23 research outputs found
Physicochemical characterization of polysaccharides extracted from sesame leaves: a potential matrix for sustained release tablets
Purpose
In the developing world the pharmaceutical sector depends heavily on imported raw materials which elevate the cost of
medicines beyond the reach of the majority of the local population; despite often being rich in renewable sources which could
be used as excipients. In this study we have extracted and characterised a largely undeveloped polysaccharide, sesamum gum,
with a view to application as an alternative pharmaceutical excipient.
Methods
Polysaccharide from the leaves of Sesamum indicum was extracted by maceration in distilled water followed by precipitation
in absolute ethanol. The material was oven dried and milled to a particle size of 250 m. The resulting material was
characterized using X-ray diffractometry (XRD), Fourier transform infra-red spectroscopy, differential scanning calorimetry
and thermogravimetric analysis. The total carbohydrate content, protein content and intrinsic viscosity of the extracted gum
were determined according to standard protocols. Constituent sugar analysis of the material was determined by high
performance anion exchange chromatography after hydrolysis of the samples using 2M trifluoroacetic acid for 3 hours.
Compaction studies were carried out using a Testometric materials testing machine and data analysed by Heckel analysis.
Results
The polysaccharide gum had a total carbohydrate content of 98.1% and protein content of 1.7%. XRD spectra were typical of
an amorphous material with a maximum decomposition temperature of 266.7 °C. Intrinsic viscosity was determined to be
approximately 3.31 and 4.40 dl/g in 0.1 M NaCl and deionized water respectively. Dispersions of the polysaccharide are
viscoelastic and exhibit shear-thinning behaviour. The polysaccharide contains fucose (0.1%), rhamnose (1.1%), arabinose
(2.8%), galactose (48.9%), glucose (2.7%), mannose (6.8%) and xylose (33.6%) as neutral sugars, and glucuronic acid
(3.0%) and galacturonic acid (1.1%) as acid sugars. Heckel analysis indicates that sesamum consolidates plastically having
mean yield pressure of 131.45 MPa.
Conclusion
Sesamum polysaccharide is typically amorphous with a low content of uronic acids. Results suggest it is a thermally stable,
high molecular weight polymer which exhibits shear-thinning behaviour in the hydrated form. The polymer in the dry state is
a highly compactable material which has the potential to be exploited as a matrix former in sustained release tablets
Eudragit E100 and Polysaccharide Polymer Blends as Matrices for Modified-Release Drug Delivery I: Physicomechanical Properties
Purpose: To compare the effects of two states of polymer/polymer blending (dry and aqueous/lyophilized) on the physicomechanical properties of tablets, containing blends of locust bean gum (LB) with Eudragit® E100 (E100) and sodium carboxymethylcellulose (SCMC) as matrices.Methods: LB, SCMC and E100 were blended in their dry (as purchased) state or modified by aqueous blending and subsequent lyophilization, prior to use as matrices in tablets. The polymer blends were characterized by infra-red spectroscopy (FTIR), flow and compressibility tests, as well as physicomechanical analysis of their tablets.Results: No significant variations were noticeable in the FTIR peaks of the individual polymers in the dry and the aqueous/lyophilized states. Aqueous/lyophilized blending of the polymers resulted in better flow properties. The aqueous/lyophilized matrices were denser with improved mechanical strength and the tablets were harder than those produced from dry blended polymers.Conclusion: Dry blending of LB with E100 and SCMC greatly improved the physicomechanical properties of the tablets. This was further enhanced by aqueous/lyophilized blending.Keywords: Drug delivery, Polymer blend, Eudragit, Locust bean gum, Levodopa, Sodium carboxymethylcellulose, Matrix, Physicomechanical propertie
Eudragit E100 and Polysaccharide Polymer Blends as Matrices for Modified-Release Drug Delivery II: Swelling and Release Studies
Purpose: To compare the effects of two states of polymer/polymer blending (dry and aqueous/lyophilized) of locust bean gum with Eudragit® E100 and sodium carboxymethylcellulose on swelling and drug (levodopa) release from their tablet matrices.Methods: Sodium carboxymethylcellulose (SCMC), Eudragit® (E100) and locust bean (LB) were blended in their dry (as purchased) state or modified by aqueous blending and subsequent lyophilization prior to use as tablet matrices. The tablets were evaluated for swelling and in vitro drug release. Furthermore, in vivo absorption was predicted from the in vitro release data by convolution method.Results: E100 matrices exhibited little or no swelling while the matrices of SCMC and LB and their blends exhibited a degree of swelling > 180 %. Aqueous blending and lyophilization modulated the rate of release from matrices formulated with LB, SCMC and their polymer/polymer blends. Drug release profiles of the lyophilized polymer/polymer blends matrices were dissimilar to those of the dry polymer/polymer blends. Formulations F1aq, F2aq and F3aq exhibited fairly uniform absorption in the first 8 h, indicating the possibility of producing a steady delivery of drug.Conclusion: Polymer blending of LB, SCMC and E100, achieved by aqueous blending and lyophilization, enhances the performance of the matrices thereby exhibiting controlled levodopa release with no burst effect and the tablets retained their three-dimensional network.Keywords: Controlled release, Drug delivery, Eudragit, Locust bean, Levodopa, Matrix, Polymer blend, Sodium carboxymethylcellulos
Ex vivo and In vivo characterization of interpolymeric blend/nanoenabled gastroretentive levodopa delivery systems
One approach for delivery of narrow absorption window drugs is to formulate gastroretentive drug delivery systems. This study was undertaken to provide insight into in vivo performances of two gastroretentive systems (PXLNET and IPB matrices) in comparison to Madopar® HBS capsules. The pig model was used to assess gastric residence time and pharmacokinetic parameters using blood, cerebrospinal fluid (CSF), and urine samples. Histopathology and cytotoxicity testing were also undertaken. The pharmacokinetic parameters indicated that levodopa was liberated from the drug delivery systems, absorbed, widely distributed, metabolized, and excreted. were 372.37, 257.02, and 461.28 ng/mL and MRT were 15.36, 14.98, and 13.30 for Madopar HBS capsules, PXLNET, and IPB, respectively. In addition, X-ray imaging indicated that the gastroretentive systems have the potential to reside in the stomach for 7 hours. There was strong in vitro-in vivo correlation for all formulations with values of 0.906, 0.935, and 0.945 for Madopar HBS capsules, PXLNET, and IPB, respectively. Consequently, PXLNET and IPB matrices have pertinent potential as gastroretentive systems for narrow absorption window drugs (e.g., L-dopa) and, in this application specifically, enhanced the central nervous system and/or systemic bioavailability of such drugs.The National Research Foundation
(NRF) of South Africahttps://www.hindawi.com/journals/pdam2017Paraclinical Science
Natural Polymers in Micro- and Nanoencapsulation for Therapeutic and Diagnostic Applications: Part I: Lipids and Fabrication Techniques
Encapsulation, specifically microencapsulation is an old technology with increasing applications in pharmaceutical, agrochemical, environmental, food, and cosmetic spaces. In the past two decades, the advancements in the field of nanotechnology opened the door for applying the encapsulation technology at the nanoscale level. Nanoencapsulation is highly utilized in designing effective drug delivery systems (DDSs) due to the fact that delivery of the encapsulated therapeutic/diagnostic agents to various sites in the human body depends on the size of the nanoparticles. Compared to microencapsulation, nanoencapsulation has superior performance which can improve bioavailability, increase drug solubility, delay or control drug release and enhance active/passive targeting of bioactive agents to the sites of action. Encapsulation, either micro- or nanoencapsulation is employed for the conventional pharmaceuticals, biopharmaceuticals, biologics, or bioactive drugs from natural sources as well as for diagnostics such as biomarkers. The outcome of any encapsulation process depends on the technique employed and the encapsulating material. This chapter discusses in details (1) various physical, mechanical, thermal, chemical, and physicochemical encapsulation techniques, (2) types and classifications of natural polymers (polysaccharides, proteins, and lipids) as safer, biocompatible and biodegradable encapsulating materials, and (3) the recent advances in using lipids for therapeutic and diagnostic applications. Polysaccharides and proteins are covered in the second part of this chapter
Natural Polymers in Micro- and Nanoencapsulation for Therapeutic and Diagnostic Applications: Part II - Polysaccharides and Proteins
Encapsulation remains a fundamental and consistent approach of fabrication of drug and diagnostic delivery systems in the health space and natural polymers such as polysaccharides and proteins continue to play significant roles. Micro- or nanoencapsulation is employed for the conventional pharmaceuticals, biopharmaceuticals, or biologics, bioactives from natural sources and diagnostics such as biomarkers. The outcome of any encapsulation depends on the technique employed and the encapsulating material. The encapsulating materials employed influence the physical and chemical attributes of the fabricated micro- and nanocapsules. The encapsulating materials could be natural or synthetic, however, natural polymers are preferred because they are human and environmentally friendly. Polysaccharides and proteins are abundant in nature, biogenic, biocompatible, biodegradable and possess biological functions making them materials of choice for encapsulation of drugs and diagnostics. This chapter reviews the recent and advanced applications of polysaccharides and proteins as nanocarrier materials for micro- and nanoencapsulation of therapeutics and diagnostics
Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery
Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.8–43.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery
Naturapolyceutics: The Science of Utilizing Natural Polymers for Drug Delivery
Naturapolyceutics defines the emerging science and technology platform that blends natural polymers and pharmaceutics for the design and development of drug delivery systems. Natural polymers due to their biological properties, sustainability, chemical flexibility, human and eco-friendliness are promising in this field. As drug delivery advances, there will be need for more polymers. Given that polymers utilized in pharmaceuticals require regulatory approval, robust processes are undertaken to facilitate the production of pharmaceutical grade natural polymers. This review provides insight into the processes—extraction, purification, modifications and characterizations—involved in the eventual utilization of natural polymers for drug delivery. The versatility of natural polymers and particularly modified natural polymers in targeted drug delivery, micro-/nano-drug delivery, theranostics, BioMEMs and generally in research and development of highly efficient, safe and quality products is demonstrated. Natural polymers are polymers of today and tomorrow. Therefore, the shift to undertake training, extensive research and subsequent commercialization of more natural polymers—novel and underutilized—for drug delivery is now
Nanotechnology and Drug Delivery Part 2: Nanostructures for Drug Delivery
This is the second part of a review on nanotechnology in general and
particularly as it pertains to drug deliver. In the earlier paper (Part
1), nanotechnology in nature, its history as well as design and methods
were discussed. Its applications, benefits and risks were also
outlined. In this paper (Part 2), various nanostructures employed in
drug delivery, their methods of fabrication and challenges of nano drug
delivery are reviewed. Nanotechnology is one approach to overcome
challenges of conventional drug delivery systems based on the
development and fabrication of nanostructures. Some challenges
associated with the technology as it relates to drug effectiveness,
toxicity, stability, pharmacokinetics and drug regulatory control are
discussed in this review. Clearly, nanotechnology is a welcome
development that is set to transform drug delivery and drug supply
chain management, if optimally developed