of choice consists of instilling antihypertensive formulations on the ocular surface. The chronicity of the pathology, together with the low bioavailability of the drugs that are applied on the ocular surface, make it necessary to instill the formulations very frequently, which is associated, in many cases, with the appearance of dry eye disease (DED). The objective of this work is the design of topical ocular formulations capable of treating glaucoma and, at the same time, preventing DED. For this, two liposome formulations, loaded with brimonidine or with travoprost, were Tadeveloped using synthetic phospholipids and enriched by the addition of compounds with osmoprotective activity. The proposed formulations not only presented physicochemical characteristics (size, pH, osmolarity, surface tension, and viscosity) and encapsulation efficiency values (EE% of 24.78% and ≥99.01% for brimonidine and travoprost, respectively) suitable for ocular surface administration, but also showed good tolerance in human corneal and conjunctival cell cultures, as well as an in vitro osmoprotective activity. The hypotensive effect of both liposomal formulations was evaluated in normotensive albino New Zealand rabbits, showing a faster and longer lasting reduction of intraocular pressure in comparison to the corresponding commercialized products used as control. According to these results, the hypotensive liposomal formulations combined with osmoprotective agents would result in a very promising platform for the treatment of glaucoma and the simultaneous protection of the ocular surface.