Increasing the dissolution rate and oral bioavailability of the poorly water-soluble drug valsartan using novel hierarchical porous carbon monoliths

Application of Multivariate Methods to Evaluate Differential Material Attributes of HPMC from Different Sources

The aim of the present study is to achieve differential material attributes (DMAs) of hydroxypropyl methylcellulose (HPMC) with different viscosity grades (K4M, K15M, and K100M) from different manufacturers (Anhui Shanhe and Dow Chemical). Two kinds of multivariate methods, principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), were adopted. The physicochemical properties of HPMC were systematically investigated via various techniques (e.g., SEM, particle size detection, and SeDeM characterization). Data from 33 characterization variables were applied to the multivariate methods. The PCA and OPLS-DA results indicated the differences between the HPMC from two manufacturers by the common variables that include the tablet hardness (HD), tensile strength (TS), bulk density, interparticle porosity, Carr index, cohesion index, Hausner ratio, flowability, and the width of the particle size distribution (span). Interestingly, these variables showed a certain correlation with each other, supporting the characterization results. Except for these different variables of the HPMC obtained by multivariate analysis results, distinguishable shapes and surface morphologies also appeared between different sources. To sum up, the powder properties (particle size, surface topography, dimension, flowability, and compressibility) and the tablet properties (HD and TS) were recognized as the DMAs of HPMC samples. This work provided the multivariate methods for the physicochemical characterization of HPMC, with potential in the quality control and formulation development.

Influence of Charge and Heat on the Mechanical Properties of Scaffolds from Ionic Complexation of Chitosan and Carboxymethyl Cellulose

As one of the most abundant, multifunctional biological polymers, polysaccharides are considered promising materials to prepare tissue engineering scaffolds. When properly designed, wetted porous scaffolds can have biomechanics similar to living tissue and provide suitable fluid transport, both of which are key features for in vitro and in vivo tissue growth. They can further mimic the components and function of glycosaminoglycans found in the extracellular matrix of tissues. In this study, we investigate scaffolds formed by charge complexation between anionic carboxymethyl cellulose and cationic protonated chitosan under well-controlled conditions. Freeze-drying and dehydrothermal heat treatment were then used to obtain porous materials with exceptional, unprecendent mechanical properties and dimensional long-term stability in cell growth media. We investigated how complexation conditions, charge ratio, and heat treatment significantly influence the resulting fluid uptake and biomechanics. Surprisingly, materials with high compressive strength, high elastic modulus, and significant shape recovery are obtained under certain conditions. We address this mostly to a balanced charge ratio and the formation of covalent amide bonds between the polymers without the use of additional cross-linkers. The scaffolds promoted clustered cell adhesion and showed no cytotoxic effects as assessed by cell viability assay and live/dead staining with human adipose tissue-derived mesenchymal stem cells. We suggest that similar scaffolds or biomaterials comprising other polysaccharides have a large potential for cartilage tissue engineering and that elucidating the reason for the observed peculiar biomechanics can stimulate further research.

Amelioration of lipophilic compounds in regards to bioavailability as self-emulsifying drug delivery system (SEDDS)

Background

High lipophilicity and poor aqueous solubility are the endemic problems of new drug molecules. Sixty to seventy percent of these drugs are unable to solubilize completely in aqueous media, or have very low permeability. This hampers their oral absorption and further leads to their poor bioavailability. Various researches are in progress to overcome these limitations. Novel technologies like nano-carrier systems have become popular for improving the solubility of drugs.

Main body

Lipid-based formulations, among nano systems, are taking pace for the enhancement of solubility, oral absorption, and hence the bioavailability of drugs. Among the lipid formulations, self-emulsification systems are gaining popularity by offering various advantages to delivery systems. Self-emulsifying drug delivery systems (SEDDS) are isotropic blends of oil and surfactant/co-surfactants. These ingredients upon gentle agitation in aqueous media results in the formation of o/w emulsion. In spite of many works published in SEDDS, the major concerns of this article are to discuss the various approaches to formulate a good lipid-based carrier system for poorly aqueous soluble drugs, role of various polymers, and their categories used in the formulation along-with the modern technologies used for enhancing the stability of liquid SEDDS. This review majorly focuses upon the problems related to the poor aqueous solubility of the newer lipid molecules and the solutions to overcome their solubility and in addition bioavailability.

