About
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Had an amazing time at the Controlled Release Society Annual Meeting in Bologna, Italy, presenting my work on itaconate particles as a treatment for…
Had an amazing time at the Controlled Release Society Annual Meeting in Bologna, Italy, presenting my work on itaconate particles as a treatment for…
Liked by Stephen W. Hoag
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I learn something new every time I hear Tim lecture, a wealth of information.
I learn something new every time I hear Tim lecture, a wealth of information.
Shared by Stephen W. Hoag
Experience & Education
Publications
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Effect of Common Excipients on the Oral Drug Absorption of Biopharmaceutics Classification System Class 3 Drugs Cimetidine and Acyclovir
Journal of Pharmaceutical Sciences
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Analysis of curing of a sustained release coating formulation by application of NIR spectroscopy to monitor changes associated with glyceryl monostearate
Drug Development and Industrial Pharmacy
For controlled release, latex or pseudolatex coatings to function as designed, it must be cured at temperatures at or slightly above the polymer's glass transition temperature. The focus of this study is to develop an understanding of the curing process and to develop near infrared spectroscopy as a tool for monitoring curing. Differential scanning calorimetry studies were used to determine how the thermal properties of glyceryl monostearate (GMS) and its polymorphic forms relate to the extent…
For controlled release, latex or pseudolatex coatings to function as designed, it must be cured at temperatures at or slightly above the polymer's glass transition temperature. The focus of this study is to develop an understanding of the curing process and to develop near infrared spectroscopy as a tool for monitoring curing. Differential scanning calorimetry studies were used to determine how the thermal properties of glyceryl monostearate (GMS) and its polymorphic forms relate to the extent of Eudragit® polymer coat curing at different curing temperatures. The different GMS melting endotherms were used to monitor the extent of curing and as references for model development. The calculated melting peak areas for the GMS were plotted versus time and found to be dependent on time and temperature used for curing. Principal component analysis and parallel factor analysis were used to investigate the effect of curing on the films and showed that spectral changes could be could be directly related to the changes associated with the GMS during curing. Partial least square models developed could predict the extent of curing and the final state of GMS post curing.
Other authorsSee publication -
Analysis of curing of a sustained release coating formulation by application of NIR spectroscopy to monitor changes associated with glyceryl monostearate
Drug Development and Industrial Pharmacy
For controlled release, latex or pseudolatex coatings to function as designed, it must be cured at temperatures at or slightly above the polymer's glass transition temperature. The focus of this study is to develop an understanding of the curing process and to develop near infrared spectroscopy as a tool for monitoring curing. Differential scanning calorimetry studies were used to determine how the thermal properties of glyceryl monostearate (GMS) and its polymorphic forms relate to the extent…
For controlled release, latex or pseudolatex coatings to function as designed, it must be cured at temperatures at or slightly above the polymer's glass transition temperature. The focus of this study is to develop an understanding of the curing process and to develop near infrared spectroscopy as a tool for monitoring curing. Differential scanning calorimetry studies were used to determine how the thermal properties of glyceryl monostearate (GMS) and its polymorphic forms relate to the extent of Eudragit® polymer coat curing at different curing temperatures. The different GMS melting endotherms were used to monitor the extent of curing and as references for model development. The calculated melting peak areas for the GMS were plotted versus time and found to be dependent on time and temperature used for curing. Principal component analysis and parallel factor analysis were used to investigate the effect of curing on the films and showed that spectral changes could be could be directly related to the changes associated with the GMS during curing. Partial least square models developed could predict the extent of curing and the final state of GMS post curing.
Other authorsSee publication -
Near-infrared spectroscopic analysis of the breaking force of extended-release matrix tablets prepared by roller-compaction: influence of plasticizer levels and sintering temperature
Drug Development and Industrial Pharmacy
The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a…
The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a fixed roll-gap of 1.5 mm, feed screw speed to roller speed ratio of 5:1 and roll pressure of 4 MPa. The granules, after removing fines, were compacted into tablets on a Stokes B2 rotary tablet press at a compression force of 7 kN. The tablets were thermally treated at different temperatures (Room Temperature, 50, 75 and 100 °C) for 5 h. These tablets were scanned in reflectance mode in the wavelength range of 400–2500 nm and were evaluated for breaking force. Tablet breaking force significantly increased with increasing plasticizer levels and with increases in the sintering temperature. An increase in tablet hardness produced an upward shift (increase in absorbance) in the NIR spectra. The principle component analysis (PCA) of the spectra was able to distinguish samples with different plasticizer levels and sintering temperatures. In addition, a 9-factor partial least squares (PLS) regression model for tablets containing Eudragit® RL PO had an r2 of 0.9797, a standard error of calibration of 0.6255 and a standard error of cross validation (SECV) of 0.7594. Similar analysis of tablets containing Eudragit® RS PO showed an r2 of 0.9831, a standard error of calibration of 0.9711 and an SECV of 1.192.
Other authorsSee publication -
Physical States and Thermodynamic Principles in Pharmaceutics
Textbook: Pharmaceutics Basic Principles and Application to Pharmacy Practice, Edited by: Alekha Dash, Somnath Singh and Justin Tolman
A single and engaging textbook that covers all aspects of pharmaceutics with an emphasis on the basic science and its application to pharmacy practice. Based on curricular guidelines mandated by the American Council for Pharmacy Education (ACPE), the book incorporates laboratory skills by identifying portions of each principle that can be used in a clinical setting.
Other authorsSee publication -
• Analysis of Curing of a Sustained Release Coating Formulation by Application of NIR Spectroscopy to Monitor Changes Physical-Mechanical Properties
International Journal of Pharmaceutics
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Investigation of the physical-mechanical properties of Eudragit® RS PO / RL PO and their mixtures with common pharmaceutical excipients
Drug Development and Industrial Pharmacy
Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility…
Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility profiles. The Heckel analysis of both polymers exhibited a speed-sensitive deformation behavior typical to plastic materials. The yield values of the binary mixes of the polymers with microcrystalline cellulose revealed a linear relationship with the weight fractions of individual components. The yield values of binary mixes of both the polymers with dibasic calcium phosphate exhibited slight negative deviations from linearity. Both polymers exhibited axial relaxation after ejection typical of viscoelastic materials, as measured by the elastic recovery index values. The work of compaction and the elastic recovery index values of the binary mixtures were found to be linearly related to the weight fractions of the individual components thus, confirming ideal mixing behavior based on the composition. Addition of microcrystalline cellulose to both polymers significantly improved their tabletability and compactibility. The tensile strengths of the compacts prepared with neat materials and binary mixes with microcrystalline cellulose, dibasic calcium phosphate and lactose were the function of their solid fraction and independent of the tableting speeds tested; thus, validating compactibility as a reliable parameter in predicting acceptable tablet properties.
Other authorsSee publication -
Investigation of the physical-mechanical properties of Eudragit® RS PO / RL PO and their mixtures with common pharmaceutical excipients
Drug Development and Industrial Pharmacy
Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility…
Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility profiles. The Heckel analysis of both polymers exhibited a speed-sensitive deformation behavior typical to plastic materials. The yield values of the binary mixes of the polymers with microcrystalline cellulose revealed a linear relationship with the weight fractions of individual components. The yield values of binary mixes of both the polymers with dibasic calcium phosphate exhibited slight negative deviations from linearity. Both polymers exhibited axial relaxation after ejection typical of viscoelastic materials, as measured by the elastic recovery index values. The work of compaction and the elastic recovery index values of the binary mixtures were found to be linearly related to the weight fractions of the individual components thus, confirming ideal mixing behavior based on the composition. Addition of microcrystalline cellulose to both polymers significantly improved their tabletability and compactibility. The tensile strengths of the compacts prepared with neat materials and binary mixes with microcrystalline cellulose, dibasic calcium phosphate and lactose were the function of their solid fraction and independent of the tableting speeds tested; thus, validating compactibility as a reliable parameter in predicting acceptable tablet properties.
Other authorsSee publication -
Assessment of the critical factors affecting the porosity of roller compacted ribbons and the feasibility of using NIR chemical imaging to evaluate the porosity distribution
International Journal of Pharmaceutics
The purpose of this study was to assess the porosity variation of roller compacted ribbons made using different process parameters; in addition, the feasibility of using near-infrared chemical imaging (NIR-CI) to evaluate porosity variations was examined. Ribbons of neat microcrystalline cellulose were compacted using a range of roll pressures (RP), roll speeds (RS) and feed screw speeds (FSS). The ribbon porosity decreased as RP increased with the exception of ribbons produced by the…
The purpose of this study was to assess the porosity variation of roller compacted ribbons made using different process parameters; in addition, the feasibility of using near-infrared chemical imaging (NIR-CI) to evaluate porosity variations was examined. Ribbons of neat microcrystalline cellulose were compacted using a range of roll pressures (RP), roll speeds (RS) and feed screw speeds (FSS). The ribbon porosity decreased as RP increased with the exception of ribbons produced by the combination of high RS and low FSS where increasing RP increases the porosity of the ribbons. Lower RS was found to produce ribbons with lower porosity and the porosity increases as the RS increased. Increased FSS will decrease ribbon porosity at higher RS while it slightly increase the ribbon porosity at lower RS. A simple linear regression model showed NIR-CI was able to predict the ribbon porosity with a correlation of 0.9258. NIR-CI is able to characterize differences in porosity as a function of position on the ribbon where regions with lower porosity show higher absorbance. Nevertheless, NIR-CI is able to show sinusoidal variation in intensities along the roller compacted ribbon among all settings studied.
Other authorsSee publication -
Assessment of the critical factors affecting the porosity of roller compacted ribbons and the feasibility of using NIR chemical imaging to evaluate the porosity distribution
International Journal of Pharmaceutics
The purpose of this study was to assess the porosity variation of roller compacted ribbons made using different process parameters; in addition, the feasibility of using near-infrared chemical imaging (NIR-CI) to evaluate porosity variations was examined. Ribbons of neat microcrystalline cellulose were compacted using a range of roll pressures (RP), roll speeds (RS) and feed screw speeds (FSS). The ribbon porosity decreased as RP increased with the exception of ribbons produced by the…
The purpose of this study was to assess the porosity variation of roller compacted ribbons made using different process parameters; in addition, the feasibility of using near-infrared chemical imaging (NIR-CI) to evaluate porosity variations was examined. Ribbons of neat microcrystalline cellulose were compacted using a range of roll pressures (RP), roll speeds (RS) and feed screw speeds (FSS). The ribbon porosity decreased as RP increased with the exception of ribbons produced by the combination of high RS and low FSS where increasing RP increases the porosity of the ribbons. Lower RS was found to produce ribbons with lower porosity and the porosity increases as the RS increased. Increased FSS will decrease ribbon porosity at higher RS while it slightly increase the ribbon porosity at lower RS. A simple linear regression model showed NIR-CI was able to predict the ribbon porosity with a correlation of 0.9258. NIR-CI is able to characterize differences in porosity as a function of position on the ribbon where regions with lower porosity show higher absorbance. Nevertheless, NIR-CI is able to show sinusoidal variation in intensities along the roller compacted ribbon among all settings studied.
Other authorsSee publication
Patents
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“Drug Authentication” US Patent No. 8,719,043 B2
Issued US
Other inventors -
Organizations
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American Association of Pharmaceutical Scientists: AAPS
American association for the advancement of science (aaas)
- Present
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I am excited to share that I have been promoted to Associate Professor with Tenure at Pharmaceutical Sci UMSOP! I am so grateful to all of my past…
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US Pharmacopeia's Danielle Seiler, Morgan A. Jacobs, Atul Dubey, Weidong Zhao PhD came to Stephen W. Hoag's lab at University of Maryland School of…
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Business is taking off in Europe! This week I joined Anita Gashi at the DDF Summit (Drug Delivery & Formulation) in Berlin. It was a great…
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Congratulations to Susan dosReis the University of Maryland, Baltimore Graduate School Outstanding Mentor of the Year. Outstanding mentoring of…
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New photos of the 2024 Global Leadership Award of the Chinese Association for Biomaterials Award (from Daegu, Korea) arrived today. Thanks to Prof…
New photos of the 2024 Global Leadership Award of the Chinese Association for Biomaterials Award (from Daegu, Korea) arrived today. Thanks to Prof…
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I am delighted to announce that I have successfully defended my PhD thesis. I would like to extend my deepest gratitude to my advisor, Dr. Aliasger…
I am delighted to announce that I have successfully defended my PhD thesis. I would like to extend my deepest gratitude to my advisor, Dr. Aliasger…
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All you ever wanted to know about excipients……….. the three musketeers at CPhI in Philadelphia Chris Moreton Brian Carlin Dave Schoneker
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Gov. Wes Moore signed a bill on Thursday for permanent state funding for the University of Maryland Institute for Health Computing in North Bethesda.…
Gov. Wes Moore signed a bill on Thursday for permanent state funding for the University of Maryland Institute for Health Computing in North Bethesda.…
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