Determination of Cloretazine (VNP40101M) and its active metabolite (VNP4090CE) in human plasma by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS)

A sensitive method for the determination of Cloretazine (VNP40101M) and its metabolite (VNP4090CE) with an internal standard (ISTD) in human plasma was developed using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Acidified plasma samples (500 microL) were prepared using solid phase extraction (SPE) columns, and 25 microL of the reconstituted sample was injected onto an Ascentis C18 HPLC column (3 microm, 5 cmx2.1 mm) with an isocratic mobile phase. Analytes were detected with an API-3000 LC-MS/MS System at unit (Q1) and low (Q3) resolution in negative multiple reaction monitoring mode: m/z 249.0 (precursor ion) to m/z 114.9 (product ion) for both Cloretazine (at 3.64 min) and VNP4090CE (at 2.91 min), and m/z 253.0 (precursor ion) to m/z 116.9 (product ion) for the ISTD. The mean recovery for Cloretazine (VNP40101M) and its metabolite (VNP4090CE) was greater than 87% with a lower limit of quantification of 1.0 ng/mL for Cloretazine (S/N=9.7, CV相似文献   

Oral formulation of a novel antiviral agent,PG301029, in a mixture of Gelucire 44/14 and DMA (2∶1, wt/wt)

To develop an oral formulation for PG301029, a novel potent agent for the treatment of Hepatitis C virus infection, that not only has very low aqueous solubility but also degrades rapidly in water. The solubility of PG301029 was determined in water, various aqueous media, and several neat organic solvents. The stability of PG301029 was monitored at room temperature in buffess for 4 days, and in several neat organic solvents for up to 8 mo. Drug concentrations were measured by high-performance liquid chromatography (HPLC). Based on solubility and stability data, Gelucire 44/14 and DMA (N,N-dimethylacetamide) at a weight ratio of 2 to 1 were chosen as the formulation vehicle. After the vehicle was prepared, it was maintained in liquid form at ∼40°C until the PG301029 was dissolved. The final formulation product was a semisolid at room temperature. The bioavailability of the formulation was tested on 4 female BALB/c mice. PG301029 is insoluble in all tested aqueous media, while its solubility is promising in DMA. This compound is unstable in aqueous media and some organic solvents; however, it is stable in DMA. This proposed formulation is able to hold up to 10 mg/mL of drug and is stable at 4°C. The shelf life for this formulation stored at 4°C is extrapolated to be greater than 4 years. This formulation dramatically increases the bioavailability of PG301029. This nonaqueous formulation solves the stability, solubility, and bioavailability problems for PG301029. This semisolid formulation can easily be incorporated into soft elastic capsules.     

Design of a liquid nano-sized drug delivery system with enhanced solubility of rivaroxaban for venous thromboembolism management in paediatric patients and emergency cases

Abstract

The increasing incidence of venous thromboembolism (VTE) in paediatric population has stimulated the development of liquid anticoagulant formulations. Thus our goal is to formulate a liquid formulation of poorly-water soluble anticoagulant, rivaroxaban (RIVA), for paediatric use and to assess the possibility of its intravenous administration in emergencies. Self-nanoemulsifying drug delivery systems (SNEDDSs) were developed and characterized. SNEDDS constituents were estimated from the saturated solubility study followed by plotting the corresponding ternary phase diagrams to determine the best self-emulsified systems. Thermodynamic stability, emulsification, dispersibility, robustness to dilution tests, in vitro dissolution, particle size, and zeta potential were executed to optimize the formulations. The optimized formulation, that composed of Capryol 90:Tween 20:PEG 300 (5:45:50), increased RIVA solubility (285.7-fold than water), it formed nanoemulsion with a particle size of 16.15?nm, PDI of 0.25 and zeta potential of ?21.8. It released 100.83?±?2.78% of RIVA after 5?min. SNEDDS was robust to dilution with oral and parenteral fluids and showed safety to human RBCs. SNEDDS showed enhanced bioavailability after oral and intravenous administration than the oral drug suspension (by 1.25 and 1.26-fold, respectively). Moreover, it exhibited enhanced anticoagulant efficacy in the prevention and treatment of carrageenan-induced thrombosis rat model.     

Solution Formulation Development of a VEGF Inhibitor for Intravitreal Injection

PF-00337210 is a potent, selective small molecule inhibitor of VEGFRs and has been under consideration for the treatment of age-related macular degeneration. An ophthalmic solution formulation intended for intravitreal injection was developed. This formulation was designed to maximize drug properties such that the formulation would precipitate upon injection into the vitreous for sustained delivery. As a parenteral formulation with additional constraints dictated by this specialized delivery route, multiple features were balanced in order to develop a successful formulation. Some of these considerations included low dosing volumes (≤0.1 mL), a limited repertoire of safe excipients for intravitreal injection, and the unique physical chemical properties of the drug. The aqueous solubility as a function of pH was characterized, buffer stressing studies to select the minimal amount of buffer were conducted, and both chemical and physical stability studies were executed. The selected formulation consisted of an isotonic solution comprised of PF-00337210 free base in a citrate-buffered vehicle containing NaCl for tonicity. The highest strength for regulatory toxicology studies was 60 mg/mL. The selected formulation exhibited sufficient chemical stability upon storage with no precipitation, and acceptable potency and recovery through an intravitreal dosing syringe. Formulation performance was simulated by precipitation experiments using extracted vitreous humor. In simulated injection experiments, PF-00337210 solutions reproducibly precipitated upon introduction to the vitreous so that a depot was formed. To our knowledge, this is the first time that a nonpolymeric in situ-forming depot formulation has been developed for intravitreal delivery, with the active ingredient as the precipitating agent.     

Enhanced water-soluble derivative of PC407 as a novel potential COX-2 inhibitor injectable formulation

PC407 is an effective COX-2 inhibitor in non-steroidal anti-inflammatory drug development but the poor solubility limits their usefulness. The aim of the study was to prepare and evaluate 4-oxo-4-[4-(5-(naphthalen-2-yl)-3-(trifluoromethyl)-1H-pyrazol-1-yl)benzenesulfonamido]butyrate disodium, a derivative of PC407 with enhanced water solubility for injectable formulation. The prepared derivative displayed interesting high aqueous solubility (20.3 mg/mL, much superior to the parent compound PC407, 1.6 μg/mL) with confirmed in vivo analgesic activity. This derivative represents the profiles of prodrug and potential candidate of PC407 for the development of injectable COX-2 inhibitor due to extraordinary water solubility, low toxicity, and impressive analgesic activity.     

Novel Self-Nanoemulsifying Drug Delivery Systems (SNEDDS) for Oral Delivery of Cinnarizine: Design, Optimization, and In-Vitro Assessment

Due to its extreme lipophilicity, the oral delivery of cinnarizine (CN) encounters several problems such as poor aqueous solubility and pH-dependent dissolution, which result in low and erratic bioavailability. The current study aims to design self-nanoemulsifying drug delivery systems (SNEDDS) of CN that circumvent such obstacles. Equilibrium solubility of CN was determined in a range of anhydrous and diluted lipid-based formulations. Dynamic dispersion tests were carried out to investigate the efficiency of drug release and magnitude of precipitation that could occur upon aqueous dilution. Droplet sizes of selected formulations, upon (1:1,000) aqueous dilution, were presented. The optimal formulations were enrolled in subsequent dissolution studies. The results showed that increasing lipid chain length and surfactant lipophilicity raised the formulation solvent capacity, while adding co-solvents provoked a negative influence. The inclusion of mixed glycerides and/or hydrophilic surfactants improved the drug release efficiency. Generally, no significant precipitation was observed upon aqueous dilution of the formulations. Five formulations were optimal in terms of their superior self-emulsifying efficiency, drug solubility, dispersion characteristics, and lower droplet size. Furthermore, the optimal formulations showed superior dissolution profile compared to the marketed (Stugeron®) tablet. Most importantly, they could resist the intensive precipitation observed with the marketed tablet upon shifting from acidic to alkaline media. However, SNEDDS containing medium-chain mixed glycerides showed the highest drug release rate and provide great potential to enhance the oral CN delivery. Accordingly, the lipid portion seems to be the most vital component in designing CN self-nanoemulsifying systems.     

Pharmacokinetics of saquinavir after intravenous and oral dosing of saquinavir: hydroxybutenyl-beta-cyclodextrin formulations

The current research evaluated the ability of hydroxybutenyl-beta-cyclodextrin (HBenBCD) to enhance saquinavir in vitro solubility and in vivo oral bioavailability; both the base and mesylate salt forms of saquinavir were investigated. HBenBCD was effective and significantly improved saquinavir solubility in aqueous media. In the presence of 10 wt % HBenBCD, saquinavir base solubility in water was increased to ca. 5.5 +/- 0.4 mg/mL and represents a 27-fold increase from that observed in water (207 +/- 5 microg/mL) in the absence of HBenBCD. Saquinavir-HBenBCD formulations were found to have rapid dissolution over a wide pH range (1.2-6.8), and saquinavir solubility in these media was maintained throughout the experiments. When saquinavir-HBenBCD formulations were administered to Wistar-Hannover rats, saquinavir was rapidly absorbed and rapidly eliminated. Rapid saquinavir elimination was particularly pronounced when saquinavir-HBenBCD formulations were given as an oral aqueous gavage. Saquinavir oral bioavailability in rats obtained from saquinavir mesylate capsules (2.0% +/- 0.7%) was increased (9 +/- 4)-fold (18.6% +/- 7.3%) when dosed with saquinavir base-HBenBCD capsules. Clearly, HBenBCD can significantly improve the solubility and oral bioavailability of saquinavir; however, further formulation studies are required to optimize saquinavir oral delivery using this technology.     

Fenretinide-polyvinylalcohol conjugates: new systems allowing fenretinide intravenous administration

N-(4-hydroxyphenyl)retinamide (fenretinide, 4-HPR) has been shown to be active toward many tumors without appreciable side effects. However its in vitro activity does not match a correspondent efficacy in vivo. The main reason is that the drug's hydrophobicity hinders its bioavailability in the body fluids. Even if the drug is previously dissolved in organic solvents, such as ethanol or DMSO, the subsequent dilution in body fluids trigger its precipitation in fine aggregates characterized by very low dissolution efficiency, never reaching amounts suitable for therapeutic response. To date no intravenous formulation of 4-HPR exists on the market. The 4-HPR linkage to a hydrophilic polymer by a covalent bond easily hydrolyzable in aqueous environment is expected to increase the drug's aqueous solubility, providing the free drug after hydrolysis of the covalent bond. This may be a useful tool for the preparation of aqueous intravenous formulations of 4-HPR. For this purpose, we linked 4-HPR to polyvinylalcohol (PVA) by a carbonate bond at different drug/hydroxy vinyl monomer molar ratios. We demonstrated that conjugation increased 4-HPR aqueous solubility and strongly inhibited neuroblastoma cell proliferation. In addition, in an in vivo neuroblastoma metastatic model, we obtained a significant antitumor effect as a consequence of the improved drug bioavailability.     

Physicochemical Characterization of Berberine Chloride: A Perspective in the Development of a Solution Dosage Form for Oral Delivery

The objective of the present research was to evaluate the physicochemical characteristics of berberine chloride and to assess the complexation of drug with 2-hydroxypropyl-β-cyclodextrin (HPβCD), a first step towards solution dosage form development. The parameters such as log P value were determined experimentally and compared with predicted values. The pH-dependent aqueous solubility and stability were investigated following standard protocols at 25°C and 37°C. Drug solubility enhancement was attempted utilizing both surfactants and cyclodextrins (CDs), and the drug/CD complexation was studied employing various techniques such as differential scanning calorimetry, Fourier transform infrared, nuclear magnetic resonance, and scanning electron microscopy. The experimental log P value suggested that the compound is fairly hydrophilic. Berberine chloride was found to be very stable up to 6 months at all pH and temperature conditions tested. Aqueous solubility of the drug was temperature dependent and exhibited highest solubility of 4.05 ± 0.09 mM in phosphate buffer (pH 7.0) at 25°C, demonstrating the effect of buffer salts on drug solubility. Decreased drug solubility was observed with increasing concentrations of ionic surfactants such as sodium lauryl sulfate and cetyl trimethyl ammonium bromide. Phase solubility studies demonstrated the formation of berberine chloride–HPβCD inclusion complex with 1:1 stoichiometry, and the aqueous solubility of the drug improved almost 4.5-fold in the presence of 20% HPβCD. The complexation efficiency values indicated that the drug has at least threefold greater affinity for hydroxypropyl-β-CD compared to randomly methylated-β-CD. The characterization techniques confirmed inclusion complex formation between berberine chloride and HPβCD and demonstrated the feasibility of developing an oral solution dosage form of the drug.KEY WORDS: berberine chloride, complexation, cyclodextrin, solubility, surfactants     

Core-cross-linked polymeric micelles as paclitaxel carriers

Cross-linkable di- and triblock copolymers of poly(epsilon-caprolactone) (PCL) and monomethoxyl poly(ethylene glycol) (MPEG) were synthesized. These amphiphilic copolymers self-assembled into nanoscale micelles capable of encapsulating hydrophobic paclitaxel in their hydrophobic cores in aqueous solutions. To further enhance their thermodynamic stability, the micelles were cross-linked by radical polymerization of the double bonds introduced into the PCL blocks. Reaction conditions were found to significantly affect both the cross-linking efficiency and the micelle size. The encapsulation of paclitaxel into the micelles was confirmed by the proton nuclear magnetic resonance (1H NMR) spectroscopy. Encouragingly, paclitaxel-loading efficiency of micelles was enhanced significantly upon micelle core-cross-linking. Both the micelle size and the drug loading efficiency increased markedly with increasing the PCL block lengths, no matter if the micelles were core-cross-linked or not. However, paclitaxel-loading did not obviously affect the micelle size or size distribution. The cross-linked micelles exhibited a significantly enhanced thermodynamic stability against dilution with aqueous solvents. The efficient cellular uptake of paclitaxel loaded in the nanomicelles was demonstrated by confocal laser scanning microscopy (CLSM) imaging. This new biodegradable nanoscale carrier system merits further investigations for parenteral drug delivery.     

Soluplus-Solubilized Citrated Camptothecin—A Potential Drug Delivery Strategy in Colon Cancer

Camptothecin (CPT), a potent antitumor drug, exhibits poor aqueous solubility and rapid conversion from the pharmacologically active lactone form to inactive carboxylate form at physiological pH. Solid dispersion of CPT in Soluplus®, an amphiphilic polymeric solubilizer, was prepared to increase the aqueous solubility of CPT and the resultant solid dispersion along with citric acid was formulated as hard gelatin capsules that were subsequently coated with Eudragit S100 polymer for colonic delivery. FTIR spectrum of the solid dispersion confirmed the presence of CPT. PXRD and DSC revealed the semicrystalline nature of solid dispersion. The solubility of the drug was found to increase ~40 times in the presence of Soluplus and ~75 times in solid dispersion. The capsules showed no drug release in 0.01 N HCl but released 86.4% drug in lactone form in phosphate buffer (pH 7.4) and the result appears to be due to citric acid-induced lowering of pH of buffer from 7.4 to 6.0. Thus the presence of citric acid in the formulation led to stabilization of the drug in its pharmacologically active lactone form. Cytotoxicity studies conducted with the formulation of solid dispersion with citric acid, utilizing cell cytotoxicity test (MTT test) on Caco-2 cells, confirmed cytotoxic nature of the formulation.     

Preparation and Evaluation of Self-nanoemulsifying Tablets of Carvedilol

The purpose of this study was to combine the advantages of self-nanoemulsifying drug delivery systems and tablets as a conventional dosage form emphasizing the excipients’ effect on the development of a new dosage form. Systems composed of HCO-40, Transcutol® HP, and medium-chain triglyceride were prepared. Essential properties of the prepared systems regarding carvedilol solubility, a model drug, and self-emulsification time were determined. In order to optimize self-nanoemulsifying drug delivery systems (SNEDDS), formulation dispersion–drug precipitation test was performed in the absence and presence of cellulosic polymers. Furthermore, SNEDDS was loaded onto liquisolid powders. P-glycoprotein (P-gp) activity of the selected SNEDDS was tested using HCT-116 cells. Carvedilol showed acceptable solubility in the selected excipients. It also demonstrated improvement in the stability upon dilution with aqueous media in the presence of cellulosic polymers. Use of granulated silicon dioxide improved the physical properties of liquisolid powders containing SNEDDS. It improved the compressibility of the selected powders and the tested SNEDDS showed marked P-gp inhibition activity. Prepared self-nanoemulsifying tablet produced acceptable properties of immediate-release dosage forms and expected to increase the bioavailability of carvedilol.     

Formulation Development of Parenteral Phospholipid-based Microemulsion of Etoposide

The aim of the present study was to investigate the potential of a phospholipid-based microemulsion formulation for parenteral delivery of anticancer drug, etoposide. The microemulsion area was identified by constructing pseudoternary phase diagrams. The prepared microemulsions were subjected to different thermodynamic stability tests. The microemulsion formulations that passed thermodynamic stability tests were characterized for optical birefringence, droplet size, viscosity measurement, and pH measurements. To assess the safety of the formulations for parenteral delivery, the formulation was subjected to compatibility studies with various intravenous infusions and in vitro erythrocyte toxicity study. The developed formulation was found to be robust and safe for parenteral delivery.     

A Self-microemulsifying Drug Delivery System (SMEDDS) for a Novel Medicative Compound Against Depression: a Preparation and Bioavailability Study in Rats

AJS is the code name of an untitled novel medicative compound synthesized by the Tasly Holding Group Company (Tianjin, China) based on the structure of cinnamamide, which is one of the Biopharmaceutics Classification System (BCS) class II drugs. The drug has better antidepressant effect, achieved by acting on the 5-hydroxytryptamine receptor. However, the therapeutic effects of the drug are compromised due to its poor water solubility and lower bioavailability. Herein, a self-microemulsifying drug delivery system (SMEDDS) was developed to improve its solubility and oral bioavailability. AJS-SMEDDS formulation was optimized in terms of drug solubility in the excipients, droplet size, stability, and drug precipitation using a pseudo-ternary diagram. The pharmacokinetic study was performed in rats, and the drug concentration in plasma samples was assayed using the high-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS) method. The optimized formulation for SMEDDS has a composition of castor oil 24.5%, Labrasol 28.6%, Cremphor EL 40.8%, and Transcutol HP 2.7% (co-surfactant). No drug precipitation or phase separation was observed from the optimized formulation after 3 months of storing at 25°C. The droplet size of microemulsion formed by the optimized formulation was 26.08 ± 1.68 nm, and the zeta potential was −2.76 mV. The oral bioavailability of AJS-SMEDDS was increased by 3.4- and 35.9-fold, respectively, compared with the solid dispersion and cyclodextrin inclusion; meanwhile, the C_max of AJS-SMEDDS was about 2- and 40-fold as great as the two controls, respectively. In summary, the present SMEDDS enhanced oral bioavailability of AJS and was a promising strategy to orally deliver the drug.KEY WORDS: bioavailability, HPLC-MS/MS, self-microemulsifying drug delivery system, solubilization, stability     

High affinity binding of paclitaxel to human serum albumin.

Paclitaxel, a very potent antitumor agent is a hydrophobic molecule with low aqueous solubility. Its currently used formula (Taxol) contains the drug in a 1 : 1 (v/v) mixture of ethanol and Cremophor EL. To minimize vehicle-related toxicity, we developed a novel, water-soluble formulation in which paclitaxel is bound noncovalently to human serum albumin. For this purpose, studies of the paclitaxel-albumin binding equilibrium were performed. Paclitaxel dissolved in ethanol was added to the aqueous solution of human serum albumin. Precipitated paclitaxel was removed and unbound drug was separated by ultrafiltration. Paclitaxel concentration was measured by RP-HPLC. Binding data were evaluated based both on the Scatchard plot and the general binding equation describing binding equilibria with the stepwise stoichiometric binding constants. The Scatchard plot was found to be curvilinear with a slight positive slope of the final part. Parameters of high affinity specific binding were determined from the initial part of the curve (nsp = 1.3 and Ksp = 1.7 x 10(6) M(-1)). Stoichiometric binding constants were estimated by fitting the general binding equation to the experimental data (K1 = 2.4 x 10(6) M(-1) and K2 = 1.0 x 10(5) M(-1)). Saturation of the protein with paclitaxel, similarly to other ligands of albumin, could not be reached. The greatest observed value of r (number of paclitaxel molecules bound to one albumin molecule) was 6.6.     

Synthesis of a water-soluble prodrug of entacapone

Entacapone was reacted with phosphorous oxychloride in dry pyridine to yield a phosphate ester. The phosphate promoiety increased aqueous solubility of the parent drug by more than 1700- and 20-fold at pH 1.2 and 7.4, respectively. The phosphate ester provides adequate stability (t(1/2) = 2227 h; pH 7.4) towards chemical hydrolysis, and allowed for release of the parent drug via enzymatic hydrolysis in liver homogenate.     

Microemulsion Transdermal Formulation for Simultaneous Delivery of Valsartan and Nifedipine: Formulation by Design

The objective of the study was to optimize the proportion of different components for formulating oil in water microemulsion formulation meant for simultaneous transdermal delivery of two poorly soluble antihypertensive drugs. Surface response methodology of Box-Behnken design was utilized to evaluate the effect of two oils (Captex 500 - x1 and Capmul MCM - x2) and surfactant (Acrysol EL135 - x3) on response y1 (particle size), y2 (solubility of valsartan), and y3 (solubility of nifedipine). The important factors which significantly affected the responses were identified and validated using ANOVA. The model was diagnosed using normal plot of residuals and Box-Cox plot. The design revealed an inverse correlation between particle size and concentration of Capmul MCM and Acrysol EL 135. However, an increase in concentration of Captex 500 led to an increase in particle size of microemulsion. Solubility of valsartan decreased while that of nifedipine increased with increase in concentration of Captex 500. Capmul MCM played a significant role in increasing the solubility of valsartan. The effect of Acrysol EL 135 on solubility of both drugs, although significant, was only marginal as compared to that of Captex 500 and Capmul MCM. The optimized microemulsion was able to provide an enhancement ratio of 27.21 and 63.57-fold for valsartan and nifedipine, respectively, with respect to drug dispersion in aqueous surfactant system when evaluated for permeation studies. The current studies candidly suggest the scope of microemulsion systems for solubilizing as well as promoting the transport of both drugs across rat skin at an enhanced permeation rate.     

The thiol groups of the Folch-Pi protein from bovine white matter. Exposure, reactivity and significance.

The number and the reactivity of accessible thiol groups of the Folch-Pi apoprotein and proteolipid (50% of myelin proteins) were studied, by using a specific thiol-disulphide interchange reaction, in connection with the known solubility of this protein in organic and aqueous solvents. The high reactivity of 2,2'-dipyridyl disulphide towards thiol groups leads to the titration of 4.8 mol of SH groups/mol of protein (Mr 30000) in alkaline and acidic chloroform/methanol (2:1, v/v). Unlike previous findings, this value was consistently found from batch to batch and remained stable with time. In the proteolipid 1 mol of SH groups/mol was not accessible as compared with the apoprotein. In aqueous solvents, a similar number of 4.4 mol of SH groups/mol was also found. For the first time, kinetic studies carried out in chloroform/methanol discriminated between two classes of thiol groups. The reaction of 2 mol of SH groups/mol was characterized by apparent second-order rate constants whose values were 5-10-fold higher than those of the other class. Kinetic studies and cyanylation experiments in aqueous solvents also indicated the high reactivity of these thiol groups with Ellman's reagent. Together with kinetic results, studies on the stoichiometry of the interchange reaction of equimolar solutions of protein and disulphide indicate that these highly reactive thiol groups are near to each other in the amino acid sequence. The location of the thiol groups at the boundary between hydrophilic and hydrophobic domains of the Folch-Pi protein is suggested in connection with their possible structural and biological significance.     

Chitosan-based delivery systems for curcumin: A review of pharmacodynamic and pharmacokinetic aspects

Effective drug delivery is one of the most important issues associated with the administration of therapeutic agents that have low oral bioavailability. Curcumin is an active ingredient in the turmeric plant, which has low oral bioavailability due to its poor aqueous solubility. One strategy that has been considered for enhancing the aqueous solubility, and, thus, its oral bioavailability, is the use of chitosan as a carrier for curcumin. Chitosan is a biodegradable and biocompatible polymer that is relatively water-soluble. Therefore, various studies have sought to improve the aqueous solubility of chitosan. The use of different pharmaceutical excipients and formulation strategies has the potential to improve aqueous solubility, formulation processing, and the overall delivery of hydrophobic drugs. This review focuses on various methods utilized for chitosan-based delivery of curcumin.     

Synthetic modification of carboxymethylcellulose and use thereof to prepare a nanoparticle forming conjugate of docetaxel for enhanced cytotoxicity against cancer cells

A nanoparticle formulation of docetaxel (DTX) was designed to address the strengths and limitations of current taxane delivery systems: PEGylation, high drug conjugation efficiency (>30 wt %), a slow-release mechanism, and a well-defined and stable nanoparticle identity were identified as critical design parameters. The polymer conjugate was synthesized with carboxymethylcellulose (CMC), an established pharmaceutical excipient characterized by a high density of carboxylate groups permitting increased conjugation of a drug. CMC was chemically modified through acetylation to eliminate its gelling properties and to improve solvent solubility, enabling high yield and reproducible conjugation of DTX and poly(ethylene glycol) (PEG). The optimal conjugate formulation (Cellax) contained 37.1 ± 1.5 wt % DTX and 4.7 ± 0.8 wt % PEG, exhibited a low critical aggregation concentration of 0.6 μg/mL, and formed 118-134 nm spherical nanoparticles stable against dilution. Conjugate compositions with a DTX degree of substitution (DS) outside the 12.3-20.8 mol % range failed to form discrete nanoparticles, emphasizing the importance of hydrophobic and hydrophilic balance in molecular design. Cellax nanoparticles released DTX in serum with near zero order kinetics (100% in 3 weeks), was internalized in murine and human cancer cells, and induced significantly higher toxic effects against a panel of tumor cell lines (2- to 40-fold lower IC50 values) compared to free DTX.