Conclusion

As per the researches done in formulation and optimization of SEDDS for the enhancement of bioavailability of lipophilic molecules, it can be stated that the aqueous solubility as well as bioavailability can be increased by many folds compared to their marketed or other oral formulations.

Synthesis of a Porous C3N-Derived Framework with High Yield by Gallic Acid Cross-Linking Using Salt Melts

Porous carbon/nitrogen frameworks are an emerging class of noble organic materials with a wide range of potential applications. However, the design and controlled synthesis of those materials are still a challenge. Herein, we present the rational design of such a system with high microporosity, specific surface areas of up to 946 m² g^-1, and excellent condensation yields. The obtained noble frameworks were used for the delivery of larger organic molecules and changed the melting behavior of some daily drug molecules along their highly polarizable surfaces.

Three-Dimensional High-Porosity Chitosan/Honeycomb Porous Carbon/Hydroxyapatite Scaffold with Enhanced Osteoinductivity for Bone Regeneration

Three-dimensional honeycomb porous carbon (HPC) has attracted increasing attention in bioengineering due to excellent mechanical properties and a high surface-to-volume ratio. In this paper, a three-dimensional chitosan (CS)/honeycomb porous carbon/hydroxyapatite composite was prepared by nano-sized hydroxyapatite (nHA) on the HPC surface in situ deposition, dissolved in chitosan solution, and vacuum freeze-dried. The structure and composition of CS/HPC/nHA were characterized by scanning electron microscopy, transmission electron miscroscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy, and the porosity, swelling ratio, and mechanical properties of the scaffold were also tested. The as-prepared scaffolds possess hierarchical pores and organic-inorganic components, which are similar in composition and structure to bone tissues. The synthesized composite scaffold has high porosity and a certain mechanical strength. By culturing mouse bone marrow mesenchymal stem cells on the surface of the scaffold, it was confirmed that the scaffold facilitated its growth and promoted its differentiation into the osteogenesis direction. In vivo experiments further demonstrate that the CS/HPC/nHA composite scaffold has a significant advantage in promoting bone formation in the bone defect area. All the results suggested that the CS/HPC/nHA scaffolds have great application prospect in bone tissue engineering.

Proliposomes for oral delivery of total biflavonoids extract from Selaginella doederleinii: formulation development, optimization, and in vitro-in vivo characterization

Purpose

Amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone are five major active ingredients in the total biflavonoids extract from Selaginella doederleinii (TBESD) with favorable anticancer properties. However, the natural-derived potent antitumor agent of TBESD is undesirable due to its poor solubility. The present study was to develop and optimize a proliposomal formulation of TBESD (P-TBESD) to improve its solubility, oral bioavailability and efficacy.

Materials and methods

P-TBESD containing a bile salt, a protective hydrophilic isomalto-oligosaccharides (IMOs) coating, were successfully prepared by thin film dispersion-sonication method. The physicochemical and pharmacokinetic properties of P-TBESD were characterized, and the antitumor effect was evaluated using the HT-29 xenograft-bearing mice models in rats.

Results

Compared with TBESD, the relative bioavailability of amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone from P-TBESD were 669%, 523%, 761%, 955% and 191%, respectively. The results of pharmacodynamics demonstrated that both TBESD and P-TBESD groups afforded antitumor effect without systemic toxicity, and the antitumor effect of P-TBESD was significantly superior to that of raw TBESD, based on the tumor growth inhibition and histopathological examination.

Conclusion

Hence, IMOs-modified proliposomes have promising potential for TBESD solving the problem of its poor solubility and oral bioavailability, which can serve as a practical oral preparation for TBESD in the future cancer therapy.

