Faster Drug Release Rate Research Articles

Systematic study of stability, loading efficiency and release mechanisms, and cellular interaction of vaterite with various sizes

Porous vaterite particles are regarded as promising candidates for drug-carrying system due to their good biocompatibility, degradability, physicochemical properties. However, different particle sizes can significantly affect their drug loading efficiency (LE) and release mechanism through adsorption-desorption mechanism. Herein, we successfully synthesized CaCO3 with high content of nanoscale vaterite at subzero temperatures. The results of six different sizes of vaterite in water, PBS, SBF and NaCl revealed that particle size and medium composition had important effects on its stability. The dissolution and recrystallization kinetics of the particles were explored through the time-dependent curves of pH and Ca2+ concentration induced by the particles in PBS and SBF solutions, which provided support for the drugs release mechanism. The LE of these vaterites for Rhodamine-6G and the release mechanism in PBS and SBF media were systematically studied, indicating that smaller vaterites had higher LE and faster drug release rate, which were attributed to their higher overall surface area and free energy, and the release model supported that the drug release not only depended on diffusion mechanism but was affected by self-dissolution and recrystallization. Furthermore, vaterite exhibited good cytocompatibility through the co-culture of particles and cells, and the cells showed stronger interaction behavior to small vaterites compare to larger vaterites.

Development and characterization of pH-responsive nanocarriers for chemo-photothermal combination therapy of acidic tumors.

The combination of photothermal therapy and chemotherapy has been considered a promising strategy for improving the excellent antitumor activities of these treatments. In this study, we developed a new simple type of pH-sensitive chemo-photothermal combination agent capable of repeated exposures to a near-infrared (NIR) laser and evaluated its anticancer efficacy in vitro and in vivo. Doxorubicin (Dox) and gold nanoclusters (GNCs) were successfully co-loaded into pH-sensitive nanoparticles (poly(ethylene glycol)-poly[(benzyl-l-aspartate)-co-(N-(3-aminopropyl)imidazole-L-aspartamide)] (PEG-PABI)), resulting in a particle size of approximately120 nm with a narrow size distribution. The dual drug-loaded nanoparticles (Dox/GNC-loaded PEG-PABI micelles (Dox/GNC-Ms)) showed consistent pH-sensitive properties and heat generation efficiency after repeated NIR laser exposure. In particular, GNC-M has improved photothermal stability while maintaining high photothermal conversion efficiency, addressing the shortcomings of previous gold nanoparticles. As the concentration of GNC-Ms, irradiation light exposure time, and light source intensity increased, the amount of heat generated and the anticancer effect increased. When Dox was encapsulated with GNCs (Dox/GNC-Ms), a faster drug release rate under acidic pH conditions and a strong synergistic effect against U87MG cells were observed. When the Dox/GNC-M system was extended to in vivo studies, it effectively increased the temperature of the tumor tissue under near-infrared irradiation and showed excellent anticancer efficacy. Therefore, the Dox/GNC-M system could be a simple but promising strategy for chemo-photothermal combination treatment capable of targeting acidic tumors.

Microfluidics-based PLGA nanoparticles of ratiometric multidrug: From encapsulation and release rates to cytotoxicity in human lens epithelial cells

Multidrug nanomedicine is an effective therapeutic approach for the treatment of chronic diseases and cancers. However, co-encapsulation and release of drug combination at a fixed ratio by nanoparticles, particularly for long acting ocular formulations, remains challenging. Herein, poly (lactic-co-glycolic acid) nanoparticles ratiometrically co-encapsulating hydrophilic dual drugs, mitomycin C and doxorubicin, was obtained (D/M PLGANPs) by combining microfluidics and the Design of Experiments approaches. The formulation variable of lactide-to-glycolide ratios (L/G 50:50, 75:15 and 85:15) was used to achieve fast, medium and slow drug release rates of D/M PLGANPs. The dissolution of D/M PLGANPs in simulated intraocular fluid exhibited sustained release of dual drugs at the fixed ratio over 7 days, and analysis using the Korsmeyer-Peppas model showed mechanism of drug release to be governed by diffusion. More importantly, in human lens epithelial cells, the drug release rate was negatively correlated with drug potency. The slower drug release from D/M PLGANPs led to lower efficacy of drug combination against pathogenesis of cellular migration and proliferation, the key pathogenic processes of capsular opacification after cataract surgery. Compared to fast (L/G 50:50) and medium (L/G 75:15) drug release rate of D/M PLGANPs, the slow release formulation (L/G 85:15) exhibited the least cellular uptake of the dual drugs and the ratio of drug combination was not maintained intracellularly. The present study implicates the potential of using microfluidics for synthesizing polymeric nanoparticles of ratiometric drug combination and highlights the drug release rate as the critical determinant of efficacy for the long-acting nanomedicine design.

