Preparation and in vitro evaluation of melatonin-loaded HA/PVA gel formulations

Melatonin-loaded hyaluronic acid (HA) and poly(vinyl alcohol) (PVA) gels were prepared by using freeze–thaw technique and an emulsion method followed by freeze–thaw technique to produce a new synergistic system for topical application. Freeze–thaw hydrogels and emulgels were characterized by means of Fourier transform infrared spectroscopy, rheology and swelling tests. The porous structure of the hydrogels was shown by scanning electron microscopy observations and thermal properties were tested by differential scanning calorimetry measurements. Bioadhesion and in vitro release characterization of formulations were performed by texture profile analysis and dialysis bag method, respectively. The pore size of both formulations was ranging from 900?nm to 30?μm. Melatonin showed a good compatibility with the polymeric matrices as the pores were smaller for the drug-loaded systems. In vitro release studies showed that the release was improved by emulgel formulations. After 24?h, the release percentage was found to be 13.240%?±?1.094 and 15.192%?±?2.270 for hydrogel and emulgel, respectively. Emulgels had better bioadhesion properties than simple freeze–thaw samples. As a conclusion, regarding the in vitro characterization studies HA and PVA hydrogel and emulgel formulations and their lyophilized forms could be promising systems for topical application of melatonin.     

Effect of sodium carboxymethylcellulose and fucidic acid on the gel characterization of polyvinylalcohol-based wound dressing

The purpose of this study was to investigate the effect of sodium carboxymethylcellulose (Na-CMC) and fucidic acid on the gel characterization for the development of sodium fucidate-loaded wound dressing. The cross-linked hydrogel films were prepared with polyvinyl alcohol (PVA) and sodium carboxymethylcellulose (Na-CMC) using the freeze-thawing method. Their gel properties such as gel fraction, swelling, water vapor transmission test, morphology, tensile strength and thermal property were investigated. In vitro protein adsorption test and release were performed. Na-CMC decreased the gel fraction and tensile strength of the hydrogels, but increased the swelling ability, water vapor transmission rate, elasticity and porosity of hydrogels. Thus, the wound dressing developed with PVA and Na-CMC was more swellable, flexible and elastic than that with only PVA because of its cross-linking interaction with PVA. However, the drug had a negative effect on the gel properties of hydrogels but there were no significant differences. In particular, the hydrogel composed of 2.5% PVA, 1.125% Na-CMC and 0.2% drug might give an adequate level of moisture and build up the exudates on the wound area. Thus, this sodium fucidate-loaded hydrogel could be a potential candidate for wound dressing with excellent forming.     

Multi‐arm PEG/Silica Hydrogel for Sustained Ocular Drug Delivery

In the present study, a series of sustained drug delivery multiarm poly(ethylene glycol) (PEG)/silica hydrogels were prepared and characterizedThe hydrogels were formed by hydrolysis and condensation of poly(4‐arm PEG silicate) using the sol‐gel methodThe relationships between water content in the PEG/silica hydrogel and stability as well as rheological properties were evaluatedScanning electron microscopy analysis of the PEG/silica hydrogels revealed water content‐dependent changes in microstructureAn increase in water content resulted in larger pores within the hydrogel, longer gelation time and higher viscosityThe PEG/silica hydrogels were loaded with dexamethasone (DMS) or dexamethasone sodium phosphate (DMSP), drugs that are hydrophobic and hydrophilic in nature, respectivelyEvaluation of in vitro release revealed a zero‐order release profile for DMS over the first 6 days, suggesting that degradation of the silica hydrogel matrix was the primary mechanism of drug releaseIt was also found that the drug‐release profile could be tailored by varying the water content used during hydrogel preparationIn contrast, more than 90% of DMSP was released within 1 h, suggesting that DMSP release was only controlled by diffusionOverall, results from this study indicate that PEG/silica hydrogels may be promising drug‐eluting depot materials for the sustained delivery of hydrophobic, ophthalmic drugs© 2013 Wiley Periodicals, Incand the American Pharmacists Association J Pharm Sci 103:216–226, 2014     

Rheological and mucoadhesive characterization of poly(vinylpyrrolidone) hydrogels designed for nasal mucosal drug delivery

Poly(vinylpyrrolidone) (PVP) hydrogels were crosslinked by gamma irradiation to add structure and rigidity, and then rheological and mucoadhesive properties were evaluated. The effects of PVP concentration, radiation dose, and additives, such as poly(ethylene glycol) (PEG) and glycerol, on rheological properties were investigated. In an oscillatory analysis, an increase in polymer concentrations increased the storage modulus (G′) and the loss modulus (G″) but decreased the loss tangent (tan δ < 1). The relationships between G′or G″ and the frequency levelled off at higher frequencies, which is indicative of polymer chain entanglement and network formation. Each of the 6% PVP hydrogels exhibited plastic flow with rheopectic behavior. PVP concentration, radiation dose, and the presence of PEG or glycerol influenced the rheological and mucoadhesive properties of the hydrogels. However, adding acyclovir to the formulation did not have a profound effect on the rheological behavior of the hydrogels. The results suggest that a 3% PVP hydrogel with 1% PEG crosslinked with 20 kGy is the most appropriate hydrogel. The results demonstrated the successful complementary application of oscillatory and flow rheometry to characterize and develop a hydrogel for mucosal drug administration.     

Controlled release of dexamethasone from poly(vinyl alcohol) hydrogel

This study investigated a chemically crosslinked poly(vinyl alcohol) (PVA) hydrogel controlled drug delivery system to deliver the anti-inflammatory drug dexamethasone (DEX). The PVA hydrogels, with different crosslinking densities, were characterized by swelling studies, electron scanning microscopy, viscosity, Fourier transform infrared spectroscopy (FTIR) and in vitro release assessment. Increasing crosslinking density slowed and decreased swelling and water absorption. FTIR analysis suggested DEX has possible interactions with the crosslinker and the PVA polymer. In vitro release of DEX from PVA hydrogels was sustained for 33 days and appeared to fit the Higuchi and Korsmeyer–Peppas models. This work indicates the likelihood of PVA hydrogel as a controlled drug release system for DEX for anti-inflammatory uses.     

Physical characterisation and component release of poly(vinyl alcohol)-tetrahydroxyborate hydrogels and their applicability as potential topical drug delivery systems

Poly(vinyl alcohol)-tetrahydroxyborate (PVA-THB) hydrogels are dilatant formulations with potential for topical wound management. To support this contention, the physical properties, rheological behaviour and component release of candidate formulations were investigated. Oscillatory rheometry and texture profile analysis were used at room temperature and 37 °C. Results showed that it was possible to control the rheological and textural properties by altering component concentration and modifying the type of PVA polymer used. Hydrogels made using PVA grades with higher degrees of hydrolysis displayed favourable characteristics from a wound healing perspective. In vitro release of borate and PVA were assessed in order to evaluate potential clinical dosing of free species originating from the hydrogel structure. Component diffusion was influenced by both concentration and molecular weight, where relevant, with up to 5% free PVA cumulative release observed after 30 min. The results of this study demonstrated the importance of poly(vinyl alcohol) selection for ensuring appropriate gel formation in PVA-THB hydrogels. The benefits of higher degrees of hydrolysis, in particular, included lower excipient release and reduced bioadhesion. The unique physical characteristics of these hydrogels make them an appealing delivery vehicle for chronic and acute wound management purposes.     

Accelerated wound healing and anti-inflammatory effects of physically cross linked polyvinyl alcohol–chitosan hydrogel containing honey bee venom in diabetic rats

Diabetes is one of the leading causes of impaired wound healing. The objective of this study was to develop a bee venom-loaded wound dressing with an enhanced healing and anti-inflammatory effects to be examined in diabetic rats. Different preparations of polyvinyl alcohol (PVA), chitosan (Chit) hydrogel matrix-based wound dressing containing bee venom (BV) were developed using freeze–thawing method. The mechanical properties such as gel fraction, swelling ratio, tensile strength, percentage of elongation and surface pH were determined. The pharmacological activities including wound healing and anti-inflammatory effects in addition to primary skin irritation and microbial penetration tests were evaluated. Moreover, hydroxyproline, glutathione and IL-6 levels were measured in the wound tissues of diabetic rats. The bee venom-loaded wound dressing composed of 10 % PVA, 0.6 % Chit and 4 % BV was more swellable, flexible and elastic than other formulations. Pharmacologically, the bee venom-loaded wound dressing that has the same pervious composition showed accelerated healing of wounds made in diabetic rats compared to the control. Moreover, this bee venom-loaded wound dressing exhibited anti-inflammatory effect that is comparable to that of diclofenac gel, the standard anti-inflammatory drug. Simultaneously, wound tissues covered with this preparation displayed higher hydroxyproline and glutathione levels and lower IL-6 levels compared to control. Thus, the bee venom-loaded hydrogel composed of 10 % PVA, 0.6 % Chit and 4 % BV is a promising wound dressing with excellent forming and enhanced wound healing as well as anti-inflammatory activities.     

Studies on controlled release of indomethacin from PVA hydrogel

The polyvinyl alcohol (PVA) hydrogel containing 1-methyl-2-pyrrolidinone (MP) and sorbitol was preapred by the freeze and thaw method. The release rate of indomethacin from PVA hydrogel was used as a criterion for deciding the optimum formula of hydrogel using the computer optimization technique. The hydrogel of optimum formula was composed of PVA (10 w/v%), MP (0 w/v%), and sorbitol (40 w/v%) and the release rate of indomethacin was 1.981 μg/ml·min^1/2.     

Controlled release of dexamethasone from PLGA microspheres embedded within polyacid-containing PVA hydrogels

The development of zero-order release systems capable of delivering drug(s) over extended periods of time is deemed necessary for a variety of biomedical applications. We hereby describe a simple, yet versatile, delivery platform based on physically cross-linked poly(vinyl alcohol) (PVA) microgels (cross-linked via repetitive freeze/thaw cycling) containing entrapped dexamethasone-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres for controlled delivery over a 1-month period. The incorporation of polyacids, such as humic acids, Nafion, and poly(acrylic acid), was found to be crucial for attaining approximately zero-order release kinetics, releasing 60% to 75% of dexamethasone within 1 month. Microspheres alone entrapped in the PVA hydrogel resulted in negligible drug release during the 1-month period of investigation. On the basis of a comprehensive evaluation of the structure-property relationships of these hydrogel/microsphere composites, in conjunction with their in vitro release performance, it was concluded that these polyacids segregate on the PLGA microsphere surfaces and thereby result in localized acidity. These surface-associated polyacids appear to cause acid-assisted hydrolysis to occur from the surface inwards. Such systems show potential for a variety of localized controlled drug delivery applications such as coatings for implantable devices.     

Thermosensitive PEG–PCL–PEG (PECE) hydrogel as an in situ gelling system for ocular drug delivery of diclofenac sodium

Development of efficient ocular drug delivery systems was still a challenging task. The objective of this article was to develop a thermosensitive PEG–PCL–PEG (PECE) hydrogel and investigate its potential application for ocular drug delivery of diclofenac sodium (DIC). PECE block polymers were synthesized by coupling MPEG-PCL co-polymer using IPDI reagent, and then its sol–gel transition as a function with temperature was investigated by a rheometer. The results showed that 30% (w/v) PECE aqueous solution exhibited sol–gel transition at approximately 35?°C. In vitro release profiles showed the entrapped DIC was sustained release from PECE hydrogels up to 7 days and the initial drug loading greatly effect on release behavior of DIC from PECE hydrogels. MTT assay results indicated that no matter PECE or 0.1% (w/v) DIC-loaded PECE hydrogels were nontoxic to HCEC and L929 cells after 24?h culturing. In vivo eye irritation test showed that the instillation of either 30% (w/v) PECE hydrogels or 0.1% (w/v) DIC-loaded PECE hydrogels to rabbit eye did not result in eye irritation within 72?h. In vivo results showed that the AUC_0–48?h of 0.1% (w/v) DIC-loaded PECE hydrogels exhibited 1.6-fold increment as compared with that of commercial 0.1% (w/v) DIC eye drops, suggesting the better ophthalmic bioavailability could be obtained by the instillation of 0.1% (w/v) DIC-loaded PECE hydrogels.     

青藤碱固体脂质纳米粒凝胶骨架缓释片的制备及处方优化

目的：制备青藤碱固体脂质纳米粒凝胶骨架缓释片,考察凝胶骨架缓释片处方因素对青藤碱固体脂质纳米粒体外释药行为的影响。方法：采用乳化蒸发-低温固化法制备青藤碱固体脂质纳米粒。以羟丙基纤维素（HPMC）为骨架材料制备青藤碱固体脂质纳米粒凝胶骨架缓释片,单因素考察吸附剂种类、骨架材料比例、PEG种类和骨架材料用量对缓释片体外释药的影响,正交试验进一步优化处方,并对释药模型进行拟合。结果：骨架材料比例和PEG种类是影响青藤碱固体脂质纳米凝胶骨架缓释片体外释药行为的主要影响因素,优化后的处方体外释放行为符合一级释药模型,释药方程为ln（1-M_t/M_∞）=-0.187 2 t+0.071 2（r=0.991 1）,累积释放度在12 h内可达90.15%。结论：优化后的青藤碱固体脂质纳米粒凝胶骨架缓释片制备工艺简单,重复性良好,在12 h内具有良好的体外缓释特征。     

The effect of lipid composition and liposome size on the release properties of liposomes-in-hydrogel

To study the release of liposome-associated drugs into hydrogels, we designed and synthesized two pH-sensitive rhodamine derivatives to use as model compounds of different lipophilicities. The dyes were fluorescent when in the free form released from liposomes into the chitosan hydrogel, but not when incorporated within liposomes. The effect of liposomal composition, surface charge and vesicle size on the release of those incorporated dyes was evaluated. The lipophilicity of the rhodamine derivatives affected both the amount and rate of release. While liposome size had only a minor effect on the release of dyes into the hydrogel, the surface charge affected the release to a greater extent. By optimizing the characteristics of liposomes we could develop a liposomes-in-hydrogel system for application in wound therapy. We further characterized liposomes-in-hydrogel for their rheological properties, textures and moisture handling, as well as their potential to achieve a controlled release of the dye. The polymer-dependent changes in the hydrogel properties were observed upon addition of liposomes. The charged liposomes exhibited stronger effects on the textures of the chitosan hydrogels than the neutral ones. In respect to the ability of the system to handle wound exudates, chitosan-based hydrogels were found to be superior to Carbopol-based hydrogels.     

A photo-crosslinked poly(vinyl alcohol) hydrogel growth factor release vehicle for wound healing applications

The objective of this study was to develop and evaluate a hydrogel vehicle for sustained release of growth factors for wound healing applications. Hydrogels were fabricated using ultraviolet photo-crosslinking of acrylamide-functionalized nondegradable poly(vinyl alcohol) (PVA). Protein permeability was initially assessed using trypsin inhibitor (TI), a 21 000 MW model protein drug. TI permeability was altered by changing the solids content of the gel and by adding hydrophilic PVA fillers. As the PVA content increased from 10% to 20%, protein flux decreased, with no TI permeating through 20% PVA hydrogels. Further increase in model drug release was achieved by incorporating hydrophilic PVA fillers into the hydrogel. As filler molecular weight increased, TI flux increased. The mechanism for this is most likely an alteration in protein/gel interactions and transient variations in water content. The percent protein released was also altered by varying protein loading concentration. Release studies conducted using growth factor in vehicles with hydrophilic filler showed sustained release of platelet-derived growth factor (PDGF-β,β) for up to 3 days compared with less than 24 hours in the controls. In vitro bioactivity was demonstrated by doubling of normal human dermal fibroblas numbers when exposed to growth factor-loaded vehicle compared to control. The release vehicle developed in this study uses a rapid and simple fabrication method, and protein release can be tailored by modifying solid content, incorporating biocompatible hydrophilic fillers, and varying protein loading concentration.     

Drug release behaviors of a pH sensitive semi-interpenetrating polymer network hydrogel composed of poly(vinyl alcohol) and star poly[2-(dimethylamino)ethyl methacrylate

A series of pH sensitive semi-interpenetrating polymer network (semi-IPN) structural hydrogels composed of poly(vinyl alcohol) (PVA) and 21-arm star poly[2-(dimethylamino)ethyl methacrylate] (star PDMAEMA) with different molecular weight were prepared. Riboflavin was used as a model drug to evaluate the drug loading capacities and drug release behaviors of the semi-IPN structural hydrogels. The molecular weight of the star PDMAEMA polymers was calculated by GPC, and the formation of semi-IPN structure was confirmed by FTIR and SEM. It was found that the molecular weight of star PDMAEMA has significant effect on the structure, swelling ratio and drug release behaviors of the semi-IPN hydrogel at different pH conditions. The results suggested that the PVA/star PDMAEMA-50,000 hydrogel exhibited highest swelling ratio and drug loading capacity. The pH-sensitive semi-IPN hydrogel based on star PDMAEMA could be a promising drug delivery system due to the controllable porous structure.     

Cyclodextrin/PEG based hydrogels for multi-drug delivery

Cyclodextrin-PEG hydrogels were prepared by reaction of hexamethlyene isocyanate-activated beta-cyclodextrins with 1.9kDa NH(2)PEGNH(2). The reaction was carried out in anhydrous dimethylsulfoxide by using 0.25:1, 0.33:1, 0.5:1, 0.67:1, 1:1, and 2:1 CD/PEG molar ratios. The addition of acetic acid to the reaction mixture was found to slow the cross-linking reaction, yielding homogeneous matrices. The mechanical characterization indicated that the elasticity of the matrices increased as the CD content in the hydrogel increased while the elongation was irrespective of the hydrogel composition. By incubation in water and ethanol, the hydrogels underwent complete swelling in 5-10min. The water up-take increased logarithmically as the CD/PEG ratio decreased to reach a swelling degree of 800% (swollen hydrogel/dry hydrogel, w/w%). The ethanol uptake increased with a power correlation as the CD/PEG ratio decreased to reach a swelling degree of about 1000% with 0.25:1 CD/PEG hydrogel. Lysozyme, beta-estradiol, and quinine were loaded by swell embedding. The lysozyme loading increased as the CD/PEG ratio decreased while the incorporation of beta-estradiol and quinine displayed inverse correlation with respect to the CD/PEG ratio. The maximal incorporation (loaded drug/dry hydrogel, w/w%) for lysozyme, beta-estradiol and quinine was 2, 0.6, and 2.4%, respectively. Lysozyme was quickly released from the matrices, and the release was faster as the CD/PEG ratio decreased. Also, beta-estradiol and quinine release rates were inversely proportional to the CD/PEG ratio, but in these cases, the release profiles were strongly affected by the drug interaction with the hexamethylated beta-cyclodextrins in the matrices.     

Comparison of the Effect of Bioadhesive Polymers on Stability and Drug Release Kinetics of Biocompatible Hydrogels for Topical Application of Ibuprofen

The study is focused on formulation of biocompatible hydrogels with a poorly soluble drug ibuprofen (5%) and comprehensive evaluation and comparison of effect of different bioadhesive polymers on their suitability for application on skin, physical stability during the accelerated and natural aging tests (by performing centrifugation test, light microscopy, differential scanning calorimetry, rheological and pH measurements), and in vitro drug release kinetics. Hydrogels, formulated with xanthan gum 1% (XIB), sodium carboxymethylcellulose 5% (CMCIB), poloxamer 407 16% (PIB), and carbomer 1% (KIB), were soft pseudoplastic semisolids with thixotropy and biocompatible pH. The type of the polymer significantly affected apparent viscosity of the hydrogels and miscibility rate with artificial sweat, their physical stability, and shape, size, and aggregation of the drug crystals and degree of crystallization. The drug release in all investigated hydrogels was diffusion-controlled in accordance with the Higuchi model and sustained for 12 h, with the drug release rate and the amount of drug released depended on the polymer. The described formulation approach enabled discrimination of the hydrogels with unsatisfactory application properties (CMCIB) and physical stability (KIB), and selection of the hydrogel with promising characteristics in terms of all investigated aspects (XIB) which could be considered for further evaluation.     

Topotecan hydrochloride liposomes incorporated into thermosensitive hydrogel for sustained and efficient in situ therapy of H22 tumor in Kunming mice

Abstract

Topotecan hydrochloride (TPT) has potential for the treatment of ovarian cancer, but the activity of TPT tends to decrease due to the ring-opening at physiological pH. In this study, we proposed to incorporate TPT liposomes into injectable thermosensitive in situ hydrogel, consisting of chitosan (CS) and β-glycerophosphate (β-GP), for sustained release and preservation of active lactone form of TPT. The rheology studies were carried out to investigate the sol–gel temperature, flow behavior and viscosity of these CS/β-GP systems. The optimized formulation exhibited sol–gel transition at 40.2?±?0.4?°C, with pseudoplastic flow behavior. The drug release rate of TPT liposomes loaded CS/β-GP hydrogel in phosphate buffer saline (pH?=?7.4) was found to be slowed down, and the lactone fraction of TPT in the hydrogel matrix was maintaining 40% after 50?h. In addition, the antitumor efficacy in Kunming mice bearing Hepatoma-22 tumor, after intratumoral injection of TPT liposomes loaded CS/β-GP hydrogel, was higher than that of TPT in saline and TPT in CS/β-GP hydrogel. Those results demonstrated that TPT liposomes loaded CS/β-GP hydrogel could become a potential formulation for improving the antitumor efficacy of TPT and suggested an important technology platform for intratumoral administration of derivative of camptothecin-family drugs.     

In situ Hydrogels Prepared by Photo-initiated Crosslinking of Acrylated Polymers for Local Delivery of Antitumor Drugs

A triblock copolymer was synthesized by ring opening polymerization of ε‐caprolactone in the presence of poly(ethylene glycol) (PEG). The resulted PCL-PEG-PCL triblock copolymer, PEG and monomethoxy (MPEG) were functionalized by end group acrylation. NMR and FT-IR analyses evidenced the successful synthesis and functionalization of polymers. A series of photo-crosslinked hydrogels composed of acrylated PEG-PCL-Acr and MPEG-Acr or PEG-Acr were prepared by exposure to visible light using lithium phenyl-2,4,6-trimethylbenzoylphosphinate as initiator. The hydrogels present a porous and interconnected structure as shown by SEM. The swelling performance of hydrogels is closely related to the crosslinking density and hydrophilic content. Addition of MPEG or PEG results in increase in water absorption capacity of hydrogels. In vitro degradation of hydrogels was realized in the presence of a lipase from porcine pancreas. Various degradation rates were obtained which mainly depend on the hydrogel composition. MTT assay confirmed the good biocompatibility of hydrogels. Importantly, in situ gelation was achieved by irradiation of a precursor solution injected in the abdomen of mice. Doxorubicin (DOX) was selected as a model antitumor drug to evaluate the potential of hydrogels in cancer therapy. Drug-loaded hydrogels were prepared by in situ encapsulation. In vitro drug release studies showed a sustained release during 28 days with small burst release. DOX-loaded hydrogels exhibit antitumor activity against A529 lung cancer cells comparable to free drug, suggesting that injectable in situ hydrogel with tunable properties could be most promising for local drug delivery in cancer therapy.     

延胡索乙素固体脂质纳米粒缓释片制备及工艺优化

目的：制备延胡索乙素固体脂质纳米粒缓释片，并研究延胡索乙素固体脂质纳米粒缓释片的释药模型和释药机理。方法：乳化-溶剂挥发法制备延胡索乙素固体脂质纳米粒，以乳糖作为冻干剂，羟丙基甲基纤维素（HPMC）为缓释材料进一步制备缓释片。在单因素考察的基础上，设计正交试验优化延胡索乙素固体脂质纳米粒缓释片处方，并对缓释片体外释药模型和释药机理进行探讨。结果：延胡索乙素固体脂质纳米粒缓释片最佳处方为缓释材料HPMC K4M和HPMC K15M比例为1：1，用量为40 mg，PEG 4000的用量为20 mg，硬脂酸镁用量为片芯质量的0.5%。延胡索乙素固体脂质纳米粒缓释片最佳处方的体外释放行为符合Higuchi释药模型，释药方程为：Mt/M_∞=0.286 8 t^1/2-0.073 8（r=0.990 8），12 h内累积释放度为93.56%，缓释片释药机理为扩散和溶蚀共存。结论：制备的延胡索乙素固体脂质纳米粒缓释片，工艺重复性较好，其释药行为符合Higuchi释药模型。     

Facile design of lidocaine-loaded polymeric hydrogel to persuade effects of local anesthesia drug delivery system: complete in vitro and in vivo toxicity analyses

The principal goal of the present investigation was to enterprise new and effective drug delivery vesicle for the sustained delivery of local anesthetic lidocaine hydrochloride (LDC), using a novel combination of copolymeric hydrogel with tetrahydroxyborate (COP–THB) to improve bioactivity and therapeutic potential. To support this contention, the physical and mechanical properties, rheological characteristics, and component release of candidate formulations were investigated. An optimized formulation of COP–THB containing LDC to an upper maximum concentration of 1.5% w/w was assessed for drug crystallization. The biocompatibility of the prepared COP–THB hydrogel was exhibited strong cell survival (96%) and growth compatibility on L929 fibroblast cell lines, which was confirmed by using methods of MTT assay and microscopic observations. The COP–THB hydrogel release pattern is distinct from that of COP–THB/LDC hydrogels by the slow-release rate and the low percentage of cumulative release. In vivo evaluations were demonstrated the anesthetic effects and toxicity value of treated samples by using mice models. In addition, COP–THB/LDC hydrogels significantly inhibit in vivo tumor growth in mice model and effectively reduced it is in vivo toxicity. The pharmacological evaluation showed that encapsulation of LDC in COP–THB hydrogels prolonged its anesthetic action with favorable in vitro and in vivo compatibility. This novel design may theoretically be used in promising studies involving the controlled release of local anesthetics.

Highlights

• Development a modified sustained release system for the local anesthetic lidocaine.
• PVP-THB hydrogel to improve the pharmacological properties of the drug and their anesthetic activities.
• Profiles of PVP-THB/LDC showed that the effective release of associated lidocaine.
• This new formulation could potentially be used in future local anesthetics.