Hierarchical silica monolithic tablets as novel carriers for drug delivery

This paper proposes the use of carriers with hierarchical porous structures as novel monolithic tablets for modified drug release. The influence of pore structure on the tamsulosin release profile is presented. The hierarchical arrangement of porous structure in monolithic tablets and the deposition of tamsulosin inside the silica carrier enable to control the kinetic of release and the amount of tamsulosin released. We developed a mathematical model of tamsulosin release from two carriers with different hierarchy of meso- and macropores. A model of this nature will allow to predict the release of tamsulosin from other carriers with a similar pore structure. We hope this research will improve the design process of novel carriers, and thus, will allow to tailor the porous structure of a carrier to achieve the desired release profile.

3D Printing Technology in Design of Pharmaceutical Products

Background:

Three-dimensional printing (3DP) is a novel technology for fabrication of personalized medicine. As of late, FDA affirmed 3D printed tranquilize item in August 2015, which is characteristic of another section of Pharmaceutical assembling. 3DP incorporates a wide range of assembling procedures, which are altogether founded on computer-aided design (CAD), and controlled deposition of materials (layer-by-layer) to make freestyle geometries. Conventionally, many pharmaceutical processes like compressed tablet have been used from many years for the development of tablet with established regulatory pathways. But this simple process is outdated in terms of process competence and manufacturing flexibility (design space). 3DP is a new technology for the creation of plan, proving to be superior for complex products, customized items and items made on-request. It creates new opportunities for improving efficacy, safety, and convenience of medicines.

Method:

There are many of the 3D printing technology used for the development of personalized medicine on demand for better treatment like 3D powder direct printing technology, fused-filament 3D printing, 3D extrusion printer, piezoelectric inkjet printer, fused deposition 3D printing, 3D printer, ink-jet printer, micro-drop inkjet 3DP, thermal inkjet printer, multi-nozzle 3D printer, stereolithographic 3D printer.

Result:

This review highlights features how item and process comprehension can encourage the improvement of a control technique for various 3D printing strategies.

Conclusion:

It is concluded that the 3D printing technology is a novel potential for manufacturing of personalized dose medicines, due to better patient compliance which can be prepared when needed.

Setting up multivariate specifications on critical raw material attributes to ensure consistent drug dissolution from high drug-load sustained-release matrix tablet

The purpose of this study was to describe the raw material variability that influenced the in-vitro dissolution behavior of high drug-load sustained-release matrix tablet and to ensure the consistent quality of the final product. The Panax notoginseng saponins (PNS) - hydroxypropyl methylcellulose - anhydrous lactose - magnesium stearate (57:20:23:0.5%, w/w) was used as the model formulation. PNS extract powders with lot-to-lot and source-to-source differences were collected to cover the common cause variations and their physicochemical properties were characterized by the chromatographic fingerprints and the SeDeM expert system. It was found that the release behavior of active pharmaceutical ingredients (APIs) in PNS from different batches exhibited considerable variations. Latent variable modeling results demonstrated that the physical properties of raw materials played major roles in predicting the drug dissolution. PNS extracts with high specific surface area, the width of particle size distribution and hygroscopicity or low moisture content led to an increase in drug release. In order to perform efficient pass/fail judgments for incoming new materials, multivariate specifications of critical material attributes (CMAs) were established and the multivariate design space in line with the quality by design (QbD) principles was explored to achieve the release target.

Recent advances in functionalized micro and mesoporous carbon materials: synthesis and applications

Functionalized nanoporous carbon materials have attracted the colossal interest of the materials science fraternity owing to their intriguing physical and chemical properties including a well-ordered porous structure, exemplary high specific surface areas, electronic and ionic conductivity, excellent accessibility to active sites, and enhanced mass transport and diffusion. These properties make them a special and unique choice for various applications in divergent fields such as energy storage batteries, supercapacitors, energy conversion fuel cells, adsorption/separation of bulky molecules, heterogeneous catalysts, catalyst supports, photocatalysis, carbon capture, gas storage, biomolecule detection, vapour sensing and drug delivery. Because of the anisotropic and synergistic effects arising from the heteroatom doping at the nanoscale, these novel materials show high potential especially in electrochemical applications such as batteries, supercapacitors and electrocatalysts for fuel cell applications and water electrolysis. In order to gain the optimal benefit, it is necessary to implement tailor made functionalities in the porous carbon surfaces as well as in the carbon skeleton through the comprehensive experimentation. These most appealing nanoporous carbon materials can be synthesized through the carbonization of high carbon containing molecular precursors by using soft or hard templating or non-templating pathways. This review encompasses the approaches and the wide range of methodologies that have been employed over the last five years in the preparation and functionalisation of nanoporous carbon materials via incorporation of metals, non-metal heteroatoms, multiple heteroatoms, and various surface functional groups that mostly dictate their place in a wide range of practical applications.

