Encapsulation of benznidazole in nanostructured lipid carriers and increased trypanocidal activity in a resistant Trypanosoma cruzi strain

Abstract Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi, whose treatment has remained unsatisfactory for over 50 years, given that it is limited to two drugs. Benznidazole (BZN) is an efficient antichagasic drug used as the first choice, although its poor water-solubility, irregular oral absorption, low efficacy in the chronic phase, and various associated adverse effects are limiting factors for treatment. Incorporating drugs with such characteristics into nanostructured lipid carriers (NLC) is a promising alternative to overcome these limiting obstacles, enhancing drug efficacy and bioavailability while reducing toxicity. Therefore, this study proposed NLC-BZN formulations in different compositions prepared by hot-melt homogenization followed by ultrasound, and the optimized formulation was characterized by FTIR, DRX, DSC, and thermogravimetry. Biological activities included in vitro membrane toxicity (red blood cells), fibroblast cell cytotoxicity, and trypanocidal activity against epimastigotes of the Colombian strain of T. cruzi. The optimized NLC-BZN had a small size (110 nm), negative zeta potential (-18.0 mV), and high encapsulation (1.64% of drug loading), as shown by infrared spectroscopy, X-ray diffraction, and thermal analysis. The NLC-BZN also promoted lower in vitro membrane toxicity (<3% hemolysis), and 50% cytotoxic concentration (CC50) for NLC-BZN in L929 fibroblast cells (110.7 µg/mL) was twice the value as the free BZN (51.3 µg/mL). Our findings showed that the NLC-BZN had higher trypanocidal activity than free BZN against the epimastigotes of the resistant Colombian strain, and this novel NLC-BZN formulation proved to be a promising tool in treating Chagas disease and considered suitable for oral and parenteral administration

Advances in nanocrystal technology and its application to improve the pharmacological efficacy for poorly-water soluble drugs / 药学学报

In order to solve the problems of erratic drug absorption and low bioavailability after oral administration for poorly-water soluble drugs due to low solubility, a series of novel pharmaceutical dosage forms as solid dispersion, liposome, microemulsion, vesicle, cyclodextrin inclusion complexes and drug nanocrystal have been developed in recent years. Among which drug nanocrystal attracts more attentions for its simpler preparation method, higher drug loading and easier manufacturing technology in the design of dosage forms suitable for different administration routes. In this paper, the nanocrystals of the poorly-water soluble drugs prepared based on bottom-up and top-down technologies were introduced. The characteristics and applications of the nanocrystal-based dosage forms as suspension, tablet and capsule were also introduced and carefully evaluated with the focus on their pharmacokinetics, pharmacodynamics and tissue targeted drug distribution after delivery by oral administration, intravenous injection and pulmonary inhalation. The advantages of drug nanocrystals in their therapeutics effects over the bulk drugs were discussed together with the inherent mechanism. Finally, the problems existing in basic research and scaled-up manufacture of drug nanocrystal as well as the possible ways of solution were listed out so as to make the nanocrystal-based preparations exert their maximum therapeutic effect after clinical application.

Tert-butanol application and related research progress in biomedicine / 药学学报

italic>Tert-butanol is an organic solvent, widely used in the medical field and chemical industry. It could be characterized by high crystallization temperature and vapor pressure. It could be easily sublimed and removed during the freeze-drying process. This review mainly describes the use of tert-butanol in the lyophilized formulations of poorly soluble drugs, the lyophilization solvent of porous structure productions, and as an ice crystal growth guider. In addition, the application of tert-butanol in nano drugs and aerogels has also been reviewed, as well as the current research progress in its quality and safety.

Biphasic dissolution test and its application in the evaluation of poorly soluble drug preparations / 药学学报

Biphasic dissolution test, consisting of immiscible aqueous and organic phase, is an in vitro dissolution method that simultaneously measures the dissolution and partition of drugs. Due to the advantages of simulating in vivo absorption and overcoming the influence of surfactants on dissolution, it has been widely used to evaluate the poorly soluble drugs in vitro dissolution. Based on the relevant research in this field in recent years, this review summarizes the history, dissolution device, theoretical model and application of the biphasic dissolution test. Finally, the prospects in the development of biphasic dissolution test are also outlined.

