Special Issue "Solubilization and Controlled Release Strategy of Poorly Water-Soluble Drugs"

A special issue of Pharmaceuticals (ISSN 1424-8247). This special issue belongs to the section "Pharmaceutical Technology".

Deadline for manuscript submissions: 14 October 2022 | Viewed by 9055

Special Issue Editor

Prof. Dr. María Ángeles Peña Fernández
E-Mail Website
Guest Editor
Departamento Ciencias Biomédicas, Facultad de Farmacia, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain
Interests: drug formulation; pharmaceutical technology; formulation development and characterization
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The processes of solubilization and controlled release of drugs that are not very soluble in water are of great relevance to the pre-formulation of drugs in pharmaceutical developments.

In recent years, a large number of drugs have been industrialized, but almost 70% of them have low solubility in water, which limits their dissolution rate and, consequently, their bioavailability. Undoubtedly, it is a problem of far-reaching repercussions for the pharmaceutical industry, so the discovery of new technological tools for the hydrosolubilization of drugs that do not affect their physical–chemical and therapeutic properties will constitute an extraordinary achievement.

On the other hand, from a pharmacological point of view, the search for knowledge of the interaction mechanism and the different properties of drug-controlled release systems is currently of great importance in drug formulation, especially in relation to their efficacy therapy, as well as achieving the correct amount of active ingredient, the right time and the precise place of action.

This Special Issue is dedicated to the latest advances in solubilization and controlled release processes for poorly soluble drugs. We invite authors to submit original research or review articles on these topics, including the development of novel solubilization strategies, as well as innovative alternative methods to obtain new controlled-release pharmaceutical forms, suitable for a specific patient and the pathology to be treated, without forgetting the best form of administration to obtain the optimal efficacy and safety of the drugs.

Dr. María Peña Fernández
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Pharmaceuticals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • drug formulation
  • solubilization
  • controlled release systems
  • solubility
  • poor water-soluble drugs

Published Papers (10 papers)

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Research

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Article
Preparation of Solid Self-Nanoemulsifying Drug Delivery Systems (S-SNEDDS) by Co-Extrusion of Liquid SNEDDS and Polymeric Carriers—A New and Promising Formulation Approach to Improve the Solubility of Poorly Water-Soluble Drugs
Pharmaceuticals 2022, 15(9), 1135; https://doi.org/10.3390/ph15091135 - 11 Sep 2022
Viewed by 313
Abstract
The present study focused on a new formulation approach to improving the solubility of drugs with poor aqueous solubility. A hot melt extrusion (HME) process was applied to prepare drug-loaded solid self-nanoemulsifying drug delivery systems (S-SNEDDS) by co-extrusion of liquid SNEDDS (L-SNEDDS) and [...] Read more.
The present study focused on a new formulation approach to improving the solubility of drugs with poor aqueous solubility. A hot melt extrusion (HME) process was applied to prepare drug-loaded solid self-nanoemulsifying drug delivery systems (S-SNEDDS) by co-extrusion of liquid SNEDDS (L-SNEDDS) and different polymeric carriers. Experiments were performed with L-SNEDDS formulations containing celecoxib, efavirenz or fenofibrate as model drugs. A major objective was to identify a polymeric carrier and process parameters that would enable the preparation of stable S-SNEDDS without impairing the release behavior and storage stability of the L-SNEDDS used and, if possible, even improving them further. In addition to commercially available (co)polymers already used in the field of HME, a particular focus was on the evaluation of different variants of a recently developed aminomethacrylate-based copolymer (ModE) that differed in Mw. Immediately after preparation, the L-SNEDDS and S-SNEDDS formulations were tested for amorphicity by differential scanning calorimetry. Furthermore, solubility and dissolution tests were performed. In addition, the storage stability was investigated at 30 °C/65% RH over a period of three and six months, respectively. In all cases, amorphous formulations were obtained and, especially for the model drug celecoxib, S-SNEDDS were developed that maintained the rapid and complete drug release of the underlying L-SNEDDS even over an extended storage period. Overall, the data obtained in this study suggest that the presented S-SNEDDS approach is very promising, provided that drug-loaded L-SNEDDS are co-processed with a suitable polymeric carrier. In the case of celecoxib, the E-173 variant of the novel ModE copolymer proved to be a novel polymeric carrier with great potential for application in S-SNEDDS. The presented approach will, therefore, be pursued in future studies to establish S-SNEDDS as an alternative formulation to other amorphous systems. Full article
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Article
Bilosomes as Nanoplatform for Oral Delivery and Modulated In Vivo Antimicrobial Activity of Lycopene
Pharmaceuticals 2022, 15(9), 1043; https://doi.org/10.3390/ph15091043 - 24 Aug 2022
Viewed by 246
Abstract
Owing to the disseminating resistance among pathogenic bacteria, especially Klebsiella pneumoniae, there is a high need for alternate compounds with antibacterial activity. Herein, lycopene was isolated from Lycopersicon esculentum L. Molecular docking approach was employed to explore lycopene binding affinity to selected [...] Read more.
Owing to the disseminating resistance among pathogenic bacteria, especially Klebsiella pneumoniae, there is a high need for alternate compounds with antibacterial activity. Herein, lycopene was isolated from Lycopersicon esculentum L. Molecular docking approach was employed to explore lycopene binding affinity to selected vital proteins of K. pneumoniae with the binding mechanisms being investigated. This proposed a promising antibacterial activity of lycopene. However, the pharmacological use of lycopene is hampered by its poor solubility and limited oral bioavailability. Accordingly, bilosomes were fabricated for oral lycopene delivery. The computed entrapment efficiency, mean vesicular size, and zeta potential values for the optimized formulation were 93.2 ± 0.6%, 485.8 ± 35.3 nm, and −38.3 ± 4, respectively. In vitro drug release studies revealed controlled lycopene release from constructed bilosomes, with the drug liberation being based on the Higuchi kinetics model. Transmission electron microscopic evaluation of bilosomes revealed spherical nanovesicles free from aggregates. Moreover, the in vitro and in vivo antibacterial activity of lycopene and its constructed formulations against multidrug-resistant K. pneumoniae isolates were explored. The optimized bilosomes exhibited the lowest minimum inhibitory concentrations ranging from 8 to 32 µg/mL. In addition, scanning electron microscopy revealed remarkable deformation and lysis of the bilosomes-treated bacterial cells. Regarding in vivo investigation, a lung infection model in mice was employed. The tested bilosomes reduced the inflammation and congestion in the treated mice’s lung tissues, resulting in normal-sized bronchioles and alveoli with very few congested vessels. In addition, it resulted in a significant reduction in pulmonary fibrosis. In conclusion, this study investigated the potential activity of the naturally isolated lycopene in controlling infections triggered by multidrug-resistant K. pneumoniae isolates. Furthermore, it introduced bilosomes as a promising biocompatible nanocarrier for modulation of oral lycopene delivery and in vivo antimicrobial activity. Full article
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Article
Determination of the Dissolution/Permeation and Apparent Solubility for Microencapsulated Emamectin Benzoate Using In Vitro and Ex Vivo Salmo salar Intestine Membranes
Pharmaceuticals 2022, 15(6), 652; https://doi.org/10.3390/ph15060652 - 25 May 2022
Cited by 1 | Viewed by 586
Abstract
In this work, two microencapsulation techniques were used to protect and improve the absorption of emamectin benzoate (EB), which is an antiparasitic drug used to control Caligus rogercresseyi. EB has a low aqueous solubility, which affects its absorption in the intestine of [...] Read more.
