351
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Zhu Q, Toth SJ, Simpson GJ, Hsu HY, Taylor LS, Harris MT. Crystallization and dissolution behavior of naproxen/polyethylene glycol solid dispersions. J Phys Chem B 2013; 117:1494-500. [PMID: 23320811 DOI: 10.1021/jp3106716] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The crystallization kinetics of naproxen (NAP) in NAP/polyethylene glycol (NAP/PEG) solid dispersions prepared at different crystallization temperatures was studied by in situ small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS). It was found that the crystallization rate of NAP was faster at 25 °C in comparison to 40 °C. This resulted in different sizes of NAP domains, and consequently impacted the dissolution behavior. The sizes of NAP domains prepared at 40 °C were larger than those at 25 °C, as determined with surface area analysis, utilizing second-order nonlinear optical imaging of chiral crystals (SONICC). Consistent with this observation, the corresponding dissolution rate of the NAP/PEG dispersion prepared at 40 °C was indeed slower than that prepared at 25 °C. The microstructure of the NAP/PEG solid dispersions and the dissolution behavior also showed a dependence on the chemical composition of the solid dispersions.
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Affiliation(s)
- Qing Zhu
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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352
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Mahieu A, Willart JF, Dudognon E, Danède F, Descamps M. A new protocol to determine the solubility of drugs into polymer matrixes. Mol Pharm 2013; 10:560-6. [PMID: 23253068 DOI: 10.1021/mp3002254] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper we present a new protocol to determine faster the solubility of drugs into polymer matrixes. The originality of the method lies in the fact that the equilibrium saturated states are reached by demixing of supersaturated amorphous solid solutions and not by dissolution of crystalline drug into the amorphous polymer matrix as for usual methods. The equilibrium saturated states are thus much faster to reach due to the extra molecular mobility resulting from the strong plasticizing effect associated with the supersaturation conditions. The method is validated using the indomethacin/polyvinylpyrrolidone mixture whose solubility diagram was previously determined by usual techniques. The supersaturated states have been directly obtained in the solid state by comilling, and the investigations have been performed by differential scanning calorimetry and powder X-ray diffraction.
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Affiliation(s)
- Aurélien Mahieu
- Université de Lille Nord de France, F-59000 Lille, USTL UMET (Unité Matériaux et Transformations), UMR CNRS 8207, F-59650 Villeneuve d'Ascq, France
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353
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Lust A, Laidmäe I, Palo M, Meos A, Aaltonen J, Veski P, Heinämäki J, Kogermann K. Solid-state dependent dissolution and oral bioavailability of piroxicam in rats. Eur J Pharm Sci 2013; 48:47-54. [DOI: 10.1016/j.ejps.2012.10.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/26/2012] [Accepted: 10/10/2012] [Indexed: 10/27/2022]
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354
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Formulation Development of Amorphous Solid Dispersions Prepared by Melt Extrusion. AAPS ADVANCES IN THE PHARMACEUTICAL SCIENCES SERIES 2013. [DOI: 10.1007/978-1-4614-8432-5_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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355
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Grohganz H, Löbmann K, Priemel P, Tarp Jensen K, Graeser K, Strachan C, Rades T. Amorphous drugs and dosage forms. J Drug Deliv Sci Technol 2013. [DOI: 10.1016/s1773-2247(13)50057-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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356
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Xiang TX, Anderson BD. Molecular dynamics simulation of amorphous indomethacin-poly(vinylpyrrolidone) glasses: solubility and hydrogen bonding interactions. J Pharm Sci 2012; 102:876-91. [PMID: 23280486 DOI: 10.1002/jps.23353] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 08/17/2012] [Accepted: 10/09/2012] [Indexed: 11/07/2022]
Abstract
Amorphous drug dispersions are frequently employed to enhance solubility and dissolution of poorly water-soluble drugs and thereby increase their oral bioavailability. Because these systems are metastable, phase separation of the amorphous components and subsequent drug crystallization may occur during storage. Computational methods to determine the likelihood of these events would be very valuable, if their reliability could be validated. This study investigates amorphous systems of indomethacin (IMC) in poly(vinylpyrrolidone) (PVP) and their molecular interactions by means of molecular dynamics (MD) simulations. IMC and PVP molecules were constructed using X-ray diffraction data, and force-field parameters were assigned by analogy with similar groups in Amber-ff03. Five assemblies varying in PVP and IMC composition were equilibrated in their molten states then cooled at a rate of 0.03 K/ps to generate amorphous glasses. Prolonged aging dynamic runs (100 ns) at 298 K and 1 bar were then carried out, from which solubility parameters, the Flory-Huggins interaction parameter, and associated hydrogen bonding properties were obtained. Calculated glass transition temperature (T(g)) values were higher than experimental results because of the faster cooling rates in MD simulations. Molecular mobility as characterized by atomic fluctuations was substantially reduced below the T(g) with IMC-PVP systems exhibiting lower mobilities than that found in amorphous IMC, consistent with the antiplasticizing effect of PVP. The number of IMC-IMC hydrogen bonds (HBs) formed per IMC molecule was substantially lower in IMC-PVP mixtures, particularly the fractions of IMC molecules involved in two or three HBs with other IMC molecules that may be potential precursors for crystal growth. The loss of HBs between IMC molecules in the presence of PVP was largely compensated for by the formation of IMC-PVP HBs. The difference (6.5 MPa(1/2)) between the solubility parameters in amorphous IMC (25.5 MPa(1/2)) and PVP (19.0 MPa(1/2)) suggests a small, positive free energy of mixing, although it is close to the criterion for miscibility (<7 MPa(1/2)). In contrast to the solubility-parameter method, the calculated Flory-Huggins interaction parameter (-0.61 ± 0.25), which takes into account the IMC-PVP interaction energy, predicts complete miscibility at all PVP compositions, in agreement with experimental observations. These results from MD simulations were combined with experimental values for the crystalline γ-polymorph of IMC and amorphous IMC to estimate the solubility of IMC in amorphous PVP dispersions and the theoretical enhancement in the aqueous solubility of IMC molecularly dispersed in PVP at various volume fractions.