Desenvolvimento e caracterização de dispersões sólidas de efavirenz / Development and characterization of efavirenz solid dispersions

A baixa solubilidade aquosa dos insumos farmacêuticos ativos (IFA) é um grande desafio no desenvolvimento de formulações farmacêuticas, pois pode resultar em biodisponibilidade insuficiente e variável. Diversas estratégias de modificação do estado sólido dos compostos ativos, têm sido propostas para incrementar a solubilidade de fármacos pouco solúveis em água. Dentre as estratégias abordadas a ispersão sólida (DS) é uma das formas mais promissoras de aumentar a solubilidade, dissolução e a biodisponibilidade de IFAs com baixa solubilidade aquosa. O efavirenz (EFV) é um inibidor não nucleosídeo da transcriptase reversa (NNRTI) e um dos componentes da terapia antirretroviral de alta atividade (HAART), sendo parte da primeira linha de tratamento de infecções do vírus HIV tipo 1. O antirretroviral está classificado como pertencente à classe II do SCB, e exibe baixa solubilidade aquosa (solubilidade menor que 10 µg/mL) e alta permeabilidade com absorção dependente da taxa de dissolução, resultando em biodisponibilidade oral baixa e variável. A administração de fármacos pouco solúveis na forma de DS é um método atraente para aumentar a biodisponibilidade in vivo. Neste estudo, um método de triagem rápida por evaporação de solvente foi empregado para preparar DS de EFV, variando-se proporções em misturas compostas pelos carreadores, polivinilpirrolidona K-28/32 (PVP K-28/32), copovidona (CoPVP), hidroxipropilmetilcelulose ftalato (HPMCP-50, HPMCP-55 e HPMCP-55s), poloxâmero 188 (P188) e poloxâmero 407 (P407). A solubilidade das DS foi avaliada por meio do método do equilíbrio (shake-flask), onde selecionou-se os polímeros P188 e P407 que conduziram a uma elevada capacidade de saturação em meio aquoso, superior a 1.000 vezes ao fármaco puro. As propriedades físico-químicas e do estado sólido das amostras foram avaliadas por meio de calorimetria exploratória diferencial (DSC); termogravimetria (TG); espectroscopia do infravermelho com transformada de Fourier (FTIR), difratometria de raios X pelo método do pó (DRXP) e ensaios de dissolução com emprego do aparato IV USP. Os resultados de DRXP demonstraram que os carreadores P188 e P407 foram capazes de estabilizar o EFV na forma amorfa nas DS, fato esse evidenciado pela ausência de picos característicos do antirretroviral

he low aqueous solubility of the active pharmaceutical ingredient (API) is a major challenge in the development of pharmaceutical formulations as it may result in insufficient and variable bioavailability. Several strategies for modifying the solid-state of the active compounds have been proposed to increase solubility of drugs that are poorly soluble in water. Among the strategies approaches, solid dispersion (SD) is one of the most promising ways to increase solubility, dissolution and bioavailability of APIs with low aqueous solubility. Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and one of the components of highly active antiretroviral therapy (HAART), being part of the first line of treatment of type 1 HIV virus infections. The antiretroviral is classified as belonging to BCS class II, and exhibits low aqueous solubility (solubility less than 10 µg / mL) and high permeability with dissolution ratedependent absorption, resulting in low and variable oral bioavailability. Drug delivery of poorly aqueous soluble drugs in form SD is an appealing method to increase in vivo bioavailability. In this study, a fast screening method of solvent evaporation method was used to prepare EFV SD, varying the proportions in mixtures composed by the carriers polyvinylpyrrolidone K-28/32 (PVP K-28/32), copovidone (CoPVP), hydroxypropylmethylcellulose phthalate (HPMCP-50, HPMCP-55 e HPMCP-55s), poloxamer 188 (P188) e poloxamer 407 (P407). The solubility of the samples was evaluated by the method of equilibrium (shake-flask), wherein the polymers P188 and P407 were selected due to the capacity to promote high saturation in aqueous medium, 1,000 times superior to the pure drug. The physicochemical and solid-state properties of the samples were evaluated by differential scanning calorimetry (DSC); thermogravimetry (TG); Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and dissolution assays using the IV USP apparatus. The results of XRPD demonstrated that the carriers P188 and P407 were able to stabilize the EFV in amorphous form in the SD, a fact evidenced by the absence of characteristic peaks of the antiretroviral

The Improvement Of Betulin-3, 28-Diphosphate Water-Solubility By Complexation With Amines–Meglumine And Xymedon

