Pub Date : 2008-05-15DOI: 10.2174/1874126600802010033
S. Qureshi
Often the quality of drug products is evaluated based on chemical tests, commonly described in different phar- macopeias such as the USP. These tests includes: assay (potency), uniformity of dosage form and dissolution test. Pres- ently, these tests are conducted separately with three procedures. Furthermore, dissolution tests are also conducted using multiple product-specific procedures. This makes the current practice of evaluation of the quality of pharmaceutical prod- ucts complex and resource (human and financial) intensive. Recently a new improved dissolution methodology, based on a modified spindle known as crescent-shaped spindle, has been proposed. Using the proposed methodology, all these tests may be conducted based on a single dissolution test procedure. Such an approach would, therefore, provide a simpler al- ternative to the current practice with significant economical benefits. The attributes of the proposed approach which lead to the concept of product evaluation based on a single dissolution test procedure, are described here by testing a number of diltiazem products having different strengths and release characteristics. The quality of drug products is evaluated based on chemical tests commonly described in different pharmacope- ias such as USP. In general tests are conducted to establish presence of the expected amount of drug in the product (po- tency), uniformity or consistency of drug content in a prod- uct, such as, from tablet to tablet, and expected drug dissolu- tion or release characteristics of a product. At present, these tests are conducted separately with at least three procedures. A new spindle known as crescent-shaped spindle has been proposed for improved drug dissolution testing (1-3). The superiority of the new spindle appears to be due to its effi- cient extraction ability, because of improved product- medium interaction in the dissolution vessel. It may be ar- gued that as all the above mentioned tests are based on the extraction of drug from a product, the new approach based on the new spindle may provide a common approach for these tests. This would provide a simpler alternative to the current practice, with a significant economical benefit. This article provides a discussion and experimental evi- dence showing that a simpler and more relevant testing ap- proach based on dissolution testing may be used for an over- all evaluation of the quality of pharmaceutical products.
{"title":"A Simple and Economical Approach/Concept to Evaluate Quality of Pharmaceutical Products Based on an Improved Dissolution Testing Methodology","authors":"S. Qureshi","doi":"10.2174/1874126600802010033","DOIUrl":"https://doi.org/10.2174/1874126600802010033","url":null,"abstract":"Often the quality of drug products is evaluated based on chemical tests, commonly described in different phar- macopeias such as the USP. These tests includes: assay (potency), uniformity of dosage form and dissolution test. Pres- ently, these tests are conducted separately with three procedures. Furthermore, dissolution tests are also conducted using multiple product-specific procedures. This makes the current practice of evaluation of the quality of pharmaceutical prod- ucts complex and resource (human and financial) intensive. Recently a new improved dissolution methodology, based on a modified spindle known as crescent-shaped spindle, has been proposed. Using the proposed methodology, all these tests may be conducted based on a single dissolution test procedure. Such an approach would, therefore, provide a simpler al- ternative to the current practice with significant economical benefits. The attributes of the proposed approach which lead to the concept of product evaluation based on a single dissolution test procedure, are described here by testing a number of diltiazem products having different strengths and release characteristics. The quality of drug products is evaluated based on chemical tests commonly described in different pharmacope- ias such as USP. In general tests are conducted to establish presence of the expected amount of drug in the product (po- tency), uniformity or consistency of drug content in a prod- uct, such as, from tablet to tablet, and expected drug dissolu- tion or release characteristics of a product. At present, these tests are conducted separately with at least three procedures. A new spindle known as crescent-shaped spindle has been proposed for improved drug dissolution testing (1-3). The superiority of the new spindle appears to be due to its effi- cient extraction ability, because of improved product- medium interaction in the dissolution vessel. It may be ar- gued that as all the above mentioned tests are based on the extraction of drug from a product, the new approach based on the new spindle may provide a common approach for these tests. This would provide a simpler alternative to the current practice, with a significant economical benefit. This article provides a discussion and experimental evi- dence showing that a simpler and more relevant testing ap- proach based on dissolution testing may be used for an over- all evaluation of the quality of pharmaceutical products.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129983334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-04-29DOI: 10.2174/1874126600802010026
A. Stancampiano, G. Puglisi, R. Pignatello
A series of aliphatic esters of the NSAID naproxen (NAP) were synthesised and encapsulated in solid lipid nanoparticles (SLN) to evaluate the influence of lipophilicity on drug loading and release, as well as physicochemical properties and stability of SLN. The lipophilicity of esters mainly showed to influence their affinity for the solid lipid matrix, modifying the drug release profile compared to the parent drug, whereas drug encapsulation efficiency and the technological properties and stability of SLN were not affected. After storage at room temperature the in vitro release profiles of esters changed with respect to freshly prepared systems, depending on the lipophilicity of the dispersed derivative. In particular, the SLN containing the medium-chain hexyl and octyl esters showed a 70-80% increase of drug release after storage; SLN loaded with NAP or the lower ethyl and butyl esters did not show significant changes in the drug release rate. Such findings reveal that the affinity of NAP esters for the lipid network of the nanoparticles is strongly dependent on their lipophilicity and an excessive increase of the latter negatively influences the allocation and retention on these com- pounds in the nanoparticles.
{"title":"Effect of Lipophilicity of Dispersed Drugs on the Physicochemical and Technological Properties of Solid Lipid Nanoparticles","authors":"A. Stancampiano, G. Puglisi, R. Pignatello","doi":"10.2174/1874126600802010026","DOIUrl":"https://doi.org/10.2174/1874126600802010026","url":null,"abstract":"A series of aliphatic esters of the NSAID naproxen (NAP) were synthesised and encapsulated in solid lipid nanoparticles (SLN) to evaluate the influence of lipophilicity on drug loading and release, as well as physicochemical properties and stability of SLN. The lipophilicity of esters mainly showed to influence their affinity for the solid lipid matrix, modifying the drug release profile compared to the parent drug, whereas drug encapsulation efficiency and the technological properties and stability of SLN were not affected. After storage at room temperature the in vitro release profiles of esters changed with respect to freshly prepared systems, depending on the lipophilicity of the dispersed derivative. In particular, the SLN containing the medium-chain hexyl and octyl esters showed a 70-80% increase of drug release after storage; SLN loaded with NAP or the lower ethyl and butyl esters did not show significant changes in the drug release rate. Such findings reveal that the affinity of NAP esters for the lipid network of the nanoparticles is strongly dependent on their lipophilicity and an excessive increase of the latter negatively influences the allocation and retention on these com- pounds in the nanoparticles.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132235031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-13DOI: 10.2174/1874126600802010020
H. Onishi, K. Kume, Ken-ichi Koyama, Y. Machida
The degree of deacetylation and molecular weight of carboxymethyl-chitin (CM) were manipulated using 10% (w/v) NaOH aqueous solution at 25˚C and 5 M HCl aqueous solution at 40˚C, respectively. The resultant CMs were char- acterized by 1 H-NMR spectroscopy and size exclusion chromatography/multi-angle light scattering. The degree of deace- tylation of 7 - 35% (mol/mol) and molecular weight of 43,000 - 449,000 were achieved. Nanoparticles were prepared us- ing W/O emulsification and amide coupling. Nanoparticles with the size of less than 400 nm were obtained using CM with a high degree of deacetylation and low molecular weight, CM48-L. When the mixture of CM-mitomycin C conjugate and CM48-L underwent W/O emulsification and amide coupling, nanoparticles with the size of ca. 350 nm were obtained, and released mitomycin C fairly fast but gradually. CM with a high degree of deacetylation and low molecular weight was suggested to be useful for the production of CM nanoparticles.
