PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of aapspharmspringer.comThis journalToc AlertsSubmit OnlineOpen Choice
 
AAPS PharmSciTech. 2007 September; 8(3): E145–E151.
Published online 2007 August 31. doi:  10.1208/pt0803070
PMCID: PMC2750566

A novel fiber-optic photometer for in situ stability assessment of concentrated oil-in-water emulsions

Abstract

The purpose of this research was to evaluate a novel fiberoptic photometer for its ability to monitor physical instabilities occurring in concentrated emulsions during storage. For this, the fiber-optic photometer was used to measure transmission of oil-in-water emulsions stabilized with hypromellose (HPMC) as a function of oil volume fraction and droplet size distribution (DSD). To detect physical instabilities like creaming and coalescence, the transmissivity of the samples was studied at 2 different hight levels over a certain period of time. The corresponding droplet size distributions were determined by laser diffraction with PIDS. Transmissivity was found to depend on the number of dispersed droplets and thus is sensitive to both the variation of phase volume fraction as well as the emulsions droplet size distribution. At constant DSD, light transmission decreased linearly with increasing oil content within a large interval of phase volume fractions from 0.01 to 0.3. At constant phase volume fraction, an increase in droplet size increased light transmission. Investigation of creaming on emulsions with different droplet size distributions showed changes in the initial delay times and creaming velocities. In contrast to creaming phenomenon coalescence can be identified by height independent changes of the transmissivity. In conclusion, transmissivity of oil-in-water emulsions observed by the novel fiber-optic photometer is sensitive to phase volume fraction, droplet size distribution, and thus can be used as a tool for stability studies on concentrated emulsions.

Keywords: Fiber-optic photometer, Optical analyser, Hypromellose, Emulsion stability, Concentrated dispersion

Full Text

The Full Text of this article is available as a PDF (525K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Danner T, Schubert H. Verringerung der Tropfenkoaleszenz beim Herstellen von Emulsionen. Chemie Ingenieur Technik. 1989;72:928–928. doi: 10.1002/1522-2640(200009)72:9<928::AID-CITE9281>3.0.CO;2-A. [Cross Ref]
2. Nelson PV, Povey MJW, Wang Y. An ultrasound velocity and attenuation scanner for viewing the temporal evolution of a dispersed phase in fluid. Rev Sci Instrument. 2001;72:4234–4241. doi: 10.1063/1.1408936. [Cross Ref]
3. Mengual O, Meunier G, Cayre I, Puech K, Snabre P. Characterisation of instability of concentrated dispersion by a new optical analyser: the TURBISCAN MA 1000. Colloids Surf A. 1999;152:111–124. doi: 10.1016/S0927-7757(98)00680-3. [Cross Ref]
4. Rimpler S, Daniels R. In-situ partcle sizing in highly concentrated oil-in-water emulsions. Pharm Tech Eur. 1995;8:72–80.
5. Sobisch T, Lerche D. Application of a new separation analyzer for the characterization of dispersions stabilized with clay derivatives. Colloid Polym Sci. 2000;278:369–374. doi: 10.1007/s003960050527. [Cross Ref]
6. Horozov TS, Binks BP. Stability of suspensions, emulsions, and foams by a novel automated analyser. Langmuir. 2004;20:9007–9013. doi: 10.1021/la0489155. [PubMed] [Cross Ref]
7. Sarkar N. Structural interpretation of the interfacial properties of aqueous solutions of methylcellulose and hydroxypropylmethylcellulose. Polym. 1984;25:481–486. doi: 10.1016/0032-3861(84)90206-4. [Cross Ref]
8. Daniels R, Barta A. Pharmacopoeial cellulose ethers as oil-in water emulsifiers. Eur J Pharm Biopharm. 1994;40:128–133.
9. Wollenweber C, Makievski AV, Miller R, Daniels R. Adsorption of hydroxypropyl methulcellulose at the liquid/liquid interface and the effect on emulsion stability. Colloids Surf A. 2000;172:91–101. doi: 10.1016/S0927-7757(00)00569-0. [Cross Ref]
10. McNally R, editor. The United States Pharmacopeia, XXIII. Rockville, MD: United States Pharmacopoeial Convention, Inc; 1994.
11. Martin A, Swarbrick J, Cammarata A. Physical Pharmacy. Philadelphia, PA: Lea & Feibiger; 1983.
12. Schuhmann R, Müller RH. Analysis of disperse systems by light scattering methods. Comparison of Mie evaluation with and without polarization intensity differential scattering technology. Pharm Ind. 1995;57:579–584.
13. Müller RH, Schuhmann R. Teilchengrößenmessung in der Laborpraxis. Stuttgart, Germany: Wissenschaftliche Verlag GmbH; 1997. pp. 65–66.
14. Lachman L, Lieberman HA, Kanig JL. The Theory and Practice of Industrial Pharmacy: Emulsions. Philadelphia: Lea & Febiger; 1976. pp. 209–209.
15. Cannell JS. Fundamentals of stability testing. Int J Cosmet Sci. 1985;7:291–303. doi: 10.1111/j.1467-2494.1985.tb00423.x. [PubMed] [Cross Ref]
16. Miller DJ. Coalescence in crude oil emulsions investigated by light transmission method. Colloid Polym Sci. 1987;265:342–346. doi: 10.1007/BF01417934. [Cross Ref]
17. Pohl M, Kempa L, Schubert H, Freudig B. Qualitätsschwankung auf der Spur. Inline-Prozesskontrolle beim Herstellen von Suspensionen und Emulsionen. Verfahrenstechnik. 2004;9:48–49.
18. Daniels R, Rimpler S. Effect of heat sterilisation on the stability of o/w emulsions containing HPMC as emulsifier. Pharmacol Lett. 1993;3:80–83.
19. Manoj P, Fillery-Travis AJ, Watson AD, et al. Characterization of a Depletion-Flocculated Polydisperse Emulsion. I: Creaming Behavior. J Colloid Interface Sci. 1998;207:283–293. doi: 10.1006/jcis.1998.5801. [PubMed] [Cross Ref]

Articles from AAPS PharmSciTech are provided here courtesy of American Association of Pharmaceutical Scientists