Objective: To study betulin-3,28-diphosphate (BDP) water solubility improved by forming salt complexes with hydrophilic amino alcohols: meglumine as acidosis corrector and xymedon as the water-soluble antioxidant. Methods: We used 13C-, 31P-NMR, UV-spectroscopy and potentiometric titration to study the BDP-amine salt complexes formation and their solubility using HPLC-analysis. Results: The participation of xymedon in the proton transfer reaction with BDP in aqueous solutions was confirmed by the bathochromic shift of the carbonyl band from 299.1 nm to 304.2 nm, and by a hyperchromic effect (molar extinction ε from 8508 to 10 441 l·mol-1·cm-1) in UV-spectra. BDP complexation with meglumine was estimated by UV-spectral molar ratio method at 256 nm. Molar ratio of BDP-amine complexes (1:4) was proved by 31P-NMR. The chemical shift of phosphorus at C-3 atom of BDP (δ =-0.58 ppm) changed to+3.39 ppm, and at C-28 atom (δ =+0.28 ppm)–to+4.60 ppm. BDP solubility increased 100-600 fold according to HPLC-analysis. Conclusion: BDP interaction with amine in an aqueous solution was shown to proceed via a proton transfer due to relatively weak forces such as London forces, hydrogen bonding, electrostatic and hydrophobic interactions. In general, the formation of BDP salt complexes with amines in solution determines BDP water solubility. Water-soluble BDP enables to develop hydrophilic dosage forms.

Delivery of Poorly Water Soluble Lidocaine by Dissolving Microneedles / 中国药学杂志

OBJECTIVE: To prepare dissolving microneedles using Gantrez S-97 and PVPk30 as composite matrix materials to accelerate the delivery of poorly water soluble drugs and study the preparation, appearance, mechanical properties, intradermal solubility, drug efficacy and crystallization behavior of dissolving microneedles. METHODS: Using polydimethylsiloxane(PDMS) as the negative mode, microneedles were prepared by the reverse casting method. SEM was used to observe the morphological appearance of the microneedles. The mechanical properties of the microneedles were investigated by texture analyzer and histological sections. Delivery of lidocaine was characterized by intradermal dissolution and pharmacodynamics. Crystallization behavior of lidocaine was characterized by DSC. RESULTS: Lidocaine dissolving microneedles had good needle shape and possessed sufficient mechanical strength to penetrate into the skin. The microneedles could dissolve in the dermis within 3 min and retain anesthetic effect, and the drug existed in amorphous form in the microneedles. CONCLUSION: Cosolvent preparation of dissolving microneedles has potential for promoting the delivery of poorly water soluble drugs.

Application of supercritical fluid precipitation technology for preparation of poorly water-soluble drugs / 中国药学杂志

To improve the dissolution and bioavailability of poorly water-soluble drugs have been being emphasis and difficulty in pharmaceutical research. Supercritical fluid precipitation(SFP) technology has an extensive prospect in new drug delivery systems of the poorly water-soluble drugs base on its advantages, such as green, friendliness to the environment and it is possible to achieve industrial-scale production. In this paper, related literatures were retrieved to summarize the application of SFP for preparation of poorly water-soluble drugs in recent years.

Recent progress on the solubility improvement for poorly water-soluble drugs by forming solid dispersions with novel carriers and advanced techniques / 中国药学杂志

To improve the in vitro dissolution and in vivo absorption as well as the bioavailability after oral administration by increasing the solubility with the formation of solid dispersion remains a great challenge for the oral dosage form design of poorly water-soluble drugs. Compared with the other pharmaceutical techniques in improving the solubility for poorly water-soluble drugs, priorities are usually given to solid dispersion for its manufacturing convenience. Following the characteristics introduction, we were focused this review on the novel carriers and advanced techniques used for preparing solid dispersions. Amphiphilic polymers used as novel solid dispersion carriers are Solutol HS 15, Soluplus and poly [MPC-co-BMA]. Inorganic materials like magnesium aluminum metasilicat, mesoporous silica microparticle and mesoporous magnesium carbonate are introduced together with the advanced solid dispersing techniques such as supercritical fluid technology, high speed electro-spinning and microenvironmental pH modified technology.

Preparation of porous starch foam to improve the dissolution rate of dabigatran etexilate / 中国药学杂志

OBJECTIVE: To prepare porous starch foam to improve the solubility and dissolution rate of dabigatran etexilate. METHODS: Porous starch foam (PSF) was synthesized as a carrier by solvent exchange method. Dabigatran etexilate (DE) was loaded onto the nanopores of PSF by solvent evaporation method. Scanning electron microscopy was used for investigating the morphology and structure of PSF. The dispersal state of DE in drug-loaded sample (PSF-DE) was determined by differential scanning calorimetry, powder X-ray diffraction and fourier transform infrared spectroscopy. The dissolution rate was measured by in-vitro dissolution experiment. RESULTS: Porous starch foam was prepared successfully and the spatial restriction of nanopores effectively suppressed crystal-linity of dabigatran etexilate as shown by structure characterization. The in-vitro dissolution experiment showed that the dissolution rate; of dabigatran etexilate was improved significantly. CONCLUSION: Porous starch foam can improve the hydrophilicity of the poorly water-soluble drug dabigatran etexilate.

