CONTEXT: The preparation of liquisolid systems (LSS) represents a promising method for enhancing a dissolution rate and bioavailability of poorly soluble drugs. The release of the drug from LSS tablets is affected by many factors, including the disintegration time. OBJECTIVE: The evaluation of differences among LSS containing varying amounts and types of commercially used superdisintegrants (Kollidon® CL-F, Vivasol® and Explotab®). MATERIALS AND METHODS: LSS were prepared by spraying rosuvastatin solution onto Neusilin® US2 and further processing into tablets. Varying amounts of superdisintegrants were used and the differences among LSS were evaluated. The multiple scatter plot method was used to visualize the relationships within the obtained data. RESULTS AND DISCUSSION: All disintegrants do not showed negative effect on the flow properties of powder blends. The type and concentration of superdisintegrant had an impact on the disintegration time and dissolution profiles of tablets. Tablets with Explotab® showed the longest disintegration time and the smallest amount of released drug. Fastest disintegration and dissolution rate were observed in tablets containing Kollidon® CL-F (≥2.5% w/w). Also tablets with Vivasol® (2.5-4.0% w/w) showed fast disintegration and complete drug release. CONCLUSION: Kollidon® CL-F and Vivasol® in concentration ≥2.5% are suitable superdisintegrants for LSS with enhanced release of drug.

• MeSH
• anticholesteremika aplikace a dávkování   chemie   MeSH
• farmaceutické pomocné látky chemie   MeSH
• povidon chemie   MeSH
• příprava léků MeSH
• rosuvastatin kalcium aplikace a dávkování   chemie   MeSH
• rozpustnost MeSH
• silikáty chemie   MeSH
• škrob analogy a deriváty   chemie   MeSH
• sloučeniny hliníku chemie   MeSH
• sloučeniny hořčíku chemie   MeSH
• tablety chemie   MeSH
• uvolňování léčiv MeSH
• Publikační typ
• časopisecké články MeSH

To enhance dissolution rate of meloxicam (MX), a poorly soluble model drug, a natural polysaccharide excipient chitosan (CH) is employed in this work as a carrier to prepare binary interactive mixtures by either mixing or co-milling techniques. The MX-CH mixtures of three different drug loads were characterized for morphological, granulometric, and thermal properties as well as drug crystallinity. The relative dissolution rate of MX was determined in phosphate buffer of pH 6.8 using the USP-4 apparatus; a significant increase in MX dissolution rate was observed for both mixed and co-milled mixtures comparing to the raw drug. Higher dissolution rate of MX was evidently connected to surface activation by mixing or milling, which was pronounced by the higher specific surface energy as detected by inverse gas chromatography. In addition to the particle size reduction, the carrier effect of the CH was confirmed for co-milling by linear regression between the MX maximum relative dissolution rate and the total surface area of the mixture (R2 = 0.863). No MX amorphization or crystalline structure change were detected. The work of adhesion/cohesion ratio of 0.9 supports the existence of preferential adherence of MX to the coarse particles of CH to form stable interactive mixtures.

• MeSH
• chitosan * MeSH
• meloxikam MeSH
• pomocné látky MeSH
• rozpustnost MeSH
• Publikační typ
• časopisecké články MeSH

Co-milling of a drug with a co-former is an efficient technique to improve the solubility of drugs. Besides the particle size reduction, the co-milling process induces a structural disorder and the creation of amorphous regions. The extent of drug solubility enhancement is dependent on the proper choice of co-milling co-former. The aim of this work was to compare the effects of different co-formers (meglumine and polyvinylpyrrolidone) on the dissolution rates of glass forming (indomethacin) and non-glass forming (mefenamic acid) model drugs. A positive impact of the co-milling on the dissolution behavior was observed in all co-milled mixtures, even if no substantial amorphization was observed. While meglumine exhibited pronounced effects on the dissolution rate of both drugs, the slightest enhancement was observed in mixtures with polyvinylpyrrolidone. The evaluation of specific release rate revealed the surface activation of drug particle is responsible for improving the dissolution rate of both drug types, but for the glass former, this surface activation could be persistent while maintaining a high dissolution rate even until a high fraction of drug is released. Our results, therefore, indicate that adequate co-former choice and consideration of drug glass forming ability are important for a successful co-milling approach to poorly water-soluble drugs.

