Formulation and Evaluation of Baclofen-Meloxicam Orally Disintegrating Tablets (ODTs) Using Co-Processed Excipients and Improvement of ODTs Performance Using Six Sigma Method.

PURPOSE: This study aimed to formulate an orally disintegrating tablet (ODT) containing both baclofen and meloxicam together for treating osteoarthritis. METHODS: Direct compression method was used to prepare ODTs using three types of co-processed excipients (Prosolv ODT G2®, F-melt®, and Pharmaburst®500). ODTs were evaluated according to weight variation, thickness, friability, hardness, drug content, wetting time, in-vitro disintegration time, in-vitro dissolution test, and palatability. To enhance the in-vitro dissolution of meloxicam and palatability of ODT, a six sigma methodology was used, and an improvement phase was established where ODTs were prepared using lyophilization and levigation techniques. Finally, a pharmacokinetic study of the improved ODT was accomplished in comparison to the conventional oral tablet. RESULTS: Pharmaburst-based formula (F4) showed the shortest wetting time and, consequently, the shortest disintegration time and the highest percentage of drug dissolved within 3 min compared to the other formulae. All the improved ODTs had a bitterness taste score vary from (0) palatable and (+1) tasteless. The current sigma level was 3.628 σ and 3.33 σ for palatability and solubility of ODT, respectively, which indicated the process was successfully improved compared with the previous sigma level of 2.342 σ of both processes. Pharmacokinetic study of the improved ODTs showed a significant decrease of Tmax to 120 and 30 min instead of 180 and 120 min for meloxicam and baclofen, respectively. CONCLUSION: ODTs were successfully improved using the six sigma methodology, the pharmacokinetic parameters of both drugs were enhanced due to rapid absorption through the oral mucosa.

Development and Quality evaluation of sustained release pellets of eperisone HCl.

The objective was to develop eperisone HCl sustained-release pellets through extrusion spheronization technique and to determine the influence of different hydrophobic (polymeric based and wax-based) and hydrophilic (polymeric based) matrix former on the release of eperisone HCl (BCS class I drug) and on pellet sphericity. The pellet formulations consisted of different hydrophobic and hydrophilic matrix formers like HPMC K4M (10-20%) HPMC K15M (10%), EC (7cps) (10-20%), Carnauba wax (10-20%), Compritol ATO 888 (10-20%), Glyceryl monostearate (10%), lactose and microcrystalline cellulose. The initial burst release of the drug from matrix pellet formulations was effectively controlled by coating with 5% EC (ethylcellulose) dispersion. The dissolution profile and drug release kinetics of coated pellet formulations were determined at both acidic and basic pH medium. SEM (Scanning electron microscope) technique was used to determine the surface morphology and cross-section of F5 and F7 pellet formulation. The mechanism of drug release of coated formulation followed non-Fickian diffusion. FTIR spectroscopy was conducted and no drug and excipients interaction was observed. The results had shown that optimized coated formulation was F5 and F7 which effectively extend the drug release for 12 hours.

Development and Stability Control of Pediatric Oral Tizanidine Hydrochloride Formulations for Hospital Use.

Tizanidine hydrochloride is a centrally acting skeletal muscle relaxant used in the treatment of spasticity. This drug is sold only as tablets or capsules, which highlights the need to develop oral liquid formulations that allow administration to children and adults with impaired swallowing. This study aim was to develop and improve tizanidine hydrochloride liquid formulations from raw material and to evaluate their stability. A stability-indicating high performance liquid chromatography method was validated for two formulations developed. Fifteen formulations were developed containing syrup and fifteen containing sodium carboxymethyl cellulose as vehicles, to select the two most suitable for stability testing. The formulations were prepared in triplicate and placed in amber polyethylene terephthalate and glass bottles, which were stored under three different conditions: at room temperature (15-30°C), under refrigeration (2-8°C), and at 40°C. The physicochemical and microbiological stability of formulations were evaluated, applying high performance liquid chromatography and microbiological count. The studied formulations at 15-30°C, 2-8°C, and 40°C can be used for a period of 70 days, and all parameters are inside of recommended specifications, enough to allow its use in the context for which it was developed, the application in hospital. The formulations developed in this work have simple components to avoid adverse reactions in vulnerable populations. Results of this study could be applied as a reference for hospital use; once it demonstrated the reliability of storage time interval and proper conditions for use.

3D-Printed Gastroretentive Sustained Release Drug Delivery System by Applying Design of Experiment Approach.

This study aimed to develop a novel oral drug delivery system for gastroretentive sustained drug release by using a capsular device. A capsular device that can control drug release rates from the inner immediate release (IR) tablet while floating in the gastric fluid was fabricated and printed by a fused deposition modeling 3D printer. A commercial IR tablet of baclofen was inserted into the capsular device. The structure of the capsular device was optimized by applying a design of experiment approach to achieve sustained release of a drug while maintaining sufficient buoyancy. The 2-level factorial design was used to identify the optimal sustained release with three control factors: size, number, and height of drug-releasing holes of the capsular device. The drug delivery system was buoyant for more than 24 h and the average time to reach 80% dissolution (T80) was 1.7-6.7 h by varying the control factors. The effects of the different control factors on the response factor, T80, were predicted by using the equation of best fit. Finally, drug delivery systems with predetermined release rates were prepared with a mean prediction error ≤ 15.3%. This approach holds great promise to develop various controlled release drug delivery systems.

Design, characterization and in vivo evaluation of modified release baclofen floating coated beads.

Baclofen is a centrally acting skeletal muscle relaxant approved by the US Food and Drug Administration (FDA) for the treatment of muscle spasticity, but the immediate release mode of administration and rapid absorption has been associated with adverse effects. The main objective of this study was to prepare modified release floating beads of baclofen in order to decrease the unwanted side effects. The beads were prepared using alginate and coated with Eudragit RS100, Eudragit L100 and cetyl alcohol. They were evaluated for their encapsulation efficiency, buoyance characteristics, morphology, and in vitro release. They have also been tested in vivo for their oral bioavailability and potential side effects. The prepared beads showed floating properties up to 12 h with different lag times ranging from 45.67 to 72.33 sec. Morphological evaluation using scanning electron microscopy (SEM) revealed that the coated beads show smooth with no pores or cracks surfaces. Real-time morphology of the beads during in vitro release testing was studied by the SEM. Optimized formulation of baclofen coated beads exhibited favorable mechanical properties, in addition, it provided extended baclofen release for up to 6 h. In addition, in vivo studies showed that the coated beads effectively decreased the hypotensive side effect associated with rapid plasma peaking from Baclofen® immediate-release tablets. In addition, there were significant differences between the values of Cmax, Tmax, and AUC0-24 of optimized modified release baclofen floating formulations when compared to Baclofen® immediate-release tablets.

Selective acetylcholinesterase inhibitors derived from muscle relaxant dantrolene.

Dantrolene, the only therapeutic agent for malignant hyperthermia, is known to have not only a muscle relaxant effect, but also a neuroprotective effect and Alzheimer's disease improving effect. Recently, it has been reported that dantrolene has a weak inhibitory effect on acetylcholinesterase (AChE), which is a therapeutic drug target for Alzheimer's disease. Thus, we focused on developing of AChE inhibitors with benzylpiperidine/piperazine moieties that are based on the dantrolene skeleton. Several derivatives showed an inhibitory activity. Among them, ortho-nitro derivative 8c showed the most potent inhibitory activity with the IC50 value of 34.2 nM. Furthermore, Lineweaver-Burk plot analysis indicated that 8c is AChE-selective inhibitor, which shows only a weak inhibitory effect on butyrylcholinesterase (BuChE) and a non-competitive inhibition.

Differential Pulse Anodic Voltammetric Determination of Chlorzoxazone in Pharmaceutical Formulation using Carbon Paste Electrode.

The electrochemical behavior of chlorzoxazone at the carbon paste electrode was investigated in 0.04 mol/L Britton-Robinson buffer pH 6.50 using cyclic and differential pulse voltammetric techniques. Cyclic voltammetric studies indicated that the oxidation of the drug was irreversible and controlled mainly by diffusion. Experimental and instrumental parameters were optimized (50 mV/s scan rate, 50 mV pulse amplitude, and 0.04 mol/L Britton-Robinson (BR) buffer pH 6.50 as a supporting electrolyte) and a sensitive differential pulse anodic voltammetric method has been developed for the determination of the drug over the concentration range 0.17-1.68 µg/mL chlorzoxazone, with detection and quantitation limits of 0.05 and 0.16 µg/mL, respectively. The proposed voltammetric method was successfully applied to the determination of the drug in its pharmaceutical formulation (Myoflex tablets), and in spiked human urine samples.

Automatic Dissolution Testing with High-Temporal Resolution for Both Immediate-Release and Fixed-Combination Drug Tablets.

Dissolution testing plays many important roles throughout the pharmaceutical industry, from the research and development of drug products to the control and evaluation of drug quality. However, it is a challenging task to perform both high-efficient separation and high-temporal detection to achieve accurate dissolution profile of each active ingredient dissolved from a drug tablet. In our study, we report a novel non-manual-operation method for performing the automatic dissolution testing of drug tablets, by combining a program-controlled sequential analysis and high-speed capillary electrophoresis for efficient separation of active ingredients. The feasibility of the method for dissolution testing of real drug tablets as well as the performance of the proposed system has been demonstrated. The accuracy of drug dissolution testing is ensured by the excellent repeatability of the sequential analysis, as well as the similarity of the evaluation of dissolution testing. Our study show that the proposed method is capable to achieve simultaneous dissolution testing of multiple ingredients, and the matrix interferences can be avoided. Therefore it is of potential valuable applications in various fields of pharmaceutical research and drug regulation.

A network of weak hydrogen bonds in the crystal structure of Tetrazepam.

The crystal structure of tetrazepam, a benzodiazepine derivative formerly used for its muscle relaxant properties, has been solved and found to be monoclinic, space group P21/c, with lattice parameters a=12.7386(7)Å, b=11.3774(7)Å, c=10.3084(7)Å, ß=103.175(5) and Vunit-cell=1454.69(16) Å3 at room temperature (293K) with Z=4 molecules in the unit-cell. A network of weak hydrogen bonds involving aliphatic hydrogen atoms plays an important role in the formation of this structure.

Application of 3D printing technology and quality by design approach for development of age-appropriate pediatric formulation of baclofen.

Pediatric population is a sensitive sector of the healthcare and pharmaceutical field with additional needs compared to the adult population. Extemporaneous formulations for children are generally prepared by manipulating adult formulations, but medication errors can result in suboptimal efficacy and with significant safety concerns. The aim of proposed project was to explore a 3D printing technology for the development of customized minicaplets of baclofen for the pediatric population. Based on results of 3-point bend test, polyvinyl alcohol (PVA) with sorbitol (10% w/w) were selected for preparation of baclofen loaded filaments using hot melt extrusion (HME). Effect of dimension, infill percentage and infill pattern on dose, disintegration time and release profile were investigated. Characteristic crystalline peaks of baclofen were absent in DSC thermograms and XRD pattern of filament and minicaplets. Minicaplets printed in diamond (fast) infill pattern with 100% infill showed higher disintegration time (38 mins) compared to linear, sharkfill and hexagonal pattern. 32 full factorial orthogonal design suggested that baclofen release (D50 and D85) was marginally affected by infill percentage but significantly affected by caplet dimension (p < 0.05). Thus, low cost FDM 3D printing technique can be a promising alternative for preparation of dose and release customized pediatric dosage forms.

TP003 is a non-selective benzodiazepine site agonist that induces anxiolysis via α2GABAA receptors.

Benzodiazepines (BDZ), which potentiate the action of GABA at four subtypes of GABAA receptors (α1, α2, α3, and α5GABAARs), are highly effective against anxiety disorders, but also cause severe side effects greatly limiting their clinical application. Both, preclinical studies in genetically engineered mice, and preclinical and clinical trials with subtype-selective compounds indicate that undesired effects can in principle be avoided by targeting specific GABAAR subtypes. While there is general consensus that activity at α1GABAARs should be avoided, controversy exists as to whether α2 or α3GABAARs need to be targeted for anxiolysis. While previous experiments in GABAAR point-mutated mice demonstrated a critical role of α2GABAARs, studies solely relying on pharmacological approaches suggested a dominant contribution of α3GABAARs. As most α1GABAAR-sparing BDZ site agonists discriminate little between α2 and α3GABAARs, these claims rest almost exclusively on a single compound, TP003, that has been reported to be a selective α3GABAAR modulator. Here, we have revisited the in vitro pharmacological profile of TP003 and, in addition, tested TP003 in GABAAR triple point-mutated mice, in which only either α1, α2, or α3GABAARs were left BDZ sensitive. These experiments revealed that TP003 behaves as a partial, rather non-selective BDZ site agonist in vitro that acts in vivo through α1, α2, and α3GABAARs (α5GABAAR-mediated effects were not tested). With respect to anxiolysis, our results support a critical contribution of α2GABAARs, but not of α3GABAARs. TP003 should therefore not be considered an α3GABAAR selective agent. Previously published studies using TP003 should be interpreted with caution.

Enantioresolution of (RS)-baclofen by liquid chromatography: A review.

Baclofen is a commonly used racemic drug and has a simple chemical structure in terms of the presence of only one stereogenic center. Since the desirable pharmacological effect is in only one enantiomer, several possibilities exist for the other enantiomer for evaluation of the disposition of the racemic mixture of the drug. This calls for the development of enantioselective analytical methodology. This review summarizes and evaluates different methods of enantioseparation of (RS)-baclofen using both direct and indirect approaches, application of certain chiral reagents and chiral stationary phases (though very expensive). Methods of separation of diastereomers of (RS)-baclofen prepared with different chiral derivatizing reagents (under microwave irradiation at ease and in less time) on reversed-phase achiral columns or via a ligand exchange approach providing high-sensitivity detection by the relatively less expensive methods of TLC and HPLC are discussed. The methods may be helpful for determination of enantiomers in biological samples and in pharmaceutical formulations for control of enantiomeric purity and can be practiced both in analytical laboratories and industry for routine analysis and R&D activities.

Solubility and Stability of Baclofen 3 mg/mL Intrathecal Formulation and Its Compatibility With Implantable Programmable Intrathecal Infusion Systems.

BACKGROUND: Commercial baclofen formulations used with infusion pumps are available at therapeutic concentrations of 0.5-2.0 mg/mL. However, patients who receive higher daily doses of baclofen may benefit from products with greater baclofen concentrations since their refill frequency would be reduced (up to a maximum of 180 days). We evaluated baclofen solubility, baclofen 3 mg/mL intrathecal (IT) formulation stability, and chemical and physical compatibility with Medtronic SynchroMed® II and Codman Medstream® programmable IT infusion pumps. METHODS: For solubility evaluations, baclofen powder was dissolved into isotonic saline and tested at 5°C, 25°C, and 40°C. To demonstrate drug product stability, both physical and chemical stability attributes of baclofen 3 mg/mL in prefilled syringes were evaluated over 36 months with storage at 25°C. For a simulated in-use stability (compatibility) study, a 3 mg/mL baclofen IT formulation was placed in SynchroMed II and Codman Medstream pumps at 37ºC for study durations, and evaluated at different flow rates. Pump effluent was collected at various times and analyzed by high-performance liquid chromatography for baclofen content. On completion of the in-use stability study, pumps exposed to baclofen 3 mg/mL were dissected and visually evaluated for signs of deterioration. RESULTS: Baclofen solubility was found to be 3.2 mg/mL at 5°C, 3.6 mg/mL at 25°C, and 3.9 mg/mL at 40°C. During the 36-month stability study of prefilled syringes stored at 25°C, baclofen content remained unchanged and no precipitation was observed. The simulated in-use pump study performed at 37ºC showed that a baclofen 3 mg/mL IT formulation was stable at different flow rates and throughout different expected residence times for both pump models. Components from both pumps exhibited no noticeable deterioration after exposure to the 3 mg/mL formulation. CONCLUSION: Baclofen 3 mg/mL IT formulation was stable during long-term storage at 25°C and remained stable under conditions matching those encountered in clinical practice (37°C).

Inhibition of pseudoperoxiadse activity of human red blood cell hemoglobin by methocarbamol.

After red blood cells lysis, hemoglobin is released to blood circulation. Hemoglobin is carried in blood by binding to haptoglobin. In normal individuals, no free hemoglobin is observed in the blood, because most of the hemoglobin is in the form of haptoglobin complex. In some diseases that are accompanied by hemolysis, the amount of released hemoglobin is higher than its complementary haptoglobin. As a result, free hemoglobin appears in the blood, which is a toxic compound for these patients and may cause renal failure, hypertensive response and risk of atherogenesis. Free hemoglobin has been determined to have peroxidase activity and considered a pseudoenzyme. In this study, the effect of methocarbamol on the peroxidase activity of human hemoglobin was investigated. Our results showed that the drug inhibited the pseudoenzyme by un-competitive inhibition. Both Km and Vmax decreased by increasing the drug concentration. Ki and IC50 values were determined as 6 and 10mM, respectively. Docking results demonstrated that methocarbamol did not attach to heme group directly. A hydrogen bond linked NH2 of carbamate group of methocarbamol to the carboxyl group of Asp126 side chain. Two other hydrogen bonds could be also observed between hydroxyl group of the drug and Ser102 and Ser133 residues of the pseudoenzyme.

Baclofen Solution for Low-Volume Therapeutic Delivery.

OBJECTIVES: Baclofen is a zwitterion molecule where increased ions in the excipient increase the solubility. We developed baclofen in a stable solution similar to cerebrospinal fluid (CSF) without bicarbonate and proteins to improve the solubility of the baclofen and to reduce the potential toxicity to the central nervous system (CNS) and subarachnoid space. The objective is to develop a solution of baclofen wherein baclofen is solubilized in a multivalent physiological ion solution such as artificial cerebrospinal fluid (aCSF) at a concentration from 2 mg/cc to 10 mg/cc. METHODS: First, to determine the solubility of Baclofen in aCSF, solubility was determined at six different pH levels at 37°C, by the addition of aCSF to a known amount of Baclofen. The final concentrations were confirmed by high performance liquid chromatography (HPLC) analysis. Second, the stability of Baclofen at 4 mg/cc investigated in a test manufacturing batch utilizing standard methods of production of 1500 20 cc vials inverted for 18 months at 25°C at 60% humidity. The stability and purity of the baclofen was verified at 18 months by HPLC analysis. RESULTS: Baclofen was initially soluble between pH of 6-8 above 7 mg/cc but fell back to 6.3-5.8 mg/cc level with time. Baclofen produced in vials with inversion were noted to be stable at 4 mg/cc at 18 months with less than 2% breakdown of the baclofen in solution. CONCLUSION: Baclofen is much more soluble in artificial CSF than normal saline. The artificial CSF may also be less toxic to the subarachnoid space than saline.

HPLC enantioseparation of racemic bupropion, baclofen and etodolac: modification of conventional ligand exchange approach by pre-column formation of chiral ligand exchange complexes.

Separation of racemic mixture of (RS)-bupropion, (RS)-baclofen and (RS)-etodolac, commonly marketed racemic drugs, has been achieved by modifying the conventional ligand exchange approach. The Cu(II) complexes were first prepared with a few l-amino acids, namely, l-proline, l-histidine, l-phenylalanine and l-tryptophan, and to these was introduced a mixture of the enantiomer pair of (RS)-bupropion, or (RS)-baclofen or (RS)-etodolac. As a result, formation of a pair of diastereomeric complexes occurred by 'chiral ligand exchange' via the competition between the chelating l-amino acid and each of the two enantiomers from a given pair. The diastereomeric mixture formed in the pre-column process was loaded onto HPLC column. Thus, both the phases during chromatographic separation process were achiral (i.e. neither the stationary phase had any chiral structural feature of its own nor did the mobile phase have any chiral additive). Separation of diastereomers was successful using a C18 column and a binary mixture of MeCN and TEAP buffer of pH 4.0 (60:40, v/v) as mobile phase at a flow rate of 1 mL/min and UV detection at 230 nm for (RS)-Bup, 220 nm for (RS)-Bac and 223 nm for (RS)-Etd. Baseline separation of the two enantiomers was obtained with a resolution of 6.63 in <15 min. Copyright © 2016 John Wiley & Sons, Ltd.

[Intrathecal baclofen therapy and management of severe spasticity].

Continuous infusion of intrathecal baclofen (ITB), via implanted pump, is a powerful tool in the management of severe spasticity in neurological disorders. The advantages of ITB therapy are that it is non-destructive, reversible, and programmable, allowing for neuromodulation. Patients reported significant subjective improvements and decreases in muscle tone after baclofen injection, but excessive doses of ITB resulted in motor weakness. Few complications and adverse effects were reported. ITB therapy appears to be a promising treatment to improve residual motor control in patients with severe spasticity.

FT-IR, FT-Raman spectra, and DFT computations of the vibrational spectra and molecular geometry of chlorzoxazone.

Far-IR, mid-IR, and FT-Raman spectra of the chlorzoxazone (CZX) were recorded. The observed vibrational wavenumbers were analyzed and assigned to different normal modes of vibration of the molecule. Density functional calculations were performed to support wavenumber assignments of the observed bands. The equilibrium geometry and harmonic wavenumbers of CZX were calculated by the DFT B3LYP method. All tautomeric forms and dimer form of CZX were determined and optimized. Additionally, experimental FT-IR spectrum in ethanol solution was recorded and compared with solid phase experimental data for the first time. The combination of the DFT B3LYP with polarized continuum model (PCM) was employed to characterize the solvent effects in ethanol solution.

Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: spectroscopic and quantum chemical studies.

Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, (1)H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80°C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO(-)], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]⋅4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional.