Michael A Repka


Affiliation: University of Mississippi
Country: USA


  1. Ye X, Kallakunta V, Kim D, Patil H, Tiwari R, Upadhye S, et al. Effects of Processing on a Sustained Release Formulation Prepared by Twin-Screw Dry Granulation. J Pharm Sci. 2019;: pubmed publisher
    ..The continuous processing nature, simplicity of operation, and ease of optimization made TSDG competitive compared with other conventional dry granulation techniques. ..
  2. Ibrahim M, Zhang J, Repka M, Chen R. Characterization of the Solid Physical State of API and Its Distribution in Pharmaceutical Hot Melt Extrudates Using Terahertz Raman Imaging. AAPS PharmSciTech. 2019;20:62 pubmed publisher
    ..The study demonstrates that THz Raman imaging is ideally suited for the identification of different solid physical states of the APIs in a polymer matrix, and provides direct visualization of their distribution in HME extrudates. ..
  3. McFall H, Sarabu S, Shankar V, Bandari S, Murthy S, Kolter K, et al. Formulation of aripiprazole-loaded pH-modulated solid dispersions via hot-melt extrusion technology: In vitro and in vivo studies. Int J Pharm. 2019;554:302-311 pubmed publisher
    ..This novel study not only discusses the incorporation of acidifiers in SDs but also the preparation of SDs using HME technology as effective techniques to improve drug release and bioavailability. ..
  4. Kallakunta V, Patil H, Tiwari R, Ye X, Upadhye S, Vladyka R, et al. Exploratory studies in heat-assisted continuous twin-screw dry granulation: A novel alternative technique to conventional dry granulation. Int J Pharm. 2019;555:380-393 pubmed publisher
    ..The tablets were stable after testing for 6 months at 25 °C/60% RH. This novel continuous dry granulation technique may offer an excellent alternative to conventional dry granulation techniques. ..
  5. Bookwala M, Thipsay P, Ross S, Zhang F, Bandari S, Repka M. Preparation of a crystalline salt of indomethacin and tromethamine by hot melt extrusion technology. Eur J Pharm Biopharm. 2018;131:109-119 pubmed publisher
  6. Vo A, Feng X, Zhang J, Zhang F, Repka M. Dual mechanism of microenvironmental pH modulation and foam melt extrusion to enhance performance of HPMCAS based amorphous solid dispersion. Int J Pharm. 2018;550:216-228 pubmed publisher
    ..It also significantly enhanced drug dissolution in a two-step biorelevant medium (p < 0.05). This novel approach improved both manufacturing processability and dissolution of HPMCAS-based solid dispersions. ..
  7. Dumpa N, Sarabu S, Bandari S, Zhang F, Repka M. Chronotherapeutic Drug Delivery of Ketoprofen and Ibuprofen for Improved Treatment of Early Morning Stiffness in Arthritis Using Hot-Melt Extrusion Technology. AAPS PharmSciTech. 2018;19:2700-2709 pubmed publisher
    ..Formulations of both KTP and IBU were stable for 4 months at accelerated stability conditions of 40°C/75% RH. In summary, HME is a novel technique for developing CTDDS. ..
  8. Vo A, He H, Zhang J, Martin S, Chen R, Repka M. Application of FT-NIR Analysis for In-line and Real-Time Monitoring of Pharmaceutical Hot Melt Extrusion: a Technical Note. AAPS PharmSciTech. 2018;19:3425-3429 pubmed publisher
    ..The obtained results suggested that inline FT-NIR analysis, along with a tailored NIR reflector, is a viable process analytical tool to monitor active pharmaceutical ingredient concentration as well as processing parameters. ..
  9. Zhang J, Vo A, Feng X, Bandari S, Repka M. Pharmaceutical Additive Manufacturing: a Novel Tool for Complex and Personalized Drug Delivery Systems. AAPS PharmSciTech. 2018;19:3388-3402 pubmed publisher
    ..Thus, this review will provide an overview and discussion on advanced pharmaceutical AM technologies, which can be used to produce unique controlled drug delivery systems and personalized dosages for the future of personalized medicine. ..