• MeSH
• indomethacin MeSH
• léčivé přípravky * MeSH
• povidon * MeSH
• příprava léků MeSH
• rozpustnost MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH

A nanofibrous membrane carrier for nearly water insoluble drug diosmin was formulated. The aim of this study was to evaluate the drug release and dissolution properties in an aqueous buffer of pH 7.8, and to compare the suitability of the drug carrier with the available drug forms and screen diosmin absorption extent. The membranes were produced from HPC/PVA/PEO-drug water solutions and then evaluated by SEM and DSC measurements. The results showed that diosmin was incorporated within the nanofibers in an amorphous state, and/or as a solid dispersion. The results of in vitro release experiments excerpt a very fast release of the drug, followed by the formation of an over saturated solution and partial precipitation of the drug (a "spring" effect). The enormous increases in dissolution of the drug from a nanofibrous carrier, compared to a micronized and crystalline form, was achieved. The in vivo bioavailability study carried out on rats showed higher initial drug plasma levels and higher AUC values after administration of the nanofibrous drug formulation, compared to the micronized form. The results of the study demonstrated that the improvement of the diosmin in vitro dissolution also brought the enhanced in vivo absorption extent of the drug.

• MeSH
• aplikace orální MeSH
• diosmin aplikace a dávkování   krev   chemie   farmakokinetika   MeSH
• intestinální absorpce MeSH
• nanovlákna aplikace a dávkování   chemie   MeSH
• nosiče léků aplikace a dávkování   chemie   farmakokinetika   MeSH
• potkani Wistar MeSH
• příprava léků metody   MeSH
• rozpustnost MeSH
• roztoky MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The paper brings an overview of most important methods for attaining the purpose, such as solubilization using tensides, cosolvents, chelates, cyclodextrins, pH modifiers, interactive powder mixtures, forming solid dispersions and microgranulates. The review summarizes main advantages and drawbacks of the methods and gives some examples. Although, the most frequently used technology in pharmaceutical industry is currently drug micronization, the above methods offer a well established way of enhancing solubility of drugs in water.

• MeSH
• farmaceutická technologie MeSH
• farmaceutická vehikula chemie   MeSH
• farmaceutické pomocné látky chemie   MeSH
• financování organizované MeSH
• léčivé přípravky chemie   MeSH
• rozpustnost MeSH

Commonly applied approaches to enhance the dissolution properties of low water-soluble crystalline active pharmaceutical ingredients (APIs) include their amorphization by incorporation into a polymeric matrix and the formation of amorphous solid dispersions, or blending APIs with low-molecular-weight excipients and the formation of a co-amorphous system. This study focused on the preparation and characterization of binary (consisting of indomethacin (IND) and polymer - copovidone (PVP VA 64), as a carrier, or amino acid - L-arginine (ARG), as a co-former) and ternary (comprising the same API, polymer, and amino acid) formulations. Formulations were produced by ball milling (BM) and/or hot-melt extrusion (HME), and extensive physicochemical characterization was performed. Specifically, the physicochemical and solid-state properties of a model IND-ARG system incorporated into a polymeric matrix of PVP VA 64 by HME and BM as well as by combined BM/HME method together with the impact of the preparation strategy on the dissolution profiles and long-term physical stability were investigated. Ball-milled binary and ternary formulations were found to be amorphous. The residual crystals corresponding to IND-ARG salt were identified in the ternary formulations produced via HME. Despite the presence of a crystalline phase, dissolution tests showed that ternary systems prepared by HME exhibited improved IND solubility when compared to pure crystalline IND and their corresponding physical mixture. None of the binary and ternary formulations that were initially fully amorphous did undergo recrystallization during the entire period of preservation (minimum of 12 months) in dry conditions at 25 °C.