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Affiliation(s)
- Tian-Xiang Xiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, USA
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357
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Tian Y, Booth J, Meehan E, Jones DS, Li S, Andrews GP. Construction of Drug–Polymer Thermodynamic Phase Diagrams Using Flory–Huggins Interaction Theory: Identifying the Relevance of Temperature and Drug Weight Fraction to Phase Separation within Solid Dispersions. Mol Pharm 2012; 10:236-48. [DOI: 10.1021/mp300386v] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yiwei Tian
- The Drug Delivery and Biomaterials
Group, School of Pharmacy, Medical Biology Centre, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern
Ireland, United Kingdom
| | - Jonathan Booth
- Pharmaceutical Development, AstraZeneca, Silk Rd Business Park, Macclesfield, SK10
2NA
| | - Elizabeth Meehan
- Pharmaceutical Development, AstraZeneca, Silk Rd Business Park, Macclesfield, SK10
2NA
| | - David S. Jones
- The Drug Delivery and Biomaterials
Group, School of Pharmacy, Medical Biology Centre, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern
Ireland, United Kingdom
| | - Shu Li
- The Drug Delivery and Biomaterials
Group, School of Pharmacy, Medical Biology Centre, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern
Ireland, United Kingdom
| | - Gavin P. Andrews
- The Drug Delivery and Biomaterials
Group, School of Pharmacy, Medical Biology Centre, Queen's University, 97 Lisburn Road, Belfast, BT9 7BL, Northern
Ireland, United Kingdom
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358
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Bellantone RA, Patel P, Sandhu H, Choi DS, Singhal D, Chokshi H, Malick AW, Shah N. A Method to Predict the Equilibrium Solubility of Drugs in Solid Polymers near Room Temperature Using Thermal Analysis. J Pharm Sci 2012; 101:4549-58. [DOI: 10.1002/jps.23319] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 08/12/2012] [Accepted: 08/23/2012] [Indexed: 11/11/2022]
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359
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Paudel A, Nies E, Van den Mooter G. Relating Hydrogen-Bonding Interactions with the Phase Behavior of Naproxen/PVP K 25 Solid Dispersions: Evaluation of Solution-Cast and Quench-Cooled Films. Mol Pharm 2012; 9:3301-17. [DOI: 10.1021/mp3003495] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Amrit Paudel
- Laboratory of Pharmacotechnology
and Biopharmacy, KU Leuven, Leuven, Belgium
| | - Erik Nies
- Department of Chemistry, Polymer
Chemistry and Materials, KU Leuven, Heverlee, Belgium
| | - Guy Van den Mooter
- Laboratory of Pharmacotechnology
and Biopharmacy, KU Leuven, Leuven, Belgium
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360
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Kawakami K. Miscibility analysis of particulate solid dispersions prepared by electrospray deposition. Int J Pharm 2012; 433:71-8. [DOI: 10.1016/j.ijpharm.2012.04.082] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 04/30/2012] [Indexed: 11/27/2022]
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361
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Langham ZA, Booth J, Hughes LP, Reynolds GK, Wren SA. Mechanistic Insights into the Dissolution of Spray-Dried Amorphous Solid Dispersions. J Pharm Sci 2012; 101:2798-810. [DOI: 10.1002/jps.23192] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 02/12/2012] [Accepted: 04/24/2012] [Indexed: 11/09/2022]
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362
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Choi H, Lee H, Lee MK, Lee J. Polymer-Directed Crystallization of Atorvastatin. J Pharm Sci 2012; 101:2941-51. [PMID: 22628192 DOI: 10.1002/jps.23206] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/14/2012] [Accepted: 05/02/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Hyemin Choi
- Department of Chemical Engineering and Materials Science, Chung-Ang University, Seoul 156-756, Republic of Korea
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363
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Kim Y, Liemmawal ED, Pourgholami MH, Morris DL, Stenzel MH. Comparison of Shell-Cross-Linked Micelles with Soft and Glassy Cores as a Drug Delivery Vehicle for Albendazole: Is There a Difference in Performance? Macromolecules 2012. [DOI: 10.1021/ma300644v] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoseop Kim
- Centre
for Advanced Macromolecular Design (CAMD) and ‡Cancer Research Laboratories, Department
of Surgery, St. George Hospital, University of New South Wales, Sydney NSW 2052, Australia
| | - Elviana D. Liemmawal
- Centre
for Advanced Macromolecular Design (CAMD) and ‡Cancer Research Laboratories, Department
of Surgery, St. George Hospital, University of New South Wales, Sydney NSW 2052, Australia
| | - Mohammad H. Pourgholami
- Centre
for Advanced Macromolecular Design (CAMD) and ‡Cancer Research Laboratories, Department
of Surgery, St. George Hospital, University of New South Wales, Sydney NSW 2052, Australia
| | - David L. Morris
- Centre
for Advanced Macromolecular Design (CAMD) and ‡Cancer Research Laboratories, Department
of Surgery, St. George Hospital, University of New South Wales, Sydney NSW 2052, Australia
| | - Martina H. Stenzel
- Centre
for Advanced Macromolecular Design (CAMD) and ‡Cancer Research Laboratories, Department
of Surgery, St. George Hospital, University of New South Wales, Sydney NSW 2052, Australia
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364
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Van Eerdenbrugh B, Lo M, Kjoller K, Marcott C, Taylor LS. Nanoscale Mid-Infrared Imaging of Phase Separation in a Drug–Polymer Blend. J Pharm Sci 2012; 101:2066-73. [DOI: 10.1002/jps.23099] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 11/05/2022]
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365
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Chen X, Yuan C, Wong CKY, Zhang G. Molecular modeling of temperature dependence of solubility parameters for amorphous polymers. J Mol Model 2012; 18:2333-41. [PMID: 21975540 PMCID: PMC3360869 DOI: 10.1007/s00894-011-1249-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Accepted: 09/20/2011] [Indexed: 11/30/2022]
Abstract
A molecular modeling strategy is proposed to describe the temperature (T) dependence of solubility parameter (δ) for the amorphous polymers which exhibit glass-rubber transition behavior. The commercial forcefield "COMPASS" is used to support the atomistic simulations of the polymer. The temperature dependence behavior of δ for the polymer is modeled by running molecular dynamics (MD) simulation at temperatures ranging from 250 up to 650 K. Comparing the MD predicted δ value at 298 K and the glass transition temperature (T(g)) of the polymer determined from δ-T curve with the experimental value confirm the accuracy of our method. The MD modeled relationship between δ and T agrees well with the previous theoretical works. We also observe the specific volume (v), cohesive energy (U(coh)), cohesive energy density (E(CED)) and δ shows a similar temperature dependence characteristics and a drastic change around the T(g). Meanwhile, the applications of δ and its temperature dependence property are addressed and discussed.
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Affiliation(s)
- Xianping Chen
- Department of Precision and Microsystem Engineering, Delft University of Technology, Delft, the Netherlands.
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366
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Hugo M, Kunath K, Dressman J. Selection of excipient, solvent and packaging to optimize the performance of spray-dried formulations: case example fenofibrate. Drug Dev Ind Pharm 2012; 39:402-12. [PMID: 22591213 DOI: 10.3109/03639045.2012.685176] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Along with other options, solid dispersions prepared by spray drying offer the possibility of formulating poorly soluble drugs in a rapidly dissolving format. As a wide range of potential excipients and solvents is available for spray drying, it is usually necessary to carry out a comprehensive array of studies to arrive at an optimal formulation. OBJECTIVE To study the influence of formulation parameters such as co-sprayed excipients, solvents and packaging on the manufacture, in vitro performance and stability of spray-dried oral drug products using fenofibrate as a model drug. MATERIALS AND METHODS Solid dispersions of fenofibrate with different amorphous polymers were manufactured from two solvent systems by spray drying. These were characterized in terms of physicochemical properties, crystalline content and dissolution behavior in biorelevant media upon production and after storage in two packaging systems (Glass and Activ-Vials(™)). RESULTS AND DISCUSSION Spray drying the same formulation from two different solvents led to different physicochemical properties, dissolution behavior and long-term stability. The dissolution behavior and long-term stability also varied significantly among excipients. The viscosity of the polymer and the packaging material proved to be important to the long-term stability. CONCLUSION For spray-dried products containing fenofibrate, the excipients were ranked according to dissolution and stability performance as follows: PVP derivatives >> HPMC 2910/15, HPMCAS-MF, HP-β-CD >> PVP:PVA 2:8. EtOH 96% proved superior to acetone/water for spray drying with polymers. The results were used to propose a general approach to developing spray-dried formulations of poorly soluble drugs.
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Affiliation(s)
- Marc Hugo
- Institute of Pharmaceutical Technology, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
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367
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Löbmann K, Strachan C, Grohganz H, Rades T, Korhonen O, Laitinen R. Co-amorphous simvastatin and glipizide combinations show improved physical stability without evidence of intermolecular interactions. Eur J Pharm Biopharm 2012; 81:159-69. [DOI: 10.1016/j.ejpb.2012.02.004] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 02/02/2012] [Accepted: 02/06/2012] [Indexed: 11/26/2022]
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368
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Kushida I, Gotoda M. Investigation for the amorphous state of ER-34122, a dual 5-lipoxygenase/cyclooxygenase inhibitor with poor aqueous solubility, in HPMC solid dispersion prepared by the solvent evaporation method. Drug Dev Ind Pharm 2012; 39:1582-8. [PMID: 22519663 DOI: 10.3109/03639045.2012.679279] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ER-34122, a poorly water-soluble dual 5-lipoxygenase/cyclooxygenase inhibitor, exists as a crystalline form. According to an Oak Ridge thermal ellipsoid plot drawing, carbonyl oxygen O (5) makes an intermolecular hydrogen bond with the hydrogen bonded to N (3) in the crystal structure. The FTIR and the solid-state ¹³C NMR spectra suggest that the network is spread out in the amorphous state and the hydrogen bonding gets weaker than that in the crystalline phase, because the carbonyl signals significantly shift in both spectra. When amorphous ER-34122 was heated, crystallization occurred at around 140°C. Similar crystallization happened in the solid dispersion; however, the degree of crystallization was much lower than that observed in the pure amorphous material. Also, the DSC thermogram of the solid dispersion did not show any exothermic peaks implying crystallization. The heat of fusion (ΔHf) determined in the pure amorphous material was nearly equal to that for the crystalline form, whereas the ΔHf value obtained in the solid dispersion was less than a third of them. These data prove that crystallization of the amorphous form is dramatically restrained in the solid dispersion system. The carbonyl wavenumber shifts in the FTIR spectra indicate that the average hydrogen bond in the solid dispersion is lower than that in the pure amorphous material. Therefore, HPMC will suppress formation of the intermolecular network observed in ER-34122 crystal and preserve the amorphous state, which is thermodynamically less stable, in the solid dispersed system.
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Affiliation(s)
- Ikuo Kushida
- Analytical Research, CMC Japan, Pharmaceutical Science & Technology Core Function Unit, Eisai Product Creation Systems, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
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369
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Baird JA, Taylor LS. Evaluation of amorphous solid dispersion properties using thermal analysis techniques. Adv Drug Deliv Rev 2012; 64:396-421. [PMID: 21843564 DOI: 10.1016/j.addr.2011.07.009] [Citation(s) in RCA: 324] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 07/25/2011] [Accepted: 07/28/2011] [Indexed: 11/28/2022]
Abstract
Amorphous solid dispersions are an increasingly important formulation approach to improve the dissolution rate and apparent solubility of poorly water soluble compounds. Due to their complex physicochemical properties, there is a need for multi-faceted analytical methods to enable comprehensive characterization, and thermal techniques are widely employed for this purpose. Key parameters of interest that can influence product performance include the glass transition temperature (T(g)), molecular mobility of the drug, miscibility between the drug and excipients, and the rate and extent of drug crystallization. It is important to evaluate the type of information pertaining to the aforementioned properties that can be extracted from thermal analytical measurements, in addition to considering any inherent assumptions or limitations of the various analytical approaches. Although differential scanning calorimetry (DSC) is the most widely used thermal analytical technique applied to the characterization of amorphous solid dispersions, there are many established and emerging techniques which have been shown to provide useful information. Comprehensive characterization of fundamental material descriptors will ultimately lead to the formulation of more robust solid dispersion products.
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Affiliation(s)
- Jared A Baird
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA
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370
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371
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Sun Y, Zhu L, Wu T, Cai T, Gunn EM, Yu L. Stability of amorphous pharmaceutical solids: crystal growth mechanisms and effect of polymer additives. AAPS JOURNAL 2012; 14:380-8. [PMID: 22434258 DOI: 10.1208/s12248-012-9345-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 03/05/2012] [Indexed: 11/30/2022]
Abstract
We review recent progress toward understanding and enhancing the stability of amorphous pharmaceutical solids against crystallization. As organic liquids are cooled to become glasses, fast modes of crystal growth can emerge. One such growth mode, the glass-to-crystal or GC mode, occurs in the bulk, and another exists at the free surface, both leading to crystal growth much faster than predicted by theories that assume diffusion defines the kinetic barrier of crystallization. These phenomena have received different explanations, and we propose that GC growth is a solid-state transformation enabled by local mobility in glasses and that fast surface crystal growth is facilitated by surface molecular mobility. In the second part, we review recent findings concerning the effect of polymer additives on crystallization in organic glasses. Low-concentration polymer additives can strongly inhibit crystal growth in the bulk of organic glasses, while having weaker effect on surface crystal growth. Ultra-thin polymer coatings can inhibit surface crystallization. Recent work has shown the importance of molecular weight for crystallization inhibitors of organic glasses, besides "direct intermolecular interactions" such as hydrogen bonding. Relative to polyvinylpyrrolidone, the VP dimer is far less effective in inhibiting crystal growth in amorphous nifedipine. Further work is suggested for better understanding of crystallization of amorphous organic solids and the prediction of their stability.
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Affiliation(s)
- Ye Sun
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, USA.
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372
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Sathigari SK, Radhakrishnan VK, Davis VA, Parsons DL, Babu RJ. Amorphous-state characterization of efavirenz--polymer hot-melt extrusion systems for dissolution enhancement. J Pharm Sci 2012; 101:3456-64. [PMID: 22437488 DOI: 10.1002/jps.23125] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 02/05/2012] [Accepted: 02/29/2012] [Indexed: 11/09/2022]
Abstract
The aim of this study was to improve the dissolution rate of efavirenz (EFV) by formulating a physically stable dispersion in polymers. Hot-melt extrusion (HME) was used to prepare solid solutions of EFV with Eudragit EPO (a low-glass transition polymer) or Plasdone S-630 (a high-glass transition polymer). The drug-polymer blends were characterized for their thermal and rheological properties as a function of drug concentration to understand their miscibility and processability by HME. The solid-state stability of extrudates was characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and dissolution studies. Thermal and rheological studies revealed that the drug is miscible with both polymers, and a decrease in melt viscosity was observed as the drug concentration increased. XRD and DSC studies confirmed the existence of amorphous state of EFV in the extrudates during storage. The dissolution rate of EFV from the extrudates was substantially higher than the crystalline drug. FTIR studies revealed an interaction between the EFV and Plasdone S-630, which reduced the molecular mobility and prevented crystallization upon storage. EFV and Eudragit EPO systems lack specific interactions, but are less susceptible to crystallization due to the antiplasticization effect of the polymer.
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373
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Yang M, Wang P, Gogos C. Prediction of acetaminophen's solubility in poly(ethylene oxide) at room temperature using the Flory-Huggins theory. Drug Dev Ind Pharm 2012; 39:102-8. [PMID: 22356356 DOI: 10.3109/03639045.2012.659188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Solid dispersion technologies such as hot-melt extrusion and spray drying are often used to enhance the solubility of poorly soluble drugs. The biggest challenge associated with solid dispersion systems is that amorphous drugs may phase-separate from the polymeric matrix and recrystallize during storage. A more fundamental understanding of drug-polymer mixtures is needed for the industry to embrace the solid dispersion technologies. In this study, a theoretical model based on Flory-Huggins lattice theory was utilized to predict the solubility of a model drug acetaminophen (APAP) in a semi-crystalline polymer poly(ethylene oxide) (PEO) at 300 K. The interaction parameter χ was calculated to be -1.65 from the depression of drug's melting temperature determined from rheological and differential scanning calorimetry analysis. The equilibrium solubility in amorphous PEO was estimated to be 11.7% at 300 K. Assuming no APAP molecules dissolve in the crystalline part of PEO, the adjusted theoretical solubility is around 2.3% considering PEO being 80% crystalline. The solubility of APAP in PEG 400 was calculated to be 14.6% by using the same χ value, close to the experimental measurement 17.1%. The drug's solubility could be altered noticeably by the change of both χ and polymer molecular weight. The study also suggests that the depression of drug's melting point is a good indicator for preliminary polymer screening. The polymer that reduces the melting point the most is likely to be most miscible with the drug.
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Affiliation(s)
- Min Yang
- The Otto H. York Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
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374
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Qian KK, Bogner RH. Application of Mesoporous Silicon Dioxide and Silicate in Oral Amorphous Drug Delivery Systems. J Pharm Sci 2012; 101:444-63. [DOI: 10.1002/jps.22779] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/06/2011] [Accepted: 09/15/2011] [Indexed: 11/08/2022]
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375
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376
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Van den Mooter G. The use of amorphous solid dispersions: A formulation strategy to overcome poor solubility and dissolution rate. DRUG DISCOVERY TODAY. TECHNOLOGIES 2012; 9:e71-e174. [PMID: 24064267 DOI: 10.1016/j.ddtec.2011.10.002] [Citation(s) in RCA: 396] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
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377
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Abu-Diak OA, Jones DS, Andrews GP. Understanding the Performance of Melt-Extruded Poly(ethylene oxide)–Bicalutamide Solid Dispersions: Characterisation of Microstructural Properties Using Thermal, Spectroscopic and Drug Release Methods. J Pharm Sci 2012; 101:200-13. [DOI: 10.1002/jps.22748] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 07/18/2011] [Accepted: 08/12/2011] [Indexed: 11/06/2022]
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378
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Inkjet printing as a novel medicine formulation technique. J Control Release 2011; 156:179-85. [DOI: 10.1016/j.jconrel.2011.07.033] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/22/2011] [Accepted: 07/23/2011] [Indexed: 11/20/2022]
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379
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Liu X, Lu M, Guo Z, Huang L, Feng X, Wu C. Improving the chemical stability of amorphous solid dispersion with cocrystal technique by hot melt extrusion. Pharm Res 2011; 29:806-17. [PMID: 22009589 DOI: 10.1007/s11095-011-0605-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 09/29/2011] [Indexed: 11/28/2022]
Abstract
PURPOSE To explore in-situ forming cocrystal as a single-step, efficient method to significantly depress the processing temperature and thus minimize the thermal degradation of heat-sensitive drug in preparation of solid dispersions by melting method (MM) and hot melt extrusion (HME). METHODS Carbamazepine (CBZ)-nicotinamide (NIC) cocrystal solid dispersions were prepared with polymer carriers PVP/VA, SOLUPLUS and HPMC by MM and/or HME. The formation of cocrystal was investigated by differential scanning calorimetry and hot stage polarized optical microscopy. State of CBZ in solid dispersion was characterized by X-ray powder diffraction and optical microscopy. Interactions between CBZ, NIC and polymers were investigated by FTIR. Dissolution behaviors of solid dispersions were compared with that of pure CBZ. RESULTS CBZ-NIC cocrystal with melting point of 160°C was formed in polymer carriers during heating process, and the preparation temperature of amorphous CBZ solid dispersion was therefore depressed to 160°C. The dissolution rate of CBZ-NIC cocrystal solid dispersion was significantly increased. CONCLUSIONS By in-situ forming cocrystal, chemically stable amorphous solid dispersions were prepared by MM and HME at a depressed processing temperature. This method provides an attractive opportunity for HME of heat-sensitive drugs.
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Affiliation(s)
- Xu Liu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, Guangdong, People's Republic of China
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380
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Gu J, Cheng WP, Hoskins C, Lin PKT, Zhao L, Zhu L, Qu X, Yang Z. Nano self-assemblies based on cholate grafted poly-L-lysine enhanced the solubility of sterol-like drugs. J Microencapsul 2011; 28:752-62. [PMID: 21967462 DOI: 10.3109/02652048.2011.615951] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The physicochemical compatibility between amphiphilic polymers and hydrophobic drugs has been recognized as an important issue for improving the drug solubilisation in polymeric micelle formulations. In this work, poly-L-lysine (PLL) grafted by cholate pendants as the only hydrophobic moiety were synthesized in order to facilitate the solubilisation of sterol drugs. Results showed that micelles formed by cholate grafted PLL encapsulated significantly higher level of prednisolone and estradiol than palmitoylated PLL micelles, whereas the solubilisation capacity of non-sterol drug (griseofulvin) is inefficient for both polymers. This suggests that higher drug-polymer incorporation can be achieved by the inclusion of hydrophobic moieties with similar architecture as the drugs, i.e. 'drug-like' functional groups, which will be useful for the future design of colloidal systems for the encapsulation of specific drug.
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Affiliation(s)
- Jingxia Gu
- State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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381
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Alonzo DE, Gao Y, Zhou D, Mo H, Zhang GG, Taylor LS. Dissolution and Precipitation Behavior of Amorphous Solid Dispersions. J Pharm Sci 2011; 100:3316-3331. [DOI: 10.1002/jps.22579] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 03/28/2011] [Accepted: 03/31/2011] [Indexed: 11/11/2022]
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382
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Al-Obaidi H, Ke P, Brocchini S, Buckton G. Characterization and stability of ternary solid dispersions with PVP and PHPMA. Int J Pharm 2011; 419:20-7. [PMID: 21801822 DOI: 10.1016/j.ijpharm.2011.06.052] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 10/17/2022]
Abstract
The effect of adding a third polymer to immiscible binary solid dispersions was investigated. The model actives griseofulvin (GF), progesterone (PG) and phenindione (PD) were selected because they exemplify a key property of many poorly soluble molecules of having at least one hydrogen bonding acceptor moiety while not having any hydrogen bond donating moieties. Ternary solid dispersions of the drug, PVP (polyvinylpyrrolidone) (proton acceptor) and PHPMA (poly[2-hydroxypropyl methacrylate]) (proton acceptor and donor) were prepared by spray drying. Stability results showed that binary solid dispersions (API and PVP) of GF and PVP crystallized quickly while the amorphous form was not possible to prepare for PG and PD. The amorphous form was prolonged upon the incorporation of PHPMA in the solid dispersion (API, PHPMA and PVP). Based on measuring the melting points, the energy of mixing the drug with the polymer was calculated using the Flory-Huggins theory. The results showed that GF had the lowest free energy followed by PG and finally PD which agreed well with the stability results. These results suggest that the addition of a third polymer to immiscible binary solid dispersions can significantly improve the stability of the amorphous form.
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Affiliation(s)
- Hisham Al-Obaidi
- Institute of Pharmaceutical Sciences, King's College London, Franklin Wilkins Building, 150 Stamford Street, London SE1 9NH, UK.
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383
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Danquah MK, Zhang XA, Mahato RI. Extravasation of polymeric nanomedicines across tumor vasculature. Adv Drug Deliv Rev 2011; 63:623-39. [PMID: 21144874 DOI: 10.1016/j.addr.2010.11.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 11/22/2010] [Accepted: 11/30/2010] [Indexed: 12/18/2022]
Abstract
Tumor microvasculature is fraught with numerous physiological barriers which hinder the efficacy of anticancer agents. These barriers include chaotic blood supply, poor tumor vasculature permeability, limited transport across the interstitium due to high interstitial pressure and absence of lymphatic network. Abnormal microvasculature also leads to hypoxia and acidosis which limits effectiveness of chemotherapy. These barriers restrict drug or drug carrier extravasation which hampers tumor regression. Targeting key features of the tumor microenvironment such as tumor microvessels, interstitial hypertension and tumor pH is a promising approach to improving the efficacy of anticancer drugs. This review highlights the current knowledge on the distinct tumor microenvironment generated barriers which limit extravasation of drugs and focuses on modalities for overcoming these barriers using multi-functional polymeric carriers. Special attention is given to utilizing polymeric nanomedicines to facilitate extravasation of anticancer drugs for future cancer therapy.
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Affiliation(s)
- Michael K Danquah
- Department of Pharmaceutical Sciences, 19. South Manassas St., Memphis, TN 38103-3308, USA
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384
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Moore MD, Wildfong PLD. Informatics calibration of a molecular descriptors database to predict solid dispersion potential of small molecule organic solids. Int J Pharm 2011; 418:217-26. [PMID: 21756988 DOI: 10.1016/j.ijpharm.2011.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 05/15/2011] [Accepted: 06/01/2011] [Indexed: 10/18/2022]
Abstract
The use of a novel, in silico method for making an intelligent polymer selection to physically stabilize small molecule organic (SMO) solid compounds formulated as amorphous molecular solid dispersions is reported. 12 compounds (75%, w/w) were individually co-solidified with polyvinyl pyrrolidone:vinyl acetate (PVPva) copolymer by melt-quenching. Co-solidified products were analyzed intact using differential scanning calorimetry (DSC) and the pair distribution function (PDF) transform of powder X-ray diffraction (PXRD) data to assess miscibility. Molecular descriptor indices were calculated for all twelve compounds using their reported crystallographic structures. Logistic regression was used to assess correlation between molecular descriptors and amorphous molecular solid dispersion potential. The final model was challenged with three compounds. Of the 12 compounds, 6 were miscible with PVPva (i.e. successful formation) and 6 were phase separated (i.e. unsuccessful formation). 2 of the 6 unsuccessful compounds exhibited detectable phase-separation using the PDF method, where DSC indicated miscibility. Logistic regression identified 7 molecular descriptors correlated to solid dispersion potential (α=0.001). The atomic mass-weighted third-order R autocorrelation index (R3m) was the only significant descriptor to provide completely accurate predictions of dispersion potential. The three compounds used to challenge the R3m model were also successfully predicted.
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Affiliation(s)
- Michael D Moore
- Duquesne University Graduate School of Pharmaceutical Sciences, 600 Forbes Ave., Pittsburgh, PA 15282, USA
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385
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Qian KK, Bogner RH. Spontaneous Crystalline-to-Amorphous Phase Transformation of Organic or Medicinal Compounds in the Presence of Porous Media, Part 1: Thermodynamics of Spontaneous Amorphization. J Pharm Sci 2011; 100:2801-15. [DOI: 10.1002/jps.22519] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 01/06/2011] [Accepted: 01/19/2011] [Indexed: 11/12/2022]
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386
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Zhu Q, Harris MT, Taylor LS. Time-Resolved SAXS/WAXS Study of the Phase Behavior and Microstructural Evolution of Drug/PEG Solid Dispersions. Mol Pharm 2011; 8:932-9. [PMID: 21452866 DOI: 10.1021/mp200041j] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qing Zhu
- School of Chemical Engineering and ‡Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Michael T. Harris
- School of Chemical Engineering and ‡Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Lynne S. Taylor
- School of Chemical Engineering and ‡Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
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387
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Differences in crystallization rate of nitrendipine enantiomers in amorphous solid dispersions with HPMC and HPMCP. Int J Pharm 2011; 407:111-8. [DOI: 10.1016/j.ijpharm.2011.01.035] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/21/2010] [Accepted: 01/19/2011] [Indexed: 11/17/2022]
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388
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Mahlin D, Ponnambalam S, Heidarian Höckerfelt M, Bergström CAS. Toward In Silico Prediction of Glass-Forming Ability from Molecular Structure Alone: A Screening Tool in Early Drug Development. Mol Pharm 2011; 8:498-506. [DOI: 10.1021/mp100339c] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Denny Mahlin
- Department of Pharmacy, Uppsala University, Uppsala Biomedical Center, P.O. Box 580, SE-751 23 Uppsala, Sweden
| | - Sopana Ponnambalam
- Department of Pharmacy, Uppsala University, Uppsala Biomedical Center, P.O. Box 580, SE-751 23 Uppsala, Sweden
| | - Mina Heidarian Höckerfelt
- Department of Pharmacy, Uppsala University, Uppsala Biomedical Center, P.O. Box 580, SE-751 23 Uppsala, Sweden
| | - Christel A. S. Bergström
- Department of Pharmacy, Uppsala University, Uppsala Biomedical Center, P.O. Box 580, SE-751 23 Uppsala, Sweden
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389
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Zhao Y, Inbar P, Chokshi HP, Malick AW, Choi DS. Prediction of the thermal phase diagram of amorphous solid dispersions by Flory-Huggins theory. J Pharm Sci 2011; 100:3196-3207. [PMID: 21416468 DOI: 10.1002/jps.22541] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/11/2011] [Accepted: 02/16/2011] [Indexed: 02/05/2023]
Abstract
Miscibility of drug and polymer is one of the key parameters in amorphous formulation design. The purpose of this work is to provide a theoretical approach to evaluate miscibility between drug and polymer in amorphous solid dispersions. The model system is indomethacin and polyvinylpyrrolidone-vinyl acetate copolymer. The Flory-Huggins (F-H) interaction parameter, χ, of drug and polymer was estimated at different temperatures by two methods: melting point depression of drug in various polymer ratios at the melting temperature, and Hildebrand and Scott solubility parameter calculation at 25°C. The simplified first-order relation between the F-H interaction parameter and temperature was established. This allows the construction of a temperature-composition phase diagram of a two-component amorphous system. The spinodal curve was generated and provides an insight into the thermodynamic stability of an amorphous solid dispersion at various temperatures. The predicted stability of the model system was compared with the experimental data. The merits and deficiency of the proposed approach were fully discussed.
