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         Capsicum Gel is Capsicum Oleoresin in a suitable hydrophilic gel base.  It contains not less than 90.0 per cent and not more than 110.0 per cent of the labelled amount of capsaicin (C₁₈H₂₇NO₃).

Strength available  0.025 per cent w/w of capsaicin.

Dose  Topical, to the affected areas, three or four times a day.

Warning 

1. Contact with eyes, nose, lips, wounded skin, and sensitive skin should be avoided.

       2. Transient erythema, burning and s tinging without vesicular eruption at the  application area may occur.

Packaging and storage  Capsicum Gel shall be kept in collapsible tubes or in tightly closed containers, protected from light and stored at a temperature not exceeding 30°.

Labelling  The label on the container states (1) the amount of capsaicin; (2) the expiration date.

Identification  The retention time of the major peak in the chromatogram of the Assay preparation corresponds to the capsaicin peak of the standard preparation, as obtained in the Assay. 

Microbial limit  Complies with the requirements for Category 1B in the “Limits for Microbial Contamination” (Appendix 10.5). 

Assay  Carry out the determination as described in the “Liquid Chromatography” (Appendix 3.5).

       Mobile phase  Prepare a mixture of 2 volumes of acetonitrile and 3 volumes of a 1 per cent v/v solution of formic acid.  Make adjustments if necessary.

      Standard preparation  Dissolve an accurately weighed quantity of Capsaicin RS in ethanol to obtain a solution having a known concentration of about 30 μg per mL.

       Assay preparation  Transfer an accurately weighed quantity of Capsicum Gel, containing about 1.5 mg of capsaicin, to a 125-mL Erlenmeyer flask.  Add 25.0 mL of ethanol, shake well and sonicate for about 30 minutes.  Quantitatively transfer the solution to a 50-mL volumetric flask, dilute with ethanol to volume and mix.  Centrifuge the resulting solution at 855×g  (3000 rpm) for 15 minutes.  Pass a portion of the clear solution through a filter having  a 0.5-μm or finer porosity. 

     Chromatographic system  The chromatographic procedure may be carried out using (a) a stainless s teel column (15 cm × 4.6 mm) packed with octadecylsilane chemically bonded to porous silica or ceramic microparticles (5 μm) equipped with a similarly packed guard column, (b) Mobile phase at a flow rate of 1.4 mL per minute (The retention time is about  20 minutes for the main capsaicin peak.), and (c) an ultraviolet photometer set at 280 nm.

      To determine the suitability of the chromatographic system, chromatograph Standard preparation, and record the peak response as directed under Procedure:  the relative standard deviation for replicate injections is not more than 2.0 per cent, the column efficiency  determined from the capsaicin peak is not less than 5000 theoretical plates, and the symmetry factor for the capsaicin peak is not more than 1.5.  Chromatograph Assay preparation and record the peak response as directed under Procedure:  the relative retention times are about 0.9 for nordihydrocapsaicin, 1.0 for capsaicin, and 1.6 for dihydrocapsaicin; and the  resolution factor, R, between the nordihydrocapsaicin peak and the capsaicin peak is not less than 1.2.

     Procedure  Separately inject equal volumes (about 20 μL) of Standard preparation and Assay preparation into the chromatograph, record the chromatograms for a period of time that is twice that of the retention time of capsaicin, and measure the responses for the capsaicin peaks.   

     Calculation  Calculate the content of capsaicin in the portion of the Gel taken, using declared content of C₁₈H₂₇NO₃ in Capsaicin RS.

Other requirements  Complies with the requirements described under “Topical Preparations” (Appendix 1.16H).