In this work, two microencapsulation techniques were used to protect and improve the absorption of emamectin benzoate (EB), which is an antiparasitic drug used to control Caligus rogercresseyi. EB has a low aqueous solubility, which affects its absorption in the intestine of Salmo salar. Microparticles were produced by spray drying and ionic gelation, using Soluplus® (EB–SOL) and sodium alginate (EB–ALG) as polymers, respectively. Studies were conducted on dissolution/permeation, apparent permeability (Papp), apparent solubility (Sapp), and absorption using synthetic and biological membranes. Based on these results, the amount of EB in the microparticles needed to achieve a therapeutic dose was estimated. The EB–ALG microparticles outperformed both EB–SOL and free EB, for all parameters analyzed. The results show values of 0.45 mg/mL (80.2%) for dissolution/permeation, a Papp of 6.2 mg/mL in RS–L, an absorption of 7.3% in RS, and a Sapp of 53.1% in EM medium. The EB–ALG microparticles decrease the therapeutic dose necessary to control the parasite, with values of 3.0−2 mg/mL and 1.1−2 mg/mL for EB in EM and RS, respectively. The Korsmeyer–Peppas kinetic model was the best model to fit the EB–ALG and EB–SOL dissolution/permeation experiments. In addition, some of our experimental results using synthetic membranes are similar to those obtained with biological membranes, which suggests that, for some parameters, it is possible to replace biological membranes with synthetic membranes. The encapsulation of EB by ionic gelation shows it is a promising formulation to increase the absorption of the poorly soluble drug. In contrast, the spray-dried microparticles produced using Soluplus® result in even less dissolution/permeation than free EB, so the technique cannot be used to improve the solubility of EB. Full article
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Article
Development of Nanocrystal Compressed Minitablets for Chronotherapeutic Drug Delivery
Pharmaceuticals 2022, 15(3), 311; https://doi.org/10.3390/ph15030311 - 04 Mar 2022
Cited by 2 | Viewed by 799
Abstract
The present work aimed to develop a chronotherapeutic system of valsartan (VS) using nanocrystal formulation to improve dissolution. VS nanocrystals (VS-NC) were fabricated using modified anti-solvent precipitation by employing a Box–Behnken design to optimize various process variables. Based on the desirability approach, a [...] Read more.
The present work aimed to develop a chronotherapeutic system of valsartan (VS) using nanocrystal formulation to improve dissolution. VS nanocrystals (VS-NC) were fabricated using modified anti-solvent precipitation by employing a Box–Behnken design to optimize various process variables. Based on the desirability approach, a formulation containing 2.5% poloxamer, a freezing temperature of −25 °C, and 24 h of freeze-drying time can fulfill the optimized formulation’s requirements to result in a particle size of 219.68 nm, 0.201 polydispersity index, and zeta potential of −38.26 mV. Optimized VS-NC formulation was compressed (VNM) and coated subsequently with ethyl cellulose and HPMC E 5. At the same time, fast dissolving tablets of VS were designed, and the best formulation was loaded with VNM into a capsule size 1 (average fill weight—400–500 mg, lock length—19.30 mm, external diameter: Cap—6.91 mm; Body—6.63 mm). The final tab in cap (tablet-in-capsule) system was studied for in vitro dissolution profile to confirm the chronotherapeutic release of VS. As required, a bi-pulse release of VS was identified with a lag time of 5 h. The accelerated stability studies confirmed no significant changes in the dissolution profiles of the tab in cap system (f2 similarity profile: >90). To conclude, the tab in cap system was successfully developed to induce a dual pulsatile release, which will ensure bedtime dosing with release after a lag-time to match with early morning circadian spikes. Full article
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Article
New IMB16-4 Nanoparticles Improved Oral Bioavailability and Enhanced Anti-Hepatic Fibrosis on Rats
Pharmaceuticals 2022, 15(1), 85; https://doi.org/10.3390/ph15010085 - 11 Jan 2022
Cited by 2 | Viewed by 527
Abstract
Liver fibrosis is challenging to treat because of the lack of effective agents worldwide. Recently, we have developed a novel compound, N-(3,4,5-trichlorophenyl)-2(3-nitrobenzenesulfonamido) benzamide referred to as IMB16-4. However, its poor aqueous solubility and poor oral bioavailability obstruct the drug discovery programs. To increase [...] Read more.
Liver fibrosis is challenging to treat because of the lack of effective agents worldwide. Recently, we have developed a novel compound, N-(3,4,5-trichlorophenyl)-2(3-nitrobenzenesulfonamido) benzamide referred to as IMB16-4. However, its poor aqueous solubility and poor oral bioavailability obstruct the drug discovery programs. To increase the dissolution, improve the oral bioavailability and enhance the antifibrotic activity of IMB16-4, PVPK30 was selected to establish the IMB16-4 nanoparticles. Drug release behavior, oral bioavailability, and anti-hepatic fibrosis effects of IMB16-4 nanoparticles were evaluated. The results showed that IMB16-4 nanoparticles greatly increased the dissolution rate of IMB16-4. The oral bioavailability of IMB16-4 nanoparticles was improved 26-fold compared with that of pure IMB16-4. In bile duct ligation rats, IMB16-4 nanoparticles significantly repressed hepatic fibrogenesis and improved the liver function. These findings indicate that IMB16-4 nanoparticles will provide information to expand a novel anti-hepatic fibrosis agent. Full article
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Article
Chitosan as Valuable Excipient for Oral and Topical Carvedilol Delivery Systems
Pharmaceuticals 2021, 14(8), 712; https://doi.org/10.3390/ph14080712 - 23 Jul 2021
Cited by 5 | Viewed by 1149
Abstract
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 [...] Read more.
