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In vivo evaluation of submicron emulsions with pilocarpine: the effect of pH and chemical form of the drug.
J Microencapsul 2001 Mar-Apr; 18(2):173-81JM

Abstract

Submicron emulsions containing 2.0% w/v pilocarpine as pilocarpine HCl, soybean oil (10% w/v) and egg lecithin (1.2% w/v) were formulated. Emulsions at pH 5.0, 6.5 and 8.5 were applied to the rabbit's eye, and the reduction in pupil diameter was measured for 6 h. The miotic effect was compared with that obtained with aqueous solutions at the same pH. A prolonged miotic effect was observed when the submicron emulsion was used as a vehicle. After application of emulsions at pH 5.0, 6.5 or 8.5, the time when 20% reduction of pupil diameter was still observed was 3.9 +/- 1.1 h, 4.3 +/- 1.3 h and 5.3 +/- 0.8 h, respectively, while, after application of a solution, this parameter was shorter by 30-40%. AUC(0-6h) values were larger after application of the submicron emulsions in comparison to aqueous solutions; however, statistically significant differences were only observed for emulsions at pH 6.5. Although the bioavailability of the drug is pH dependent, emulsions at higher pH cannot be considered for clinical use because of pilocarpine degradation which occurs with a similar rate as in aqueous solutions. Introduction of pilocarpine into the oily phase in the form of pilocarpine base or its oleate did not improve either the physicochemical or the pharmacological properties of the formulations. Irrespective of the pH and chemical form of pilocarpine used for emulsion preparation, practically all drug was found in the aqueous phase of the emulsion; thus, partitioning to the oily phase was negligible.

Authors+Show Affiliations

Department of Pharmaceutical Technology, Medical University of Gdansk, Poland. msznito@farmacja.amg.gda.plNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11253934

Citation

Sznitowska, M, et al. "In Vivo Evaluation of Submicron Emulsions With Pilocarpine: the Effect of pH and Chemical Form of the Drug." Journal of Microencapsulation, vol. 18, no. 2, 2001, pp. 173-81.
Sznitowska M, Janicki S, Zurowska-Pryczkowska K, et al. In vivo evaluation of submicron emulsions with pilocarpine: the effect of pH and chemical form of the drug. J Microencapsul. 2001;18(2):173-81.
Sznitowska, M., Janicki, S., Zurowska-Pryczkowska, K., & Mackiewicz, J. (2001). In vivo evaluation of submicron emulsions with pilocarpine: the effect of pH and chemical form of the drug. Journal of Microencapsulation, 18(2), pp. 173-81.
Sznitowska M, et al. In Vivo Evaluation of Submicron Emulsions With Pilocarpine: the Effect of pH and Chemical Form of the Drug. J Microencapsul. 2001;18(2):173-81. PubMed PMID: 11253934.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In vivo evaluation of submicron emulsions with pilocarpine: the effect of pH and chemical form of the drug. AU - Sznitowska,M, AU - Janicki,S, AU - Zurowska-Pryczkowska,K, AU - Mackiewicz,J, PY - 2001/3/20/pubmed PY - 2001/6/2/medline PY - 2001/3/20/entrez SP - 173 EP - 81 JF - Journal of microencapsulation JO - J Microencapsul VL - 18 IS - 2 N2 - Submicron emulsions containing 2.0% w/v pilocarpine as pilocarpine HCl, soybean oil (10% w/v) and egg lecithin (1.2% w/v) were formulated. Emulsions at pH 5.0, 6.5 and 8.5 were applied to the rabbit's eye, and the reduction in pupil diameter was measured for 6 h. The miotic effect was compared with that obtained with aqueous solutions at the same pH. A prolonged miotic effect was observed when the submicron emulsion was used as a vehicle. After application of emulsions at pH 5.0, 6.5 or 8.5, the time when 20% reduction of pupil diameter was still observed was 3.9 +/- 1.1 h, 4.3 +/- 1.3 h and 5.3 +/- 0.8 h, respectively, while, after application of a solution, this parameter was shorter by 30-40%. AUC(0-6h) values were larger after application of the submicron emulsions in comparison to aqueous solutions; however, statistically significant differences were only observed for emulsions at pH 6.5. Although the bioavailability of the drug is pH dependent, emulsions at higher pH cannot be considered for clinical use because of pilocarpine degradation which occurs with a similar rate as in aqueous solutions. Introduction of pilocarpine into the oily phase in the form of pilocarpine base or its oleate did not improve either the physicochemical or the pharmacological properties of the formulations. Irrespective of the pH and chemical form of pilocarpine used for emulsion preparation, practically all drug was found in the aqueous phase of the emulsion; thus, partitioning to the oily phase was negligible. SN - 0265-2048 UR - https://www.unboundmedicine.com/medline/citation/11253934/In_vivo_evaluation_of_submicron_emulsions_with_pilocarpine:_the_effect_of_pH_and_chemical_form_of_the_drug_ L2 - http://www.tandfonline.com/doi/full/10.1080/02652040010000442 DB - PRIME DP - Unbound Medicine ER -