Construction and in vitro/in vivo evaluation of menantine hydrochloride oral liquid sustained-release drug delivery system.

OBJECTIVE: The purpose of the present study was to formulate a menantine hydrochloride (MH) sustained-release suspension. METHODS: Menantine hydrochloride drug resin complex (MH-DRC) was prepared with strong acid cation exchange resin as carrier using water bath method. The MH-DRC was characterized using scanning electron microscopy, X-ray diffraction and infrared spectroscopy. The MH-coated microcapsule (MH-CM) with optimized formulation was further dispersed in a suitable medium to obtain a sustained-release suspension. The rats were given both the MH sustained-release suspension and the commercial MH sustained-release capsule by intragastric administration. The plasma concentration-time curves and related pharmacokinetic parameters were also investigated using a non-atrioventricular model. RESULTS: MH and ion-exchange resin were ionically bonded. AmberliteIRP®69 had a higher affinity for MH at the initial concentration of 5 mg·mL-1 and a reaction temperature of 25.0 ± 0.5 °C. In vitro drug release profile showed that both the drug resin complex and the coated microcapsules had a certain level of sustained-release effect. The t1/2 of MH sustained-release suspension was extended from 68.44 h to 72.79 h with the peak blood concentration being decreased to 3.56 µg·mL-1 and the Tmax extended to 12 h compared with the commercial MH sustained-release capsule. The concentration-time curve of the self-made MH sustained-release suspension was flattened and the average relative bioavailability (Fr) was 116.65% compared with the commercial MH sustained-release capsules. CONCLUSIONS: The findings showed that the MH sustained-release suspension was successfully formulated with acceptable pharmacokinetic indices for effective treatment of Alzheimer's disease.

Development and in vitro/in vivo evaluation of famotidine hydrochloride bioadhesive sustained release suspension.

To develop a new kind of famotidine-resin microcapsule for gastric adhesion sustained release by screening out suitable excipients and designing reasonable prescriptions to improve patient drug activities to achieve the expected therapeutic effect. The famotidine drug resin was prepared using the water bath method with carbomer 934 used as coating material. Microcapsules were prepared using the emulsified solvent coating method and appropriate excipients were used to prepare famotidine sustained release suspension. Pharmacokinetics of the developed microcapsules were studied in the gastrointestinal tract of rats. The self-made sustained-release suspension of famotidine hydrochloride effectively reduced the blood concentration and prolonged the action time. The relative bioavailability of the self-made suspension of the famotidine hydrochloride to the commercially available famotidine hydrochloride was 146.44%, with an average retention time of about 5h longer, which indicated that the new suspension had acceptable adhesion properties. The findings showed that the newly developed famotidine-resin microcapsule increased the bioavailability of the drug with a significant sustained-release property.

Fabrication of ticagrelor bioadhesive solid dispersion based on coaxial electrostatic spray to improve drug release and enhance oral bioavailability.

Due to the low solubility and poor bioavailability of Ticagrelor (TIC), the current study developed a structured bioadhesive core-shell drug delivery system to address it. Ticagreior solid dispersion (T-SD) was fabricated using the uniaxial electrostatic spray method. Ticagrelor bio adhesive solid dispersion (T-BSD) was also prepared using the coaxial electrostatic spray technique. The adhesion of T-BSD to each intestinal segment was determined using biological adhesion test. The compartment model was used to study the plasma concentration-time curve and related pharmacokinetic parameters. The results of bioadhesion tests showed a positive adhesion effect of T-BSD in each intestinal segment. The maximum plasma concentration (Cmax) of T-BSD was increased to 777.08ng/mL compared with the free drug (367ng/mL). Similarly, t1/2, MRT and Tmax of T-BSD (12.1h, 9.4h, 4h) were higher than the free drug (11.2h, 8.6h, 1h), respectively. The relative bioavailability of T-BSD was further increased to 430% compared with the free drug. The findings collectively revealed that the coaxial-electrospray technique could be a promising way to improve the bioavailability of TIC.

Preparation, characterization of clonidine hydrochloride resinates and investigation of the kinetics and thermodynamics of the ion exchange process.

Clonidine Hydrochloride (CH) resinates were prepared by plating solution with strong acid cationic-exchange resin as the carrier. The drug resinate's combination mode was characterized by SEM, DSC and X-ray diffraction. The reaction at different temperatures and the influence of different ion exchange resins on the ion exchange process were studied, The kinetics and thermodynamics of ion exchange resins under different temperatures were studied. The In vitro drug liberate from the drug-resinates was investigated in different mediums. The study proved that the combination of CH and resin was not a simple physical mixture but ionic bonded. With the increase of temperature and ion exchange and Amberlite⌖IRP69 had a higher affinity for ionic drugs. The results of In vitro release experiment showed that temperature, medium volume, stirring speed, the ionic strength and type. The In vitro release of CH resin was fitted with Viswanathan equation, it conformed to the process of particle diffusion. Also, the results showed that further coating of CH resin is necessary to achieve a significant continued release effect.

Preparation and in vitro/in vivo evaluation of a clonidine hydrochloride drug-resin suspension as a sustained-release formulation.

OBJECTIVE: The purpose of the present study was to prepare a clonidine hydrochloride (CH) sustained-release suspension. METHODS: The processes involved in the drug formulation included drug loading, impregnating, and suspension preparation. Clonidine hydrochloride drug-resin complexes (CH-DRC) were prepared using the bath method and the CH-DRC impregnated before the microencapsulation process. Based on the bottom spray fluidized bed coating method, the CH microencapsulated drug-resin complexes (CH-MC) were also prepared using Surelease® (the suspension of ethyl cellulose aqueous dispersion) as the coating material. The effects of coating (process/formulation) on the in vitro release of coating microcapsule were evaluated via single factor investigation and orthogonal design optimization. The CH-MC with optimized formulation was further dispersed in a suitable medium to obtain a sustained-release suspension. Rats were given commercial CH ordinary tablets and the CH sustained-release suspension via intragastric administration. The plasma concentration-time curve and related pharmacokinetic parameters were investigated using the non-compartment model. RESULTS: The Tmax of the CH sustained-release suspension was delayed from 2 h to 5 h compared with the CH ordinary tablets. Similarly, the Cmax was reduced from 32.138 µg·mL-1 to 18.150 µg·mL-1 with the concentration-time curve being more gentle compared with the commercially CH ordinary tablets. After oral administration, the relative bioavailability of CH sustained-release suspension (AUC0-24 of 137.703 µg·h·mL-1) to its CH ordinary tablets (AUC0-24 of 123.337 µg·h·mL-1) was 111.65%. CONCLUSIONS: The findings showed that the CH sustained-release suspension for oral administration was successfully formulated.

Preparation and Evaluation of rhINF-α-2b Sodium Hyaluronate Cross-Linked Porous Microspheres: Characterization, Sustained-Release Properties, and Antitumor Activity.

Recombinant human interferon α-2b (rhINF-α-2b), like most proteins, has several shortcomings such as relatively short half-life, low therapeutic index, high circulating drug fluctuations, and rapid degradation which could hinder its effective delivery. Novel electrostatic spray and ion exchange drug-loading techniques were combined to formulate rhINF-α-2b sodium hyaluronate cross-linked porous sustained-release microspheres (rhINF-α-2b-SHCPM), a protein delivery system. The different properties of rhINF-α-2b-SHCPM including the physicochemical nature, in vitro release behavior, and antitumor activity were evaluated. The loading rate (10.31 ± 0.94%) and encapsulation efficiency (89.09 ± 2.37%) of rhINF-α-2b-SHCPM produced acceptable values. The in vitro cumulative release rate of rhINF-α-2b-SHCPM within 24 h was also 86.26 ± 2.11% with a much better sustained release effect. Thus, the half-life (10.763 h) and retention time (14.067 h) of rhIFNα-2b-SHCPM were significantly prolonged with enhanced bioavailability (43,198.387 ng/L*h) and decreased peak concentration (15,266.4 ngL-1) compared with the free rhIFNα-2b protein (0.912 h, 0.952 h, 34,749.048 ng/L*h, and 48,870.2 ngL-1, respectively). The in vitro anti-proliferative activity and in vivo tumor inhibitory rate of rhIFNα-2b-SHCPM also increased by 90 and 55.86%, respectively, compared with the free rhIFNα-2b solution. The findings significantly supported a well-developed protein delivery system with improved sustained release, acceptable bioavailability, and increased antitumor activities. Graphical Abstract.

Anti-hyperuricemic property of 6-shogaol via self-micro emulsifying drug delivery system in model rats: formulation design, in vitro and in vivo evaluation.

The prevalence of hyperuricemia is relatively high worldwide, and a great number of patients are suffering from its complications. 6-shogaol, an alkylphenol compound purified from the root of ginger (Zingiber officinale Roscoe), has been proved to possess diverse pharmacological activities. However, its poor aqueous solubility usually leads to low bioavailability, and further clinical applications will be greatly discounted. The current study aimed to formulate a 6-shogaol-loaded-Self Microemulsifying Drug Delivery System (SMEDDS) to amend low aqueous solubility and bioavailability orally, as well as, potentiate the hyperuricemic activity of the 6-shogaol. SMEDDS was developed with central composite design established on a two system components viz., 18.62% W/W ethyl oleate (oil phase) and ratio of tween 80 (surfactant) to PEG 400 (co-surfactant) (1.73:1, W/W). Based on quadratic model, the navigation of the design space could generate spherically-shaped and homogenous droplets with respective mean particle diameter, polydispersity and of 20.00 ± 0.26 nm and 0.18 ± 0.02. The 6-shogaol-SMEDDS showed significant elevation of cumulative release compared with the free 6-shogaol and more importantly a 571.18% increment in the relative oral bioavailability of the drug. The predominant accumulation of 6-shogaol-SMEDDS in the liver suggested hepatic-targeting potentiality of the drug. Oral administration of 6-shogaol-SMEDDS in hyperuricemic rats also significantly decreased uric acid level and xanthine oxidase activity. Histological studies confirmed formulation groups indeed could provide better protection of kidney than free drug groups. Collectively, these findings indicated that the SMEDDS hold much promise in enhancing the oral delivery and therapeutic efficacy of 6-shogaol.

[Study on mechanism and structure-activity relationship of hypolipidemic polysaccharides: a review].

Hypolipidemic polysaccharides have notable activity and safety with a range of diverse sources. In this paper, the classification of hypolipidemic polysaccharides was carried out into polysaccharide sulfate, glycosaminoglycan, homopolysaccharide and heteropolysaccharide. The hypolipidemic activity mechanism and structure-activity relationship hypothesis of those polysaccharides in recent years were briefly reviewed therefore to provide references for the study and product development of polysaccharides.

An efficient in vitro and in vivo HPLC method for hydnocarpin in nanomicelles formulation.

For quantitative and other related bioactive studies of hydnocarpin, there is a need to establish an efficient, specific and sensitive analytical method (in vitro and in vivo). In this paper, an efficient HPLC method has been established and validated to analyze hydnocarpin in a nanomicelle formulation for the first time. Various chromatographic conditions for in vitro and in vivo determinations were investigated, with the application examined by pharmacokinetics and tissue distribution studies. The analysis was carried out using an HPLC system with a Waters symmetry C18 column (4.6 × 150 mm, 5 µm) at 25°C with a detecting wavelength of 342 nm. Eluting at a rate of 1.0 mL/min, a 65% methanol and 35% acetic acid solution (0.1%) served as the mobile phase for the in vitro determinations while a 62% methanol and 38% acetic acid solution (0.1%) was used for in vivo analysis with isoliquiritigenin as internal standard. The established in vitro linearity range for hydnocarpin was 0.2-20 µg/mL (R(2) = 0.9996), with the biological (in vivo) samples following the same trend. The accuracy of the method was >99% (in vitro) and 92.4-105.3% (in vivo). Also, the precision met the acceptance criterion. These results indicate that the established method exhibited high specificity, accuracy, linearity and precision. Additionally, this efficient HPLC method was applied to pharmacokinetics and tissue distribution studies.

[Progresses in screening active compounds from herbal medicine by affinity chromatography].

Affinity chromatography is a chromatographic method for separating molecules using the binding characteristics of the stationary phase with potential drug molecules. This method can be performed as a high throughput screening method and a chromatographic separation method to screen a variety of active drugs. This paper summarizes the history of affinity chromatography, screening technology of affinity chromatography, and application of affinity chromatography in screening bio-active compounds in herbal medicines, and then discusses its application prospects, in order to broaden applications of the affinity chromatography in drug screening.

Simultaneous HPLC determination of ergosterol and 22,23-dihydroergosterol in Flammulina velutipes sterol-loaded microemulsion.

An efficient HPLC method was developed and validated for the simultaneous determination of ergosterol and 22,23-dihydroergosterol in Flammulina velutipes sterol-loaded microemulsions (FVSMs). The different chromatographic conditions for in vitro and in vivo determinations were investigated, with the application examined by tissue distribution. Chromatographic separation was achieved on an Inertsil ODS-SP (250 × 4.6 mm, 5 µm) analytical column using a mobile phase of 98% methanol (in vitro), and 93% methanol for stomach samples and 96% methanol for other samples (in vivo) at 1.0 mL/min. The sterol content was detected at 282 nm. The established in vitro linearity ranges for ergosterol and 22,23-dihydroergosterol were 0.58-72.77 µg/mL (r1 = 0.9999) and 0.59-73.25 µg/mL (r2 = 0.9999), respectively, with the biological (in vivo) samples following the same trend. The accuracy of the method was >99% (in vitro) and between 93%-108% (in vivo). The LOQ was 2.15 µg/L for ergosterol and 2.41 µg/L for 22,23-dihydroergosterol in the in vitro studies. Also, the precisions met the acceptance criterion. These results indicate that the established HPLC method was specific, linear, accurate, precise and sensitive for the separation and simultaneous determination of ergosterol and 22,23-dihydroergosterol.

Development and thermodynamic evaluation of novel lipid raft stationary phase chromatography for screening potential antitumor agents.

Novel lipid raft stationary phase chromatography (LRSC), with lipid rafts that contain abundant tropomyosin-related tyrosine kinase A receptors immobilized on the stationary phase, was developed for a high-throughput screening of potentially active antitumor agents. Lestaurtinib was used as a model compound to determine the operational parameters of the LRSC. Of all the factors considered, the particle size of column packing, the column temperature and the flow rate were of immense importance in determining the performance of the established LRSC system. In order to profoundly comprehend the binding interaction between the model drug and the receptors on the column, thermodynamic studies were employed. The results revealed that the interaction was spontaneous and exothermic, a typical enthalpy-driven process. Additionally, the primary forces were hydrogen bonding and van der Waals forces. In evaluating the applicability of the method, active extracts from Albizziae Cortex were screened out using the LRSC system under the optimized conditions. The bioactive components were successfully confirmed by the MTT assay. In conclusion, it could be said that the LRSC is a good model for screening potential antitumor agents because of its viability, rapid response and scalable features.

The preparation of the sustained release metformin hydrochloride microcapsules by the Wurster fluidized bed.

The main objective of this study was to prepare sustained release metformin hydrochloride microcapsules by the Wurster fluidized bed and to obtain the optimized coating process and formulation. Fine microcapsules without agglomeration were obtained in a continuous coating process with the atomization air pressure of 0.2Mpa and an appropriate coating speed temperature. With other design variables of coating process fixed, the effects of different fluidizing air volume, coating temperature, coating speed, coating material, coating materials amount, plasticizer type and plasticizer amount on drug release were investigated respectively. Coating solution was achieved by dissolving EC45cps of 21 g, EC100cps of 7 g, DBS of 2.8 g and talcum powder of 8 g in ethanol to get a final volume of 500 ml. Particles of 150g along with 500mL coating solution would be fine. The results showed that with the air volume of 35 m3•h-1, coating temperature of 35o, coating speed of 6 mL•min-1 and proper amount of coating solution, fine microcapsules were obtained. The mean diameter of the microcapsules obtained eventually were 213 µm and the drug content were 23%, which was suitable for producing a suspension. Particle diameter distribution corresponded to the normal distribution and obviously prolonged drug-release was achieved.

Preparation and evaluation of sustained release pirfenidone-loaded microsphere dry powder inhalation for treatment of idiopathic pulmonary fibrosis.

Pirfenidone (PFND) is a recommended oral drug used to treat idiopathic pulmonary fibrosis, but have low bioavailability and high hepatotoxicity. The study, therefore, seeks to improve the therapeutic activities of the drug via increased bioavailability and reduced associated side effects by developing a novel drug delivery system. The electrostatic spray technology was used to prepare a sustained release pirfenidone-loaded microsphere dry powder inhalation with PEG-modified chitosan (PFND-mPEG-CS-MS). The entrapment efficiency, drug loading, and in vitro cumulative drug release rate (at 24 h and with a sustained release effect) of PFND-mPEG-CS-MS were 77.35±3.01%, 11.45±0.64%, and 90.4%, respectively. The Carr's index of PFND-mPEG-CS-MS powder was 17.074±2.163% with a theoretical mass median aerodynamic diameter (MMADt) of 0.99±0.07 µm, and a moisture absorption weight gain rate (Rw) of 4.61±0.72%. The emptying rate, pulmonary deposition rate (fine particle fraction) and actual mass median aerodynamic diameter (MMADa) were 90%∼95%, 48.72±7.04% and 3.10±0.16 µm, respectively. MTT bioassay showed that mPEG-CS-MS (200 µg/mL) had good biocompatibility (RGR = 90.25%) and PFND-mPEG-CS-MS (200 µg/mL) had significant inhibitory activity (RGR = 49.82%) on fibroblast growth. The pharmacokinetic data revealed that the t1/2 (5.02 h) and MRT (10.66 h) of PFND-mPEG-CS-MS were prolonged compared with the free PFND (t1/2, 1.67 h; MRT, 2.71 h). The pharmacodynamic results also showed that the formulated-drug group had slight pathological changes, lower lung hydroxyproline content, and reduced hepatotoxicity compared with the free-drug group. The PFND-mPEG-CS-MS further significantly down-regulated TGF-ß cytokines, Collagen I, and α-SMA protein expression levels compared with the free drug. The findings indicated that the PFND-mPEG-CS-MS had a good sustained release effect, enhanced bioavailability, decreased toxicity, and increased anti-fibrotic activities.

Enhanced oral bioavailability and in vivo antioxidant activity of chlorogenic acid via liposomal formulation.

In the present study, a formulation system consisting of cholesterol and phosphatidyl choline was used to prepare an effective chlorogenic acid-loaded liposome (CAL) with an improved oral bioavailability and an increased antioxidant activity. The developed liposomal formulation produced regular, spherical and multilamellar-shaped distribution nanoparticles. The pharmacokinetic analysis of CAL compared with chlorogenic acid (CA), showed a higher value of Cmax(6.42 ± 1.49 min versus 3.97 ± 0.39 min) and a delayed Tmax(15 min versus 10 min), with 1.29-fold increase in relative oral bioavailability. The tissue distribution in mice also demonstrated that CAL predominantly accumulated in the liver which indicated hepatic targeting potential of the drug. The increased activities of antioxidant enzymes (Total Superoxide Dismutase (T-SOD) and Glutathione Peroxidase (GSH-Px)) and total antioxidant capacity (T-AOC), in addition to decreased level of malondialdehyde (MDA) in CCl4-induced hepatotoxicity study further revealed that CAL exhibited significant hepatoprotective and antioxidant effects. Collectively, these findings present a liposomal formulation with significantly improved oral bioavailability and an increased in vivo antioxidant activity of CA.

Biocompatibility Research of a Novel pH Sensitive Ion Exchange Resin Microsphere.

The main objective of this study was to investigate biocompatibility and provide in-vivo pharmacological and toxicological evidence for further investigation of the possibility of pH sensitive ion exchange resin microsphere for clinical utilizations. Acute toxicity study and general pharmacological studies were conducted on the pH sensitive ion exchange resin microsphere we prepared. The general pharmacological studies consist of the effects of the pH sensitive ion exchange resin microsphere on the nervous system of mice, the functional coordination of mice, the hypnosis of mice treated with nembutal at subliminal dose, the autonomic activities of tested mice, and the heart rate, blood pressure, ECG and breathing of the anesthetic cats. The LD50 of pH sensitive ion exchange resin microsphere after oral administration was more than 18.84 g·Kg(-1). Mice were orally administered with 16 mg·Kg(-1), 32 mg·Kg(-1) and 64 mg·Kg(-1) of pH sensitive ion exchange resin microsphere and there was no significant influence on mice nervous system, general behavior, function coordination, hypnotic effect treated with nembutal at subliminal dose and frequency of autonomic activities. Within the 90 min after 5 mg·Kg(-1), 10 mg·Kg(-1), 20 mg·Kg(-1) pH sensitive ion exchange resin microsphere was injected to cat duodenum, the heart rate, blood pressure, breathing and ECG of the cats didn't make significant changes in each experimental group compared with the control group. The desirable pharmacological and toxicological behaviors of the pH sensitive ion exchange resin microsphere exhibited that it has safe biocompatibility and is possible for clinical use.

Cytotoxic effect of novel Flammulina velutipes sterols and its oral bioavailability via mixed micellar nanoformulation.

The aim of this study was to investigate the anti-tumor effect of sterols initially separated from Flammulina velutipes and the pharmacokinetics and tissue distribution after oral administration of F. velutipes sterol nanomicelles (FVSNs). F. velutipes sterol (FVS) consisted of mainly ergosterol (54.78%), 22,23-dihydroergosterol (27.94%) and ergost-8(14)-ene-3ß-ol (discovered for the first time in F. velutipes). In vitro cytotoxicity assay of FVS against U251 cells and HeLa cells showed that at 72h treatment, the FVS (IC50=23.42µg/mL) exhibited strong inhibitory effect against U251 cells, even overwhelmed the standard anti-tumor drug (5-fluorouracil) to an extent, while the HeLa cells were not significantly susceptible to the FVS. To improve the solubility and bioavailability of FVS, a model for insoluble anti-tumor drugs, FVSNs were prepared. In vitro characterization of FVSNs revealed satisfactory size distribution, loading capacity and encapsulation efficiency. Pharmacokinetic study in SD rats demonstrated that the mixed micellar nanoformulation significantly enhanced the bioavailability of FVS than free drug. Additionly, tissue distribution in mice manifested that the biodistribution of FVSNs as compared to the free FVS suspension were significantly improved. In conclusion, the nanomicelles developed in our study provided a promising delivery system for enhancing the oral bioavailability and selective biodistribution of FVS, a potential anti-tumor agent.

Enhanced oral bioavailability of a sterol-loaded microemulsion formulation of Flammulina velutipes, a potential antitumor drug.

PURPOSE: To investigate the growth inhibition activity of Flammulina velutipes sterol (FVS) against certain human cancer cell lines (gastric SGC and colon LoVo) and to evaluate the optimum microemulsion prescription, as well as the pharmacokinetics of encapsulated FVS. METHODS: Molecules present in the FVS isolate were identified by gas chromatography/mass spectrometry analysis. The cell viability of FVS was assessed with methyl thiazolyl tetrazolium (MTT) bioassay. Based on the solubility study, phase diagram and stability tests, the optimum prescription of F. velutipes sterol microemulsions (FVSMs) were determined, followed by FVSMs characterization, and its in vivo pharmacokinetic study in rats. RESULTS: The chemical composition of FVS was mainly ergosterol (54.8%) and 22,23-dihydroergosterol (27.9%). After 72 hours of treatment, both the FVS (half-maximal inhibitory concentration [IC(50)] = 11.99 µg · mL(-1)) and the standard anticancer drug, 5-fluorouracil (IC(50) = 0.88 µg · mL(-1)) exhibited strong in vitro antiproliferative activity against SGC cells, with IC(50) > 30.0 µg · mL(-1); but the FVS performed poorly against LoVo cells (IC(50) > 40.0 µg · mL(-1)). The optimal FVSMs prescription consisted of 3.0% medium chain triglycerides, 5.0% ethanol, 21.0% Cremophor EL and 71.0% water (w/w) with associated solubility of FVS being 0.680 mg · mL(-1) as compared to free FVS (0.67 µg · mL(-1)). The relative oral bioavailability (area-under-the-curve values of ergosterol and 22,23-dihydroergosterol showed a 2.56-fold and 4.50-fold increase, respectively) of FVSMs (mean diameter ~ 22.9 nm) as against free FVS were greatly enhanced. CONCLUSION: These results indicate that the FVS could be a potential candidate for the development of an anticancer drug and it is readily bioavailable via microemulsion formulations.