• MeSH
• arginin * MeSH
• indomethacin * MeSH
• polymery MeSH
• rozpustnost MeSH
• vinylové sloučeniny MeSH
• Publikační typ
• časopisecké články MeSH

Merala sa rozpustnost kalciového antagonistu nimodipínu vo vode a vo vodných roztokoch β-cyklodextrínu (β-CD, až 0,014 mol/l) a rozpustnejšieho hydroxypropyl-β-cyklodextrínu (HP-β-CD, až 0,05 mol/l) s priememým stupňom substitúcie 0,8. Zvýšenie rozpustnosti bolo priamoúmerné koncentrácii cyklodextrínu, pričom v roztoku β-CD bola rozpustnost nimodipínu až 2,2 mg/100 ml, v roztoku HP-β-CD až 6 mg/100 ml, za daných podmienok po 14 dňoch rozpúšťania. Riedením vodou sa takto solubilizovaný nimodipín nezráža. Zo smerníc lineárnych fázových diagramov rozpustnosti sa vypočítali príslušné asociačné konštanty tvorby inklúznych komplexov (1:1) v roztoku nimodipínu s β-CD (401 mol-1 1) a s HP-p-CD (268 mol-1 1). Kinetika rozpúšťania substancie nimodipínu v roztoku HP-β-CD sledovaná od 3 min. až po 14 dní sa vyznačovala oscilováním medzi presýteným roztokom a rozpúšťacou rovnováhou, pre prípravu stálych roztokov v rozpúšťacej rovnováhe sa preto odporúča merať disolučnú krivku v dlhšom časovom intervale. Rozotieracou metódou sa pripravili veľmi lahko rozpustné tuhé zmesi nimodipínu s HP-β-CD a termickou analýzou sa dokázala tvorba tuhého komplexu 1:1.

The solubility of the calcium antagonist nimodipine was measured in water and in aqueous solutions of both β-cyclodextrin (β-CD, up to 0.014 mol/l) and the more soluble hydroxypropyl-β-cyclodextrin (HP-β-CD, up to 0.05 mol/l) with an average substitution degree of 0.8. The solubility enhancement of nimodipine was proportional to the cyclodextrin concentration, it was up to 2.2 mg/100 ml and 6 mg/100 ml in the respective solutions of β-CD and HP-β-CD, under the studied conditions, after 14 days of nimodipine dissolution. The solubilized nimodipine does not precipitate on diluting the Solutions with water. The association constant of the inclusion complexes (1:1) were evaluated from the slopes of the linear phase solubility diagrams of nimodipine in the respective solutions of β-CD (401 mol-1 1) and HP-β-CD (268 mol-1 1). The kinetics of dissolution of the solid nimodipine in the solution of HP-β-CD was followed from 3 min till 14 days and oscillations between the supersaturation and the equilibrium solution were observed. Long term measurements of the dissolution curve are thus recommended if stable solutions, in terms of the solubility equilibrium, are to be prepared. Easily soluble solid mixtures of nimodipine with HP-β-CD were prepared by the kneading method and the formation of the solid complex 1:1 was demonstrated by the differential thermal analysis.

• MeSH
• cyklodextriny farmakokinetika   farmakologie   MeSH
• nimodipin farmakokinetika   farmakologie   MeSH
• rozpustnost MeSH

Bioavailability of baicalin (BAI), an example of traditional Chinese medicine, has been modified by loading into liposome. Several liposome systems of different composition i.e., lipid/cholesterol (L), long-circulating stealth liposome (L-PEG) and folate receptor (FR)-targeted liposome (L-FA) have been used as the drug carrier for BAI. The obtained liposomes were around 80 nm in diameter with proper zeta potentials about -25 mV and sufficient physical stability in 3 months. The entrapment efficiency and loading efficiency of BAI in the liposomes were 41.0-46.4% and 8.8-10.0%, respectively. The morphology details of BAI lipsosome systems i.e., formation of small unilamellar vesicles, have been determined by cryogenic transmission electron microscopy (cryo-TEM) and small angle X-ray scattering (SAXS). In vitro cytotoxicity of BAI liposomes against HeLa cells was evaluated by MTT assay. BAI loaded FR-targeted liposomes showed higher cytotoxicity and cellular uptake compared with non-targeted liposomes. The results suggested that L-FA-BAI could enhance anti-tumor efficiency and should be an effective FR-targeted carrier system for BAI delivery.

• MeSH
• antiflogistika nesteroidní chemie   farmakokinetika   farmakologie   MeSH
• difrakce rentgenového záření MeSH
• elektronová kryomikroskopie MeSH
• flavonoidy chemie   farmakokinetika   farmakologie   MeSH
• folátové receptory zakotvené GPI antagonisté a inhibitory   metabolismus   MeSH
• HeLa buňky MeSH
• konfokální mikroskopie MeSH
• kyselina listová analogy a deriváty   chemie   MeSH
• lidé MeSH
• liposomy chemie   ultrastruktura   MeSH
• maloúhlový rozptyl MeSH
• nádory děložního čípku metabolismus   patologie   MeSH
• polyethylenglykoly chemie   MeSH
• stabilita léku MeSH
• transmisní elektronová mikroskopie MeSH
• uvolňování léčiv MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Plant mucilages are commonly employed as excipients in pharmaceutical manufacturing. Ocimum basilicum (Lamiaceae family), a source of hydrophilic mucilage referred herein as Ocicum, was evaluated for the solubility enhancer of a model drug, aceclofenac, in solid dispersions prepared using different methods. Polymer was extracted from O. basilicum and solid dispersions of aceclofenac were fabricated with Ocicum or Poloxamer 407 using polymer-to-drug ratios of 1:1, 1:2 and 1:3 utilizing solvent evaporation, lyophilization and melt methods. Ocicum was evaluated for its safety via acute toxicity study including different biochemical and hematological parameters including liver and kidney profiles. Moreover, different characterization studies including melting-point, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and differential thermal analysis (TGA) were used for evaluation of polymer and solid dispersions. Furthermore, solubility and dissolution studies were performed to confirm solubility enhancement. Ocicum was found to be safer, and different characterization studies confirmed the purity of the compounds. In addition, Ocicum exhibited up to 6.27-fold enhanced solubility as compared to pure aceclofenac; similarly, 4.51-fold increased solubility by the synthetic polymer in their respective solid dispersions was shown. Furthermore, Ocicum-based solid dispersions showed substantial improvement in dissolution of aceclofenac. Therefore, it can be concluded from the above-mentioned results that Ocicum might be used as an economical natural oral delivery carrier alternative to the synthetic polymers.

• Publikační typ
• časopisecké články MeSH

Signal enhancements of up to two orders of magnitude in protein NMR can be achieved by employing HDO as a vector to introduce hyperpolarization into folded or intrinsically disordered proteins. In this approach, hyperpolarized HDO produced by dissolution-dynamic nuclear polarization (D-DNP) is mixed with a protein solution waiting in a high-field NMR spectrometer, whereupon amide proton exchange and nuclear Overhauser effects (NOE) transfer hyperpolarization to the protein and enable acquisition of a signal-enhanced high-resolution spectrum. To date, the use of this strategy has been limited to 1D and 1H-15N 2D correlation experiments. Here we introduce 2D 13C-detected D-DNP, to reduce exchange-induced broadening and other relaxation penalties that can adversely affect proton-detected D-DNP experiments. We also introduce hyperpolarized 3D spectroscopy, opening the possibility of D-DNP studies of larger proteins and IDPs, where assignment and residue-specific investigation may be impeded by spectral crowding. The signal enhancements obtained depend in particular on the rates of chemical and magnetic exchange of the observed residues, thus resulting in non-uniform 'hyperpolarization-selective' signal enhancements. The resulting spectral sparsity, however, makes it possible to resolve and monitor individual amino acids in IDPs of over 200 residues at acquisition times of just over a minute. We apply the proposed experiments to two model systems: the compactly folded protein ubiquitin, and the intrinsically disordered protein (IDP) osteopontin (OPN).

• MeSH
• lidé MeSH
• nukleární magnetická rezonance biomolekulární * MeSH
• osteopontin chemie   MeSH
• ubikvitin chemie   MeSH
• vnitřně neuspořádané proteiny chemie   MeSH
• voda chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH