Formulation, Characterization, and Evaluation of Ketorolac Tromethamine-Loaded Biodegradable Microspheres

Ketorolac Loaded Poly(lactic-co-glycolic acid) Coating of AZ31 in the Treatment of Bone Fracture Pain

Biodegradable metal alloys may be successfully used to support bone repair, avoiding second surgery commonly needed when inert metal alloys are used. Combining a biodegradable metal alloy with a suitable pain relief agent could improve patient quality of life. AZ31 alloy was coated using a poly(lactic-co-glycolic) acid (PLGA) polymer loaded with ketorolac tromethamine using the solvent casting method. The ketorolac release profile from the polymeric film and the coated AZ31 samples, the PLGA mass loss of polymeric film, and the cytotoxicity of the optimized coated alloy were assessed. The coated sample showed a ketorolac release that was prolonged for two weeks, which was slower than that of just the polymeric film, in simulated body fluid. PLGA mass loss was complete after a 45-day immersion in simulated body fluid. The PLGA coating was able to lower AZ31 and ketorolac tromethamine cytotoxicity observed in human osteoblasts. PLGA coating also prevents AZ31 cytotoxicity, which was identified in human fibroblasts. Therefore, PLGA was able to control ketorolac release and protect AZ31 from premature corrosion. These characteristics allow us to hypothesize that the use of ketorolac tromethamine-loaded PLGA coating on AZ31 in the management of bone fractures can favor osteosynthesis and relief pain.

Ketorolac-Loaded PLGA-/PLA-Based Microparticles Stabilized by Hyaluronic Acid: Effects of Formulation Composition and Emulsification Technique on Particle Characteristics and Drug Release Behaviors

This study aimed to develop ketorolac microparticles stabilized by hyaluronic acid based on poly(lactide-co-glycolide) (PLGA), poly(lactide) (PLA), and their blend for further application in osteoarthritis. The polymer blend may provide tailored drug release and improved physicochemical characteristics. The microparticles were prepared by water-in-oil-in-water (w/o/w) double emulsion solvent evaporation using two emulsification techniques, probe sonication (PS) and high-speed stirring (HSS), to obtain the microparticles in different size ranges. The results revealed that the polymer composition and emulsification technique influenced the ketorolac microparticle characteristics. The PS technique provided significantly at least 20 times smaller average size (1.3-2.2 µm) and broader size distribution (1.5-8.5) than HSS (45.5-67.4 µm and 1.0-1.4, respectively). The encapsulation efficiency was influenced by the polymer composition and the emulsification technique, especially in the PLA microparticles. The DSC and XRD results suggested that the drug was compatible with and molecularly dissolved in the polymer matrix. Furthermore, most of the drug molecules existed in an amorphous form, and some in any crystalline form. All of the microparticles had biphasic drug release composed of the burst release within the first 2 h and the sustained release over 35 days. The obtained microparticles showed promise for further use in the treatment of osteoarthritis.

Pharmacokinetics and analgesic effect of ketorolac floating delivery system

OBJECTIVES

The efficacy of ketorolac tromethamine (KT) floating alginate beads as a drug delivery system for better control of KT release was investigated. The formulation with the highest drug loading, entrapment efficiency, swelling, buoyancy, and in vitro release would be selected for further in vivo analgesic effect in the mice and pharmacokinetics study in rats compared to the tablet dosage form.

METHODS

KT floating alginate beads were prepared by extrusion congealing technique. KT in plasma samples was analyzed using a UPLC MS/MS assay.

RESULTS

The percentage yield, drug loading and encapsulation efficiency were increased proportionally with the hydroxypropylmethyl cellulose (HPMC) polymer amount in the KT floating beads. A reverse relationship was observed between HPMC amount in the beads and the KT in vitro release rate. F3-floating beads were selected, due to its better in vitro results (continued floating for >8 h) than others. A longer analgesic effect was observed for F3 in fed mice as compared to the tablets. After F3 administration to rats, the Cmax (2.2 ± 0.3 µg/ml) was achieved at ∼2 h and the decline in KT concentration was slower. F3 showed a significant increase in the AUC (1.89 fold) in rats as compared to the tablets.

CONCLUSION

KT was successfully formulated as floating beads with prolonged in vitro release extended to a better in vivo characteristic with higher bioavailability in rats. KT in floating beads shows a superior analgesic effect over tablets, especially in fed mice.

Ketorolac tromethamine floating beads for oral application: Characterization and in vitro/in vivo evaluation

The floating beads have been employed to make a sustained release of the drug in the stomach and to decrease the dose of the drug and hence overcome its side effects. The common benefits of the floating beads were it is easy preparation, without the need of a high temperature, and high percentage of the drug entrapment. In the present work, the Ketorolac tromethamine (KT) floating beads were prepared by extrusion congealing method utilizing calcium carbonate as a gas forming agent. The physical characters of the produced beads were investigated such as KT yield, KT loading, and entrapment efficiency of the drug. In addition, floating behavior, swelling, particle size, morphology and KT stability were also evaluated. In vitro drug release study was carried out, and the kinetics of the release was evaluated using the linear regression method. Furthermore, the in vivo analgesic effect of KT after oral administration of the selected formula of floating beads (F10) was carried out using hot plate and tail flick methods. Oral commercial KT tablets and KT solution were used for the comparison. The prepared beads remained floated for more than 8 h. The optimized formulation (F10) exhibited prolonged drug release (more than 8 h) and the drug release follows the Higuchi kinetic model, with a Fickian diffusion mechanism according to Korsmeyer-Peppas (n = 0.466). Moreover, F10 showed a sustained analgesic effect as compared to the commercial tablet.

Polímeros sintéticos biodegradáveis: matérias-primas e métodos de produção de micropartículas para uso em drug delivery e liberação controlada

Micropartículas produzidas a partir de polímeros sintéticos têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas micropartículas apresentam as vantagens de proteção do princípio ativo, mucoadesão e gastrorresistência, melhor biodisponibilidade e maior adesão do paciente ao tratamento. Além disso, utiliza menores quantidade de princípio ativo para obtenção do efeito terapêutico proporcionando diminuição dos efeitos adversos locais, sistêmicos e menor toxidade. Os polímeros sintéticos empregados na produção das micropartículas são classificados biodegradáveis ou não biodegradáveis, sendo os biodegradáveis mais utilizados por não necessitam ser removidos cirurgicamente após o término de sua ação. A produção das micropartículas poliméricas sintéticas para encapsulação tanto de ativos hidrofílicos quanto hidrofóbicos pode ser emulsificação por extração e/ou evaporação do solvente; coacervação; métodos mecânicos e estão revisados neste artigo evidenciando as vantagens, desvantagens e viabilidade de cada metodologia. A escolha da metodologia e do polímero sintético a serem empregados na produção desse sistema dependem da aplicação terapêutica requerida, bem como a simplicidade, reprodutibilidade e factibilidade do aumento de escala da produção.

Systemic and mucosal delivery of drugs within polymeric microparticles produced by spray drying

Encapsulation of therapeutic and diagnostic materials into polymeric particles is a means to protect and control or target the release of active substances such as drugs, vaccines, and genetic material. In terms of mucosal delivery, polymeric encapsulation can be used to promote absorption of the active substance, while particles can improve the half-life of drugs administered systemically. Spray drying is an attractive technology used to produce such microparticles, because it combines both the encapsulation and drying steps in a rapid, single-step operation. Even so, spray drying is not classically associated with processes used for drug and therapeutic material encapsulation, since elevated temperatures could potentially denature the active substance. However, a comprehensive review of the literature revealed a number of studies demonstrating that spray drying can be used to produce microparticulate formulations with labile therapeutics. Polymers commonly employed include synthetics such as methacrylic copolymers and polyesters, and natural materials including chitosan and alginate. Drugs and active substances are diverse and included antibiotics, anti-inflammatory agents, and chemotherapeutics. Regarding the delivery of spray-dried particles, the pulmonary, oral, colonic, and nasal mucosal routes are often investigated because they offer a convenient means of administration, which promotes physician and patient compliance. In addition, spray drying has been widely used to produce polymeric microparticles for systemic delivery in order to control the delivery of drugs, vaccines, or genetic material that may exhibit poor pharmacokinetic profiles or pose toxicity concerns. This review presents a brief introduction to the technology of spray drying and outlines the delivery routes and the applications of spray-dried polymeric microparticles.

