Initial Drug Concentration Research Articles

N-doped carbon as a highly active and sustainable metal-free catalyst for the enhanced degradation of non-steroidal anti-inflammatory drugs in single and binary systems

This work synthesized an N-doped Carbon (NdC) using acetonitrile as a carbon and nitrogen source and zeolite Y as a structure-directing agent. The synthesis was carried out without organic solvents, resulting in carbonization inside and outside the zeolite pores, as confirmed by several characterization techniques. The NdC catalyst presented a remarkable band gap of 0.78 eV, leading to its test as a catalyst in the photodegradation of two widely used pharmaceuticals: ketoprofen (KTP) and ibuprofen (IBP). The optimal reaction conditions were obtained under rather mild conditions, using the natural pH of the solution, a catalyst dosage of 0.1 g L−1, and an initial drug concentration of 40 mg L−1. The degradation kinetics were better represented by the pseudo-first-order model, with high kinetic rate constant (k) values, which were found to be 0.077 min−1 for KTP and 0.091 min−1 for IBP. The NdC catalyst remained stable for reuse in up to 4 cycles, exhibiting excellent removal results for both drugs. Moreover, near-complete mineralization was achieved in 30 min in binary systems. Thus, despite its low surface area, which has shown to be an attractive characteristic for catalysis, NdC was able to present excellent optical properties and remarkable photocatalytic performance, pointing to its high efficiency for the degradation of recalcitrant pollutants, such as KTP and IBP.

Evaluation of synergistic adsorption approach for terbinafine removal by cotton shell powder immobilized zerovalent copper: Adsorption kinetics and DFT simulation

Cotton shell powder (CS), nano zerovalent copper (nZVC) and cotton shell powder immobilized zerovalent copper (ZVC@CS) were evaluated for their adsorption efficiencies towards terbinafine hydrochloride (TBH), an antifungal drug. The nZVC and ZVC@CS synthesized via one pot redox precipitation method were characterized by FTIR, XRD, BET, FESEM and TGA analysis. The TGA and AAS analysis confirmed the loading of nearly 10% of nZVC on cotton shell powder in ZVC@CS. The effect of operational parameters (pH, adsorbent dose, initial drug concentration, time, etc.) determining the extent of terbinafine hydrochloride adsorption on ZVC@CS were investigated to ascertain the optimal experimental conditions to achieve maximum adsorption efficiencies. To investigate the adsorption behavior of TBH on ZVC@CS, the experimental data were fitted for five different adsorption models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson and Hill isotherms. The TBH adsorption data was best fit with Hill isotherm model indicating cooperative sorption of TBH molecules on ZVC@CS surface. Among the five kinetic equations namely the pseudo-first-order (PFO), the pseudo-second-order (PSO), Elovich model, the intraparticle diffusion model, and Boyd kinetic model used to estimate the adsorption mechanism, the PFO kinetic model give best fit with a good correlation for the physisorption of TBH on ZVC@CS composite. The mechanism of the adsorption process was observed to be complex, consisting of both surface adsorption and pore diffusion. However, the Boyd plot confirms external mass transport as the rate limiting step for the adsorption of TBH on ZVC@CS. The synergistic adsorption of TBH on ZVC@CS was hypothesized, and the idea was supported by structure optimization results from DFT studies. The ZVC@CS exhibits equilibrium TBH adsorption efficiency (qmax) of 285.3 mg.g−1, significantly higher than adsorbents used in literature for the TBH removal.It is suggested that ZVC@CS may serve as sustainable adsorbents for the removal of cationic contaminants from acidic medium.

Application of Hydrogels in the Device of Ophthalmic Iontophoresis: Theory, Developments and Perspectives.

