Preparation and characterization of carvedilol-loaded poly(d,l) lactide nanoparticles/microparticles as a sustained-release system

Optimizing formulation parameters for the development of carvedilol injectable in situ forming depots

In situ forming depots (ISFDs) represent attractive alternatives to the conventional sustained drug delivery systems. Carvedilol, a short half-life drug used on a daily basis to manage chronic conditions, could benefit from this technology. The aim of this work was to develop, for the first time, a new injectable long-acting carvedilol-ISFD. Accordingly, 4 different grades of polyesters with varying properties as i) lactide-to glycolide ratio (polylactide-co-glycolide (PLGA) vs. polylactide (PLA)), and ii) end functionality (acid- vs. ester-capped) were utilized for the preparation of ISFD formulations. In addition, 4 different organic solvents with varying properties (i.e. N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethyl acetate, and benzyl benzoate) were also investigated. It was found that NMP and DMSO were more suitable for the formation of depots. Furthermore, all ISFD formulations demonstrated excellent encapsulation efficiency (i.e. 96-98%). Interestingly, both PLGA-based ISFDs (acid-capped and ester-capped) exhibited similar release behaviors and were able to extend carvedilol release over 30 days. On the other hand, acid-capped and ester-capped PLA-based ISFDs exhibited slower release over the 30 days with an average release of only 36% and 60%, respectively. In conclusion, the developed carvedilol-ISFDs resulted in a tunable extended-release behavior, simply by choosing the appropriate grade of polymer. These results open the door toward a novel injectable carvedilol-ISFD formulation.

The Formation of Self-Assembled Nanoparticles Loaded with Doxorubicin and d-Limonene for Cancer Therapy

Self-assembled nanoparticles present unique properties that have potential applications in the development of a successful drug delivery system. Doxorubicin (DOX) is an important anti-neoplastic anthracycline chemotherapeutic drug widely described. However, it suffers from serious dose-dependent cardiotoxicity. d-Limonene is a major constituent of numerous citrus oils that is considered a specific monoterpene against free radicals producing antioxidant activity. Herein, we aimed to design three types of self-assembled nanodelivery systems (nanoemulsion, niosomes, and polylactide nanoparticles) for loading both DOX and d-limonene to enhance the solubilization of d-limonene and provide antioxidant activity with excellent anticancer activity. As confirmed by dynamic light scattering and transmission electron microscopy, the nanoparticles were prepared successfully with diameter sizes of 52, 180, and 257 nm for the DOX-loaded nanoemulsion, niosomes, and polylactide nanoparticles, respectively. The zeta potential values were above -30 mV in all cases, which confirms the formation of stable nanoparticles. The loading efficiency of DOX was the highest in the case of the DOX-loaded nanoemulsion (75.8%), followed by niosomes (62.8%), and the least was in the case of polylactide nanoparticles with a percentage of 50.2%. The in vitro release study of the DOX-loaded nanoparticles showed a sustained release profile of doxorubicin with the highest release in the case of DOX-loaded PDLLA nanoparticles. The kinetic release model for all developed nanoparticles was the Peppas-Sahlin model, demonstrating DOX release through Fickian diffusion phenomena. Moreover, all developed nanoparticles maintain the antioxidant activity of d-limonene. The cytotoxicity study of the DOX-loaded nanoparticles showed concentration-dependent anticancer activity with excellent anticancer activity in the case of the DOX-loaded nanoemulsion and polylactide nanoparticles. These nanoparticles will be further studied in vivo to prove the cardioprotective effect of d-limonene in combination with DOX.

Self-assembly of diclofenac prodrug into nanomicelles for enhancing the anti-inflammatory activity

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for the treatment of various types of inflammatory conditions. Diclofenac is a very common NSAID that is utilized to relieve pain and reduce fever and, most importantly, inflammation. However, it suffers from low water solubility and a low dissolution profile. Therefore, we aim to develop a new drug delivery system based on the synthesis of amphiphilic structures that are capable of self assembling into nano-micelles which will be a water-soluble delivery system for the diclofenac. The amphiphilic structure consists of a hydrophilic moiety of triethylene glycol (TEG), polyethylene glycol PEG 400, or PEG 600 linked with the hydrophobic drug diclofenac through an ester linkage. The diclofenac derivatives were successfully synthesized as confirmed by nuclear magnetic resonance. Moreover, the formation of the micellar structure of the synthesized amphiphilic derivatives was confirmed by atomic force microscopy obtaining a spherical shape of the micelles with average diameters of 200 nm for Dic-PEG400-Dic, and 110 nm for Dic-PEG600-Dic. The critical micelle concentration has been determined as 2.7 × 10^-3 mg mL^-1 for Dic-PEG400-Dic, and 1 × 10^-4 mg mL^-1 for Dic-PEG600-Dic. The in vitro diclofenac release profile by esterase enzyme was conducted and showed almost complete conversion to free diclofenac within 35 h in the case of Dic-PEG400-Dic micelles and more than 85% of Dic-PEG600-Dic micelles. Then the anti-inflammatory activity was determined by testing the TNF-α production in LPS-stimulated Balb/c mice. Diclofenac micelles significantly suppressed TNF-α production after a 5 mg kg^-1 dose was given. The developed micelles showed TNF-α inhibition up to 87.4% and 84% after 48 hours of treatment in the case of Dic-PEG400-Dic and Dic-PEG600-Dic micelles respectively in comparison to 42.3% in the case of diclofenac alone. Dic-PEG400-Dic micelles showed the most potent anti-inflammatory activity with improved TNF-α suppression through time progress. Therefore, the developed nano-micelles provide a facile synthetic approach to enhance diclofenac water solubility, improve the anti-inflammatory effect and achieve a sustained release profile to get better patient compliance.

Design of multicomponent indomethacin-paracetamol and famotidine loaded nanoparticles for sustained and effective anti-inflammatory therapy

Indomethacin is one of the nonsteroidal anti-inflammatory drugs (NSAIDs) that are widely prescribed drug for pain and inflammation. However, its notoriety of causing gastrointestinal effect, low water solubility, and its short half-life would affect patient compliance and its oral absorption and accordingly justify the need to develop a formula with a controlled and sustained release manner in combination with anti-ulcer drugs. Herein, we synthesized indomethacin-paracetamol co-drug loaded in nanoemulsion and encapsulated in famotiditine loaded polycaprolactone (PCL) nanoparticles. The synthesis of the co-drug was achieved by the formation of a hydrolyzable ester between the indomethacin and paracetamol. The synthesized co-drug was preloading in nanoemulsion (Co-NE), which encapsulated into famotidine PCL nanoparticles utilizing the nanoprecipitation approach. The developed nanosystem showed hydrodynamic size less than 200 nm and the zeta potential value above -30 mV. TEM images confirmed the morphological structure of the formed nanoemulsion and the loaded PCL nanoparticles. Stability studies revealed that the developed nanosystem was stable at different temperatures and pHs over 1 month. Moreover, improvement of the solubilities of these three drugs leading to have a controlled-release multicomponent system of both co-drug and famotidine over 3 days. This multicomponent nanoparticle might be a potential platform to overcome the obstacles of NSAIDs, synergize drugs with different mechanisms of actions by co-encapsulating a small-sized nanoemulsion into PCL nanoparticles for reaching the goal of effective anti-inflammatory therapy.