Acetoxy DMU-loaded carboxymethylchitosan nanocapsules: preparation and in vitro release evaluation followed by an analytical methodology validation

ABSTRACT Acetoxy DMU (Ac.DMU – 1,2,3-trimethoxy-5-(4-acetoxystyryl) benzene) is a potential new drug, compared to resveratrol, due to its improved pharmacokinetic properties. Nanoencapsulation using Ac.DMU and carboxymethylchitosan (CMCh) polymer is a promising alternative for improving the bioavailability of drugs in human bodies. Nanocapsules (NCs) based on CMCh with Ac.DMU (Ac.DMU-NCs) by emulsion solvent diffusion technique in different drug-to-polymer ratios have been prepared with encapsulation efficiency of 69.4% and 51.5% and characterized by dynamic light scattering, ζ-potential, and infrared spectroscopy techniques. In vitro release experiments of free Ac.DMU and Ac.DMU-NCs showed an improvement in the solubility of Ac.DMU by NCs, enabling a fast drug release rate. In addition, the method was validated through analyses of specificity, linearity, limit of detection and quantification, accuracy, and precision according to the standards suggested by the International Conference on Harmonization. UV–Vis spectroscopy used to quantify Ac.DMU ensured reliable results for the amount of encapsulated Ac.DMU. The results suggest a promising potential of NCs as carriers of the hydrophobic drug Ac.DMU for controlled release.

Influence of Hydrotrope on Solubility and Bioavailability of Curcumin: its Complex Formation and Solid-State Characterization

: In this study, meglumine (Meg) and arginine (Arg), acting as the hydrotrope, were used to form the stable curcumin (Cur)-hydrotrope complexes, respectively. Based on the single factor experiment optimization, the Cur-Meg/or Cur-Arg complex was prepared and then characterized by fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that Cur-Meg/Arg complexes bound together by hydrogen bonds/or ionic bond were successfully prepared and the amorphous state of Cur appeared in their complexes. Compared with Cur-Meg complex, Cur-Arg had better stability in stress testing. Cur-Meg/Arg complexes had faster drug release rate in vitro and the area-under-curve (AUC) of Cur-Meg/Arg solutions in rat were at least 6.3-fold larger than that of the Cur suspensions. These findings suggest that hydrotropy combined with solid dispersion technique is a simple and effective way to improve the bioavailability of Cur. Highlights The optimal Cur-Meg/or Cur-Arg complex powder was prepared and characterized. The Cur release rate in vitro was significantly improved. The bioavailability can be improved when using Cur-Meg/or Cur-Arg complex. A simple and effective way to improve the bioavailability of Cur.

Microwave‐assisted ring‐opening copolymerization and property of polycarbonates

AbstractRecently, the microwave‐assisted heating method has become a commonly used and environmentally friendly heating technology in the field of organic and polymeric synthetic chemistry. A series of poly(5,5‐dimethyl trimethylenecarbonate‐co‐2‐phenyl‐5,5‐bis[oxymethyl] trimethylenecarbonate) (P[DTC‐co‐PTC]) were synthesized by microwave‐assisted ring‐opening polymerization of 5,5‐dimethyl trimethylene carbonate (DTC) and 2‐phenyl‐5,5‐bis(oxymethyl) trimethylene carbonate (PTC) using tin(II) 2‐ethylhexanoate and aluminum isopropoxidase, the catalysts. These co‐polycarbonates were further reduced by a palladium‐carbon catalyst (Pd/C catalyst, 10%) to make partly deprotected polycarbonates (HPDPC). These two co‐polycarbonates were characterized by gel permeation chromatography, 1HNMR, Fourier transform infrared spectroscopy, UV, differential scanning calorimetry, and automatic contact‐angle measurements. The influences of the microwave irradiation time, microwave power, monomer feed molar ratio, different catalysts, and monomer/catalyst feed molar ratio on the molecular weights of co‐polycarbonates were also investigated. In vitro water absorption, degradation and drug release tests indicated that partly deprotected co‐polycarbonate HPDPC possessed greater hydrophilicity, faster degradation rate, and faster drug release rate than that of corresponding P(DTC‐co‐PTC). Therefore, microwave‐assisted polymerization is a clean and cheap heating method and can be used for ring‐opening copolymerization of carbonates, which enhances the hydrophilicity and biodegradation rate of aliphatic polycarbonates.

Theranostic supramolecular polymers formed by the self-assembly of a metal-chelating prodrug.

Therapeutic constructs with imaging modalities hold great promise for improving the treatment efficacy for cancer and many other diseases. We report here the design and synthesis of a self-assembling prodrug (SAPD) by the direct linkage of camptothecin (CPT), an anticancer drug, to a metal-chelating agent, DOTA. We found that under physiological conditions the DOTA-conjugated CPT prodrug can self-assemble into tubular supramolecular polymers (SPs) with a length of several micrometers. Our studies also suggest that the resultant assemblies were stable in biological environments and exhibited a fast drug release rate in the presence of intracellular glutathione. Furthermore, the SAPD exhibited remarkable in vitro efficacy against various cancer cell lines and effectively inhibited the growth of tumor spheroids. We believe that the design and optimization of self-assembling theranostic conjugates could provide a robust yet simple platform for the development of new imaging-guided drug delivery systems.

Blending of PLGA-PEG-PLGA for Improving the Erosion and Drug Release Profile of PCL Microspheres.

PCL has a long history as an industrialized biomaterial for preparing microspheres, but its hydrophobic property and slow degradation rate often cause drug degeneration, quite slow drug release rate and undesirable tri-phasic release profile. In this study, we used the blending material of PLGA-PEG-PLGA and PCL to prepare microspheres. The microspheres degradation and drug release behaviors were evaluated through their molecular weight reduction rate, mass loss rate, morphology erosion and drug release profile. The hydrophilic PLGA-PEG-PLGA is expected to improve the degradation and drug release behaviors of PCL microspheres. Microspheres in blending materials exhibited faster erosion rates than pure PCL microspheres, forming holes much quickly on the particle's surface for the drug to diffuse out. A higher proportion of PLGA-PEG-PLGA caused faster degradation and erosion rates. The blending microspheres showed much faster drug release rates than pure PCL microspheres. With blending of 25wt% PLGA-PEG-PLGA, the release rate of microspheres speeded up significantly, while, with a further increase of PLGA-PEG-PLGA proportion (50%, 75%, 100%), it accelerated a little. The microspheres with PCL/PLGA-PEG-PLGA of 1/1 exhibited a linear-like drug release profile. The results could be a guideline for preparing microspheres based on blending materials to obtain a desirable release.

Visible-Light-Responsive Surface Molecularly Imprinted Polymer for Acyclovir through Chicken Skin Tissue.

The phototoxicity of UV light limits the application of conventional azobenzene-based photoresponsive molecularly imprinted polymers in the biomedical field. This paper reports a tetra-ortho-methoxy-substituted azobenzene, N-(4-((4-amino-2,6-dimethoxyphenyl)diazenyl)-3,5-dimethoxyphenyl)methacrylamide (ADDDM), whose photoswitching is induced by all visible-light irradiation (440 nm for trans form to cis form and 630 nm for cis form to trans form) in N,N-dimethylformamide and tetrahydrofuran (1:9, v/v). Using ADDDM as the monomer, a visible-light-responsive surface molecularly imprinted polymer (VSMIP) on silica microspheres was fabricated for acyclovir (ACV). VSMIP showed a higher drug loading capacity, better specificity, faster drug release rate, and faster photoisomerization rate constant to ACV than the corresponding visible-light-responsive surface molecularly nonimprinted polymer (VSNIP). The selectivity of VSMIP to ACV and competing materials (ganciclovir and triacetylganciclovir) was examined by ultraviolet-visible spectroscopy, and the VSMIP showed excellent specificity of recognition toward ACV. The VSMIP can realize a visible-light-triggered (440/630 nm) release and uptake of ACV through chicken skin tissue (1 mm in thickness).

Mechanisms of enhanced antiglioma efficacy of polysorbate 80-modified paclitaxel-loaded PLGA nanoparticles by focused ultrasound.

The presence of blood‐brain barrier (BBB) greatly limits the availability of drugs and their efficacy against glioma. Focused ultrasound (FUS) can induce transient and local BBB opening for enhanced drug delivery. Here, we developed polysorbate 80‐modified paclitaxel‐loaded PLGA nanoparticles (PS‐80‐PTX‐NPs, PPNP) and examined the enhanced local delivery into the brain for glioma treatment by combining with FUS. Our result showed PPNP had good stability, fast drug release rate and significant toxicity to glioma cells. Combined with FUS, PPNP showed a stronger BBB permeation efficiency both in the in vitro and in vivo BBB models. Mechanism studies revealed the disrupted tight junction, reduced P‐glycoprotein expression and ApoE‐dependent PS‐80 permeation collectively contribute to the enhanced drug delivery, resulting in significantly stronger antitumour efficacy and longer survival time in the tumour‐bearing mice. Our study provided a new strategy to efficiently and locally deliver drugs into the brain to treat glioma.

Fast dissolving moxifloxacin hydrochloride antibiotic drug from electrospun Eudragit L-100 nonwoven nanofibrous Mats

Antimicrobial electrospun nonwoven Eudragit L-100 nanofibrous mats containing Moxifloxacin hydrochloride (MOX-HCL) were fabricated for fast dissolving drug delivery systems (DDSs) associated with wound infection. The morphological characterization of nanofibers using ESEM revealed that the average diameter of non-woven nanofibrous mats ranges 200‐600 nm. The nanofiber showed cylindrical shape with crack on the surface. Differential scanning calorimetric (DSC) and Wide Angle X-ray diffraction (WAXRD) demonstrate that the drug exists in an amorphous state in the nanofibers. Nanofibrous mats were also tested for mechanical strength, contact angle, swelling assay, haemolysis and disintegration test. In vitro disintegration tests demonstrated that the dissolution of Eudragit L-100 fiber mats was within 25 s which was higher compared to the pure drug. The Eudragit nanofibers showed pH-dependent drug release profiles, with slow release at pH 1.2 and burst release (around 30 s) at pH 6.8. The in-vitro quantitative and qualitative antimicrobial assay showed that the developed Eudragit L-100 nanofibrous mats with MOX-HCL concentration of 1%, 5% and 15 wt% exhibited antibacterial activities against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. The in-vitro cytotoxicity assay using mouse fibroblast NIH/3T3 cells demonstrated significant biocompatibility of nanofiber mats. As per the results of biological evaluation, Eudragit L-100 nanofibrous mats with 1wt% MOX-HCL could be a suitable substrate for biomedical applications. Eudragit L-100 nanofibrous mats containing Moxifloxacin hydrochloride (MOX-HCL) showed immediate DDSs for localized drug release in the wound infection at slightly acidic or alkaline conditions where faster drug release rate is required for wound healing.

FORMULATION EVALUATION AND OPTIMIZATION OF ORODISPERSIBLE TABLETS OF PANTOPRAZOLE SODIUM BY THE USING OF DIFFERENT SUPERDISINTEGRANTS

Objective: The objective of this study was to formulate and optimize an orodispersible formulation of pantoprazole sodium using a 32 factorial design for optimized the superdisintegrant concentration. Methods: Various concentrations (2%, 4%, and 6%) of superdisintegrants (sodium starch glycollate [SSG] and crospovidone [CP]) were added in the formulation, all processing steps are carried out at a temperature below 250c and relative humidity <35%. Procedure to manufacture orodispersible tablets by direct compression was established. Results: The results show that the presence of a superdisintegrants is desirable for orodispersion. The best-optimized batch found was the batch having amount of CP 4.37 mg and SSG 10.59 mg. All the formulations satisfied the limits of orodispersion with a dispersion time of <30 s best formulation showed a disintegration time (DT) of 30 s, % friability is 0.82%, drug content of 96– 99.4, and fast drug release rate of 80 % of drug release within 10 min. Conclusion: The optimized batch was evaluated for thickness, weight variation, hardness, friability, DT dissolution, and accelerated stability study for a period of 3 months. The similarity factor was calculated for comparison of dissolution profile before and after stability studies. The f2 value was found more than 50 that indicate a good similarity between both the dissolution profiles. Hence, the results of stability studies reveal that the developed formulation has good stability.

Influence of Solvent on the Drug-Loading Process of Amphiphilic Nanogel Star Polymers.

We present an all-atom molecular dynamics study of the effect of a range of organic solvents (dichloromethane, diethyl ether, toluene, methanol, dimethyl sulfoxide, and tetrahydrofuran) on the conformations of a nanogel star polymeric nanoparticle with solvophobic and solvophilic structural elements. These nanoparticles are of particular interest for drug delivery applications. As drug loading generally takes place in an organic solvent, this work serves to provide insight into the factors controlling the early steps of that process. Our work suggests that nanoparticle conformational structure is highly sensitive to the choice of solvent, providing avenues for further study as well as predictions for both computational and experimental explorations of the drug-loading process. Our findings suggest that when used in the drug-loading process, dichloromethane, tetrahydrofuran, and toluene allow for a more extensive and increased drug-loading into the interior of nanogel star polymers of the composition studied here. In contrast, methanol is more likely to support shallow or surface loading and, consequently, faster drug release rates. Finally, diethyl ether should not work in a formulation process since none of the regions of the nanogel star polymer appear to be sufficiently solvated by it.

Design of pH-Sensitive Nanovesicles via Cholesterol Analogue Incorporation for Improving in Vivo Delivery of Chemotherapeutics.

pH-responsive polymersomes have emerged as promising nanocarriers for antitumor drugs to realize their fast release and action in a weakly acidic microenvironment of tumor cells. Herein, however, we designed a remarkably pH-responsive polymersome self-assembled from amphiphilic benzimidazole-based polyphosphazenes via the incorporation of cholesteryl hemisuccinate (CholHS), a type of cholesteric molecule, into the polymersome bilayers to inhibit the drug release during blood circulation. Actually, unwanted premature drug leakage before arriving at the acidic tumor site has become a serious problem for polymersomes encapsulating water-soluble drugs, especially when the drug loading is at a high level, thus limiting the therapeutic efficacy. In this study, polymersomes displayed high loading capability of doxorubicin hydrochloride as 12.83%. More importantly, CholHS incorporation decreased the membrane permeability of the polymersome and effectively retarded the cargo release under physiological conditions but induced the fast drug-release rate at pH 5.5, demonstrating a more remarkably acid-responsive release behavior when compared to that of the CholHS-free polymersomes. Further in vivo investigations including pharmacokinetic and antitumor activity studies verified the extended circulation time and enhanced antitumor efficacy of the drug-loaded CholHS-incorporated polymersomes.

Formulation by design approach for development of ultrafine self-nanoemulsifying systems of rosuvastatin calcium containing long-chain lipophiles for hyperlipidemia management

The present work entails systematic development of liquid self-nanoemulsifying drug delivery systems (L-SNEDDS) of rosuvastatin calcium containing long-chain lipophiles using QbD-driven Formulation by Design (FbD) approach. Elements of quality target product profile (QTPP) were defined and critical material attributes (CQAs) earmarked. Excipient screening was performed for selecting a suitable long-chain lipophile along with a surfactant and a cosolvent. Maximal drug solubility was observed in Peceol (i.e., lipid), Tween 80 (i.e., surfactant) and Transcutol HP (i.e., cosolvent), which during pseudoternary phase titration study indicated maximal nanoemulsion region at 1:1 ratio of surfactant: cosolvent mixture. Risk analysis and factor screening study indicated selection of excipient levels as the critical material attributes (CMAs). D-optimal mixture design was used for systematic optimization of L-SNEDDS, which exhibited emulsification time of 131s, globule size <100nm and faster drug release rate >80% in 15min. Ex vivo permeability showed >70% permeation of drug across the rat intestine, while in situ perfusion study indicated up to 1.8 and 2.1-folds improvement in permeability and absorptivity parameters of the drug from optimized L-SNEDDS over the plain drug suspension. In vivo pharmacokinetic studies revealed 1.8- and 5.7-folds enhancement in AUC0-t and Cmax, and 0.33-folds reduction in Tmax of drug from the optimized L-SNEDDS vis-à-vis the pure plain drug suspension. In vivo pharmacodynamic studies also indicated superior antihyperlipidemic activity of optimized L-SNEDDS in normalizing serum lipid levels. Overall, the research work construed significant role of long-chain lipophiles in enhancing biopharmaceutical attributes of the L-SNEDDS of rosuvastatin.

3D printed tablets loaded with polymeric nanocapsules: An innovative approach to produce customized drug delivery systems

The generation of multi-functional drug delivery systems, namely solid dosage forms loaded with nano-sized carriers, remains little explored and is still a challenge for formulators. For the first time, the coupling of two important technologies, 3D printing and nanotechnology, to produce innovative solid dosage forms containing drug-loaded nanocapsules was evaluated here. Drug delivery devices were prepared by fused deposition modelling (FDM) from poly(ε-caprolactone) (PCL) and Eudragit® RL100 (ERL) filaments with or without a channelling agent (mannitol). They were soaked in deflazacort-loaded nanocapsules (particle size: 138nm) to produce 3D printed tablets (printlets) loaded with them, as observed by SEM. Drug loading was improved by the presence of the channelling agent and a linear correlation was obtained between the soaking time and the drug loading (r2=0.9739). Moreover, drug release profiles were dependent on the polymeric material of tablets and the presence of the channelling agent. In particular, tablets prepared with a partially hollow core (50% infill) had a higher drug loading (0.27% w/w) and faster drug release rate. This study represents an original approach to convert nanocapsules suspensions into solid dosage forms as well as an efficient 3D printing method to produce novel drug delivery systems, as personalised nanomedicines.

Carboxymethyl cellulose/graphene oxide bio-nanocomposite hydrogel beads as anticancer drug carrier agent

Biodegradable carboxymethyl cellulose/graphene oxide (CMC/GO) nanocomposite hydrogel beads as a drug delivery system were prepared via physically crosslinking with FeCl3·6H2O for controlled release of anticancer drug doxorubicin (DOX). The π-π stacking interaction between DOX and GO resulted in higher loading capacity and controlled release of the DOX loaded from CMC/GO nanocomposites hydrogel. The release profile of DOX from hydrogel beads at pH 6.8 and 7.4 indicated it’s strongly pH dependence. Interaction between GO and DOX with H-bonding could be unstable under acidic conditions which resulted in faster drug release rate in pH 6.8. The formation of GO nanoparticles in the hydrogels was confirmed using X-ray diffraction (XRD), and the chemical structure and morphology of the prepared CMC/GO nanocomposite hydrogel beads were characterized using Fourier transform infrared spectroscopy (FT-IR), SEM and Transmission electron microscopy (TEM). In addition, swelling behavior of nanocomposite hydrogels was investigated in PBS solution.

Agarose bioplastic-based drug delivery system for surgical and wound dressings.

We have developed an agarose-based biocompatible drug delivery vehicle. The vehicle is in the form of thin, transparent, strong and flexible films. The biocompatibility and haemocompatibility of the films is confirmed using direct and indirect contact biological assay. Contact angle measurement exhibits hydrophilic nature of the films, and protein adsorption test shows low protein adsorption on the film surface. Drugs, antibiotics and antiseptics, retain their potency after their incorporation into the films. Our bioplastic films can be a versatile medium for drug delivery applications, especially as wound and surgical dressings where a fast drug release rate is desired.

Nano-confinement of acetaminophen into porous mannitol through adsorption method

A new formulation has been developed successfully, which includes production of highly-porous mannitol particles with high surface areas through the spray drying of mannitol solutions containing ethanol-soluble sugar or food-grade acids as templating agents. The resultant porous particles after ethanol washing have been transferred to ethanol solutions containing the drug component. The results of this study showed that deposition of acetaminophen in the pore-space of highly-porous mannitol resulted in better blending uniformity of drug dosage, as well as a fast drug release rate due to nano-confinement of drugs into porous excipients. Within the first 5 min of the experiment 80% of the drug was released for the drug-loaded samples. Low variability for the drug content was found for the finished products, even for low-dose drug products with around 4% relative standard deviation or less. The drug content of porous mannitol with a surface area and pore volume of 6.1 ± 0.1 m2 g−1 and 0.037 ± 0.003 ml/g, respectively, significantly increased from 0.62 ± 0.03 wt% to 21.7 ± 0.8 wt% when the concentration of acetaminophen was increased from 0.01 M to 0.5 M.

The effects of mPEG proportion and LA/GA ratio on degradation and drug release behaviors of PLGA-mPEG microparticles

The purpose of this research was to evaluate the effects of mPEG proportion and LA/GA ratio on degradation and release behavior of PLGA-mPEG microparticles prepared by the emulsion evaporation method. Mometasone furoate was employed as model drug and encapsulated into five types of PLGA-mPEG microparticles in the same molecular weight (Mw), but different in mPEG proportion or LA/GA ratio. All types of PLGA-mPEG microparticles showed similar drug encapsulation efficiency and particle mean size, but PLGA-mPEG microparticles with higher mPEG proportion showed a faster Mw reduction rate, mass loss rate and size decrease rate according to the in vitro degradation experiment, and also, a faster drug release rate according to the in vitro release experiment. On the other hand, higher LA/GA ratio in PLGA chain of PLGA-mPEG causes a slower Mw reduction rate, mass loss rate, size decrease rate, and thus, a slower drug release rate.