Document Detail


A comparison of two formulations of intradermal capsaicin as models of neuropathic pain in healthy volunteers.
MedLine Citation:
PMID:  19843054     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIMS: To compare the dose-response relationships of two formulations [Tween- or hydroxypropyl-b-cyclodextrin (HP-b-CD)-based] of intradermal capsaicin in healthy volunteers and to assess the effect of potential covariates of response. One, 10, 30 and 100 microg in 10 ml were compared for the outcomes of flare, spontaneous pain, mechanical allodynia and hyperalgesia in eight healthy men and eight healthy women. RESULTS: The formulations produced comparable responses at doses 1, 10 and 30 microg, but in all parameters the response was less at 100 microg with the Tween formulation.Mean area for hyperalgesia was 9 cm(2) [95% confidence interval (CI) 5, 13] higher with the HP-beta-CD formulation. Flare area was 5 cm(2) (95% CI 8, 13) greater with the HP-beta-CD formulation. There was a significant difference between pain responses from the injection site on the upper forearm compared with the lower forearm on all four pain assessments. In contrast, significant differences were seen in pain response between nondominant and dominant arm for flare, allodynia and hyperalgesia but not for spontaneous pain. A significant difference in sex was seen only for hyperalgesia. The nominal 100-microg dose of the Tween formulation contained only 39% of label strength in the aqueous phase, which may explain the lower pharmacodynamic response. CONCLUSION: The formulations are comparable over the dose range 1-30 microg. The significantly lower pain response at the 100 microg dose in the Tween compared with the HP-beta-CD formulation is likely to be due to limitations in solubility at the 100 microg level. Given the greater ease of formulation and the superior dose-response relationship, the HP-beta-CD formulation is preferable for use in the model in future studies.
Authors:
Helena Gustafsson; Johanna Akesson; Chai Li Lau; Desmond Williams; Lisa Miller; Sharon Yap; Paul Rolan
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  British journal of clinical pharmacology     Volume:  68     ISSN:  1365-2125     ISO Abbreviation:  Br J Clin Pharmacol     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-21     Completed Date:  2010-07-30     Revised Date:  2010-10-04    
Medline Journal Info:
Nlm Unique ID:  7503323     Medline TA:  Br J Clin Pharmacol     Country:  England    
Other Details:
Languages:  eng     Pagination:  511-7     Citation Subset:  IM    
Affiliation:
Pharmacy School, University of Gothenburg, Gothenburg, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Adult
Capsaicin / administration & dosage*
Chromatography, High Pressure Liquid
Dose-Response Relationship, Drug*
Excipients
Female
Hot Temperature
Humans
Hyperalgesia / chemically induced*
Injections, Intradermal
Male
Middle Aged
Pain / chemically induced*
Sensory System Agents / administration & dosage
Sex Factors
Single-Blind Method
Skin / drug effects*
Time Factors
Young Adult
beta-Cyclodextrins / administration & dosage*
Chemical
Reg. No./Substance:
0/Excipients; 0/Sensory System Agents; 0/beta-Cyclodextrins; 404-86-4/Capsaicin; 94035-02-6/2-hydroxypropyl-beta-cyclodextrin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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