Selection of surfactants and dissolution profiles of nimesulide sustained-release tablets / 军事医学

Objective To study the effect of surfactants on the dissolution profiles of poorly water-soluble acidic drug nimesulide from sustained-release tablets.Methods The anionic surfactant sodium dodecyl sulfate (SDS), cationic sur-factant cetyltrimethyl ammonium bromide (CTAB) and nonionic surfactant polysorbate 80 (Tween 80) were used to prepare nimesulide micelles .The effect of the buffer , surfactant and ionic strength on the equilibrium solubility of the drug and the in vitro release of sustained-release tablets was studied .Results and Conclusion In pH 1.2 HCl solution, water and pH 6.8 phosphate buffer, the solubilization capacity of CTAB was the highest.However, in pH 9.0 Tris buffer, when CTAB concen-tration was at about 1%, the equilibrium solubility of nimesulide was at the trough value .The in vitro release results were similar to those of equilibrium solubility and the kinetic pattern conformed to the first order equation according to the coefficient R .

Inclusion of quercetin in amino-group modified ordered mesoporous silica: drug loading and release properties / 中国药学杂志

OBJECTIVE: To prepare amino-modified ordered mesoporous silica (NH2-OMS) as a drug carrier and test the loading and release properties of poorly water soluble drug carried by it. METHODS: OMS was first prepared using cetyltrimethyl ammonium bromide as the template and then modified by 3-aminopropyl trimethoxy silane to prepare NH2-OMS. N2 adsorption-desorption, X-ray diffraction and thermogravimetric analysis were used to characterize the NH2-OMS. Quercetin was loaded onto NH2-OMS in order to explore the drug loading properties of NH2-OMS. RESULTS: The drug loading and entrapment efficiency of quercetin-NH2-OMS were about 21.0% and 58.2%, respectively, when the concentration of quercetin was 4 mmol·L-1, the reaction time was 24 h and the temperature was set at 50°C. The in vitro release test demonstrated that quercetin-NH2-OMS could form supersaturated solution in simulated intestinal fluid and gastric fluid at concentrations of 13-fold and 27-fold of the thermodynamic solubility of quercetion. CONCLUSION: NH2-OMS, as the carrier for quercetin, can significantly increase its water solubility and release rate in intestinal and gastric fluids.

Preparation of iguratimod solid dispersion via hot-melt extrusion and investigation of factors affecting dissolution profile / 中国药学杂志

OBJECTIVE: To identify a suitable polymer system for iguratimod (T-614), a poorly water-soluble compound with high melting point, and prepare a chemically stable single phase solid dispersion (SD) of T-614 by hot-melt extrusion (HME) technique to enhance its dissolution rate. METHODS: Melting method and adsorption based screening techniques were utilized to screen hydrophilic polymers suitable for immediate release formulations. T-614 SDs were prepared with polymer carriers such as PVP/VA 64, Soluplus, HPMC AS-LF and HPC-SL via HME below the drug melting point, and suitable temperature and plasticizer for HME were chosen. The dissolution behaviors of SD powder and SD tablets were compared with those of T-614 powder and commercial T-614 tablets, respectively. State of T-614 in HME SDs was characterized by X-ray powder diffraction. The homogenous SD tablets were analyzed further for physical stability in an influencing factors test. The bioavailability of SD tablets was assessed in rats. RESULTS: Results of the screening studies demonstrated that PVP/VA 64, Soluplus, HPMC AS-LF and HPC-SL provided higher degree of miscibility and dissolution enhancement. The HWE SD tablets showed significantly enhanced dissolution. The supersaturation state of HME SD powder in water was maintained for at least 120 min, suggesting that PVP/VA 64 had an inhibitory effect on recrystallization of T-614 from a supersaturated solution. Samples prepared via HME at 160°C were substantially amorphous, which were unchanged in the influencing factors test at high temperature and strong light, but recrystallization occurred at high humidity. PEG1500 appeared to be a promising plasticizer. Same bioavailability was achieved when compared with commercial T-614 tablets. CONCLUSION: The polymersas carriers for T-614 SD have significant impact on the dissolution behavior and state of T-614. Using PVP/VA 64 as the carrier, hot-melt extrusion is an effective technology for improving the in vitro dissolution of T-614.