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. Full article
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Article
Optimization of Novel Naproxen-Loaded Chitosan/Carrageenan Nanocarrier-Based Gel for Topical Delivery: Ex Vivo, Histopathological, and In Vivo Evaluation
Pharmaceuticals 2021, 14(6), 557; https://doi.org/10.3390/ph14060557 - 11 Jun 2021
Cited by 6 | Viewed by 1624
Abstract
Naproxen (NAP) is commonly used for pain, inflammation, and stiffness associated with arthritis. However, systemic administration is linked with several gastrointestinal tract (GIT) side effects. The present work aims to prepare and evaluate NAP nanoparticulate shells of chitosan (CS) and carrageenan (CRG) loaded [...] Read more.
Naproxen (NAP) is commonly used for pain, inflammation, and stiffness associated with arthritis. However, systemic administration is linked with several gastrointestinal tract (GIT) side effects. The present work aims to prepare and evaluate NAP nanoparticulate shells of chitosan (CS) and carrageenan (CRG) loaded into a Carbopol 940 (Ca-940) gel system with unique features of sustained drug delivery as well as improved permeation through a topical route. Moreover, this study aims to evaluate its ex vivo, histopathological, and in vivo anti-inflammatory activity in albino Wistar rats. The percentage of ex vivo drug permeation patterns in the optimized formulation (No) was higher (88.66%) than the control gel (36.195%). Oral toxicity studies of developed nanoparticles in albino rabbits showed that the NAP-loaded CS/CRG are non-toxic and, upon histopathological evaluation, no sign of incompatibility was observed compared to the control group. A In Vivo study showed that the optimized gel formulation (No) was more effective than the control gel (Nc) in treating arthritis-associated inflammation. The sustained permeation and the absence of skin irritation make this novel NAP nanoparticle-loaded gel based on CS/CRG a suitable drug delivery system for topical application and has the potential for improved patient compliance and reduced GIT-related side effects in arthritis. Full article
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Article
Combinations of Freeze-Dried Amorphous Vardenafil Hydrochloride with Saccharides as a Way to Enhance Dissolution Rate and Permeability
Pharmaceuticals 2021, 14(5), 453; https://doi.org/10.3390/ph14050453 - 11 May 2021
Cited by 4 | Viewed by 1125
Abstract
To improve physicochemical properties of vardenafil hydrochloride (VAR), its amorphous form and combinations with excipients—hydroxypropyl methylcellulose (HPMC) and β-cyclodextrin (β-CD)—were prepared. The impact of the modification on physicochemical properties was estimated by comparing amorphous mixtures of VAR to their crystalline form. The amorphous [...] Read more.
To improve physicochemical properties of vardenafil hydrochloride (VAR), its amorphous form and combinations with excipients—hydroxypropyl methylcellulose (HPMC) and β-cyclodextrin (β-CD)—were prepared. The impact of the modification on physicochemical properties was estimated by comparing amorphous mixtures of VAR to their crystalline form. The amorphous form of VAR was obtained as a result of the freeze-drying process. Confirmation of the identity of the amorphous dispersion of VAR was obtained through the use of comprehensive analysis techniques—X-ray powder diffraction (PXRD) and differential scanning calorimetry (DSC), supported by FT-IR (Fourier-transform infrared spectroscopy) coupled with density functional theory (DFT) calculations. The amorphous mixtures of VAR increased its apparent solubility compared to the crystalline form. Moreover, a nearly 1.3-fold increase of amorphous VAR permeability through membranes simulating gastrointestinal epithelium as a consequence of the changes of apparent solubility (Papp crystalline VAR = 6.83 × 10−6 cm/s vs. Papp amorphous VAR = 8.75 × 10−6 cm/s) was observed, especially for its combinations with β-CD in the ratio of 1:5—more than 1.5-fold increase (Papp amorphous VAR = 8.75 × 10−6 cm/s vs. Papp amorphous VAR:β-CD 1:5 = 13.43 × 10−6 cm/s). The stability of the amorphous VAR was confirmed for 7 months. The HPMC and β-CD are effective modifiers of its apparent solubility and permeation through membranes simulating gastrointestinal epithelium, suggesting a possibility of a stronger pharmacological effect. Full article
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Article
Development of a Solid Dispersion of Nystatin with Maltodextrin as a Carrier Agent: Improvements in Antifungal Efficacy against Candida spp. Biofilm Infections
Pharmaceuticals 2021, 14(5), 397; https://doi.org/10.3390/ph14050397 - 22 Apr 2021
Cited by 3 | Viewed by 910
Abstract
The aim of this study was to improve the treatment of Candida albicans biofilms through the use of nystatin solid dispersions developed using maltodextrins as a hyperosmotic carrier. Characterization studies by differential scanning calorimetry, X-ray diffraction, dissolution studies, and particle size analysis were [...] Read more.
The aim of this study was to improve the treatment of Candida albicans biofilms through the use of nystatin solid dispersions developed using maltodextrins as a hyperosmotic carrier. Characterization studies by differential scanning calorimetry, X-ray diffraction, dissolution studies, and particle size analysis were performed to evaluate changes in nystatin crystallinity. Antifungal activity and anti-biofilm efficacy were assessed by microbiological techniques. The results for nystatin solid dispersions showed that the enhancement of antifungal activity may be related to the high proportions of maltodextrins. Anti-biofilm assays showed a significant reduction (more than 80%) on biofilm formation with SD-N:MD [1:6] compared to the nystatin reference suspension. The elaboration process and physicochemical properties of SD-N:MD [1:6] could be a promising strategy for treatment of Candida biofilms. Full article
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Review