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Affiliation(s)
- Yinyan Zhao
- Department of Pharmaceutical and Analytical R&D, Hoffmann-La Roche Inc., Nutley, New Jersey 07110.
| | - Petra Inbar
- Department of Pharmaceutical and Analytical R&D, Hoffmann-La Roche Inc., Nutley, New Jersey 07110
| | - Hitesh P Chokshi
- Department of Pharmaceutical and Analytical R&D, Hoffmann-La Roche Inc., Nutley, New Jersey 07110
| | - A Wasseem Malick
- Department of Pharmaceutical and Analytical R&D, Hoffmann-La Roche Inc., Nutley, New Jersey 07110
| | - Duk Soon Choi
- Department of Pharmaceutical and Analytical R&D, Hoffmann-La Roche Inc., Nutley, New Jersey 07110
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390
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Caron V, Tajber L, Corrigan OI, Healy AM. A Comparison of Spray Drying and Milling in the Production of Amorphous Dispersions of Sulfathiazole/Polyvinylpyrrolidone and Sulfadimidine/Polyvinylpyrrolidone. Mol Pharm 2011; 8:532-42. [DOI: 10.1021/mp1003674] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vincent Caron
- School of Pharmacy and Pharmaceutical Sciences, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Lidia Tajber
- School of Pharmacy and Pharmaceutical Sciences, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Owen I. Corrigan
- School of Pharmacy and Pharmaceutical Sciences, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Anne Marie Healy
- School of Pharmacy and Pharmaceutical Sciences, University of Dublin, Trinity College, Dublin 2, Ireland
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391
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Kim JY, Kim S, Pinal R, Park K. Hydrotropic polymer micelles as versatile vehicles for delivery of poorly water-soluble drugs. J Control Release 2011; 152:13-20. [PMID: 21352878 DOI: 10.1016/j.jconrel.2011.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 02/04/2011] [Accepted: 02/11/2011] [Indexed: 11/26/2022]
Abstract
Polymer micelles have been used widely for delivery of poorly water-soluble drugs. Such drug delivery, however, has been based primarily on hydrophobic interactions. For better drug loading and improved stability, hydrotropic polymer micelles were used. To develop a versatile polymer micelle for solubilizing various poorly soluble drugs, two different hydrotropic agents were examined. The solubilizing properties of two hydrotropic agents, N,N-diethylnicotinamide (DENA) and N,N-dimethylbenzamide (DMBA), in polymeric form were investigated for their ability to solubilize five drugs with low aqueous solubility covering a wide range of hydrophobicity and molecular structures. The hydrotropes were covalently linked to the hydrophobic block of a block copolymer that also had a hydrophilic poly(ethylene glycol) (PEG) block. The solubilizing capacity of the polymeric hydrotropes was compared with that of the non polymeric hydrotropes, as well as of two conventional (non hydrotropic) copolymer systems. The solubilizing capacity of polymeric hydrotropes reflects combined effects of the micellar solubilization by the hydrophobic micelle core and hydrotropic solubilization. Because of the highly localized configuration, hydrotropes in the polymeric form are more powerful solubilizers than in the monomeric (non-polymeric) solution. It is possible to produce 1~3 orders of magnitude increase in solubility with polymeric hydrotropes at the 1% (w/v) level. Of the two hydrotropic polymeric systems in this study, the DENA-based system is highly specific, whereas the DMBA-based system is a general solubilizer of hydrophobic drugs. An additional advantage of polymeric hydrotropes over the non-polymeric form is absence of high concentrations of free hydrotropes in the formulation. Solubilization vehicles based on polymeric hydrotropes are expected to provide a new and versatile means of preparing formulations for various poorly soluble drugs and drug candidates without using organic solvents. This advantage is accompanied with the inherent controlled release property of the hydrotropic polymer micelles, making them ideal for pharmaceutical formulations used in drug candidate screening and toxicology studies.
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Affiliation(s)
- Ji Young Kim
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907, USA
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392
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Albers J, Matthée K, Knop K, Kleinebudde P. Evaluation of Predictive Models for Stable Solid Solution Formation. J Pharm Sci 2011; 100:667-80. [DOI: 10.1002/jps.22313] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 05/14/2010] [Accepted: 07/01/2010] [Indexed: 11/08/2022]
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393
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Saylor DM, Guyer JE, Wheeler D, Warren JA. Predicting microstructure development during casting of drug-eluting coatings. Acta Biomater 2011; 7:604-13. [PMID: 20858554 DOI: 10.1016/j.actbio.2010.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 09/08/2010] [Accepted: 09/15/2010] [Indexed: 11/19/2022]
Abstract
We have devised a novel diffuse interface formulation to model the development of chemical and physical inhomogeneities, i.e. microstructure, during the process of casting drug-eluting coatings. These inhomogeneities, which depend on the coating constituents and manufacturing conditions, can have a profound affect on the rate and extent of drug release, and therefore the ability of coated medical devices to function successfully. By deriving the model equations in a time-dependent reference frame, we find that it is computationally viable to probe a wide, physically relevant range of material and process quantities. To illustrate the application of the model, we have evaluated the impact of manufacturing solvent, coating thickness and evaporation rate on microstructure development. Our results suggest that modifying these process conditions can have a strong and nearly discontinuous effect on coating microstructure, and therefore on drug release. Further, we demonstrate that the model can be applied to processes that involve the incremental application of the coating in layers or passes. This new model formulation, which can also be used to predict the kinetics of drug release, provides a tool to elucidate and quantify the relationships between process variables, microstructure and performance. Establishing these relationships can reduce empiricism in materials selection and process design, providing a facile and efficient means to tailor the underlying microstructure and achieve a desired drug-release behavior.
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Affiliation(s)
- David M Saylor
- Division of Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA.
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394
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Kleinebudde P. Pharmazeutisches Produktdesign: Gezielte Freisetzung von Wirkstoffen durch unterschiedliche Extrusionstechniken. CHEM-ING-TECH 2011. [DOI: 10.1002/cite.201000162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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395
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Mohammad MA, Alhalaweh A, Velaga SP. Hansen solubility parameter as a tool to predict cocrystal formation. Int J Pharm 2011; 407:63-71. [PMID: 21256944 DOI: 10.1016/j.ijpharm.2011.01.030] [Citation(s) in RCA: 303] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 01/06/2011] [Accepted: 01/13/2011] [Indexed: 11/26/2022]
Abstract
The objective of this study was to investigate whether the miscibility of a drug and coformer, as predicted by Hansen solubility parameters (HSPs), can indicate cocrystal formation and guide cocrystal screening. It was also our aim to evaluate various HSPs-based approaches in miscibility prediction. HSPs for indomethacin (the model drug) and over thirty coformers were calculated according to the group contribution method. Differences in the HSPs between indomethacin and each coformer were then calculated using three established approaches, and the miscibility was predicted. Subsequently, differential scanning calorimetry was used to investigate the experimental miscibility and cocrystal formation. The formation of cocrystals was also verified using liquid-assisted grinding. All except one of the drug-coformers that were predicted to be miscible were confirmed experimentally as miscible. All tested theoretical approaches were in agreement in predicting miscibility. All systems that formed cocrystals were miscible. Remarkably, two new cocrystals of indomethacin were discovered in this study. Though it may be necessary to test this approach in a wide range of different coformer and drug compound types for accurate generalizations, the trends with tested systems were clear and suggest that the drug and coformer should be miscible for cocrystal formation. Thus, predicting the miscibility of cocrystal components using solubility parameters can guide the selection of potential coformers prior to exhaustive cocrystal screening work.
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396
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Determination of acetaminophen's solubility in poly(ethylene oxide) by rheological, thermal and microscopic methods. Int J Pharm 2011; 403:83-9. [DOI: 10.1016/j.ijpharm.2010.10.026] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 10/05/2010] [Accepted: 10/18/2010] [Indexed: 11/19/2022]
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397
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Sun Y, Tao J, Zhang GGZ, Yu L. Solubilities of crystalline drugs in polymers: an improved analytical method and comparison of solubilities of indomethacin and nifedipine in PVP, PVP/VA, and PVAc. J Pharm Sci 2010; 99:4023-31. [PMID: 20607809 DOI: 10.1002/jps.22251] [Citation(s) in RCA: 170] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A previous method for measuring solubilities of crystalline drugs in polymers has been improved to enable longer equilibration and used to survey the solubilities of indomethacin (IMC) and nifedipine (NIF) in two homo-polymers [polyvinyl pyrrolidone (PVP) and polyvinyl acetate (PVAc)] and their co-polymer (PVP/VA). These data are important for understanding the stability of amorphous drug-polymer dispersions, a strategy actively explored for delivering poorly soluble drugs. Measuring solubilities in polymers is difficult because their high viscosities impede the attainment of solubility equilibrium. In this method, a drug-polymer mixture prepared by cryo-milling is annealed at different temperatures and analyzed by differential scanning calorimetry to determine whether undissolved crystals remain and thus the upper and lower bounds of the equilibrium solution temperature. The new annealing method yielded results consistent with those obtained with the previous scanning method at relatively high temperatures, but revised slightly the previous results at lower temperatures. It also lowered the temperature of measurement closer to the glass transition temperature. For D-mannitol and IMC dissolving in PVP, the polymer's molecular weight has little effect on the weight-based solubility. For IMC and NIF, the dissolving powers of the polymers follow the order PVP > PVP/VA > PVAc. In each polymer studied, NIF is less soluble than IMC. The activities of IMC and NIF dissolved in various polymers are reasonably well fitted to the Flory-Huggins model, yielding the relevant drug-polymer interaction parameters. The new annealing method yields more accurate data than the previous scanning method when solubility equilibrium is slow to achieve. In practice, these two methods can be combined for efficiency. The measured solubilities are not readily anticipated, which underscores the importance of accurate experimental data for developing predictive models.
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Affiliation(s)
- Ye Sun
- School of Pharmacy and Department of Chemistry, University of Wisconsin, 777 Highland Avenue, Madison, Wisconsin 53705, USA
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398
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Kim JY, Kim S, Papp M, Park K, Pinal R. Hydrotropic solubilization of poorly water-soluble drugs. J Pharm Sci 2010; 99:3953-65. [PMID: 20607808 DOI: 10.1002/jps.22241] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The solubilizing ability of two aromatic hydrotropes, N,N-diethylnicotinamide (DENA) and N,N-dimethylbenzamide (DMBA), was investigated using a set of 13 poorly soluble, structurally diverse drugs. The number of aromatic rings in the solute molecule has a very strong effect on the solubility enhancement produced by either hydrotrope. However, although solubility enhancements in the order of 1000- to 10,000-fold were obtained with each of the hydrotropic agents, important differences were found between the two. DMBA is more hydrophobic and undergoes more extensive self-association than DENA, as determined by vapor osmometry. As a result, DMBA is generally a more powerful solubilizer of hydrophobic drugs. DENA, on the other hand, is more polar and its self-association is essentially limited to dimer formation. However, despite being less hydrophobic, DENA is an extremely powerful solubilizer of paclitaxel, a highly hydrophobic compound. Such a result is attributed to the higher hydrogen bonding ability of DENA over DMBA and the very high hydrogen bonding ability of paclitaxel. These observations in turn illustrate the strong interplay between specific and hydrophobic interactions on the observed solubilization by hydrotropic agents.
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Affiliation(s)
- Ji Young Kim
- Department of Industrial and Physical Pharmacy, Purdue University, College of Pharmacy, 575 Stadium Mall Drive, West Lafayette, Indiana 47907-2091, USA
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399
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A thermal analysis method to predict the complete phase diagram of drug–polymer solid dispersions. Int J Pharm 2010; 399:109-15. [DOI: 10.1016/j.ijpharm.2010.08.013] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 08/04/2010] [Accepted: 08/11/2010] [Indexed: 11/23/2022]
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400
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Caron V, Bhugra C, Pikal MJ. Prediction of Onset of Crystallization in Amorphous Pharmaceutical Systems: Phenobarbital, Nifedipine/PVP, and Phenobarbital/PVP. J Pharm Sci 2010; 99:3887-900. [DOI: 10.1002/jps.22232] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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