Skip to main content
Log in

In Vitro and In Vivo Assessment of the Potential of Supersaturation to Enhance the Absorption of Poorly Soluble Basic Drugs

Journal of Pharmaceutical Innovation Aims and scope Submit manuscript

Cite this article



Delaying precipitation of weakly basic drugs in supersaturated state following their transition from the acidic gastric environment to the near-neutral proximal small intestinal fluid is emerging as a promising tactic for achieving higher transitional solubility and improving bioavailability of such drugs. The aim of this study was to assess the effect of supersaturation on drug dissolution and permeation in vitro, and to evaluate the in vitro-in vivo correlation of the supersaturation effect for the poorly soluble basic drug ketoconazole.


We monitored dissolution of drugs in simulated gastric fluid followed by drug dissolution in simulated intestinal fluid and simultaneous permeation across Caco-2 cell monolayers using the IDAS2 experimental procedure. The pH shift from pH 1.6 to pH 6.5 (mimicking in vivo gastric to intestinal transition) was used to induce transient in vitro supersaturation of the tested weakly basic poorly soluble drugs. Polymeric precipitation inhibitor, hydroxypropyl methylcellulose acetate succinate (HPMCAS), was added to dissolution medium in order to increase the amplitude and duration of the pH-driven supersaturation of the weakly basic drug ketoconazole in the in vitro IDAS2 setting. The effect of HPMCAS on oral bioavailability of ketoconazole was demonstrated in the rat pharmacokinetic model.


Drug supersaturation induced by pH shift was assessed in vitro by comparing drug dissolution and permeation under the 2-stage (pH shift from gastric pH 1.6 to intestinal pH 6.5) conditions vs. 1-stage (constant intestinal pH 6.5) conditions. Compared to the 1-stage conditions, 2-stage procedure increased in vitro dissolution AUC (area under the concentration-time curve) of the weakly basic drugs dipyridamole, ketoconazole, and itraconazole by 393%, 161%, and 71%, respectively, accompanied by corresponding 543%, 264%, and 46% increase in in vitro permeation. In contrast, the BCS 2 acidic drug warfarin exhibited 9% decrease in dissolution under 2-stage conditions, which was associated with a 21% decrease in permeation. None of the tested BCS 1 drugs (minoxidil and metoprolol) exhibited supersaturation after the gastric to intestinal pH shift; consistent with the absence of supersaturation, and the permeation of these drugs was not affected by the transition from simulated gastric to simulated intestinal environments. The polymeric precipitation inhibitor, HPMCAS, increased the in vitro dissolution and permeation AUC values of ketoconazole by 187% and 119%, respectively, and ketoconazole plasma AUC0-24h and Cmax by 54% and 49% following oral administration in rats.


This study has shown that the novel in vitro dissolution-absorption methodology simulating the in vivo gastrointestinal environments that influence drug release and absorption of orally administered drugs constitutes a sensitive and physiologically relevant approach for investigating the potential utility of formulation excipients for exploiting supersaturation as a means to improve systemic drug absorption.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6


  1. Ting JM, Porter WW 3rd, Mecca JM, Bates FS, Reineke TM. Advances in polymer design for enhancing oral drug solubility and delivery. Bioconjug Chem. 2018;29(4):939–52.

    Article  CAS  PubMed  Google Scholar 

  2. Baghel S, Cathcart H, O'Reilly NJ. Polymeric amorphous solid dispersions: a review of amorphization, crystallization, stabilization, solid-state characterization, and aqueous solubilization of biopharmaceutical classification system class II drugs. J Pharm Sci. 2016;105(9):2527–44.

    Article  CAS  PubMed  Google Scholar 

  3. Bevernage J, Brouwers J, Brewster ME, Augustijns P. Evaluation of gastrointestinal drug supersaturation and precipitation: strategies and issues. Int J Pharm. 2013;453(1):25–35.

    Article  CAS  PubMed  Google Scholar 

  4. Kawakami K. Supersaturation and crystallization: non-equilibrium dynamics of amorphous solid dispersions for oral drug delivery. Expert Opin Drug Deliv. 2017;14(6):735–43.

    Article  CAS  PubMed  Google Scholar 

  5. Laitinen R, Lobmann K, Grohganz H, Priemel P, Strachan CJ, Rades T. Supersaturating drug delivery systems: the potential of co-amorphous drug formulations. Int J Pharm. 2017;532(1):1–12.

    Article  CAS  PubMed  Google Scholar 

  6. Williams HD, Trevaskis NL, Yeap YY, Anby MU, Pouton CW, Porter CJ. Lipid-based formulations and drug supersaturation: harnessing the unique benefits of the lipid digestion/absorption pathway. Pharm Res. 2013;30(12):2976–92.

    Article  CAS  PubMed  Google Scholar 

  7. Hens B, Brouwers J, Corsetti M, Augustijns P. Supersaturation and precipitation of posaconazole upon entry in the upper small intestine in humans. J Pharm Sci. 2016;105(9):2677–84.