The human eye is a consolidated organ with delicate structures and unique immune privileges. Ocular diseases are intractable due to the intrinsic biological barriers within the eyeball. Hydrogels are excellent drug-carrying substances with soft material and excellent properties. They have been extensively used to deliver drugs into ocular tissue via iontophoresis devices. Ophthalmic iontophoresis is an electrochemical technique using tiny electrical currents to deliver drugs into the eye non-invasively. The early infantile iontophoresis technique often required long applying time to achieve therapeutic dose in the posterior ocular segment. The potential limitations in the initial drug concentration and the maximum safe currents would also impede the efficiency and safety of iontophoresis. Moreover, the poor patient compliance always leads to mechanical damage to the cornea and sclera during application. Advantageously, the flexible drug-carrying hydrogel can be in direct contact with the eye during iontophoresis, thereby reducing mechanical damage to the ocular surface. Moreover, the water absorption and adjustable permeability of hydrogels can reduce the electrochemical (EC) reactions and enhance the efficiency of iontophoresis. In this review, we focus on recent developments of hydrogels iontophoresis in ophthalmologic practice. Refinements of the knowledge would provide an outlook for future application of hydrogels in treating ocular disease.

Adsorption kinetics of ciprofloxacin and ofloxacin by green-modified carbon nanotubes

This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The characterization analyses of the pre- and post-process material by XPS, TG/DTG, FT-IR, SEM/EDS, and XRD helped in the elucidation of the mechanisms, indicating greater involvement of n-n and π -π interactions. In the kinetic studies, the simple systems with CIP and OFL were similar, both showed equilibrium time around 20/30 min and increased adsorptive capacity with increasing initial drug concentration. In the multicomponent system, different fractions of CIP and OFL were tested and the time to reach equilibrium also varied between 20 and 30 min. In general, the adsorption capacity of CIP is slightly lower than that of OFL under the conditions tested. The selectivity analysis of the system showed that the selectivity's of the two drugs are identical in equimolar fractions. The mathematical modeling of the kinetic data indicated that in monocomponent systems, the model of pseudo-second order (PSO) adequately described both CIP and OFL kinetics. Furthermore, with the implementation of Artificial Neural Networks (ANN), it was possible to obtain a more assertive prediction of the behavior of single and binary systems.

Enhanced Photocatalytic Degradation of the Antidepressant Sertraline in Aqueous Solutions by Zinc Oxide Nanoparticles

Antidepressants are one of the main pollutants in the aquatic environment. They are being widely studied due to their widespread use, possible health effects, and partial removal from wastewater treatment plants by conventional methods. Photocatalysis is an effective and ecologically beneficial method in wastewater treatment. In the present study, the photocatalytic degradation of sertraline hydrochloride (SERT) in water using nano-sized zinc oxide (ZnO-NPs) was investigated. The ZnO-NPs were synthesized from zinc gluconate as a precursor by the sol–gel method. The crystal structure, morphology, surface charge, and textural properties were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analyses, transmission electron microscopy, Fourier-transform infrared spectroscopy, zeta potential, and N2 adsorption–desorption measurements. The removal of SERT in water was explored by different processes: H2O2/UV, ZnO-NPs/H2O2/UV, and ZnO-NPs/UV. Our results indicate that the combination of both UV illumination and the ZnO-NP as a catalyst was necessary for the efficient degradation of the drug. Nearly complete removal of SERT (98.7%) was achieved in 30 min with the ZnO-NPs/UV process at room temperature. The photodegradation of SERT follows first-order kinetics with a rate constant of 0.0678 min−1. The results reveal that SERT degradation with ZnO-NPs/UV is pH-dependent, as the maximum drug removal was achieved at pH 11. Initial drug concentration, catalyst dose, and hydrogen peroxide concentration were also crucial in the removal of SERT. Our findings indicate that the high specific surface area and porous structure of ZnO-NP enhance its photocatalytic performance toward photodegradation of SERT, i.e., ZnO-NP is an efficient nanophotocatalyst for the degradation of SERT under UV irradiation.

Advanced oxidation processes for pharmaceutical degradation and disinfection of wastewater: peracetic acid and graphene oxide quantum dots

A combination of graphene oxide quantum dots and peracetic acid (GQDs/PAA) was used to degrade sulfasalazine in municipal wastewater. The impact of reaction parameters such as initial concentrations of oxidant (peracetic acid) and drug (sulfasalazine) and different water matrices was evaluated. The degradation efficiency when using GQDs/PAA (50 mg/L: 0.10 mM) was almost 100% in synthetic water and 80% in municipal wastewater. The primary reactive radicals that caused the degradation of sulfasalazine in wastewater were identified as hydroxy (·OH) as well as the peroxy radicals (CH3C(=O)OO·, CH3C(=O)O·). 83.7% of total organic carbon were eliminated when 0.15 mM PAA was used while nearly 100% degradation of SZZ was achieved. A degradation pathway was proposed using the degradation intermediates obtained on quadrupole time-of-flight liquid chromatography mass spectrometry. The genotoxic and mutagenic potential of the degradation products formed during the degradation of sulfasalazine was assessed using the Ames test. It was demonstrated that none of the intermediates were mutagenic. GQDs/PAA was further tested as a potential disinfectant, and S. aureus was completely inactivated as verified by using LIVE/DEAD Baclight staining. In raw municipal wastewater, GQDs/PAA eliminated more than 90% of bacteria, thus confirming the synergy of GQDs/PAA as both a disinfectant and a photocatalyst.

Pluronic F-68 Montmorillonite As A Drug Delivery Vehicle For Extended Release Of Venlafaxine Hydrochloride.

Short half-life and low bioavailability of Venlafaxine hydrochloride (VF), an antidepressant drug, necessitates the frequent administration of VF tablets in a day in order to maintain adequate drug concentration in blood plasma. This generates the need for the development of formulations which could prolong the release of VF and reduce the multiple dosages. The present work explores the combination of Montmorillonite (Mt) with Pluronic F-68 (PF-68) (OrganoMT) for oral delivery of VF. The effect of various parameters including pH of aqueous drug solution, contact time and initial drug concentration on drug loading capacity of OrganoMT has been studied. The synthesized OrganoMT-VF complexes were characterized by various suitable techniques. XRD studies indicated that the VF molecules were intercalated within the OrganoMT layers. In vitro release behavior of VF from OrganoMT-VF complexes shows an extended-release pattern for a period of 30 h and reaches upto 70% and 60% compared to pure VF having complete release time of 5.5 h and 3.5 h in simulated gastric and intestinal fluid respectively. Various kinetic models were employed to elucidate the drug release mechanism where the best fitting was obtained with Korsmeyer Peppas model. The results suggest the possibility of designing an oral extended controlled release formulation for VF to minimize its administration frequency thereby increasing the effectiveness of drug. This improves patient compliance by reducing the dose from 4 times in 24 h to once in 24 h.

Enhanced adsorptive removal of rifampicin and tigecycline from single system using nano-ceria decorated biochar of mango seed kernel

Pharmaceutically active compounds (PhACs) represent an emerging class of contaminants. With a potential to negatively impact human health and the ecosystem, existence of pharmaceuticals in the aquatic systems is becoming a worrying concern. Antibiotics is a major class of PhACs and their existence in wastewater signifies a health risk on the long run. With the purpose of competently removing antibiotics from wastewater, cost-effective, and copiously available waste-derived adsorbents were structured. In this study, mango seeds kernel (MSK), both as a pristine biochar (Py–MSK) and as a nano-ceria-laden (Ce–Py–MSK) were applied for the remediation of rifampicin (RIFM) and tigecycline (TIGC). To save time and resources, adsorption experiments were managed using a multivariate-based scheme executing the fractional factorial design (FrFD). Percentage removal (%R) of both antibiotics was exploited in terms of four variables: pH, adsorbent dosage, initial drug concentration, and contact time. Preliminary experiments showed that Ce–Py–MSK has higher adsorption efficiency for both RIFM and TIGC compared to Py–MSK. The %R was 92.36% for RIFM compared to 90.13% for TIGC. With the purpose of comprehending the adsorption process, structural elucidation of both sorbents was performed using FT-IR, SEM, TEM, EDX, and XRD analyses which confirmed the decoration of the adsorbent surface with the nano-ceria. BET analysis revealed that Ce–Py–MSK has a higher surface area (33.83 m2/g) contrasted to the Py–MSK (24.72 m2/g). Isotherm parameters revealed that Freundlich model best fit Ce–Py–MSK–drug interactions. A maximum adsorption capacity (qm) of 102.25 and 49.28 mg/g was attained for RIFM and TIGC, respectively. Adsorption kinetics for both drugs conformed well with both pseudo-second order (PSO) and Elovich models. This study, therefore, has established the suitability of Ce–Py–MSK as a green, sustainable, cost-effective, selective, and efficient adsorbent for the treatment of pharmaceutical wastewater.

Degradation of carbamazepine by the photo-Fenton process. Approach towards the elucidation of degradation by-products

Carbamazepine (CBZ) is a pollutant of emerging concern because of its adverse effects associated. This work deals with the degradation of 1 mg L-1 of CBZ by the photo-Fenton process in water to discern the potential of this advanced oxidation process for the elimination of this persistent pollutant. For this purpose, the operating conditions were optimized using a central composite design of experiments, testing the influence of ferrous ion (Fe2+) and hydrogen peroxide (H2O2) concentrations on the degradation of CBZ. As a result, 96.4% of CBZ removal was obtained under optimal operating conditions (0.750 mg L-1 and 0.2 mg L-1 of H2O2 and Fe2+, respectively). In addition, the effect of the initial concentration of the target drug on the oxidation capacity of the photo-Fenton process was assessed by analyzing the removal kinetic constant. This value was achieved through a pseudo-first order model and resulted to be 0.0182 µmol L-1 min−1. Additionally, the degradation of CBZ in surface water was evaluated, obtaining an elimination of 74.4%. Finally, the identification of some CBZ by-products was carried out, being one of them purified and elucidated by means of the nuclear magnetic resonance technique and mass spectrometry. The referred degradation by-product was identified for the first time as 2,2′-aminodibenzaldehyde. In this regard, the photo-Fenton process is concluded to be able of degrading CBZ in natural surface water.

Evaluation modified luffa with silver nanoparticles (LF/AgNPs) for removal of a nonsteroidal anti-inflammatory (IBUPROFEN) from aqueous media

This study has investigated luffa as a natural adsorbent modified with silver nanoparticles to sequestrate ibuprofen from aqueous media. Adsorption ibuprofen as an environmental pollutant from aqueous media was studied by various factors such as agitation type, pH, initial drug concentration, contact time, agitation rate, and adsorbent dosage. The optimized experimental parameters were achieved by a one-at-a-time method in 60 min employing vortex in pH = 5, initial concentration of 200 µg/mL, and adsorbent dosage of 25 mg. Isotherms were fitted best to the Freundlich model. Kinetics shows that the adsorption of the drug follows a pseudo-second-order model. According to the obtained results, the adsorption capacity of the prepared adsorbate was 71 mg/g, and 92% of the ibuprofen was removed in the aqueous solutions under optimal conditions. Due to the modification of luffa by silver nanoparticle, the surface charge has been changed and also active sites of adsorbent has been increased. Consequences, π-metal interaction, hydrogen bonding, electrostatic interactions and π-π stacking were involved in the advancement the adsorption mechanism. The results confirmed that the modified luffa is a suitable adsorbent for removing ibuprofen from aqueous solutions.

Quantum and experimental investigation of the application of Crassostrea gasar (mangrove oyster) shell–based CaO nanoparticles as adsorbent and photocatalyst for the removal of procaine penicillin from aqueous solution

The present study was designed to synthesize and characterize calcium oxide nanoparticles (using mangrove oyster shell as a precursor) and apply the synthesized nanoparticles as a photocatalyst to degrade procaine penicillin in an aqueous solution. The photocatalyst exhibited an average band gap of 4.42eV, showed a maximum wavelength of absorbance in the UV region (i.e., 280nm), and is a microporous nanoparticle with a particle diameter of 50nm. The photocatalyzed degradation of the drug was conducted under natural sunlight, and the influence of parameters such as the period of contact, catalyst load, pH, initial drug concentration, and ionic strength was investigated concerning the degradation profile. The results obtained from response surface analysis indicated that an optimum degradation efficiency of about 93% can be obtained at a concentration, pH, and catalyst dosage of 0.125M, 2, and 0.20g respectively, at 0.902 desirabilities. The Langmuir-Hinshelwood, modified Freundlich, parabolic diffusion, pseudo-first-/second-order, and zero-, first-, and second-order kinetic parameters were tested to ascertain the best model that best described the experimental data. Consequently, the Langmuir-Hinshelwood, modified Freundlich, and pseudo-second-order models were accepted based on the minimum error and higher R2 values. Based on the Langmuir-Hinshelwood rate constants for adsorption and photodegradation as well as the evaluated valence bond potential, the degradation of the drug first proceeded through the mechanism of adsorption and followed by the oxidation of the drug by superoxide (generated from the interaction of electrons that generated by through the absorption of UV radiation). The quantum chemical calculation gave evidence that pointed towards the establishment of strong agreement with experimental data and also showed that the carboxyl functional group in the drug is the target site for adsorption and subsequent degradation.

Preparation and application of novel thermo-sensitive molecularly imprinted polymer for selective extraction of omeprazole from pharmaceutical formulation and biological fluids

ABSTRACT Omeprazole selective molecularly imprinted polymer was synthesized by polymerization using 2-hydroxyethyl methacrylate as a monomer, N-vinylcaprolactam as a thermo-sensitive polymer, and N, N′-methylenebisacrylamide as cross-linker, respectively. This study aimed to develop a novel polymer as a nanoadsorbent for the extraction of omeprazole in biological and pharmaceutical samples. To achieve maximum extraction recovery of the drug, the Nd:YAG pulsed laser irradiation was used to convert adsorbent particles into smaller sizes using water solvent at different irradiation times. Properties of prepared thermo-sensitive molecularly imprinted polymer were characterized by different analyses. The optimal extraction conditions were thermo-sensitive molecularly imprinted polymer dosage of 0.01 g, a cross-linking agent of 0.15 g, contact time of 15 min, eluent of methanol, the temperature of 25°C, initial drug concentration of 20 mg L−1, and solution pH of 4. The sorption isotherms and selective recognition of thermo-sensitive molecularly imprinted polymer were investigated in detail. Sorption results fitted well into the linearized Langmuir equation. The selectivity experiment has shown that the sorption capacity and selectivity of thermo-sensitive molecularly imprinted polymer to omeprazole were higher than those of bicalutamide and prednisolone. A high-performance liquid chromatography-ultra-violet detector method was validated and utilized for analysis of drug extracted from biological and pharmaceutical samples. The method was linear in the range of 0.5–80 mg L−1 with a relative standard deviation value of 0.094 and a limit of detection and a limit of quantification of 0.9 and 30 µg L−1, respectively. The recovery of omeprazole drug ranged from 94.3%, 99.2%, and 98.1%, respectively, in human plasma, human urine, and pharmaceutical samples.

An eco-friendly cellulose support functionalized with tin titanate nanoparticles for the fast removal of clonazepam drug from the drinking water: adsorption mechanisms

This research studied the performance of tin titanate (SnTiO3, SnT) and cellulose-based composites for the removal of clonazepam (CZP) drug by physical adsorption. The cellulose was extracted from a plant named tithonia tubaeformis, which is considered as weed in the crop fields of Mexico. The analysis by microscopy revealed that the SnTiO3 powders are formed by a mixture of coalesced grains and nanotubes with lengths in the range of 97-633 nm. Furthermore, the X-ray diffraction analysis indicated that the SnT powders present a mixture of cassiterite and rutile phases. Experiments for the CZP removal from drinking water were carried out, and several parameters such as initial drug concentration (1-10 mg/L), amount of SnT adsorbent per liter of contaminated solution (10-50 mg/L), and pH (3-10) were varied in order to study their influence on the CZP removal percentage. Essentially, we found that the SnT dosage of 50 mg/L produced the most efficient and fastest CZP removal, since 94.3% of CZP was removed after only 10 min of reaction. Moreover, a piece of cellulose (Cell) was decorated with 50 mg of SnT powder to form the Cell+SnT composite, and this was able to remove a maximum of 80.5% of CZP after 180 min of reaction. If the amount of SnT powder deposited on the Cell+SnT composite is raised up to 100 mg, the composite can remove 95.5% of CZP. The adsorption capacity was also calculated for the SnT powders and Cell+SnT composite and found that it was 6.3 times higher for the SnT powders. Furthermore, the Raman spectra recorded for the Cell+SnT composites demonstrated the presence of surface defects, which acted as adsorption centers for the CZP molecules. The results of this investigation demonstrate that eco-friendly and low-cost floatable composites can be used for the removal of pharmaceutical contaminants, which is an advantage over adsorbent powders.