Tablet fragmentation without a disintegrant: A novel design approach for accelerating disintegration and drug release from 3D printed cellulosic tablets

Fused deposition modelling (FDM) 3D printing has shown the most immediate potential for on-demand dose personalisation to suit particular patient's needs. However, FDM 3D printing often involves employing a relatively large molecular weight thermoplastic polymer and results in extended release pattern. It is therefore essential to fast-track drug release from the 3D printed objects. This work employed an innovative design approach of tablets with unique built-in gaps (Gaplets) with the aim of accelerating drug release. The novel tablet design is composed of 9 repeating units (blocks) connected with 3 bridges to allow the generation of 8 gaps. The impact of size of the block, the number of bridges and the spacing between different blocks was investigated. Increasing the inter-block space reduced mechanical resistance of the unit, however, tablets continued to meet pharmacopeial standards for friability. Upon introduction into gastric medium, the 1 mm spaces gaplet broke into mini-structures within 4 min and met the USP criteria of immediate release products (86.7% drug release at 30 min). Real-time ultraviolet (UV) imaging indicated that the cellulosic matrix expanded due to swelling of hydroxypropyl cellulose (HPC) upon introduction to the dissolution medium. This was followed by a steady erosion of the polymeric matrix at a rate of 8 μm/min. The design approach was more efficient than a comparison conventional formulation approach of adding disintegrants to accelerate tablet disintegration and drug release. This work provides a novel example where computer-aided design was instrumental at modifying the performance of solid dosage forms. Such an example may serve as the foundation for a new generation of dosage forms with complicated geometric structures to achieve functionality that is usually achieved by a sophisticated formulation approach.

Preparation and evaluation of valsartan by a novel semi-solid self-microemulsifying delivery system using Gelucire 44/14

The aim of the present study was to develop a novel semi-solid self-microemulsifying drug delivery system (SMEDDS) using Gelucire(®) 44/14 as oil with strong solid character to improve the oral bioavailability of poorly soluble drug valsartan. The solubility of valsartan in various excipients was determined, the pseudo-ternary phase diagram was constructed in order to screen the optimal excipients, and DSC analysis was performed to evaluate the melting point of SMEDDS. The optimal drug-loaded SMEDDS formulation was consisted of 30% Gelucire(®) 44/14 (oil), 40% Solutol(®) HS 15 (surfactant), and 30% Transcutol(®) P (cosurfactant) (w/w) with 80 mg valsartan/g excipients. The average droplet sizes of the optimized blank and drug-loaded SMEDDS formulations were 26.20 ± 1.43 and 33.34 ± 2.15 nm, and the melting points of them were 35.6 and 36.8 °C, respectively. The in vitro dissolution rate of optimal semi-solid SMEDDS was increased compared with commercial capsules, resulting in the 2.72-fold and 2.97-fold enhancement of Cmax and AUC0-t after oral administration in rats, respectively. These results indicated that the novel semi-solid SMEDDS formulation could potentially improve the oral bioavailability of valsartan, and the semi-solid SMEDDS was a desirable system than the traditional liquid SMEDDS because it was convenient for preparation, storage and transportation due to semi-solid state at room temperature and melted state at body temperature.

Oleic acid derivative of polyethylenimine-functionalized proliposomes for enhancing oral bioavailability of extract of Ginkgo biloba

The present systematic study focused to investigate the oleic acid derivative of branched polyethylenimine (bPEI-OA)-functionalized proliposomes for improving the oral delivery of extract of Ginkgo biloba (GbE). The GbE proliposomes were prepared by a spray drying method at varying ratios of egg yolk phosphatidylcholine and cholesterol, and the optimized formulation was tailored with bPEI-OA to obtain bPEI-OA-functionalized proliposomes. The formulations were characterized for particle size, zeta potential, and entrapment efficiency. The release of GbE from proliposomes exhibited a sustained release. And the release rate was regulated by changing the amount of bPEI-OA on the proliposomes. The physical state characterization studies showed some interactions between GbE and other materials, such as hydrogen bonds and van der Waals forces during the process of preparation of proliposomes. The in situ single-pass perfusion and oral bioavailability studies were performed in rats. The significant increase in absorption constant (Ka) and apparent permeability coefficient (Papp) from bPEI-OA-functionalized proliposomes indicated the importance of positive charge for effective uptake across the gastrointestinal tract. The oral bioavailability of bPEI-OA-functionalized proliposomes was remarkable enhanced in comparison with control and conventional proliposomes. The bPEI-OA-functionalized proliposomes showed great potential of improving oral absorption of GbE as a suitable carrier.

Soluplus®/TPGS-based solid dispersions prepared by hot-melt extrusion equipped with twin-screw systems for enhancing oral bioavailability of valsartan

BACKGROUND

Soluplus(®) (SP) and D-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS)-based solid dispersion (SD) formulations were developed by hot-melt extrusion (HME) to improve oral bioavailability of valsartan (VST).

METHODS

HME process with twin-screw configuration for generating a high shear stress was used to prepare VST SD formulations. The thermodynamic state of the drug and its dispersion in the polymers were evaluated by solid-state studies, including Fourier-transform infrared, X-ray diffraction, and differential scanning calorimetry. Drug release from the SD formulations was assessed at pH values of 1.2, 4.0, and 6.8. Pharmacokinetic study was performed in rats to estimate the oral absorption of VST.

RESULTS

HME with a high shear rate produced by the twin-screw system was successfully applied to prepare VST-loaded SD formulations. Drug amorphization and its molecular dispersion in the polymer matrix were verified by several solid-state studies. Drug release from SD formulations was improved, compared to the pure drug, particularly at pH 6.8. Oral absorption of drug in rats was also enhanced in SP and TPGS-based SD groups compared to that in the pure drug group.

CONCLUSION

SP and TPGS-based SDs, prepared by the HME process, could be used to improve aqueous solubility, dissolution, and oral absorption of poorly water-soluble drugs.

Development and optimization of press coated tablets of release engineered valsartan for pulsatile delivery

The present work is aimed to develop and optimize pulsatile delivery during dissolution of an improved formulation of valsartan to coordinate the drug release with circadian rhythm. Preliminary studies suggested that β cyclodextrin could improve the solubility of valsartan and showed AL type solubility curve. A 1:1 stoichiometric ratio of valsartan to β cyclodextrin was revealed from phase solubility studies and Job's plot. The prepared complex showed significantly better dissolution efficiency (p < 0.05) compared to pure drug, which could be due to the formation of inclusion complex as revealed from FTIR and DSC studies. Continuous dissolution-absorption studies revealed that absorption of drug from valsartan β cyclodextrin complex was significantly higher (p < 0.05) compared to pure drug, in second part press-coated tablets of valsartan β cyclodextrin complex were subsequently prepared and application of the Plackett-Burman screening design revealed that HPMC K4M and EC showed significant effect on lag time. A 3(2) full factorial design was used to measure the response of HPMC K4M and EC on lag time and time taken for 90% drug release (T90). The optimized batch prepared according to the levels obtained from the desirability function had a lag time of 6 h and consisted of HPMC K4M:ethylcellulose in a 1:1.5 ratio with 180 mg of coating and revealed a close agreement between observed and predicted value (R(2 )= 0.9694).

Folic acid-conjugated TiO2-doped mesoporous carbonaceous nanocomposites loaded with Mitoxantrone HCl for chemo-photodynamic therapy

A TiO₂-doped porous carbon drug delivery system was prepared. The ability of this system to combine chemotherapy with photodynamic activity enhanced the cancer cell killing effect.