{"title":"Preparation of Carboxymethyl-chitin Nanoparticles by Covalent Crosslinking and Their In Vitro Evaluation","authors":"H. Onishi, K. Kume, Ken-ichi Koyama, Y. Machida","doi":"10.2174/1874126600802010020","DOIUrl":"https://doi.org/10.2174/1874126600802010020","url":null,"abstract":"The degree of deacetylation and molecular weight of carboxymethyl-chitin (CM) were manipulated using 10% (w/v) NaOH aqueous solution at 25˚C and 5 M HCl aqueous solution at 40˚C, respectively. The resultant CMs were char- acterized by 1 H-NMR spectroscopy and size exclusion chromatography/multi-angle light scattering. The degree of deace- tylation of 7 - 35% (mol/mol) and molecular weight of 43,000 - 449,000 were achieved. Nanoparticles were prepared us- ing W/O emulsification and amide coupling. Nanoparticles with the size of less than 400 nm were obtained using CM with a high degree of deacetylation and low molecular weight, CM48-L. When the mixture of CM-mitomycin C conjugate and CM48-L underwent W/O emulsification and amide coupling, nanoparticles with the size of ca. 350 nm were obtained, and released mitomycin C fairly fast but gradually. CM with a high degree of deacetylation and low molecular weight was suggested to be useful for the production of CM nanoparticles.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130685909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-02-26DOI: 10.2174/1874126600802010010
M. Tungjai, Wilart Poompimon, C. Loetchutinat, S. Kothan, N. Dechsupa, S. Mankhetkorn
The objectives of this study were to investigate the behavior of flavonoids in an aqueous physiological buffer and to determine the structural and functional group substitution which is responsible for their anticancer action. The de- protonated anionic form of 7 flavonoids can easily be determined using spectrophotometry, and owing to its charged state, is highly soluble in aqueous physiological buffer and is not prone to aggregation. The protonated form of these 7 flavon- oids is much less soluble and tends to aggregate following precipitation. For all flavonoids studied except catechin and 5,5� -dihydroxy-6,7,3� ,4� -tetramethoxyflavone, it was possible to determine the rates of deprotonation; pKa value of eri- odictyol, apigenin, kaempferol, quercetin, WP 279, and WP 283 was equal to 7.00, 8.72, 7.86, 8.30, 7.70 and 9.90, respec- tively. The methoxyl group substitutions in place of hydrogen atoms and/or hydroxyl groups at various positions of car- bon atoms in ring A, B and C particularly WP 283 resulted in an increase in the solubility, lipophilicity, and specifically its anticancer efficacy (by 60-fold). The neutral forms of flavonoids are predominantly active molecules and the active sites responsible for anticancer activity are found in ring A and C, especially C4=O, C5-OH and C2=C3.
{"title":"Spectrophotometric Characterization of Behavior and the Predominant Species of Flavonoids in Physiological Buffer: Determination of Solubility, Lipophilicity and Anticancer Efficacy","authors":"M. Tungjai, Wilart Poompimon, C. Loetchutinat, S. Kothan, N. Dechsupa, S. Mankhetkorn","doi":"10.2174/1874126600802010010","DOIUrl":"https://doi.org/10.2174/1874126600802010010","url":null,"abstract":"The objectives of this study were to investigate the behavior of flavonoids in an aqueous physiological buffer and to determine the structural and functional group substitution which is responsible for their anticancer action. The de- protonated anionic form of 7 flavonoids can easily be determined using spectrophotometry, and owing to its charged state, is highly soluble in aqueous physiological buffer and is not prone to aggregation. The protonated form of these 7 flavon- oids is much less soluble and tends to aggregate following precipitation. For all flavonoids studied except catechin and 5,5� -dihydroxy-6,7,3� ,4� -tetramethoxyflavone, it was possible to determine the rates of deprotonation; pKa value of eri- odictyol, apigenin, kaempferol, quercetin, WP 279, and WP 283 was equal to 7.00, 8.72, 7.86, 8.30, 7.70 and 9.90, respec- tively. The methoxyl group substitutions in place of hydrogen atoms and/or hydroxyl groups at various positions of car- bon atoms in ring A, B and C particularly WP 283 resulted in an increase in the solubility, lipophilicity, and specifically its anticancer efficacy (by 60-fold). The neutral forms of flavonoids are predominantly active molecules and the active sites responsible for anticancer activity are found in ring A and C, especially C4=O, C5-OH and C2=C3.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114716624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-02-20DOI: 10.2174/1874126600802010001
F. Wang, Y. Chen, H. Benson
The primary objective of this study was to develop a particulate formulation for peptide delivery that would provide enhanced peptide stability, controlled release and the potential for targeting to specific tissues. Biodegradable hy- drophobic particles were prepared from poly (D,L-lactide-co-glycolide) (PLGA) by both solvent evaporation and solvent diffusion methods. Bovine insulin was chosen as a model peptide for formulation development and evaluation. By form- ing a complex between insulin and protamine, 50% incorporation of the model peptide in PLGA particles was achieved and a sustained release of insulin was observed over one week with improved stability of insulin in the PLGA matrix. The formation of an insulin-protamine complex and the method of manufacture are important determinants of the physico- chemical characteristics of the particles formed. Preliminary evaluation of the deposition of the particles within skin was determined by fluorescent images following topical application to excised human skin. Microparticles with size above 7 μm remained on the surface of the skin. Nanoparticles (<1 μm) showed permeation into the viable epidermis and dermis with deposition concentrated around the hair follicles and sebaceous glands.
本研究的主要目的是开发一种颗粒制剂用于肽递送，该制剂将提供增强的肽稳定性，控制释放和靶向特定组织的潜力。以聚(D, l -丙交酯-羟基乙酸酯)(PLGA)为原料，采用溶剂蒸发法和溶剂扩散法制备了可生物降解的疏水颗粒。选择牛胰岛素作为模型肽进行配方开发和评价。通过在胰岛素和鱼精蛋白之间形成复合物，模型肽在PLGA颗粒中掺入了50%，并在一周内观察到胰岛素的持续释放，胰岛素在PLGA基质中的稳定性得到改善。胰岛素-鱼精蛋白复合物的形成和制造方法是形成的颗粒的物理化学特性的重要决定因素。在局部应用于切除的人体皮肤后，通过荧光图像确定了颗粒在皮肤内沉积的初步评估。7 μm以上的微颗粒残留在皮肤表面。纳米颗粒(<1 μm)可渗透到活的表皮和真皮中，并集中沉积在毛囊和皮脂腺周围。
{"title":"Formulation of Nano and Micro PLGA Particles of the Model Peptide Insulin: Preparation, Characterization, Stability and Deposition in Human Skin","authors":"F. Wang, Y. Chen, H. Benson","doi":"10.2174/1874126600802010001","DOIUrl":"https://doi.org/10.2174/1874126600802010001","url":null,"abstract":"The primary objective of this study was to develop a particulate formulation for peptide delivery that would provide enhanced peptide stability, controlled release and the potential for targeting to specific tissues. Biodegradable hy- drophobic particles were prepared from poly (D,L-lactide-co-glycolide) (PLGA) by both solvent evaporation and solvent diffusion methods. Bovine insulin was chosen as a model peptide for formulation development and evaluation. By form- ing a complex between insulin and protamine, 50% incorporation of the model peptide in PLGA particles was achieved and a sustained release of insulin was observed over one week with improved stability of insulin in the PLGA matrix. The formation of an insulin-protamine complex and the method of manufacture are important determinants of the physico- chemical characteristics of the particles formed. Preliminary evaluation of the deposition of the particles within skin was determined by fluorescent images following topical application to excised human skin. Microparticles with size above 7 μm remained on the surface of the skin. Nanoparticles (<1 μm) showed permeation into the viable epidermis and dermis with deposition concentrated around the hair follicles and sebaceous glands.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124660317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-30DOI: 10.2174/1874126600701010036
D. I. Morrow, P. McCarron, A. Woolfson, R. Donnelly
Abstact: Historically, the skin was thought to be a simple homogenous barrier. However, it is now known to be a highly specialised organ, and plays a key role in homeostasis. The protective properties of the skin are provided by the outermost layer, the epidermis, which safeguards against chemical, microbial, and physical attack. The exceptional barrier properties of the skin result in it being a challenging route for the delivery of therapeutic agents. This article reviews strategies developed to enhance the skin penetration of drugs, ranging from conventional approaches, for example the use of chemical penetration enhancers to those in early-stage development, such as microscissioning.
{"title":"Innovative Strategies for Enhancing Topical and Transdermal Drug Delivery","authors":"D. I. Morrow, P. McCarron, A. Woolfson, R. Donnelly","doi":"10.2174/1874126600701010036","DOIUrl":"https://doi.org/10.2174/1874126600701010036","url":null,"abstract":"Abstact: Historically, the skin was thought to be a simple homogenous barrier. However, it is now known to be a highly specialised organ, and plays a key role in homeostasis. The protective properties of the skin are provided by the outermost layer, the epidermis, which safeguards against chemical, microbial, and physical attack. The exceptional barrier properties of the skin result in it being a challenging route for the delivery of therapeutic agents. This article reviews strategies developed to enhance the skin penetration of drugs, ranging from conventional approaches, for example the use of chemical penetration enhancers to those in early-stage development, such as microscissioning.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116170196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-30DOI: 10.2174/1874126600701010068
Chiara Zaino, Y. Zambito, G. Mollica, M. Geppi, M. F. Serafini, V. Carelli, G. Colo
This work was aimed at preparing and evaluating a physically crosslinked hydrogel for the controlled release of diverse drugs to the distal intestine. A solution of fluorescein isothiocyanate dextran, MW 4400 Da (FD4), or a dispersion of micronized dexamethasone (DMS) was microencapsulated into a PEC hydrogel, composed of polycationic N-trimethyl chitosan (TMC) and polyanionic N-carboxymethyl chitosan (CMCh). A fine spray of a 1% CMCh solution containing 1% FD4 in solution or 0.1% DMS in dispersion was directed into a 2% TMC solution, then the resulting microcapsules (MCPS) were lyophilized. MCPS were analyzed by SEM and solid-state NMR. Drug release from MCPS was too fast, so these were compressed into matrices (weight 20 mg; diameter 6 mm; drug load 2.5%, with FD4, or 3.7%, with DMS) which were enteric coated. Drug release from matrices was studied simulating matrix transit across GI environments of different pHs, from stomach to proximal colon. The enteric film hindered release in stomach and proximal small intestine. After film dissolution at ileum pH, release occurred with a pattern described by the Peppas equation (n=0.6, with DMS; n=0.7, with FD4). As the pH changed from 7.4 to 6 (from ileum to ascending colon) MCPS were liberated from matrix surface. This phenomenon sustained the release rate. The present MCPS allow controlled doses of macromolecular or mi- croparticulate drugs being uniformly loaded into controlled-release matrices based on a physically crosslinked, biodegrad- able hydrogel.
{"title":"A novel polyelectrolyte complex (PEC) hydrogel for controlled drug delivery to the distal intestine","authors":"Chiara Zaino, Y. Zambito, G. Mollica, M. Geppi, M. F. Serafini, V. Carelli, G. Colo","doi":"10.2174/1874126600701010068","DOIUrl":"https://doi.org/10.2174/1874126600701010068","url":null,"abstract":"This work was aimed at preparing and evaluating a physically crosslinked hydrogel for the controlled release of diverse drugs to the distal intestine. A solution of fluorescein isothiocyanate dextran, MW 4400 Da (FD4), or a dispersion of micronized dexamethasone (DMS) was microencapsulated into a PEC hydrogel, composed of polycationic N-trimethyl chitosan (TMC) and polyanionic N-carboxymethyl chitosan (CMCh). A fine spray of a 1% CMCh solution containing 1% FD4 in solution or 0.1% DMS in dispersion was directed into a 2% TMC solution, then the resulting microcapsules (MCPS) were lyophilized. MCPS were analyzed by SEM and solid-state NMR. Drug release from MCPS was too fast, so these were compressed into matrices (weight 20 mg; diameter 6 mm; drug load 2.5%, with FD4, or 3.7%, with DMS) which were enteric coated. Drug release from matrices was studied simulating matrix transit across GI environments of different pHs, from stomach to proximal colon. The enteric film hindered release in stomach and proximal small intestine. After film dissolution at ileum pH, release occurred with a pattern described by the Peppas equation (n=0.6, with DMS; n=0.7, with FD4). As the pH changed from 7.4 to 6 (from ileum to ascending colon) MCPS were liberated from matrix surface. This phenomenon sustained the release rate. The present MCPS allow controlled doses of macromolecular or mi- croparticulate drugs being uniformly loaded into controlled-release matrices based on a physically crosslinked, biodegrad- able hydrogel.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127349839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-11-09DOI: 10.2174/1874126600701010060
D. Zeiss, A. Bauer-Brandl
A method for repeatable loading of propranolol hydrochloride as a model drug onto the ion exchanger Amber- lite TM IRP69 was developed and different parameters for the loading process were evaluated due to their impact of the ex- tent of loading. It was found that the extent of loading in equilibrium is widely independent of the experimental method used. However, a magnetic stirrer comminutes the ion exchanger particles, which hampers repeatable loading processes. For kinetic studies, it was found that the pharmacopoeia dissolution tester gives best repeatable results compared to other stirring devices (magnetic stirrer or shaking bath). Furthermore, evaluation of the loading profiles revealed complex kinet- ics, which can be best described by (at least) two independent processes. In addition, with different ratios between ion ex- changer and propranolol, the degree of loading in the equilibrium follows an adsorption isotherm of the Langmuir type, and predicts loading capacity.
建立了一种以盐酸心得安为模型药物的离子交换剂Amber- lite TM IRP69可重复上样的方法，并考察了不同上样参数对上样量的影响。研究发现，平衡加载的程度与所采用的实验方法在很大程度上无关。然而，磁性搅拌器将离子交换器颗粒粉碎，这阻碍了可重复的加载过程。对于动力学研究，发现与其他搅拌装置(磁力搅拌器或摇浴)相比，药典溶出度测试仪提供了最好的可重复性结果。此外，加载剖面的评估揭示了复杂的动力学，这可以用(至少)两个独立的过程来最好地描述。此外，当离子交换剂与心得安的比例不同时，平衡态的负载程度遵循Langmuir型吸附等温线，并预测了负载容量。
{"title":"Ion Exchange Resins as Excipients for Drug Delivery: Issues for Reproducible Drug Loading","authors":"D. Zeiss, A. Bauer-Brandl","doi":"10.2174/1874126600701010060","DOIUrl":"https://doi.org/10.2174/1874126600701010060","url":null,"abstract":"A method for repeatable loading of propranolol hydrochloride as a model drug onto the ion exchanger Amber- lite TM IRP69 was developed and different parameters for the loading process were evaluated due to their impact of the ex- tent of loading. It was found that the extent of loading in equilibrium is widely independent of the experimental method used. However, a magnetic stirrer comminutes the ion exchanger particles, which hampers repeatable loading processes. For kinetic studies, it was found that the pharmacopoeia dissolution tester gives best repeatable results compared to other stirring devices (magnetic stirrer or shaking bath). Furthermore, evaluation of the loading profiles revealed complex kinet- ics, which can be best described by (at least) two independent processes. In addition, with different ratios between ion ex- changer and propranolol, the degree of loading in the equilibrium follows an adsorption isotherm of the Langmuir type, and predicts loading capacity.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"266 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133784414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-09-28DOI: 10.2174/1874126600701010028
R. Raffin, L. M. Colomé, E. Schapoval, D. S. Jornada, A. Pohlmann, S. Guterres
The aim of the present work was to verify the in vivo capacity of pantoprazole-loaded microparticles to protect the gastric mucosa against ulcer formation and to evaluate their stability under accelerated conditions. Pantoprazole- loaded microparticles were prepared by spray-drying in pilot scale, using Eudragit ® S100 as polymer. Transparent glass vials containing drug-loaded microparticles were stored for 6 months at 40°C and 75% RH. Photostability was tested un- der UVA light. Ulcers were induced by the oral administration of absolute ethanol to rats. Sodium bicarbonate solution, pantoprazole solution and drug-loaded microparticles were tested. Regarding the drug content during the accelerate stabil- ity study, samples showed complete encapsulation efficiency and were considered stable. The microencapsulation of pan- toprazole reduced its photodegradation. The in vivo evaluation showed that the microparticles presented ulcer index lower than the solutions. Enteric microparticles had acceptable stability under accelerated conditions and were efficient in pro- tecting the stomach against ulceration caused by ethanol.
{"title":"Gastro-Resistant Microparticles Containing Sodium Pantoprazole: Stability Studies and In Vivo Anti-Ulcer Activity","authors":"R. Raffin, L. M. Colomé, E. Schapoval, D. S. Jornada, A. Pohlmann, S. Guterres","doi":"10.2174/1874126600701010028","DOIUrl":"https://doi.org/10.2174/1874126600701010028","url":null,"abstract":"The aim of the present work was to verify the in vivo capacity of pantoprazole-loaded microparticles to protect the gastric mucosa against ulcer formation and to evaluate their stability under accelerated conditions. Pantoprazole- loaded microparticles were prepared by spray-drying in pilot scale, using Eudragit ® S100 as polymer. Transparent glass vials containing drug-loaded microparticles were stored for 6 months at 40°C and 75% RH. Photostability was tested un- der UVA light. Ulcers were induced by the oral administration of absolute ethanol to rats. Sodium bicarbonate solution, pantoprazole solution and drug-loaded microparticles were tested. Regarding the drug content during the accelerate stabil- ity study, samples showed complete encapsulation efficiency and were considered stable. The microencapsulation of pan- toprazole reduced its photodegradation. The in vivo evaluation showed that the microparticles presented ulcer index lower than the solutions. Enteric microparticles had acceptable stability under accelerated conditions and were efficient in pro- tecting the stomach against ulceration caused by ethanol.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"192 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126393348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-07-31DOI: 10.2174/1874126600701010020
T. Urakami, N. Oku
In the past decade, therapeutic potential of RNA interference (RNAi) and its application to human diseases were widely discussed in the related fields of biology, medical sciences, and pharmaceutical sciences. In course of these research and developing processes, efficient transduction of small interfering RNA (siRNA) into target cells is one of the most significant breakthroughs in revealing the feasibility of siRNA-mediated therapies. From the aspect of new siRNA derived drug development, drug delivery system (DDS) holds the key to success. Many studies in the field of DDS have revealed the principles of administration, distribution, metabolism, and excretion of drug carriers in living bodies. Fur- thermore, these principles put ideas of the theoretical formulation adapted to use in local and systemic administration of siRNA. In this review we focused on the current technology of DDS and its importance upon realizing the therapeutic use of siRNA.
{"title":"Current Status of siRNA Delivery Technology and siRNA Drug Development","authors":"T. Urakami, N. Oku","doi":"10.2174/1874126600701010020","DOIUrl":"https://doi.org/10.2174/1874126600701010020","url":null,"abstract":"In the past decade, therapeutic potential of RNA interference (RNAi) and its application to human diseases were widely discussed in the related fields of biology, medical sciences, and pharmaceutical sciences. In course of these research and developing processes, efficient transduction of small interfering RNA (siRNA) into target cells is one of the most significant breakthroughs in revealing the feasibility of siRNA-mediated therapies. From the aspect of new siRNA derived drug development, drug delivery system (DDS) holds the key to success. Many studies in the field of DDS have revealed the principles of administration, distribution, metabolism, and excretion of drug carriers in living bodies. Fur- thermore, these principles put ideas of the theoretical formulation adapted to use in local and systemic administration of siRNA. In this review we focused on the current technology of DDS and its importance upon realizing the therapeutic use of siRNA.","PeriodicalId":421840,"journal":{"name":"The Open Drug Delivery Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130639695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：