The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Mansoor Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Lipids bearing extruded-spheronized pellets for extended release of poorly soluble antiemetic agent—Meclizine HCl
Lipids in Health and Disease, 2017Co-Authors: Faaiza Qazi, Muhammad Harris Shoaib, Rabia Ismail Yousuf, Muhammad Iqbal Nasiri, Kamran Ahmed, Mansoor AhmadAbstract:Background Antiemetic agent Meclizine HCl, widely prescribed in vertigo, is available only in immediate release dosage forms. The approved therapeutic dose and shorter elimination half-life make Meclizine HCl a potential candidate to be formulated in extended release dosage form. This study was aimed to develop extended release Meclizine HCl pellets by extrusion spheronization using natural and synthetic lipids. Influence of lipid type, drug/lipid ratio and combinations of different lipids on drug release and sphericity of pellets were evaluated. Methods Thirty two formulations were prepared with four different lipids, Glyceryl monostearate (Geleol^®), Glyceryl palmitostearate (Precirol^®), Glyceryl Behenate (Compritol^®) and Carnauba wax, utilized either alone or in combinations of drug/lipid ratio of 1:0.5–1:3. Dissolution studies were performed at variable pH and release kinetics were analyzed. Fourier transform infrared spectroscopy was conducted and no drug lipid interaction was found. Results Sphericity indicated by shape factor (e_R) varied with type and concentration of lipids: Geleol^® (e_R = 0.891–0.997), Precirol^® (e_R = 0.611–0.743), Compritol^® (e_R = 0.665–0.729) and Carnauba wax (e_R = 0.499-0.551). Highly spherical pellets were obtained with Geleol^® (Aspect ratio = 1.005–1.052) whereas irregularly shaped pellets were formed using Carnauba wax (Aspect ratio = 1.153–1.309). Drug release was effectively controlled by three different combinations of lipids: (i) Geleol^® and Compritol^®, (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax. Scanning electron microscopy of Compritol^® pellets showed smooth surface with pores, whereas, irregular rough surface with hollow depressions was observed in Carnauba wax pellets. Energy dispersive spectroscopy indicated elemental composition of lipid matrix pellets. Kinetics of (i) Geleol^® and Compritol^® pellets, explained by Korsmeyer-Peppas (R^2 = 0.978–0.993) indicated non-Fickian diffusion ( n = 0.519-0.597). Combinations of (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax pellets followed Zero-order (R^2 = 0.991–0.995). Similarity test was performed using combination of Geleol^® and Compritol^® (i) as a reference. Conclusions Matrices for the extended release of Meclizine HCl from extruded-spheronized pellets were successfully formed by using three lipids (Geleol^®, Compritol^® and Carnauba wax) in different combinations. The encapsulated pellets of Meclizine HCl can be effectively used for treatment of motion sickness, nausea and vertigo for extended period of time.
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Lipids bearing extruded-spheronized pellets for extended release of poorly soluble antiemetic agent-Meclizine HCl.
Lipids in Health and Disease, 2017Co-Authors: Faaiza Qazi, Muhammad Harris Shoaib, Rabia Ismail Yousuf, Muhammad Iqbal Nasiri, Kamran Ahmed, Mansoor AhmadAbstract:Antiemetic agent Meclizine HCl, widely prescribed in vertigo, is available only in immediate release dosage forms. The approved therapeutic dose and shorter elimination half-life make Meclizine HCl a potential candidate to be formulated in extended release dosage form. This study was aimed to develop extended release Meclizine HCl pellets by extrusion spheronization using natural and synthetic lipids. Influence of lipid type, drug/lipid ratio and combinations of different lipids on drug release and sphericity of pellets were evaluated. Thirty two formulations were prepared with four different lipids, Glyceryl monostearate (Geleol®), Glyceryl palmitostearate (Precirol®), Glyceryl Behenate (Compritol®) and Carnauba wax, utilized either alone or in combinations of drug/lipid ratio of 1:0.5–1:3. Dissolution studies were performed at variable pH and release kinetics were analyzed. Fourier transform infrared spectroscopy was conducted and no drug lipid interaction was found. Sphericity indicated by shape factor (eR) varied with type and concentration of lipids: Geleol® (eR = 0.891–0.997), Precirol® (eR = 0.611–0.743), Compritol® (eR = 0.665–0.729) and Carnauba wax (eR = 0.499-0.551). Highly spherical pellets were obtained with Geleol® (Aspect ratio = 1.005–1.052) whereas irregularly shaped pellets were formed using Carnauba wax (Aspect ratio = 1.153–1.309). Drug release was effectively controlled by three different combinations of lipids: (i) Geleol® and Compritol®, (ii) Geleol® and Carnauba wax and (iii) Geleol®, Compritol® and Carnauba wax. Scanning electron microscopy of Compritol® pellets showed smooth surface with pores, whereas, irregular rough surface with hollow depressions was observed in Carnauba wax pellets. Energy dispersive spectroscopy indicated elemental composition of lipid matrix pellets. Kinetics of (i) Geleol® and Compritol® pellets, explained by Korsmeyer-Peppas (R2 = 0.978–0.993) indicated non-Fickian diffusion (n = 0.519-0.597). Combinations of (ii) Geleol® and Carnauba wax and (iii) Geleol®, Compritol® and Carnauba wax pellets followed Zero-order (R2 = 0.991–0.995). Similarity test was performed using combination of Geleol® and Compritol® (i) as a reference. Matrices for the extended release of Meclizine HCl from extruded-spheronized pellets were successfully formed by using three lipids (Geleol®, Compritol® and Carnauba wax) in different combinations. The encapsulated pellets of Meclizine HCl can be effectively used for treatment of motion sickness, nausea and vertigo for extended period of time.
Eliana B Souto - One of the best experts on this subject based on the ideXlab platform.
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Optimization of nimesulide-loaded solid lipid nanoparticles (SLN) by factorial design, release profile and cytotoxicity in human Colon adenocarcinoma cell line
2019Co-Authors: Joana R. Campos, Ana R. Fernandes, Raquel Sousa, Joana F. Fangueiro, Prapaporn Boonme, Maria Luisa Garcia, Amelia M. Silva, Beatriz C. Naveros, Eliana B SoutoAbstract:The aim of this work is development of a nontoxic, long-term stable solid lipid nanoparticles (SLN) formulation for the loading of Nimesulide (NiM) by a 22 factorial design. The optimized formulation was composed of 10 wt% of Glyceryl Behenate and 2.5 wt% of poloxamer 188. Immediately after production, Z-Ave of NiM-SLN was 166.1 ± 0.114 nm, with a polydispersity index (PI) of 0.171 ± 0051 and zeta potential nearly neutral (−3.10 ± 0.166 mV). A slight increase of Z-Ave was recorded for NiM-SLN stored at 25 °C for a period of 15 days, whereas at 4 °C particles kept size within similar range. Long-term stability was monitored using TurbiscanLab®, showing a high stability of the nanoparticles with variations in the backscattering profiles below 10%. The release profile of NiM-SLN followed a sustained pattern with ca. 30% of drug released up to 24 h. Empty-SLN and NiM-SLN were nontoxic after exposing Caco-2 cells to the highest concentration (100 μg/mL) up to 48 hours (cell viability higher than 80%). NiM-SLN were lyophilized using different cryoprotectants, producing particles of 463.1 ± 36.63 nm (PI 0.491 ± 0.027) with 5% trehalose. Solid character of NiM-SLN was confirmed by DSC, recording a recrystallization index of 83% for NiM-SLN and of 74% for lyophilized SLN.
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lopinavir loaded solid lipid nanoparticles sln for intestinal lymphatic targeting
European Journal of Pharmaceutical Sciences, 2011Co-Authors: M Aji R Alex, Eliana B Souto, A J Chacko, S JoseAbstract:Abstract The poor orally available lopinavir was successfully encapsulated in Glyceryl Behenate based solid lipid nanoparticles (Lo-SLN) for its ultimate use to target intestinal lymphatic vessels in combined chemotherapy—the so-called Highly Active Anti-Retroviral Therapy (HAART). SLN with mean particle size of 230 nm (polydispersity index, PDI
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potential use of nanostructured lipid carriers for topical delivery of flurbiprofen
Journal of Pharmaceutical Sciences, 2011Co-Authors: E Gonzalezmira, Eliana B Souto, S Nikolic, M L Garcia, M A Egea, Ana C CalpenaAbstract:ABSTRACT The potential use of nanostructured lipid carriers (NLC) composed of a fatty acid [stearic acid (SA)] or a triglyceride (Glyceryl Behenate) as solid lipids, and a mixture of medium chain triglycerides and castor oil as liquid lipids, for skin administration of flurbiprofen (FB), has been explored. Two different optimized NLC formulations (FB-SANLC based on SA vs. FB-C888NLC based on Glyceryl Behenate), with respect to the morphometrical properties (particle size and polydispersity index) and the entrapment efficiency, were used in this study. The ex vivo permeation profiles of FB-C888NLC, FB-SANLC and conventional FB solution were evaluated using human skin. An improved FB permeation was observed when the drug was delivered by skin application of FB-C888NLC, attributed to the particle size and matrix crystallinity. The differential scanning calorimetry and X-ray diffraction studies suggested major polymorphic transitions in the lipid matrix of FB-C888NLC. A good correlation between polymorphic transitions and increased drug permeation was observed. However, both NLC dispersions showed a penetration-enhancing ratio (ER) higher than conventional FB solution. The in vitro and in vivo irritancy and local tolerability were assessed by running, respectively, the SKINTEX™ and Draize test. Both FB-C888NLC and FB-SANLC were classified as nonirritant.
Sven Gohla - One of the best experts on this subject based on the ideXlab platform.
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encapsulation of retinoids in solid lipid nanoparticles sln
Journal of Microencapsulation, 2001Co-Authors: Volkhard Jenning, Sven GohlaAbstract:SLN have been suggested for a broad range of applications, such as intravenous injection, peroral, or dermal administration. The incorporation of the drug in the core of the SLN has to be ensured for these applications, but the inclusion of drugs in SLN is poorly understood. This study is a contribution to further describe the inclusion properties of colloidal lipids and to propose incorporation mechanisms. Besides the well known methods to investigate entrapment of actives in nanoparticles such as DSC or microscopy, the present study focussed on yet a different approach. Based on the different chemical stability of retinoids in water and in a lipid phase, a method to derive information on the distribution of the drug between SLN-lipid and the water phase was established. Comparing different lipids, Glyceryl Behenate gave superior entrapment compared to tripalmitate, cetyl palmitate and solid paraffin. Comparing three different drugs, entrapment increased with decreasing polarity of the molecule (tretinoin < retinol < retinyl palmitate). The encapsulation efficacy was successfully enhanced by formulating SLN from mixtures of liquid and solid lipids. These particles were solid and provided better protection of the sensitive drugs than an emulsion. X-ray investigations revealed that good encapsulation correlated with a low degree of crystallinity and lattice defects. With highly ordered crystals, as in the case of cetyl palmitate, drug expulsion from the carrier was more pronounced.
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solid lipid nanoparticles sln based on binary mixtures of liquid and solid lipids a 1h nmr study
International Journal of Pharmaceutics, 2000Co-Authors: Volkhard Jenning, Karsten Mader, Sven GohlaAbstract:SLN with improved payloads and enhanced storage stability were investigated. Based on the experiences with solid lipid nanoparticles, a new type of solid lipid nanoparticle has been developed by incorporating triglyceride containing oils in the solid shell of the particle. The structure and mixing behaviour of these particles was characterised by DSC and (1)H-NMR. DSC yields information on the melting and crystallisation behaviour of the solid and liquid constituents of the particles. NMR is especially suited for the characterisation of the liquid oil domains inside the SLN. In this study a medium chain triglyceride oil was successfully incorporated in a matrix of a solid long chain glyceride (Glyceryl Behenate). The resulting particles were solid but the oil inside the particle remained in a liquid state. The relation between oil supplementation and melting point depression of Glyceryl Behenate proved to be linear. Mobility of the oil molecules inside the particles was considerably reduced compared to the emulsified oil. Moreover, two different chemical shifts for each of the lipid signals were observed indicating two different chemical environments. The experimental data is in line with a model describing uniform distribution of the oil molecules in the Glyceryl Behenate for low oil loads. However, at higher oil loads our data indicate the formation of oil clusters within the solid nanoparticle.
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vitamin a loaded solid lipid nanoparticles for topical use drug release properties
Journal of Controlled Release, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Sven GohlaAbstract:Burst release as well as sustained release has been reported for SLN suspensions. For dermal application, both features are of interest. Burst release can be useful to improve the penetration of a drug. Sustained release becomes important with active ingredients that are irritating at high concentrations or to supply the skin over a prolonged period of time with a drug. Glyceryl Behenate SLN were loaded with vitamin A and the release profiles were studied. Franz diffusion cells were used to assess the release kinetic over a period of 24 h. Within the first 6 h retinol SLN displayed controlled release. After longer periods (12-24 h) the release rate increased and even exceeded the release rate of comparable nanoemulsions. Pure SLN dispersions are characterised by low viscosity. In contrast to membranous vesicles, SLN can also be stably incorporated in convenient topical dosage forms like hydrogels or creams. In the Franz diffusion cell these preparations showed a controlled release over 12-18 h. Similar to SLN dispersions an increase in release rate over a 24-h period was found. A good correlation between polymorphic transitions and increased drug release was observed in this study. Sustained release was often related to the metastable beta' polymorph. Drug expulsion is explained by a reduction of amorphous regions in the carrier lattice due to a beta'-->beta(i) polymorphic transition. This transformation can be controlled with surfactant mixtures or, in the case of the hydrogel and oil/water cream, with humectants or gelling agents. Thus, the release rate for the topical route of application is adjustable.
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vitamin a loaded solid lipid nanoparticles for topical use drug release properties
Journal of Controlled Release, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Sven GohlaAbstract:Abstract Burst release as well as sustained release has been reported for SLN suspensions. For dermal application, both features are of interest. Burst release can be useful to improve the penetration of a drug. Sustained release becomes important with active ingredients that are irritating at high concentrations or to supply the skin over a prolonged period of time with a drug. Glyceryl Behenate SLN were loaded with vitamin A and the release profiles were studied. Franz diffusion cells were used to assess the release kinetic over a period of 24 h. Within the first 6 h retinol SLN displayed controlled release. After longer periods (12–24 h) the release rate increased and even exceeded the release rate of comparable nanoemulsions. Pure SLN dispersions are characterised by low viscosity. In contrast to membranous vesicles, SLN can also be stably incorporated in convenient topical dosage forms like hydrogels or creams. In the Franz diffusion cell these preparations showed a controlled release over 12–18 h. Similar to SLN dispersions an increase in release rate over a 24-h period was found. A good correlation between polymorphic transitions and increased drug release was observed in this study. Sustained release was often related to the metastable β′ polymorph. Drug expulsion is explained by a reduction of amorphous regions in the carrier lattice due to a β′→βi polymorphic transition. This transformation can be controlled with surfactant mixtures or, in the case of the hydrogel and oil/water cream, with humectants or gelling agents. Thus, the release rate for the topical route of application is adjustable.
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vitamin a loaded solid lipid nanoparticles for topical use occlusive properties and drug targeting to the upper skin
European Journal of Pharmaceutics and Biopharmaceutics, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Anja Gysler, Sven GohlaAbstract:Abstract To evaluate the potential use of solid lipid nanoparticles (SLN) in dermatology and cosmetics, Glyceryl Behenate SLN loaded with vitamin A (retinol and retinyl palmitate) and incorporated in a hydrogel and o/w-cream were tested with respect to their influence on drug penetration into porcine skin. Conventional formulations served for comparison. Excised full thickness skin was mounted in Franz diffusion cells and the formulations were applied for 6 and 24 h, respectively. Vitamin A concentrations in the skin tissue suggested a certain drug localizing effect. High retinol concentrations were found in the upper skin layers following SLN preparations, whereas the deeper regions showed only very low vitamin A levels. Because of a polymorphic transition of the lipid carrier with subsequent drug expulsion following the application to the skin, the drug localizing action appears to be limited for 6–24 h. Best results were obtained with retinol SLN incorporated in the oil-in-water (o/w) cream retarding drug expulsion. The penetration of the occlusion sensitive drug retinyl palmitate was even more influenced by SLN incorporation. Transepidermal water loss (TEWL) and the influence of drug free SLN on retinyl palmitate uptake exclude pronounced occlusive effects. Therefore enhanced retinyl palmitate uptake should derive from specific SLN effects and is not due to non-specific occlusive properties.
Faaiza Qazi - One of the best experts on this subject based on the ideXlab platform.
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Lipids bearing extruded-spheronized pellets for extended release of poorly soluble antiemetic agent—Meclizine HCl
Lipids in Health and Disease, 2017Co-Authors: Faaiza Qazi, Muhammad Harris Shoaib, Rabia Ismail Yousuf, Muhammad Iqbal Nasiri, Kamran Ahmed, Mansoor AhmadAbstract:Background Antiemetic agent Meclizine HCl, widely prescribed in vertigo, is available only in immediate release dosage forms. The approved therapeutic dose and shorter elimination half-life make Meclizine HCl a potential candidate to be formulated in extended release dosage form. This study was aimed to develop extended release Meclizine HCl pellets by extrusion spheronization using natural and synthetic lipids. Influence of lipid type, drug/lipid ratio and combinations of different lipids on drug release and sphericity of pellets were evaluated. Methods Thirty two formulations were prepared with four different lipids, Glyceryl monostearate (Geleol^®), Glyceryl palmitostearate (Precirol^®), Glyceryl Behenate (Compritol^®) and Carnauba wax, utilized either alone or in combinations of drug/lipid ratio of 1:0.5–1:3. Dissolution studies were performed at variable pH and release kinetics were analyzed. Fourier transform infrared spectroscopy was conducted and no drug lipid interaction was found. Results Sphericity indicated by shape factor (e_R) varied with type and concentration of lipids: Geleol^® (e_R = 0.891–0.997), Precirol^® (e_R = 0.611–0.743), Compritol^® (e_R = 0.665–0.729) and Carnauba wax (e_R = 0.499-0.551). Highly spherical pellets were obtained with Geleol^® (Aspect ratio = 1.005–1.052) whereas irregularly shaped pellets were formed using Carnauba wax (Aspect ratio = 1.153–1.309). Drug release was effectively controlled by three different combinations of lipids: (i) Geleol^® and Compritol^®, (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax. Scanning electron microscopy of Compritol^® pellets showed smooth surface with pores, whereas, irregular rough surface with hollow depressions was observed in Carnauba wax pellets. Energy dispersive spectroscopy indicated elemental composition of lipid matrix pellets. Kinetics of (i) Geleol^® and Compritol^® pellets, explained by Korsmeyer-Peppas (R^2 = 0.978–0.993) indicated non-Fickian diffusion ( n = 0.519-0.597). Combinations of (ii) Geleol^® and Carnauba wax and (iii) Geleol^®, Compritol^® and Carnauba wax pellets followed Zero-order (R^2 = 0.991–0.995). Similarity test was performed using combination of Geleol^® and Compritol^® (i) as a reference. Conclusions Matrices for the extended release of Meclizine HCl from extruded-spheronized pellets were successfully formed by using three lipids (Geleol^®, Compritol^® and Carnauba wax) in different combinations. The encapsulated pellets of Meclizine HCl can be effectively used for treatment of motion sickness, nausea and vertigo for extended period of time.
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Lipids bearing extruded-spheronized pellets for extended release of poorly soluble antiemetic agent-Meclizine HCl.
Lipids in Health and Disease, 2017Co-Authors: Faaiza Qazi, Muhammad Harris Shoaib, Rabia Ismail Yousuf, Muhammad Iqbal Nasiri, Kamran Ahmed, Mansoor AhmadAbstract:Antiemetic agent Meclizine HCl, widely prescribed in vertigo, is available only in immediate release dosage forms. The approved therapeutic dose and shorter elimination half-life make Meclizine HCl a potential candidate to be formulated in extended release dosage form. This study was aimed to develop extended release Meclizine HCl pellets by extrusion spheronization using natural and synthetic lipids. Influence of lipid type, drug/lipid ratio and combinations of different lipids on drug release and sphericity of pellets were evaluated. Thirty two formulations were prepared with four different lipids, Glyceryl monostearate (Geleol®), Glyceryl palmitostearate (Precirol®), Glyceryl Behenate (Compritol®) and Carnauba wax, utilized either alone or in combinations of drug/lipid ratio of 1:0.5–1:3. Dissolution studies were performed at variable pH and release kinetics were analyzed. Fourier transform infrared spectroscopy was conducted and no drug lipid interaction was found. Sphericity indicated by shape factor (eR) varied with type and concentration of lipids: Geleol® (eR = 0.891–0.997), Precirol® (eR = 0.611–0.743), Compritol® (eR = 0.665–0.729) and Carnauba wax (eR = 0.499-0.551). Highly spherical pellets were obtained with Geleol® (Aspect ratio = 1.005–1.052) whereas irregularly shaped pellets were formed using Carnauba wax (Aspect ratio = 1.153–1.309). Drug release was effectively controlled by three different combinations of lipids: (i) Geleol® and Compritol®, (ii) Geleol® and Carnauba wax and (iii) Geleol®, Compritol® and Carnauba wax. Scanning electron microscopy of Compritol® pellets showed smooth surface with pores, whereas, irregular rough surface with hollow depressions was observed in Carnauba wax pellets. Energy dispersive spectroscopy indicated elemental composition of lipid matrix pellets. Kinetics of (i) Geleol® and Compritol® pellets, explained by Korsmeyer-Peppas (R2 = 0.978–0.993) indicated non-Fickian diffusion (n = 0.519-0.597). Combinations of (ii) Geleol® and Carnauba wax and (iii) Geleol®, Compritol® and Carnauba wax pellets followed Zero-order (R2 = 0.991–0.995). Similarity test was performed using combination of Geleol® and Compritol® (i) as a reference. Matrices for the extended release of Meclizine HCl from extruded-spheronized pellets were successfully formed by using three lipids (Geleol®, Compritol® and Carnauba wax) in different combinations. The encapsulated pellets of Meclizine HCl can be effectively used for treatment of motion sickness, nausea and vertigo for extended period of time.
Volkhard Jenning - One of the best experts on this subject based on the ideXlab platform.
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encapsulation of retinoids in solid lipid nanoparticles sln
Journal of Microencapsulation, 2001Co-Authors: Volkhard Jenning, Sven GohlaAbstract:SLN have been suggested for a broad range of applications, such as intravenous injection, peroral, or dermal administration. The incorporation of the drug in the core of the SLN has to be ensured for these applications, but the inclusion of drugs in SLN is poorly understood. This study is a contribution to further describe the inclusion properties of colloidal lipids and to propose incorporation mechanisms. Besides the well known methods to investigate entrapment of actives in nanoparticles such as DSC or microscopy, the present study focussed on yet a different approach. Based on the different chemical stability of retinoids in water and in a lipid phase, a method to derive information on the distribution of the drug between SLN-lipid and the water phase was established. Comparing different lipids, Glyceryl Behenate gave superior entrapment compared to tripalmitate, cetyl palmitate and solid paraffin. Comparing three different drugs, entrapment increased with decreasing polarity of the molecule (tretinoin < retinol < retinyl palmitate). The encapsulation efficacy was successfully enhanced by formulating SLN from mixtures of liquid and solid lipids. These particles were solid and provided better protection of the sensitive drugs than an emulsion. X-ray investigations revealed that good encapsulation correlated with a low degree of crystallinity and lattice defects. With highly ordered crystals, as in the case of cetyl palmitate, drug expulsion from the carrier was more pronounced.
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solid lipid nanoparticles sln based on binary mixtures of liquid and solid lipids a 1h nmr study
International Journal of Pharmaceutics, 2000Co-Authors: Volkhard Jenning, Karsten Mader, Sven GohlaAbstract:SLN with improved payloads and enhanced storage stability were investigated. Based on the experiences with solid lipid nanoparticles, a new type of solid lipid nanoparticle has been developed by incorporating triglyceride containing oils in the solid shell of the particle. The structure and mixing behaviour of these particles was characterised by DSC and (1)H-NMR. DSC yields information on the melting and crystallisation behaviour of the solid and liquid constituents of the particles. NMR is especially suited for the characterisation of the liquid oil domains inside the SLN. In this study a medium chain triglyceride oil was successfully incorporated in a matrix of a solid long chain glyceride (Glyceryl Behenate). The resulting particles were solid but the oil inside the particle remained in a liquid state. The relation between oil supplementation and melting point depression of Glyceryl Behenate proved to be linear. Mobility of the oil molecules inside the particles was considerably reduced compared to the emulsified oil. Moreover, two different chemical shifts for each of the lipid signals were observed indicating two different chemical environments. The experimental data is in line with a model describing uniform distribution of the oil molecules in the Glyceryl Behenate for low oil loads. However, at higher oil loads our data indicate the formation of oil clusters within the solid nanoparticle.
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vitamin a loaded solid lipid nanoparticles for topical use drug release properties
Journal of Controlled Release, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Sven GohlaAbstract:Burst release as well as sustained release has been reported for SLN suspensions. For dermal application, both features are of interest. Burst release can be useful to improve the penetration of a drug. Sustained release becomes important with active ingredients that are irritating at high concentrations or to supply the skin over a prolonged period of time with a drug. Glyceryl Behenate SLN were loaded with vitamin A and the release profiles were studied. Franz diffusion cells were used to assess the release kinetic over a period of 24 h. Within the first 6 h retinol SLN displayed controlled release. After longer periods (12-24 h) the release rate increased and even exceeded the release rate of comparable nanoemulsions. Pure SLN dispersions are characterised by low viscosity. In contrast to membranous vesicles, SLN can also be stably incorporated in convenient topical dosage forms like hydrogels or creams. In the Franz diffusion cell these preparations showed a controlled release over 12-18 h. Similar to SLN dispersions an increase in release rate over a 24-h period was found. A good correlation between polymorphic transitions and increased drug release was observed in this study. Sustained release was often related to the metastable beta' polymorph. Drug expulsion is explained by a reduction of amorphous regions in the carrier lattice due to a beta'-->beta(i) polymorphic transition. This transformation can be controlled with surfactant mixtures or, in the case of the hydrogel and oil/water cream, with humectants or gelling agents. Thus, the release rate for the topical route of application is adjustable.
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vitamin a loaded solid lipid nanoparticles for topical use drug release properties
Journal of Controlled Release, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Sven GohlaAbstract:Abstract Burst release as well as sustained release has been reported for SLN suspensions. For dermal application, both features are of interest. Burst release can be useful to improve the penetration of a drug. Sustained release becomes important with active ingredients that are irritating at high concentrations or to supply the skin over a prolonged period of time with a drug. Glyceryl Behenate SLN were loaded with vitamin A and the release profiles were studied. Franz diffusion cells were used to assess the release kinetic over a period of 24 h. Within the first 6 h retinol SLN displayed controlled release. After longer periods (12–24 h) the release rate increased and even exceeded the release rate of comparable nanoemulsions. Pure SLN dispersions are characterised by low viscosity. In contrast to membranous vesicles, SLN can also be stably incorporated in convenient topical dosage forms like hydrogels or creams. In the Franz diffusion cell these preparations showed a controlled release over 12–18 h. Similar to SLN dispersions an increase in release rate over a 24-h period was found. A good correlation between polymorphic transitions and increased drug release was observed in this study. Sustained release was often related to the metastable β′ polymorph. Drug expulsion is explained by a reduction of amorphous regions in the carrier lattice due to a β′→βi polymorphic transition. This transformation can be controlled with surfactant mixtures or, in the case of the hydrogel and oil/water cream, with humectants or gelling agents. Thus, the release rate for the topical route of application is adjustable.
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vitamin a loaded solid lipid nanoparticles for topical use occlusive properties and drug targeting to the upper skin
European Journal of Pharmaceutics and Biopharmaceutics, 2000Co-Authors: Volkhard Jenning, Monika Schaferkorting, Anja Gysler, Sven GohlaAbstract:Abstract To evaluate the potential use of solid lipid nanoparticles (SLN) in dermatology and cosmetics, Glyceryl Behenate SLN loaded with vitamin A (retinol and retinyl palmitate) and incorporated in a hydrogel and o/w-cream were tested with respect to their influence on drug penetration into porcine skin. Conventional formulations served for comparison. Excised full thickness skin was mounted in Franz diffusion cells and the formulations were applied for 6 and 24 h, respectively. Vitamin A concentrations in the skin tissue suggested a certain drug localizing effect. High retinol concentrations were found in the upper skin layers following SLN preparations, whereas the deeper regions showed only very low vitamin A levels. Because of a polymorphic transition of the lipid carrier with subsequent drug expulsion following the application to the skin, the drug localizing action appears to be limited for 6–24 h. Best results were obtained with retinol SLN incorporated in the oil-in-water (o/w) cream retarding drug expulsion. The penetration of the occlusion sensitive drug retinyl palmitate was even more influenced by SLN incorporation. Transepidermal water loss (TEWL) and the influence of drug free SLN on retinyl palmitate uptake exclude pronounced occlusive effects. Therefore enhanced retinyl palmitate uptake should derive from specific SLN effects and is not due to non-specific occlusive properties.