More Information


  1. Kallakunta V, Tiwari R, Sarabu S, Bandari S, Repka M. Effect of formulation and process variables on lipid based sustained release tablets via continuous twin screw granulation: A comparative study. Eur J Pharm Sci. 2018;121:126-138 pubmed publisher
    ..These findings of a single-step, continuous twin-screw granulation process are novel and demonstrate new opportunities for development of sustained release tablets. ..
  2. Bhagurkar A, Angamuthu M, Patil H, Tiwari R, Maurya A, Hashemnejad S, et al. Development of an Ointment Formulation Using Hot-Melt Extrusion Technology. AAPS PharmSciTech. 2016;17:158-66 pubmed publisher
    ..This study demonstrates a novel application of the hot-melt extrusion process in the manufacturing of topical semi-solids. ..
  3. Vo A, Feng X, Morott J, Pimparade M, Tiwari R, Zhang F, et al. A novel floating controlled release drug delivery system prepared by hot-melt extrusion. Eur J Pharm Biopharm. 2016;98:108-21 pubmed publisher
    ..Understanding the variables' effects on the formulations allows for the tailoring of this delivery system to obtain various drug release profiles. ..
  4. Ye X, Patil H, Feng X, Tiwari R, Lu J, Gryczke A, et al. Conjugation of Hot-Melt Extrusion with High-Pressure Homogenization: a Novel Method of Continuously Preparing Nanocrystal Solid Dispersions. AAPS PharmSciTech. 2016;17:78-88 pubmed publisher
    ..EFZ NCSD was found to be highly stable after storage for 6 months. In summary, the conjugation of HPH with HME technology was demonstrated to be a promising novel method for the production of NCSDs. ..
  5. Patil H, Tiwari R, Repka M. Hot-Melt Extrusion: from Theory to Application in Pharmaceutical Formulation. AAPS PharmSciTech. 2016;17:20-42 pubmed publisher
  6. Pimparade M, Morott J, Park J, Kulkarni V, Majumdar S, Murthy S, et al. Development of taste masked caffeine citrate formulations utilizing hot melt extrusion technology and in vitro-in vivo evaluations. Int J Pharm. 2015;487:167-76 pubmed publisher
    ..The lead extrudate formulations and the ODTs prepared using this formulation were subjected to human gustatory evaluation. The formulations were found to mask the unpleasant taste of caffeine citrate significantly. ..
  7. request reprint
    Mididoddi P, Repka M. Characterization of hot-melt extruded drug delivery systems for onychomycosis. Eur J Pharm Biopharm. 2007;66:95-105 pubmed
    ..The predictions of the solubility parameters were in agreement with DSC, XRD and SEM results. Bioadhesion measurements of the film on the human nail substrate were generally higher for the etched nails than that of the control nails. ..
  8. Alshetaili A, Almutairy B, Tiwari R, Morott J, Alshehri S, Feng X, et al. Preparation and Evaluation of Hot-Melt Extruded Patient-Centric Ketoprofen Mini-Tablets. Curr Drug Deliv. 2016;13:730-41 pubmed
    ..The reduced drug release at salivary pH correlated well with Astree e-Tongue studies for taste masking efficiency. ..
  9. Alshahrani S, Morott J, Alshetaili A, Tiwari R, Majumdar S, Repka M. Influence of degassing on hot-melt extrusion process. Eur J Pharm Sci. 2015;80:43-52 pubmed publisher
    ..Employing a degassing unit during hot-melt extrusion processing could help increase process efficacy and product quality. ..
  10. request reprint
    Repka M, Mididoddi P, Stodghill S. Influence of human nail etching for the assessment of topical onychomycosis therapies. Int J Pharm. 2004;282:95-106 pubmed
    ..These findings are encouraging for the future design and formulation of novel drug delivery systems for the topical treatment of onychomycosis. ..
  11. Patil H, Tiwari R, Upadhye S, Vladyka R, Repka M. Formulation and development of pH-independent/dependent sustained release matrix tablets of ondansetron HCl by a continuous twin-screw melt granulation process. Int J Pharm. 2015;496:33-41 pubmed publisher
  12. Zhang J, Feng X, Patil H, Tiwari R, Repka M. Coupling 3D printing with hot-melt extrusion to produce controlled-release tablets. Int J Pharm. 2017;519:186-197 pubmed publisher
    ..In addition, formulations can be made based on the personal needs of patients. ..
  13. Pimparade M, Vo A, Maurya A, Bae J, Morott J, Feng X, et al. Development and evaluation of an oral fast disintegrating anti-allergic film using hot-melt extrusion technology. Eur J Pharm Biopharm. 2017;119:81-90 pubmed publisher
    ..An animal model was employed to determine the taste masking of melt-extruded films. The lead film formulation was subjected to a human panel for evaluation of extent of taste masking and disintegration. ..
  14. Vo A, Feng X, Pimparade M, Ye X, Kim D, Martin S, et al. Dual-mechanism gastroretentive drug delivery system loaded with an amorphous solid dispersion prepared by hot-melt extrusion. Eur J Pharm Sci. 2017;102:71-84 pubmed publisher
    ..Felodipine (PubChem CID: 3333); hypromellose (PubChem CID: 57503849), hydroxypropyl cellulose (PubChem CID: 71306830), sodium bicarbonate (PubChem CID: 516892); sodium carbonate (PubChem CID: 10340). ..
  15. Mendonsa N, Murthy S, Hashemnejad S, Kundu S, Zhang F, Repka M. Development of poloxamer gel formulations via hot-melt extrusion technology. Int J Pharm. 2018;537:122-131 pubmed publisher
    ..In conclusion, the hot-melt extrusion technology could be successfully employed to develop poloxamer gels by overcoming the drawbacks associated with the conventional techniques. ..
  16. Tiwari R, Polk A, Patil H, Ye X, Pimparade M, Repka M. Rat Palatability Study for Taste Assessment of Caffeine Citrate Formulation Prepared via Hot-Melt Extrusion Technology. AAPS PharmSciTech. 2017;18:341-348 pubmed publisher
    ..Thus, this rat model can be considered as a low-cost alternative taste-assessment method to the most commonly used expensive human taste panel/electronic tongue method for pediatric formulations. ..
  17. Repka M, ElSohly M, Munjal M, Ross S. Temperature stability and bioadhesive properties of delta9-tetrahydrocannabinol incorporated hydroxypropylcellulose polymer matrix systems. Drug Dev Ind Pharm. 2006;32:21-32 pubmed
  18. Repka M, Bandari S, Kallakunta V, Vo A, McFall H, Pimparade M, et al. Melt extrusion with poorly soluble drugs - An integrated review. Int J Pharm. 2018;535:68-85 pubmed publisher
    ..Overall, this review also provides an outline for the currently marketed products and analyzes the strengths, weaknesses, opportunities and threats of HME application in the pharmaceutical industry. ..
  19. Zhang J, Yang W, Vo A, Feng X, Ye X, Kim D, et al. Hydroxypropyl methylcellulose-based controlled release dosage by melt extrusion and 3D printing: Structure and drug release correlation. Carbohydr Polym. 2017;177:49-57 pubmed publisher
  20. Mendonsa N, Thipsay P, Kim D, Martin S, Repka M. Bioadhesive Drug Delivery System for Enhancing the Permeability of a BCS Class III Drug via Hot-Melt Extrusion Technology. AAPS PharmSciTech. 2017;18:2639-2647 pubmed publisher
    ..Hot-melt extrusion technology was successfully employed to formulate buccal tablets of ondansetron hydrochloride. ..