    Article  CAS  PubMed  Google Scholar 

  8. Takano R, Takata N, Saito R, Furumoto K, Higo S, Hayashi Y, et al. Quantitative analysis of the effect of supersaturation on in vivo drug absorption. Mol Pharm. 2010;7(5):1431–40.

    Article  CAS  PubMed  Google Scholar 

  9. Kataoka M, Masaoka Y, Yamazaki Y, Sakane T, Sezaki H, Yamashita S. In vitro system to evaluate oral absorption of poorly water-soluble drugs: simultaneous analysis on dissolution and permeation of drugs. Pharm Res. 2003;20(10):1674–80.

    Article  CAS  Google Scholar 

  10. Kataoka M, Masaoka Y, Sakuma S, Yamashita S. Effect of food intake on the oral absorption of poorly water-soluble drugs: in vitro assessment of drug dissolution and permeation assay system. J Pharm Sci. 2006;95(9):2051–61.

    Article  CAS  Google Scholar 

  11. Wen H, Park K. Introduction and overview of oral controlled release formulation design. In: Wen H, Park K, editors. Oral controlled release formulation design and drug delivery: theory to practice. Hoboken: Wiley; 2010. p. 1–19.

    Chapter  Google Scholar 

  12. Mathias NR, Xu Y, Patel D, Grass M, Caldwell B, Jager C, et al. Assessing the risk of pH-dependent absorption for new molecular entities: a novel in vitro dissolution test, physicochemical analysis, and risk assessment strategy. Mol Pharm. 2013;10(11):4063–73.

    Article  CAS  PubMed  Google Scholar 

  13. Hens B, Brouwers J, Corsetti M, Augustijns P. Gastrointestinal behavior of nano- and microsized fenofibrate: in vivo evaluation in man and in vitro simulation by assessment of the permeation potential. Eur J Pharm Sci. 2015;77:40–7.

    Article  CAS  PubMed  Google Scholar 

  14. Curatolo W, Nightingale JA, Herbig SM. Utility of hydroxypropylmethylcellulose acetate succinate (HPMCAS) for initiation and maintenance of drug supersaturation in the GI milieu. Pharm Res. 2009;26(6):1419–31.

    Article  CAS  PubMed  Google Scholar 

  15. Warren DB, Benameur H, Porter CJ, Pouton CW. Using polymeric precipitation inhibitors to improve the absorption of poorly water-soluble drugs: a mechanistic basis for utility. J Drug Target. 2010;18(10):704–31.

    Article  CAS  PubMed  Google Scholar 

  16. Lu Z, Yang Y, Covington RA, Bi YV, Durig T, Ilies MA, et al. Supersaturated controlled release matrix using amorphous dispersions of glipizide. Int J Pharm. 2016;511(2):957–68.

    Article  CAS  PubMed  Google Scholar 

  17. McConnell EL, Basit AW, Murdan S. Measurements of rat and mouse gastrointestinal pH, fluid and lymphoid tissue, and implications for in-vivo experiments. J Pharm Pharmacol. 2008;60(1):63–70.

    Article  CAS  PubMed  Google Scholar 

  18. O’Dwyer PJ, Litou C, Box KJ, Dressman JB, Kostewicz ES, Kuentz M, et al. In vitro methods to assess drug precipitation in the fasted small intestine—a PEARRL review. J Pharm Pharmacol. 2018;71:536–56.

    Article  CAS  PubMed  Google Scholar 

  19. Kambayashi A, Yasuji T, Dressman JB. Prediction of the precipitation profiles of weak base drugs in the small intestine using a simplified transfer (“dumping”) model coupled with in silico modeling and simulation approach. Eur J Pharm Biopharm. 2016;103:95–103.

    Article  CAS  PubMed  Google Scholar 

  20. Mudie DM, Murray K, Hoad CL, Pritchard SE, Garnett MC, Amidon GL, et al. Quantification of gastrointestinal liquid volumes and distribution following a 240 mL dose of water in the fasted state. Mol Pharm. 2014;11(9):3039–47.

    Article  CAS  PubMed  Google Scholar 

  21. Xu S, Dai WG. Drug precipitation inhibitors in supersaturable formulations. Int J Pharm. 2013;453(1):36–43.

    Article  CAS  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Ismael J. Hidalgo.

Ethics declarations

Experiments that involved the use of animals adhered to strict protocols, approved by the institutional review board, that ensure the humane treatment of animals.

Conflict of Interest

The authors declare that they have no conflict of interest.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Li, J., Bukhtiyarov, Y., Spivey, N. et al. In Vitro and In Vivo Assessment of the Potential of Supersaturation to Enhance the Absorption of Poorly Soluble Basic Drugs. J Pharm Innov 15, 591–602 (2020).

Download citation

  • Published:

  • Issue Date:

  • DOI: