PharmPK Discussion - Topical dosage forms

PharmPK Discussion List Archive Index page
• On 31 Dec 2005 at 11:27:59, shahab bohlooli (sh_bohlooli.at.yahoo.com) sent the message
`Dear AllCan any one explain that how is it the way to calculate the amount ofactive ingredient in a topical dosage from like an ointment or cream?and indeed are there any mathematical procedure to reaching it?thank you in advanceS Bohlooli`
Back to the Top

• On 2 Jan 2006 at 06:18:28, "ogwal sidney" (sidneyogwal.-at-.hotmail.com) sent the message
`The following message was posted to: PharmPKYou should design your own method of calculating the amount of activeingredient. do enough litreature search on the ointment/cream you aremaking (Books journals pharmacopeia)Where you are stuck with arithmetic consult the nearest expert inPharmaceutical analysiss.o.o`
Back to the Top

• On 2 Jan 2006 at 22:28:38, Titilayo Fakeye (titifakeye.aaa.yahoo.com) sent the message
`Except I didn't get your qustion well. Usually, creams or ointmentsindicate the strength of the active ingredient for example, if thelabel of the cream says ingredient x is 1%w/w. This simply means thatin any 100g of the cream/ointment, you have 1g of that activeingredient. If you take 1g of such cream/ointment, then the amount ofactive ingredient will be one hundreth of a gram.I hope this will be useful.Titilayo`
Back to the Top

• On 3 Jan 2006 at 11:18:24, shahab bohlooli (sh_bohlooli.-at-.yahoo.com) sent the message
`Dear Titilayo Fakeyethank you for your comment, but  I mean that what is the rule forconsidering a cream 1%, for example: betamethasone has a 0.2% topicalcream why it is not 10%? is there a mathemathical explanation for it,could somebody reach this amount of active ingredient in a topicaldosage form mathematically using plasma concentration following oraladministration?thankss bohlooliSincerely YoursSincerely Yours,Dr Shahab BohlooliPharmD,PhD.Physiology & phar macology Dept.Faculty of MedicineArdabil University of Medical SciencesDaneshkah St,Ardabil 56197,Iran.`
Back to the Top

• On 4 Jan 2006 at 01:45:19, "SHAWN.SPENCER" (SHAWN.SPENCER.at.famu.edu) sent the message
`Shabab,I'll take a stab at that.  Bear in mind, that it is somewhatdifficult to follow your question.First, topical betamethasone is not formulated to provide plasmalevels, but rather to produce an effect locally (i.e., at the site ofadministration).  Thus, the strength of the formulation is that whichproduces the desired effect. Mathematically, can one model (i.e.,predict or simulate) the amount of active ingredient at theadministration site, and/or the strength of a formulation, to producea desired effect at the site of administration.  This type of dose-formulation variable-effect model sounds feasible with theappropriate experiments, and a literature review may reveal work inthat area.Hope that helpsShawn Spencer, Ph.D, R.Ph.Assistant Professor of Pharmacokinetics and BiopharmaceuticsBasic Pharmaceutical SciencesFlorida A&M UniversityDyson Pharmacy Bldg. Rm. 227Tallahassee, FL 32307Phone: 850-599-3511Fax: 850-599-3934`
Back to the Top

• On 5 Jan 2006 at 06:28:39, "ogwal sidney" (sidneyogwal.aaa.hotmail.com) sent the message
`The following message was posted to: PharmPKs.o.oThe key thing is the minimum effective concentration and minimumtoxic concentration. The difference between the two is thetherapeutic level. As long as the percentage content of the activeingredient is within the therapeutic level there is no problem. Withreference to your cream the amount of bethamethamesone be it 1% 5% or10% should not irritate the skin.As long as the percenatages arewithin therapeutic range there is no problem`
Back to the Top

Want to post a follow-up message on this topic? If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Topical dosage forms" as the subject

Copyright 1995-2010 David W. A. Bourne (david@boomer.org)