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Review
Technologies for Solubility, Dissolution and Permeation Enhancement of Natural Compounds
Pharmaceuticals 2022, 15(6), 653; https://doi.org/10.3390/ph15060653 - 25 May 2022
Viewed by 694
Abstract
The current review is based on the advancements in the field of natural therapeutic agents which could be utilized for a variety of biomedical applications and against various diseases and ailments. In addition, several obstacles have to be circumvented to achieve the desired [...] Read more.
The current review is based on the advancements in the field of natural therapeutic agents which could be utilized for a variety of biomedical applications and against various diseases and ailments. In addition, several obstacles have to be circumvented to achieve the desired therapeutic effectiveness, among which limited dissolution and/or solubility and permeability are included. To counteract these issues, several advancements in the field of natural therapeutic substances needed to be addressed. Therefore, in this review, the possible techniques for the dissolution/solubility and permeability improvements have been addressed which could enhance the dissolution and permeability up to several times. In addition, the conventional and modern isolation and purification techniques have been emphasized to achieve the isolation and purification of single or multiple therapeutic constituents with convenience and smarter approaches. Moreover, a brief overview of advanced natural compounds with multiple therapeutic effectiveness have also been anticipated. In brief, enough advancements have been carried out to achieve safe, effective and economic use of natural medicinal agents with improved stability, handling and storage. Full article
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