Preparation of ibuprofen-loaded liquid suppository using eutectic mixture system with menthol

Predicting the formation of NADES using a transformer-based model

The application of natural deep eutectic solvents (NADES) in the pharmaceutical, agricultural, and food industries represents one of the fastest growing fields of green chemistry, as these mixtures can potentially replace traditional organic solvents. These advances are, however, limited by the development of new NADES which is today, almost exclusively empirically driven and often derivative from known mixtures. To overcome this limitation, we propose the use of a transformer-based machine learning approach. Here, the transformer-based neural network model was first pre-trained to recognize chemical patterns from SMILES representations (unlabeled general chemical data) and then fine-tuned to recognize the patterns in strings that lead to the formation of either stable NADES or simple mixtures of compounds not leading to the formation of stable NADES (binary classification). Because this strategy was adapted from language learning, it allows the use of relatively small datasets and relatively low computational resources. The resulting algorithm is capable of predicting the formation of multiple new stable eutectic mixtures (n = 337) from a general database of natural compounds. More importantly, the system is also able to predict the components and molar ratios needed to render NADES with new molecules (not present in the training database), an aspect that was validated using previously reported NADES as well as by developing multiple novel solvents containing ibuprofen. We believe this strategy has the potential to transform the screening process for NADES as well as the pharmaceutical industry, streamlining the use of bioactive compounds as functional components of liquid formulations, rather than simple solutes.

In vivo and in vitro transdermal availability of Ibuprofen using novel solubility enhancing fluid nanosized carrier systems

The objective of this study was to explore the benefits of transdermal drug delivery systems as an alternative option for patients who are unable to tolerate oral administration of drugs, such as ibuprofen (IB). To achieve this, nonionic surfactants and three cosolvents were employed to develop new microemulsions (MEs) that contained IB as nanocarriers. The aim was to enhance the solubility and bioavailability of the drug after transdermal administration. The MEs were characterised by droplet size, polydispersity index (PDI), and rheological properties. Furthermore, the flux of IB was evaluated by Franz diffusion cells using excised rat skin and in vivo bioavailability using rats. The results showed that the MEs had ideal viscosity and droplet size below 100 nm. Moreover, using the developed MEs, an improvement in the solubility (170 mg/mL) and flux through the rat skin (94.6 ± 8.0 µg/cm2.h) was achieved. In addition, IB demonstrated a maximum plasma level of 0.064 mg/mL after 8 h of transdermal administration in rats using the ME with an increase in the bioavailability of about 1.5 times in comparison to the commercial IB gel. In conclusion, the developed nonionic MEs containing IB can be ideal nanocarriers and promising formulations for the transdermal administration of IB.

Development and Comprehensive Characteristics of Thermosensitive Liquid Suppositories of Metoprolol Based on Poly(lactide-co-glycolide) Nanoparticles

Thermosensitive liquid suppositories (LSs) carrying the model antihypertensive drug metoprolol tartrate (MT) were developed and evaluated. The fundamental purpose of this work was to produce, for the first time, liquid MT suppositories based on biodegradable nanoparticles and optimize their rheological and mechanical properties for prospective rectal administration. The nanoparticle system was based on a biodegradable copolymer synthesized by ring opening polymerization (ROP) of glycolide (GL) and L,L-lactide (LLA). Biodegradable nanoparticles loaded with the model drug were produced by the o/o method at the first stage of the investigation. Depending on the concentration of the drug in the sample, from 66 to 91% of MT was released over 12 h, according to first-order kinetics. Then, thermosensitive LSs with MT-loaded biodegradable nanoparticles were obtained by a cold method and their mechanical and rheological properties were evaluated. To adjust the thermogelling and mucoadhesive properties for rectal administration, the amounts of major formulation components such as poloxamers (P407, P188), Tween 80, hydroxypropylcellulose (HPC), polyvinylpyrrolidone (PVP), and sodium alginate were optimized. The in vitro release results revealed that more than 80% of the MT was released after 12 h, following also first-order kinetics. It was discovered that the diffusion process was dominant. The drug release profile was mainly governed by the rheological and mechanical properties of the developed formulation. Such a novel, thermosensitive formulation might be an effective alternative to hypertension treatment, particularly for unconscious patients, patients with mental illnesses, geriatric patients, and children.

Enabling the drug combination of celecoxib through a spherical co-agglomeration strategy with controllable and stable drug content and good powder properties

Combining celecoxib with other chemopreventive drugs is a promising method of chemoprevention for cancer, especially for colorectal cancer. However, the traditional drug combination approaches are restricted with high-cost apparatus, complex and numerous unit operations. This work aims to develop an efficient spherical co-agglomeration strategy for celecoxib in combination with lovastatin, which can achieve drug combination in a single crystallization unit. The ternary solvent system was determined based on molecular simulation, and then a stable spherical agglomeration process was developed through the design of molar fraction of anti-solvent (MFA) and stirring rate to produce spherical agglomerates with high sphericity (84.2-89.9 %) and narrow size distribution. On this basis, celecoxib-benzoic acid spherical co-agglomerates were designed to form a complete spherical co-agglomeration strategy, which includes solvent system selection, spherical agglomeration and spherical co-agglomeration. Finally, celecoxib-lovastatin spherical co-agglomerates with synergistic efficacy were successfully produced by this strategy, with controllable and stable drug content (fluctuation < 2.7 %), good powder properties, and improved tabletability.

Optimization and Evaluation of the Quercus infectoria Galls Thermosensitive In Situ Gel for Rectal Delivery

Quercus infectoria galls (QIGs) have a long history of treating ulcerative colitis (UC). The aqueous extract of QIG has an anti-UC effect. However, QIG's enema is easy to leak, and the action time and dose of the drug cannot be controlled well. Thus, QIG is inconvenient to use. This study aims to screen and prepare an optimized thermosensitive in situ gel with slow release and retention. Taking the transition sol-gel temperature (T _sol-gel) as the investigation index, the Box-Behnken design response surface method (BBD-RSM) was used to optimize the dosages of Poloxamer 407 (P407), Poloxamer 188 (P188), and hydroxypropyl methyl cellulose (HPMC). Moreover, three formulations were selected, and the in vitro release rates were further optimized. The optimized rates of P407, P188, and HPMC were 24.07%, 1.22%, and 0.60%, respectively, and T _sol-gel was 32.8°C ± 0.4°C. The cumulative release of gallic acid in the gel conformed to the first-order kinetic equation, and gallic acid was released entirely within 24 h. In addition, the morphological and chemical characterization of thermosensitive in situ gel demonstrated that excipients did not affect the characteristic functional groups of QIG and that the surface of the QIG gel had a porous and loose structure. Rheological methods showed that the QIG thermosensitive in situ gel was fluid at low temperature and semisolid at gelation temperature. Therefore, the prepared gel was sensitive to temperature and had slow-release, local retention properties.

Lopinavir-menthol co-crystals for enhanced dissolution rate and intestinal absorption

Lopinavir is an antiretroviral, antiparasitic agent and recently utilized in treatment of COVID-19. Unfortunately, lopinavir exhibited poor oral bioavailability due to poor dissolution, extensive pre-systemic metabolism, and significant P-glycoprotein intestinal efflux. Accordingly, the aim was to enhance dissolution rate and intestinal absorption of lopinavir. This employed co-processing with menthol which is believed to modify crystalline structures and inhibit intestinal efflux. Lopinavir was mixed with menthol at different molar ratios before ethanol assisted kneading. Formulations were evaluated using FTIR spectroscopy, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and dissolution studies. Optimum ratio was utilized to assess lopinavir intestinal permeability. This employed in situ rabbit intestinal perfusion technique. FTIR, DSC and XRD indicated formation of lopinavir-menthol co-crystals at optimum molar ratio of 1:2. Additional menthol underwent phase separation due to possible self-association. Co-crystallization significantly enhanced lopinavir dissolution rate compared with pure drug to increase the dissolution efficiency from 24.96% in case of unprocessed lopinavir to 91.43% in optimum formulation. Lopinavir showed incomplete absorption from duodenum and jejuno-iliac segments with lower absorptive clearance from jejuno-ileum reflecting P-gp efflux. Co-perfusion with menthol increased lopinavir intestinal permeability. The study introduced menthol as co-crystal co-former for enhanced dissolution and augmented intestinal absorption of lopinavir.

Preparation, in vitro and in vivo Evaluation of Thermosensitive in situ Gel Loaded with Ibuprofen-Solid Lipid Nanoparticles for Rectal Delivery

Background

Ibuprofen (IBU), a nonsteroidal anti-inflammatory drug, shows poor gastrointestinal absorption due to its low solubility, which limits its clinical application.

Objective

In the present study, we aimed to develop thermosensitive gel-mediated ibuprofen-solid lipid nanoparticles (IBU-SLN-ISG) to improve the dissolution and bioavailability of IBU after rectal delivery.

Methods

IBU-loaded SLNs (IBU-SLNs) were developed and optimized applying Box-Behnken design. The optimized IBU-SLNs were characterized by physicochemical parameters and morphology. Then, the optimized IBU-SLNs was incorporated into the gel and characterized for gel properties and rheology and investigated its release in vitro, pharmacokinetics in vivo, rectal irritation and rectal retention time.

Results

The optimized SLNs had an EE of 90.74 ± 1.40%, DL of 11.36 ± 1.20%, MPS of 166.77 ± 2.26 nm, PDI of 0.27 ± 0.08, and ZP of −21.00 ± 0.59 mV. The FTIR spectra confirmed successful encapsulation of the drug inside the nanoparticle as only peaks responsible for the lipid could be identified. This corroborated well with XRD spectra, which showed a completely amorphous state of the IBU-SLNs as compared to the crystalline nature of the pure drug. The gelation temperature of the prepared IBU-SLN-ISG was 33.30 ± 0.78°C, the gelation time was 14.67 ± 2.52 s, the gel strength was 54.00 ± 1.41 s, and the mucoadhesion was (11.54±0.37) × 10²dyne/cm². The in vitro results of IBU-SLNs and IBU-SLN-ISG showed a biphasic release pattern with initial burst release followed by sustained release. More importantly, IBU-SLN-ISG produced much better absorption of IBU and improved bioavailability in rats. In addition, IBU-SLN-ISG caused no irritation or damage to rectal tissues, and could be retained in the rectum for a long time.

Conclusion

Thermosensitive in situ gel loaded with IBU-solid lipid nanoparticles might be further developed as a more convenient and effective rectal dosage form.

Development, Characterization, and Evaluation of SLN-Loaded Thermoresponsive Hydrogel System of Topotecan as Biological Macromolecule for Colorectal Delivery

BACKGROUND

Chemotherapeutic drugs cause severe toxicities if administered unprotected, without proper targeting, and controlled release. In this study, we developed topotecan- (TPT-) loaded solid lipid nanoparticles (SLNs) for their chemotherapeutic effect against colorectal cancer. The TPT-SLNs were further incorporated into a thermoresponsive hydrogel system (TRHS) (TPT-SLNs-TRHS) to ensure control release and reduce toxicity of the drug. Microemulsion technique and cold method were, respectively, used to develop TPT-SLNs and TPT-SLNs-TRHS. Particle size, polydispersive index (PDI), and incorporation efficiency (IE) of the TPT-SLNs were determined. Similarly, gelation time, gel strength, and bioadhesive force studies of the TPT-SLNs-TRHS were performed. Additionally, in vitro release and pharmacokinetic and antitumour evaluations of the formulation were done.

RESULTS

TPT-SLNs have uniformly distributed particles with mean size in nanorange (174 nm) and IE of ~90%. TPT-SLNs-TRHS demonstrated suitable gelation properties upon administration into the rat's rectum. Moreover, drug release was exhibited in a control manner over an extended period of time for the incorporated TPT. Pharmacokinetic studies showed enhanced bioavailability of the TPT with improved plasma concentration and AUC. Further, it showed significantly enhanced antitumour effect in tumour-bearing mice as compared to the test formulations.

CONCLUSION

It can be concluded that SLNs incorporated in TRHS could be a potential source of the antitumour drug delivery with better control of the drug release and no toxicity.

Achievements in Thermosensitive Gelling Systems for Rectal Administration

Rectal drug delivery is an effective alternative to oral and parenteral treatments. This route allows for both local and systemic drug therapy. Traditional rectal dosage formulations have historically been used for localised treatments, including laxatives, hemorrhoid therapy and antipyretics. However, this form of drug dosage often feels alien and uncomfortable to a patient, encouraging refusal. The limitations of conventional solid suppositories can be overcome by creating a thermosensitive liquid suppository. Unfortunately, there are currently only a few studies describing their use in therapy. However, recent trends indicate an increase in the development of this modern therapeutic system. This review introduces a novel rectal drug delivery system with the goal of summarising recent developments in thermosensitive liquid suppositories for analgesic, anticancer, antiemetic, antihypertensive, psychiatric, antiallergic, anaesthetic, antimalarial drugs and insulin. The report also presents the impact of various types of components and their concentration on the properties of this rectal dosage form. Further research into such formulations is certainly needed in order to meet the high demand for modern, efficient rectal gelling systems. Continued research and development in this field would undoubtedly further reveal the hidden potential of rectal drug delivery systems.

A Novel Eutectic-Based Transdermal Delivery System for Risperidone

This paper reports for the first time the possible formation of a novel room temperature therapeutic deep eutectic solvent (THEDES) of risperidone (RIS) with some fatty acids, namely capric acid (C10; CA), lauric acid (C12; LA), and myristic acid (C14; MA). All mixtures of RIS and MA yielded a solid or pasty-like solid and were readily discarded. Some of the prepared THEDESs from RIS and CA or LA have spontaneously transformed into a transparent liquid, without any precipitate at room temperature by simple physical mixing of the components. From the DSC thermograms, phase diagrams of the eutectic systems were constructed and the lowest obtained melting point for a RIS:CA mixture was 17°C at 40:60% w/w ratio. While 22°C was recorded as the lowest melting point for RIS:LA at a ratio of 30:70% w/w, solubility improvement of RIS was up to 70,000-fold compared with water. Freeze-drying microscopy provided valuable information regarding the phase change and transitions the drug undergoes as a function of temperature and it clarifies the interpretation of the DSC results and provides valuable evidence of drug crystals co-melting within the fatty acid base. The presence of natural fatty acid as one component of THEDES and the depression in the melting point significantly (P < 0.05) enhanced RIS skin permeation. Rheological studies showed a viscosity temperature dependency of the DES and well fitted to the Arrhenius equation. Application of the obtained THEDES on the shaved skin of rats revealed the absence of any irritation or edema effects.

Novel glucosamine-loaded thermosensitive hydrogels based on poloxamers for osteoarthritis therapy by intra-articular injection

Glucosamine (GlcN) is a common drug used to treat osteoarthritis (OA). To prolong the action time of glucosamine on OA and improve its therapeutic effect, this research explored the potential application of GlcN-loaded thermosensitive hydrogels based on poloxamer 407 and poloxamer 188 for OA therapy by intra-articular injection. The thermosensitive hydrogels were prepared by cold method, and the effects of P407, P188, and GlcN on sol-gel transition temperature (T_sol-gel) were compared. After screening was performed, the optimized formulation showed good temperature sensitivity, and T_sol-gel was approximately 35 °C. In vitro release tests showed that GlcN was slowly released from the thermosensitive hydrogels. After the gels were intra-articularly administered to treat OA in rabbits, the degree of swelling and inflammatory factors were significantly decreased in the hydrogel group compared with those in the OA model group (P < 0.05). Histological results showed that the GlcN-administered group had a good repair effect on damaged cartilage. At the same dose, the effect of the thermosensitive hydrogels was better than that of the aqueous solution. Therefore, GlcN-loaded thermosensitive hydrogels based on poloxamers are promising sustainable delivery systems for OA therapy by intra-articular injection.

Eutectics and Salt of Dapsone With Hydroxybenzoic Acids: Binary Phase Diagrams, Characterization and Evaluation

Poor solubility and low dissolution rate of pharmaceuticals in many cases largely limit their bioavailability and efficacy. One of the promising approaches to improve dissolution behavior is to develop new multicomponent solid forms. Herein we use this strategy to synthesize new multicomponent solids of dapsone (DAP), which belongs to BCS class IV, with a series of hydroxybenzoic acid coformers. A new salt of DAP with 2,6-dihydroxybenzoic acid (26DHBA) and 4 eutectics with other hydroxybenzoic acids were reported through comprehensive characterizations using powder X-ray diffraction DSC, and vibrational spectroscopy techniques. The salt formation was evidenced by the presence of ionic interactions detected using FT-IR and Raman spectroscopy, and the stoichiometric ratio was determined to be 1:1. Binary phase diagrams were established to determine the composition of eutectics. The cause for salt and eutectic selection was further understood by computing molecular electrostatic potential (MEP) surface where 26DHBA shows the greatest acidity. Moreover, the powder dissolution study and microenvironment pH measurement reveal that both salt and eutectics of DAP display improvements on the dissolution rate and equilibrium concentration in which the acidity of coformers plays a dominant role. Our findings provide a direction for future coformer screening of multicomponent solids with improved pharmaceutical properties.

Exploring the novel green eutectic solvent for the synthesis of 4-hydroxy-2-methyl-N-2-pyridinyl-2H-1,2,-benzothiazine-3-carboxamide 1,1-dioxide with benzoic acid cocrystal using a co-grinding technique

In the present study, the suitability of a green eutectic solvent, a mixture of menthol and camphor for cocrystal synthesis has been investigated to improve the biopharmaceutical properties of poorly water-soluble drugs.

Sketching neoteric solvents for boosting drugs bioavailability

Emerging neoteric solvents are being the subject of growing attention due to their lower cost and environmental impact, so they are being applied in a broad spectrum of industries. Among them, the pharmaceutical sector is demanding new environmentally friendly and non-toxic solvents able to enhance drugs solubility and stability. The introduction of ionic liquids turned out to be a breakthrough in the field of Green Chemistry opening up new separation and catalysis opportunities. In this sense, the options represented by Deep Eutectic Solvents make up an attractive alternative due to the low cost of their raw material, simple synthesis, and eco-friendly character. In line with these findings, Therapeutic Deep Eutectic Solvents and Natural Deep Eutectic Solvents are new and promising alternatives to improve the bioavailability of drugs in pharmaceutical formulations. This leading article is focused on providing a general picture of the advantages and drawbacks of these new solvents as well as the main research lines and perspectives to achieve efficient drugs delivery systems.

Revealing the Role of Structural Features in Bulk Mechanical Performance of Ternary Molecular Solids of Isoniazid

Mechanical performance in ternary (3n) molecular solids has been rarely studied, and hence it is an interesting topic of investigation in the direct compression method of tableting. The structural features of 3n-eutectic (3n-Eu: INZ-ADP-NIC) and 3n-cocrystal (3n-Co: INZ:SUC:NIC) were explored to understand the bonding area-bonding strength (BA-BS) interplay. Higher compressibility and lower values of the Heckel parameter of 3n-Co as compared to 3n-Eu suggested its better deformation behavior, with BA being the predominant factor. The higher tensile strength and Walker analysis indicated a higher compressibility coefficient ( W) and lower pressing modulus ( L) for 3n-Eu, which was consistent with its better tabletability over 3n-Co. The higher compressibility and plastic energy, and higher value of L of 3n-Co, were attributed to the facile propagation (⟨-1' 0' 5'⟩) of the shearing molecular slip (-1 0 5) when subjected to the external mechanical stress. Thus, the overall higher tableting performance of 3n-Eu over 3n-Co was found due to the predominant BS and limited contribution of BA. The latter was the dominant factor in 3n-Co. Cohesive interactions, like the 3D mechanically interlocked structure of conglomerates of 3n-Eu, contributed toward the higher BS. Moreover, the prediction of better tabletability solely based on crystallographic feature slip planes (0D/1D/2D H-bonded layer (h k l) ⊥ vdW interactions) is warranted in pharmaceutical molecular solids. Eutectics with varying microstructural variants ( nL_α + nL_β + nL_γ) may open up the opportunity to manipulate the physicomechanical performance.

Advances in rectal drug delivery systems

Drug delivery via the rectum is a useful alternative route of administration to the oral route for patients who cannot swallow. Traditional rectal dosage forms have been historically used for localized treatments including delivery of laxatives, treatment of hemorrhoids and for delivery of antipyretics. However, the recent trend is showing an increase in the development of novel rectal delivery systems to deliver drug directly into the systemic circulation by taking advantage of porto-systemic shunting. The present review is based on research studies carried out between years 1969-2017. Data for this review have been derived from keyword searches using Scopus and Medline databases. Novel rectal drug delivery systems including hollow-type suppositories, thermo-responsive and muco-adhesive liquid suppositories, and nanoparticulate systems incorporated into an appropriate vehicle have offered more control over delivery of drug molecules for local or systemic actions. In addition, various methods for in vitro-in vivo evaluation of rectal drug delivery systems are covered which is as important as the formulation, and must be carried out using appropriate methodology. Continuous research and development in this field of drug delivery may unleash the hidden potential of the rectal drug delivery systems.

Cutaneous irritancy of an ibuprofen medicated plaster in healthy volunteers

OBJECTIVES

To assess the irritation and contact sensitization potential of a 200 mg ibuprofen medicated plaster.

METHODS

This double-blind, phase-1 placebo controlled study had two phases; the induction phase to evaluate the irritant potential of continuous application of the plaster, and the challenge phase to assess contact sensitivity (allergy). The cumulative irritancy potential was evaluated using an adaptation of the Shelanski method. Healthy adults (≥18 years of age) (N = 210) were treated simultaneously with one ibuprofen medicated and one placebo plaster applied in a randomized fashion to either the left or right side of the lower back. During the induction phase, plasters were applied on Days 1, 3, 5, 8, 10, 12, 15, 17, and 19 and the final plaster removed on Day 22. At each scheduled visit plasters and applications sites were assessed for degree of adhesion and skin irritation (score of 1 = no irritation to 7 = strong reaction spreading beyond test sites), respectively. The challenge phase followed a two-week washout period. A plaster was applied on Day 36 for 48 h and assessment occurred on Days 38, 39, and 40.

RESULTS

The mean cumulative irritation score during the induction phase was lower for the ibuprofen medicated plaster than the placebo plaster (0.32 vs. 1.23, respectively). Three (1.4%) subjects experience a dermal reaction of grade ≥3 for the ibuprofen medicated plaster compared with 27 (12.7%) for the placebo plaster. Following challenge with ibuprofen or placebo plasters, 12 subjects (6.2%) with the ibuprofen medicated plaster and four (2.2%) with the placebo plaster had skin reaction of assessment grade higher than the induction phase. One subject for the ibuprofen and two for the placebo plaster had reactions with grade >2. No subjects showed an increase in sensitization on Day 39 or 40 compared with Day 38.

CONCLUSIONS

The findings indicate that the both the irritancy and contact sensitization of the ibuprofen medicated plaster is acceptable.

Thermosensitive In Situ Gel Based on Solid Dispersion for Rectal Delivery of Ibuprofen

The objective of this study was to develop a thermosensitive in situ gel based on solid dispersions (SDs) for rectal delivery of ibuprofen (IBU). Thermosensitive (poloxamer 407) and mucoadhesive (hydroxypropylmethyl cellulose E5 and sodium alginate) polymers were used to prepare the in situ gel and the sol-gel transition temperature (T _sol-gel) and gel strength were optimized. The in vitro release performance and in vivo pharmacokinetic properties of the in situ gel after their rectal administration to rabbits were investigated. Compared with the solid suppository, the cumulative release of the IBU SDs loaded in situ gel was significantly increased. The in vivo pharmacokinetics indicated that in situ gel had a higher peak plasma concentration (C _max) and area under the curve (AUC_(0-∞)) in plasma than the solid suppositories. Histopathology results showed that the IBU in situ gel given at a dose of 15 mg/kg did not produce any irritation. In conclusion, this study suggested that the in situ gel could be an effective rectal formulation for IBU.

Development and characterisation of levosulpiride-loaded suppositories with improved bioavailability in vivo

The purpose of this study was to develop and characterize levosulpiride loaded liquid suppository with improved bioavailability. The content of levosulpiride-loaded liquid suppositories were optimized in a series of experiments using various weight ratios of P188, P407, Tween 80, and drug. The suppositories were liquid at room temperature, however, when rectally administered, they became gel at body temperature. Their rheological properties and release characteristics were determined in vitro while pharmacokinetic study was performed after its rectal administration in rats and compared with drug suspension. Poloxamer 188 and Twee 80 decreased the gelation temperature and gelation time, but increased the gel strength and mucoadhesive force of liquid suppositories. Liquid suppository composed of [Levosulpiride/P 188/P 407/Tween 80 (1/15/17/3%)] with a gelation temperature of about 30.7 °C remained liquid at 25 °C, but converted to gel at 30-36.5 °C, resulting in easy administration and rapid gelation inside the body. This liquid suppository gave a considerably increased dissolution rate reflected in a meaningfully higher plasma concentration and 7.1-fold AUC values of levosulpiride in rats as compared to the drug suspension. Hence, liquid suppository system could be used for enhanced bioavailability of levosulpiride-loaded pharmaceutical products.

Efficacy and tolerability of a new ibuprofen 200mg plaster in patients with acute sports-related traumatic blunt soft tissue injury/contusion

BACKGROUND

Ibuprofen is used for the treatment of non-serious pain. This study assessed the efficacy and safety of a new ibuprofen plaster for the treatment of pain associated with acute sports impact injuries/contusions.

METHODS

In this randomised, double-blind, multi-centre, placebo controlled, parallel group study, adults (n = 130; 18-58 years of age) diagnosed with acute sports-related blunt soft tissue injury/contusion were randomized to receive either ibuprofen 200 mg plaster or placebo plaster. Plasters were administered once daily for five consecutive days. The primary assessment was area under the visual analogue scale (VAS) of pain on movement (POM) over 0 to three days (VAS AUC_0-3d). Other endpoints included algometry AUC from 0 to three days (AUC_0-3d) and 0 to five days (AUC_0-5d), to evaluate improvement of sensitivity at the injured site, and patient and investigator global assessment of efficacy. Safety was monitored throughout the study.

RESULTS

The ibuprofen plaster resulted in superior reduction in AUC_0-3d compared with placebo; the Least Squares (LS) mean difference was 662.82 mm*h in favour of the ibuprofen 200mg plaster (P = 0.0011). The greater improvement in VAS AUC of POM was also observed after 12 h, 24 h, and five days of therapy. Tenderness also significantly improved with the ibuprofen plaster compared with placebo; LS mean difference in algometry/tenderness AUC_0-3d was 1.87 N/cm²*d and AUC_0-5d was 1.87 N/cm²*d (P values ≤0.0004). At all study timepoints, a greater percentage of patients and investigators rated the effectiveness of the ibuprofen 200 mg plaster as good/excellent than the placebo plaster. Treatment-emergent adverse events for the ibuprofen plaster were few (≤1.5%) and were mild in severity.

CONCLUSIONS

The results of this study indicate 200 mg plaster is effective and safe for the treatment of pain due to acute sports-related traumatic blunt soft tissue injury/contusion in adults.

Irinotecan-loaded double-reversible thermogel with improved antitumor efficacy without initial burst effect and toxicity for intramuscular administration

Intramuscularly administered, anti-tumour drugs induce severe side effects due to their direct contact with body tissues and initial burst effect. In this study, to solve this problem, a novel double-reversible thermogel system (DRTG) for the intramuscular administration of irinotecan was developed. This irinotecan-loaded DRTG was prepared by dispersing the irinotecan-loaded thermoreversible solid lipid nanoparticles (SLNs) in the thermoreversible hydrogel. In DRTG, the former was solid at 25°C but converted to liquid at 36.5°C; in contrast, the latter existed in a liquid form but transformed to gel state in the body. The DRTG was easily administered intramuscularly. Its particle size and drug content were not noticeably changeable, resulting that it was stable at 40°C for at least 6months. Compared to the irinotecan-loaded solution and conventional hydrogel, the DRTG significantly delayed drug release, leading to a reduced burst effect. Moreover, it showed decreased C_max and maintained the sustained plasma concentrations at a relatively low level for the long period of 60h in rats, resulting in ameliorated side effects of the anti-tumour drug. Furthermore, it gave significantly improved anti-tumour efficacy in tumour-bearing mice compared to the hydrogel but, unlike the conventional hydrogel, induced no body weight loss and local damage to the muscle. Thus, this DRTG with improved antitumor efficacy without initial burst effect and toxicity could provide a potential pharmaceutical system for the intramuscular administration of irinotecan.

STATEMENT OF SIGNIFICANCE

Intramuscularly administered, anti-tumour drugs induce severe side effects due to their direct contact with body tissues and initial burst effect. To solve this problem, we developed a novel double-reversible thermogel system (DRTG) for the intramuscular administration of irinotecan. Unlike the conventional hydrogel, the DRTG is a dispersion of the irinotecan-loaded thermoreversible solid lipid nanoparticles in the thermoreversible hydrogel. In DRTG, the former was solid at 25°C but converted to liquid at 36.5°C; in contrast, the latter existed in a liquid form but transformed to gel state in the body. This DRTG gave significantly improved anti-tumour efficacy in tumour-bearing mice compared to the hydrogel but, unlike the conventional hydrogel, induced no body weight loss and local damage to the muscle.

Irinotecan-encapsulated double-reverse thermosensitive nanocarrier system for rectal administration

Intravenously administered for the treatment of rectum cancer, irinotecan produces severe side effects due to very high plasma concentrations. A novel irinotecan-encapsulated double reverse thermosensitive nanocarrier system (DRTN) for rectal administration was developed as an alternative. The DRTN was fabricated by dispersing the thermosensitive irinotecan-encapsulated solid lipid nanoparticles (SLN) in the thermosensitive poloxamer solution. Its gel properties, pharmacokinetics, morphology, anticancer activity and immunohistopathology were assessed after its rectal administration to rats and tumor-bearing mice. In the DRTN, the solid form of the SLN and the liquid form of the poloxamer solution persisted at 25 °C; the former melted to liquid, and the latter altered to gel at 36.5 °C. The DRTN was easily administered to the anus, gelling rapidly and strongly after rectal administration. Compared to the conventional hydrogel and intravenously administered solution, it retarded dissolution and initial plasma concentration. The DRTN gave sustained release and nearly constant plasma concentrations of irinotecan at 1–3 h in rats, resulting in improved anticancer activity. It induced no damage to the rat rectum and no body weight loss in tumor-bearing mice. Thus, this irinotecan-encapsulated DRTN associated with a reduced burst effect, lack of toxicity and excellent antitumor efficacy would be strongly recommended as a rectal pharmaceutical product alternative to commercial intravenous injection in the treatment of rectum and colon cancer.

Physicochemical properties, in vitro release and in vivo evaluation of tramadol hydrochloride rectal suppository and rectal gel

Background: Tramadol is a centrally acting analgesic drug. Rectal administration of tramadol is useful in the treatment of post-operative pain or malignant pain in cases where it cannot be administered orally. In Thailand, tramadol is available only as a capsule for oral use and as a solution for injection.

Objective: Develop tramadol hydrochloride rectal suppositories and rectal gel preparations.

Methods: Tramadol rectal suppository and rectal gel were prepared. Physicochemical properties (viscosity, gel strength, mucoadhesive force) and the in vitro release of tramadol hydrochloride were investigated from different bases (Witepsol H15, polyethylene glycol, poloxamer, and hydroxyethylcellulose). The analgesic activity of rectal tramadol hydrochloride using the hot plate test was evaluated in rats.

Results: Tramadol hydrochloride rectal gel using poloxamer was more mucoadhesive to the rectal mucous membrane than was the gel with the hydroxyethylcellulose base. Tramadol hydrochloride was released rapidly in vitro from both the Witepsol H15 and polyethylene glycol bases. It was completely released from the polyethylene glycol suppository base within 15 minutes. The amount of tramadol hydrochloride release from the Witepsol H15 suppository base was about 93% at 120 minutes. When using poloxamer or hydroxyethylcellulose as a rectal base, tramadol hydrochloride was released from both bases rapidly and completely released within 15 minutes. Administration of a tramadol hydrochloride suppository in rats exhibited a more pronounced analgesic effect with the polyethylene glycol base than with the Witepsol H15-based suppositories. The rectal gel had a less pronounced analgesic effect when made with the hydroxyethylcellulose base than with the poloxamer base.

Conclusion: Tramadol hydrochloride suppositories and rectal gels with different bases showed rapid and almost complete drug release from the bases, prolonging the latency of a nociceptive response in in vivo experiments.

GC Method Validation for the Analysis of Menthol in Suppository Pharmaceutical Dosage Form

Menthol is widely used as a fragrance and flavor in the food and cosmetic industries. It is also used in the medical and pharmaceutical fields for its various biological effects. Gas chromatography (GC) is considered to be a sensitive method for the analysis of menthol. GC chromatographic separation was developed using capillary column (VF-624) and a flame ionization detector (FID). The method was validated as per ICH guidelines for various parameters such as precision, linearity, accuracy, solution stability, robustness, limit of detection, and quantification. The tested validation parameters were found to be within acceptable limits. The method was successfully applied for the quantification of menthol in suppositories formulations. Quality control departments and official pharmacopeias can use our developed method in the analysis of menthol in pharmaceutical dosage formulation and raw material.

Evaporation Behavior and Characterization of Eutectic Solvent and Ibuprofen Eutectic Solution

Liquid eutectic system of menthol and camphor has been reported as solvent and co-solvent for some drug delivery systems. However, surprisingly, the phase diagram of menthol-camphor eutectic has not been reported previously. The evaporation behavior, physicochemical, and thermal properties of this liquid eutectic and ibuprofen eutectic solution were characterized in this study. Differential scanning calorimetry (DSC) analysis indicated that a eutectic point of this system was near to 1:1 menthol/camphor and its eutectic temperature was -1°C. The solubility of ibuprofen in this eutectic was 282.11 ± 6.67 mg mL(-1) and increased the drug aqueous solubility fourfold. The shift of wave number from Fourier transform infrared spectroscopy (FTIR) indicated the hydrogen bonding of each compound in eutectic mixture. The weight loss from thermogravimetric analysis of menthol and camphor related to the evaporation and sublimation, respectively. Menthol demonstrated a lower apparent sublimation rate than camphor, and the evaporation rate of eutectic solvent was lower than the sublimation rate of camphor but higher than the evaporation of menthol. The evaporation rate of the ibuprofen eutectic solution was lower than that of the eutectic solvent because ibuprofen did not sublimate. This eutectic solvent prolonged the ibuprofen release with diffusion control. Thus, the beneficial information for thermal behavior and related properties of eutectic solvent comprising menthol-camphor and ibuprofen eutectic solution was attained successfully. The rather low evaporation of eutectic mixture will be beneficial for investigation and tracking the mechanism of transformation from nanoemulsion into nanosuspension in the further study using eutectic as oil phase.

Intranasal Eutectic Powder of Zolmitriptan with Enhanced Bioavailability in the Rat Brain

Intranasal administration can potentially deliver drugs to the brain because of the proximity of the delivery site to the olfactory lobe. We prepared triturates of micronized or crystalline zolmitriptan with a GRAS substance, nicotinamide, to form a eutectic. We characterized the formulation using differential scanning calorimetry, powder X-ray diffraction, and FTIR spectroscopy to confirm its eutectic nature and generated a phase diagram. The eutectic formulation was aerosolized using an in-house insufflator into the nares of rats. Groups of rats received zolmitriptan intravenously or intranasally, or intranasal eutectic formulation. Zolmitriptan was estimated in the olfactory lobe, cerebral cortex, cerebellum, and blood plasma at different time-points by LC-MS. Pharmacokinetics in these tissues indicated the superiority of the intranasal eutectic formulation for brain targeting when compared with results of IV solution and intranasal pure zolmitriptan powder. Enhancement of nose-to-brain transport is likely to have resulted from more rapid dissolution of the eutectic as compared to pure drug.

Transformation of eutectic emulsion to nanosuspension fabricating with solvent evaporation and ultrasonication technique

Eutectic solvent can solubilize high amount of some therapeutic compounds. Volatile eutectic solvent is interesting to be used as solvent in the preparation of nanosuspension with emulsion solvent evaporation technique. The mechanism of transformation from the eutectic emulsion to nanosuspension was investigated in this study. The 30% w/w ibuprofen eutectic solution was used as the internal phase, and the external phase is composed of Tween 80 as emulsifier. Ibuprofen nanosuspension was prepared by eutectic emulsion solvent evaporating method followed with ultrasonication. During evaporation process, the ibuprofen concentration in emulsion droplets was increased leading to a drug supersaturation but did not immediately recrystallize because of low glass transition temperature (T_g) of ibuprofen. The contact angle of the internal phase on ibuprofen was apparently lower than that of the external phase at all times of evaporation, indicating that the ibuprofen crystals were preferentially wetted by the internal phase than the external phase. From calculated dewetting value ibuprofen crystallization occurred in the droplet. Crystallization of the drug was initiated with external mechanical force, and the particle size of the drug was larger due to Ostwald ripening. Cavitation force from ultrasonication minimized the ibuprofen crystals to the nanoscale. Particle size and zeta potential of formulated ibuprofen nanosuspension were 330.87±51.49 nm and −31.1±1.6 mV, respectively, and exhibited a fast dissolution. Therefore, the combination of eutectic emulsion solvent evaporation method with ultrasonication was favorable for fabricating an ibuprofen nanosuspension, and the transformation mechanism was attained successfully.

A novel in-situ-gelling liquid suppository for site-targeting delivery of anti-colorectal cancer drugs

In order to avoid anti-cancer drugs undergoing a first-pass effect and reduce their toxicity, and to solve conventional suppositories defects, we developed an in-situ-gelling and injectable Pluronic-poly(acrylic acid) (Pluronic-PAA) liquid suppository, which could gel fast in the physiological state and had suitable gel strength and bioadhesive force. The liquid suppositories were inserted into the rectum of rabbits without difficulty and leakage, and retained in the rectum for at least 6 h and while releasing the drug. The toxicity and cytotoxic tests indicated that Pluronic and PAA were non-toxic materials and could inhibit colon cancer cells when oxaliplatin was incorporated. C max and AUC0→12h values of oxaliplatin after rectal administration of a oxaliplatin suppository were higher than those for an oxaliplatin solution administered orally. These results suggest that an in-situ-gelling and injectable liquid suppository for humans can be further developed as a more convenient and effective rectal dosage form.

Non-Covalent Derivatives: Cocrystals and Eutectics

Non-covalent derivatives (NCDs) are formed by incorporating one (or more) coformer molecule(s) into the matrix of a parent molecule via non-covalent forces. These forces can include ionic forces, Van der Waals forces, hydrogen bonding, lipophilic-lipophilic interactions and pi-pi interactions. NCDs, in both cocrystal and eutectic forms, possess properties that are unique to their supramolecular matrix. These properties include critical product performance factors such as solubility, stability and bioavailability. NCDs have been used to tailor materials for a variety of applications and have the potential to be used in an even broader range of materials and processes. NCDs can be prepared using little or no solvent and none of the reagents typical to synthetic modifications. Thus, NCDs represent a powerfully versatile, environmentally-friendly and cost-effective opportunity.

Novel thermosensitive in situ gel based on poloxamer for uterus delivery

Side effects and drug residues are major concerns affecting hormone therapy of bovine reproductive diseases. Fertility-promoting intrauterine infusion liquid (FPL), an effective alternative to hormone therapy, is associated with short retention time and low therapeutic efficacy. To address these problems, we developed a thermosensitive in situ gel based on poloxamer 407 for local uterine administration. To achieve the desired gelling temperature and enhance local retention property, we added poloxamer 188 and HPMC to the formulation containing poloxamer 407 and FPL. After screening was performed, the optimized formulation showed good temperature sensitivity in vitro and in vivo. Gelation temperature was approximately 27°C. In vitro release tests showed that icariin (the major active compound in FPL) was slow released from in situ forming gel. After the gel was locally administered, uterine and ovarian indexes were significantly increased in the gel group compared with the control group (P<0.05). The serum estradiol level of the gel group was significantly higher than that of the control group (P<0.01). Histological evaluation did not show mucosa irritation in the gel group. Therefore, the proposed in situ forming gel system based on poloxamer 407 is a promising local drug delivery system to treat bovine uterine diseases.

Formulation and evaluation of irinotecan suppository for rectal administration

Irinotecan suppository was prepared using the moulding method with a homogeneous blend. A sensitive and specific fluorescence method was developed and validated for the determination of irinotecan in plasma using HPLC. The pharmacokinetics of intravenous administered and rectal administered in rabbits was investigated. Following a single intravenous dose of irinotecan (50 mg/kg), the plasma irinotecan concentration demonstrated a bi-exponential decay, with a rapid decline over 15 min. C_max, t_1/2, AUC_0–30h and AUC_0-∞ were 16.1 ± 2.7 g/ml, 7.6 ± 1.2 h, 71.3 ± 8.8 μg·h/ml and 82.3 ± 9.5 μg·h/ml, respectively. Following rectal administration of 100 mg/kg irinotecan, the plasma irinotecan concentration reached a peak of 5.3 ± 2.5 μg/ml at 4 h. The AUC_0–30h and AUC_0-∞ were 32.2 ± 6.2 μg·h/ml and 41.6 ± 7.2 μg·h/ml, respectively. It representing ∼50.6% of the absolute bioavailability.

Evaluation of epirubicin in thermogelling and bioadhesive liquid and solid suppository formulations for rectal administration

Temperature sensitive Pluronic (Plu) and pH-sensitive polyacrylic acid (PAA) were successfully mixed in different ratios to form in situ gelling formulations for colon cancer therapy. The major formulations were prepared as the liquid and solid suppository dosage forms. Epirubicin (Epi) was chosen as a model anticancer drug. In vitro characterization and in vivo pharmacokinetics and therapeutic efficacy of Epi in six Plu/PAA formulations were evaluated. Our in vitro data indicate that Epi in Plu 14%/PAA 0.75% of both solid and liquid suppositories possess significant cytotoxicity, strong bioadhesive force, long-term appropriate suppository base, sustained release, and high accumulation of Epi in rat rectums. These solid and liquid suppositories were retained in the upper rectum of Sprague-Dawley (SD) rats for at least 12 h. An in vivo pharmacokinetic study using SD rats showed that after rectal administration of solid and liquid suppositories, Epi had greater area under the curve and higher relative bioavailability than in a rectal solution. These solid and liquid suppositories exhibited remarkable inhibition on the tumor growth of CT26 bearing Balb/c mice in vivo. Our findings suggest that in situ thermogelling and mucoadhesive suppositories demonstrate a great potential as colon anticancer delivery systems for protracted release of chemotherapeutic agents.

Development of in situ gelling and bio adhesive 5-Fluorouracil enema

In this study, a novel 5-Fluorouracil (5-FU) enema with good bio adhesion and temperature sensitivity was developed using in situ gelling technology. The preparation was formulated as a free-flowing liquid before use, while a layer of gel film was quickly formed when administered in the rectum, with a large contact surface area. It also demonstrated good biocompatibility, appropriate gel strength and bio adhesive force with excellent adhesion to rectal mucosa and prolonged action time, allowing more effective drug absorption and diffusion to surrounding tissues. Poloxamer 407 and poloxamer 188 were applied to adjust the gelling temperature. With the addition of carbopol and polycarbophil (bio adhesive substances), the solubility of 5-FU and gel strength increased, the temperature of gelation and the surface area of drug contact on mucous epithelium decreased. Decreased adhesive force between the preparation and the mucous membrane of the rectum was demonstrated with improving carbopol and polycarbophil's concentration. In vitro release demonstrated that 5-FU in situ gelling enema with different bases had a rapid and almost complete drug release. We used an optimized formulation of P407/P188/polycarbophil/5-FU (17/2.5/0.2/1.0) for animal experiments. The result showed that the drug evenly covered the surface of the rectum and there was no leakage in 6 hours. The in situ gelling enema showed significantly higher rectal tissue levels of 5-FU compared with suppository and intravenous administration, indicating that 5-FU could be well absorbed due to the enlarged releasing area, longer retention time and larger amount of dissolved active ingredients. Systemically, 5-FU levels in the enema group were similar to those in the suppository group and significantly lower than the intravenous group. The enema was not associated with morphological damage to rectal tissue. These results suggest that the bio adhesive and in situ gelling enema could be a more effective rectal delivery system of 5-FU.

Polymeric Eutectic System

The liquid eutectic system comprising 1:1 menthol:camphor was selected to use as solvent due to it was lowest viscosity. Both menthol and camphor used in this eutectic system have been reported for their many pharmaceutical used. Various polymers were tested for their solubility in this eutectic system. Eudragit® EPO showed the highest solubility. Eudragit® EPO was the one of biocompatible polymer which could dissolve in this eutectic system up to 40% w/w with no chemical interaction of each compound. Viscosity of this system showed the exponential curve as a function of polymer concentration but all concentration showed the newtonian rheology. The pH and surface tension were slightly affected by type and amount of polymers. The obtained polymeric eutectic mixture should control the drug release for pharmaceutical applications.

Menthol, Borneol, Camphor and WS-3 Eutectic Mixture

Eutectic system is a mixture or solution which the ingredients solidify or liquefy simultaneously. A eutectic mixture is therefore that unique composition of two (or more) components that has the lower crystallization temperature or melting point. This aim of this study was to prepare and characterize the eutectic systems containing menthol, borneol, camphor and N-Ethyl-5-methyl-2-(1-methylethyl) cyclohexanecarboxamide (WS-3). Menthol is able to form liquid eutectic at room temperature with camphor in the ratio of 8:2, 7:3, 6:4 and 5:5 whereas menthol and borneol in the ratio of 8:2 and 7:3, menthol and WS-3 in the ratio of 6:4 and 1:1. The rheology behavior of all liquid eutectic systems was Newtonian flow which the surface tension was in the range of 28-29 mN/m. From contact angle measurement, all liquid eutectic systems were categorized as high wettability to the glass plate. The suitable liquid eutectic system for further application as liquid carrier for injectable active compounds was 1:1 menthol:camphor because of its lowest viscosity. IR spectra indicated that there was no chemical interaction of these two materials in the selected liquid eutectic mixture.

New formulation of in situ gelling Metolose-based liquid suppository

CONTEXT

An in situ gelling liquid suppository is liquid at room temperature but forms a gel at body temperature. In our work, Metolose® SM-4000 (methylcellulose) is studied that basically shows thermal gelation at 68°C (2%, w/w).

OBJECTIVE

The objective was to study the potency of different factors (concentration, pH, additives) to change the value of thermal gelation temperature (T (t)) for Metolose® to form an in situ gelling liquid suppository.

MATERIALS AND METHODS

We studied the effect of Metolose® concentration, pH, and salts (sodium chloride, potassium chloride, sodium hydrogen carbonate, and sodium monohydrogen phosphate) on T (t) by viscosimetry. To choose the appropriate compound, in vitro drug release was examined. Rectal safety test was performed on rats in vivo after 12-hour application.

RESULTS

Increasing the Metolose® concentrations (0.5-4%, w/w), T (t) can be decreased, but it also altered the consistency of gel. pH does not affect the T (t). The water-soluble salts allowed reducing the gelation temperature to 37°C. Sodium monohydrogen phosphate in 4.5% concentration was found to be the most appropriate. The impact of examined factors on in vitro drug release of piroxicam from the in situ-formed gel was characterized according to Fickian diffusion. Metolose® and the chosen salt did not cause any morphological damage on the rectal tissues.

DISCUSSION

According to our study, Metolose® has the physical and chemical potential to be used as base for liquid suppositories.

In vitro and in vivo characteristics of a thermogelling rectal delivery system of etodolac

Rectal etodolac-Poloxamer gel systems composed of Poloxamer and bioadhesive polymers were developed and evaluated. Hydroxypropylmethyl cellulose, poly)vinyl) pyrrolidone, methyl cellulose, hydroxyethylcellulose, and carbopol were examined as mucoadhesive polymers. The characteristics of the rectal gels differed according to the properties of mucoadhesive polymers. The physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations were investigated. The analysis of release mechanism showed that the release of etodolac was proportional to the square root of time, indicating that etodolac might be released from the suppositories by Fickian diffusion. The anti-inflammatory effect of etodolac-Poloxamer gel system was also studied in rats. Moreover, liquid suppository of etodolac did not cause any morphological damage to the rectal tissues. These results suggested that in situ gelling liquid suppository with etodolac and mucoadhesive polymer was a physically safe, convenient, and effective rectal dosage form for etodolac.