Adsorption Of Clomid Drug On Activated Carbon And Zinc Oxide Surfaces

The research included study the adsorption of Clomid drug on the
 surface of activated carbon and zinc oxide. Many of parameters were
 studied which affect the adsorption process such as temperature, weight of
 adsorbent, equilibrium time, initial concentration and effect of pH.
 Activated carbon and zinc oxide were used as a model adsorbent in the
 experiments. We found that increased of temperature (30-50) °C followed
 by increased in adsorption capacity experiments were done at 30 °C and
 showed that the optimum weight of activated carbon was (0.15 g) while for
 zinc oxide was (0.1g), equilibrium time was (150 min) for the two
 adsorbents. The adsorption capacity of the two adsorbents increased with
 increasing initial concentration of drug, In addition, the experiments
 showed that the (3-7) pH was the best medium of the adsorption process.

Decontamination of enoxacin containing aqueous phase through hydrophobic deep eutectic solvents: Solvent regeneration and quantum chemical insights

The current work addresses the extraction of a drug (enoxacin) from an aqueous environment by liquid-liquid extraction using three hydrophobic deep eutectic solvents (DES) namely, (a) dl-menthol: decanoic acid (1:1), (b) dl-menthol: dodecanoic acid (2:1), and (c) dodecanoic acid: decanoic acid (1:2). The experiments were conducted at varying mass ratios of DES/ water phase at ambient condition followed by quantum chemical (QC) analysis. Within the batch process with a single cycle, the extraction efficiency and the distribution ratio of 82 % and 4.75 respectively, were reported with the DES; dl-menthol: decanoic acid (1:1). Different initial drug concentrations (5 to 20 ppm) were introduced to observe the extraction performance at various contamination levels. Followed by the batch-type extraction experiments, three different recycling schemes have been implemented to assess the reuse and recovery of DESs. A 90 % percentage extraction was achieved by recycling the DES phase with purification through activated carbon (AC) which allowed it to maintain its continuity of the aqueous phase. The higher hydrophobicity of the DES phase with relatively high drug solubility proved to be the driving force of the enhanced DES-drug interaction. This was supported by the QC analysis as comparably higher non-bonded interaction energy was obtained for the DES-enoxacin complex suggesting stronger interaction and compactness. The charge transfer (CT) process confirmed the magnitude of charge transfer between DES and the drug through natural bonding orbital (NBO) charge analysis. Non-bonded interactions with dispersion effect were confirmed by the structural arrangement analysis of the complex supported by frontier molecular orbital (FMO) analysis. The quantum theory of atom in molecules and the non covalent interaction (QTAIM & NCI) analysis suggest hydrogen bonding and dispersion interactions (van der Waals) as the basis of interaction between the molecular groups.

Adsorption characteristics of dopamine by activated carbon: Experimental and theoretical approach

In this work, we investigate the adsorption mechanism of dopamine (DP) drug using an activated carbon (AC) type through experimental and theoretical data. Experiment series were carried out at different initial values of solution pH, temperature, reaction time and initial drug concentration. The effect of protonation and deprotonation of DP molecule was also investigated. The equilibrium isotherm data were evaluated using the Dubinin-Radushkevich, Langmuir, Temkin and Freundlich models. Elovich, pseudo-first and pseudo-second order kinetic models were used to analyze kinetic data. Here we also used molecular dynamic (MD) simulation and DFT-based computational methods to reach information about the electronic properties of DP drug and its adsorption mechanism that have not been experimentally observed. Experimental results show that the Elovich kinetic model and Langmuir model best describe the adsorption phenomenon. In parallel, the experimental analysis revealed that the adsorption process is spontaneous and endothermic. Dopamine adsorption on AC occurs quickly and is pH and temperature-dependent. Frontier molecular orbital (FMO) energies for neutral, deprotonated and protonated forms of DP were determined and thoroughly explained. The basic medium significantly impacts DP drug adsorption behavior, which has the greatest adsorption energy when the pH is less than 12. It was found that DP adsorption occurs in a bidentate geometry by forming strong bonds between molecular oxygens and carbon atoms on the AC surface. Based on theoretical calculations interaction mechanisms of DP on the AC (001) surface were proposed.

Study on using rice-husk ash as an adsorbent for some antibiotic and anti-inflammatory drugs in aqueous

Rice-husk ash (RHA) is prepared from a by-product of rice production. Its main component is silic dioxide. Thanks a zeolite-like structure, it could be used as an adsorbent. In this study, RHA was used to remove some antibiotic and anti-inflammatory drugs in aqueous medium such as Cefuroxim, Dexamethasone, Methylprednisolone, Prednisolon. These drugs are recommended to use at home for Covid-19 patients. The RHA has a specific surface area of 179.797 m2/g), the pore size of 63.547 m2/g, the average particle size of 3.8 mm. The zeta potential of RHA in distilled water of -42.5 V, the point of zero charge of 6.7. The main composition of elements in RHA is Si, O, C. Among investigated samples, the Cefuroxim adsorption efficiency of RHA is the best, with a adsorption capacity reached 1.43 mg.g-1 and adsorption efficiency reached 86.00 % at the optimum adsorption condition of pH solution of 7, adsorption time of 150 min, RHA weight of 0.3 g and the initial drug concentration of 5.0 mg.L-1.

Lag Time in Diffusion-Controlled Release Formulations Containing a Drug-Free Outer Layer

Theoretical considerations along with extensive Monte Carlo simulations are used to calculate the lag time before the initiation of diffusion-controlled drug release in multilayer planar devices with an outer layer containing no drug. The presented results are also relevant in formulations coated by a drug-free membrane as well as in other reservoir systems. The diffusion of drug molecules through the outer layer towards the release medium is considered, giving rise to the observed lag time. We have determined the dependence of lag time on the thickness and the diffusion coefficient of the drug-free outer layer, as well as on the initial drug concentration and the surface area of the planar device. A simple expression, obtained through an analytical solution of diffusion equation, provides an approximate estimate for the lag time that describes the numerical results reasonably well; according to this relation, the lag time is proportional to the squared thickness of the outer layer over the corresponding diffusion coefficient and inversely proportional to the logarithm of the linear number density of the drug that is initially loaded in the inner layer.

Increasing Cellular Uptake and Permeation of Curcumin Using a Novel Polymer-Surfactant Formulation.

Several therapeutically active molecules are poorly water-soluble, thereby creating a challenge for pharmaceutical scientists to develop an active solution for their oral drug delivery. This study aimed to investigate the potential for novel polymer-surfactant-based formulations (designated A and B) to improve the solubility and permeability of curcumin. A solubility study and characterization studies (FTIR, DSC and XRD) were conducted for the various formulations. The cytotoxicity of formulations and commercial comparators was tested via MTT and LDH assays, and their permeability by in vitro drug transport and cellular drug uptake was established using the Caco-2 cell model. The apparent permeability coefficients (Papp) are considered a good indicator of drug permeation. However, it can be argued that the magnitude of Papp, when used to reflect the permeability of the cells to the drug, can be influenced by the initial drug concentration (C0) in the donor chamber. Therefore, Papp (suspension) and Papp (solution) were calculated based on the different values of C0. It was clear that Papp (solution) can more accurately reflect drug permeation than Papp (suspension). Formulation A, containing Soluplus® and vitamin E TPGs, significantly increased the permeation and cellular uptake of curcumin compared to other samples, which is believed to be related to the increased aqueous solubility of the drug in this formulation.

Monoporous Microsphere as a Dynamically Movable Drug Carrier for Osteoporotic Bone Remodeling.

To repair systematically osteoporotic bone defects, it is important to make an effort to both diminish osteoporosis and enhance bone regeneration. Herein, a specifically monoporous microsphere (MPM) carrier encapsulating dosage-sensitive and short half-time parathyroid hormone (PTH) is constructed to tackle the issue. Compared with conventional microsphere carriers involving compact, porous, and mesoporous microspheres, the MPM is desirable to achieve precisely in situ delivery and to minimize topical accumulation. The findings show that the PTH loaded inside MPMs can be gradually released from the single hole of MPMs to improve the initial drug concentration. Also, the MPMs can self-shift with the daily movement of experimental animals to effectively reduce the topical aggregation of released drugs in vitro. In vivo evaluation further confirms that the implant of MPMs-PTH plays a dual role in stimulating the regenerative repair of the cranial defect and relieving osteoporosis in the whole body. Consequently, the current work develops a dynamically movable drug delivery system to achieve precisely in situ delivery, minimize topical accumulation, and systematically repair osteoporotic bone defects.