Development of biodegradable polymer based tamoxifen citrate loaded nanoparticles and effect of some manufacturing process parameters on them: a physicochemical and in-vitro evaluation

The aim of the present study was to develop nanoparticles of tamoxifen citrate, a non-steroidal antiestrogenic drug used for the treatment of breast cancer. Biodegradable poly (D, L- lactide-co-glycolide)-85:15 (PLGA) was used to develop nanoparticles of tamoxifen citrate by multiple emulsification (w/o/w) and solvent evaporation technique. Drug-polymer ratio, polyvinyl alcohol concentrations, and homogenizing speeds were varied at different stages of preparation to optimize the desired size and release profile of drug. The characterization of particle morphology and shape was performed by field emission scanning electron microscope (FE-SEM) and particle size distribution patterns were studied by direct light scattering method using zeta sizer. In vitro drug release study showed that release profile of tamoxifen from biodegradable nanoparticles varied due to the change in speed of centrifugation for separation. Drug loading efficiency varied from 18.60% to 71.98%. The FE-SEM study showed that biodegradable nanoparticles were smooth and spherical in shape. The stability studies of tamoxifen citrate in the experimental nanoparticles showed the structural integrity of tamoxifen citrate in PLGA nanoparticles up to 60°C in the tested temperatures. Nanoparticles containing tamoxifen citrate could be useful for the controlled delivery of the drug for a prolonged period.

Polyelectrolyte complex of chondroitin sulfate and peptide with lower pI value in poly(lactide-co-glycolide) microsphere for stability and controlled release

A polyelectrolyte complex between a therapeutic peptide and chargeable polymer was applied to prevent peptide denaturation in poly(lactide-co-glycolide) (PLGA) microspheres. Chondroitin sulfate A (CsA) was employed as a polymeric additive for the formation of an ionic complex with insulin (InS). The complex prepared at pH 3.0 evidenced a nano-size in the range of 100-400 nm with a mono distribution. The stability of InS in the complex in an organic/water (O/W) interface was verified via RP-HPLC. The insulin in the complex evidenced a retention time almost identical to native InS, whereas free insulin did not evidence such a retention time. On the basis of these studies, PLGA microspheres including a complex with various CsA/InS ratios were prepared via a double-emulsion method (PLGA/CsA MS). InS loading efficiency in the system is higher than that of the microspheres without CsA. The system evidenced a lower initial burst and, following the initial burst, continuous release kinetics for 30 days. Circular dichroism (CD) spectra demonstrated that the insulin in PLGA/CsA MS is more stable than the PLGA-only microspheres (PLGA/only MS) for 20 days. These results indicate that the complex system with CsA is useful for the long-term delivery of peptides with lower pI values.

Glycol chitosan as a stabilizer for protein encapsulated into poly(lactide-co-glycolide) microparticle

Glycol chitosan (GC), a chitosan derivative conjugated with ethylene glycol, is soluble in water at a neutral/acidic pH and is viscous. This GC was incorporated into poly(lactide-co-glycolide) (PLGA) microparticles (prepared by the multi-emulsion W(1)/O/W(2) (water-in-oil-in-water) method) to stabilize lysozyme (Lys) used as a model protein. Herein, GC's viscous property helped to improve Lys encapsulation efficacy and reduce Lys denaturaton at the water/organic solvent interface. When the GC concentration in the W(1) phase increased, the formation of non-covalent Lys aggregates decreased. This may be because the aqueous microdroplets surrounded by the firm viscous interface protect Lys from the degrading environment formed by the water/organic solvent interface. In an in vitro Lys release test, 40mg incorporation of GC led to continuous Lys release of up to 78wt.% for 1 month and presented bioactivity of more than 95% for Lys released from microparticles. In addition, there was negligible immune response in the tissue treated with the GC-incorporated PLGA microparticles, whereas there was a moderate foreign body reaction in the muscle layer and many configurations of neutrophils in the tissue treated with the PLGA microparticles without GC. It is expected that GC facilitates a decrease in immune responses exacerbated as a consequence of PLGA degradation.

Protein complexed with chondroitin sulfate in poly(lactide-co-glycolide) microspheres

Chondroitin sulfate (CsA) is an acidic mucopolysaccharide, which is able to form ionic complexes with positively charged proteins. In this study, a protein-CsA complex was constructed to nano-sized particles. Zeta potential measurements revealed that a CsA-to-protein fraction of greater than 0.1 results in a neutralization of the positive charge on lysozyme (Lys). Based on this preliminary study, we have prepared poly(lactide-co-glycolide) (PLGA) microspheres harboring Lys/CsA complexes via the multi-emulsion method. Protein stability in the PLGA microspheres was preserved during both microsphere preparation and protein release. The profiles of Lys release from the PLGA microspheres evidenced nearly zero-order kinetics, depending on the quantity of CsA. An in vivo fluorescent image of experimental mouse tissue showed that the PLGA microspheres with the Lys/CsA complex had released the entirety of their Lys without no residual amount after 23 days, but microspheres without the complex harbored a great deal of residual Lys, which is attributable to its degradation by acidic PLGA degradates. The tissue reaction evidenced by the PLGA microspheres stabilized with CsA showed minimal foreign body reaction and little configuration of immune cells including neutrophils and macrophages, but the reactions of the PLGA microspheres without CsA were characterized by a relatively elevated inflammation. These results show that CsA is a viable candidate for long-acting micro-particular protein delivery.

Protein release behavior from porous microparticle with lysozyme/hyaluronate ionic complex

Porous microparticles (PMs) with a low density (<0.4 g/cm3) for pulmonary protein delivery were prepared by the water-in-oil-in-water (W1/O/W2) multi-emulsion method using a cyclodextrin derivative as a porogen. The complexation of positively charged lysozyme (Lys) and negative-charged hyaluronate (HA) was investigated for long-term protein release from PMs. The interaction of Lys and HA not only increased protein encapsulation efficiency but also stabilized Lys against a denaturing organic solvent (dichloromethane). Furthermore, PMs with Lys/HA complexes increased the Lys release period up to 7 days, as opposed to a 4h Lys release time from PMs without Lys/HA complexes. In particular, PMs containing 10mg of HA and 50mg of Lys showed almost zero-order Lys release kinetic for 7 days and preserved the bioactivity of Lys more than 98% during its entire release period. This result suggests that PMs with Lys/HA complexes may be applied in long-term pulmonary administration of protein or peptide drugs, including those that require particles to arrive at a deep lung epithelium with the help of low density (high porosity) of PMs.

Long acting porous microparticle for pulmonary protein delivery

This study investigated the porous-microparticle (PM) with low mass density and large size for pulmonary drug delivery. PM was prepared by the water-in-oil-in-water (W(1)/O/W(2)) multi-emulsion method with cyclodextrin derivative as a porogen and a stabilizer of peptide drugs. Herein, sucrose ethyl acetate (SAIB) was incorporated in PM for long acting protein release. In vitro release studies, the rapid release rate of proteins from PM was reduced due to the high viscosity of the added SAIB. As a result, BSA release from PM continued up to 7 days. This result suggests that PM having sustained release characteristics may be successfully applied for long-term pulmonary administration of protein or peptide drug. In addition, it is expected that these particles arrive at a deep lung epithelium due to low density (high porosity) and limit macrophage recognition because of big particle size (more than 5 microm).

Formulation of anastrozole microparticles as biodegradable anticancer drug carriers

The purpose of this study was to develop poly(d,l-lactic-co-glycolic acid) (PLGA)-based anastrozole microparticles for treatment of breast cancer. An emulsion/extraction method was used to prepare anastrozole sustained-release PLGA-based biodegradable microspheres. Gas chromatography with mass spectroscopy detection was used for the quantitation of the drug throughout the studies. Microparticles were formulated and characterized in terms of encapsulation efficiency, particle size distribution, surface morphology, and drug release profile. Preparative variables such as concentrations of stabilizer, drug-polymer ratio, polymer viscosity, stirring rate, and ratio of internal to external phases were found to be important factors for the preparation of anastrozole-loaded PLGA microparticles. Fourier transform infrared with attenuated total reflectance (FTIR-ATR) analysis and differential scanning calorimetry (DSC) were employed to determine any interactions between drug and polymer. An attempt was made to fit the data to various dissolution kinetics models for multiparticulate systems, including the zero order, first order, square root of time kinetics, and biphasic models. The FTIR-ATR studies revealed no chemical interaction between the drug and the polymer. DSC results indicated that the anastrozole trapped in the microspheres existed in an amorphous or disordered-crystalline status in the polymer matrix. The highest correlation coefficients were obtained for the Higuchi model, suggesting a diffusion mechanism for the drug release. The results demonstrated that anastrozole microparticles with PLGA could be an alternative delivery method for the long-term treatment of breast cancer.