Mikhania C.E., S.Farm, M.Si, Apt BARBITURAT Mikhania C.E., S.Farm, M.Si, Apt

PENDAHULUAN Senyawa barbiturat adalah senyawa turunan asam barbiturat Digunakan sebagai depresan saraf pusat  anastesi dan sedasi Struktur dasar : asam barbiturat

SIFAT-SIFAT Umumnya berupa zat padat, kristal putih/tidak berwarna dan rasanya sedikit pahit Tidak larut dalam air (bentuk keto) tapi mudah larut dalam CHCl3, eter dan lain-lain Bereaksi asam lemah dan dapat membentuk garam yang larut dalam air, misalnya dengan NaOH dan KOH Larutan garam Na/K dalam air tidak stabil dalam pemanasan

PEMBAGIAN KLASIFIKASI LAMA KERJA (Jam) CONTOH Ultra short acting 3 – 4 Tiopental Short acting 4 - 10 Pentobarbital Long acting 8 - 24 Fenobarbital, barbital

Identifikasi Jarak lebur KLT Spektrofotometri IR Reaksi warna Bentuk kristal

1. FENOBARBITAL Pemerian : A white or almost white, crystalline powder or colourless crystals Kelarutan : very slightly soluble in water, freely soluble in alcohol. It forms water-soluble compounds with alkali hydroxides and carbonates and with ammonia.

Identifikasi Reaksi Pendahuluan Reaksi Parri : zat dalam larutan methanol + pereaksi parri + NH4OH akan terjadi perubahan warna.

Identifikasi (cont.) Reaksi Penegasan Reaksi zwikker (zat dalam larutan methanol/etanol + pereaksi zwikker akan terbentuk warna violet Zat + air + larutan AgNO3 terbentuk warna putih Zat + Merkurium Nitrat terbentuk warna hitam Zat + H2SO4 pekat + α naftol terbentuk warna ungu Zat + Formalin + H2SO4 pekat terbentuk warna merah Reaksi Kristal Sampel + aseton + air Sampel + Fe Complex Sampel + Cu Complex

Identifikasi (cont.) Determine the melting point of the substance to be examined. Mix equal parts of the substance to be examined and phenobarbital CRS and determine the melting point of the mixture. The difference between the melting points (which are about 176 °C) is notgreater than 2 °C. Examine by infrared absorption spectrophotometry comparing with the spectrum obtained with phenobarbital CRS. Examine by thin-layer chromatography, using silica gel GF254 R as the coating substance. Test solution : Dissolve 0.1 g of the substance to be examined in alcohol R and dilute to 100 ml with the same solvent. Reference solution : Dissolve 0.1 g of phenobarbital CRS in alcohol R and dilute to 100 ml with the same solvent. Apply separately to the plate 10 μl of each solution. Develop over a path of 18 cm using the lower layer of a mixture of 5 volumes of concentrated ammonia R, 15 volumes of alcohol R and 80 volumes of chloroform R. Examine immediately in ultraviolet light at 254 nm. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution.

2. BARBITAL Pemerian : A white or almost white, crystalline powder or colourless crystals Kelarutan : slightly soluble in water, soluble in boiling water and in alcohol. It forms water-soluble compounds with alkali hydroxides and carbonates and with ammonia.

Identifikasi Determine the melting point of the substance to be examined. Mix equal parts of the substance to be examined and barbital CRS and determine the melting point of the mixture. The difference between the melting points (which are about 190 °C) is not greater than 2 °C. Examine by infrared absorption spectrophotometry comparing with the spectrum obtained with barbital CRS.

Identifikasi (cont.) Examine by thin-layer chromatography using silica gel GF254 R as the coating substance. Test solution : Dissolve 75 mg of the substance to be examined in alcohol R and dilute to 25 ml with the same solvent. Reference solution : Dissolve 75 mg of barbital CRS in alcohol R and dilute to 25 ml with the same solvent. Apply separately to the plate 10 μl of each solution. Develop over a path of 18 cm using the lower layer of a mixture of 5 volumes of concentrated ammonia R, 15 volumes of alcohol R and 80 volumes of chloroform R. Examine immediately in ultraviolet light at 254 nm. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution. It gives the reaction of non-nitrogen substituted barbiturates

3. PENTOBARBITAL Pemerian : A white or almost white, crystalline powder or colourless crystals Kelarutan : very slightly soluble in water, freely soluble in ethanol. It forms water-soluble compounds with alkali hydroxides and carbonates and with ammonia.

Identifikasi Determine the melting point of the substance to be examined. Mix equal parts of the substance to be examined and pentobarbital CRS and determine the melting point of the mixture. The difference between the melting points (which are about 133 °C) is not greater than 2 °C. Examine by thin-layer chromatography (2.2.27), using silica gel GF254 R as the coating substance. Test solution : Dissolve 0.1 g of the substance to be examined in alcohol R and dilute to 100 ml with the same solvent. Reference solution : Dissolve 0.1 g of pentobarbital CRS in alcohol R and dilute to 100 ml with the same solvent. Apply to the plate 10 μl of each solution. Develop over a path of 18 cm using the lower layer of a mixture of 5 volumes of concentrated ammonia R, 15 volumes of alcohol R and 80 volumes of chloroform R. Examine immediately in ultraviolet light at 254 nm. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution. To about 10 mg add about 10 mg of vanillin R and 2 ml of sulphuric acid R. Mix and heat on a water-bath for 2 min. A reddish-brown colour develops. Cool and add cautiously 5 ml of ethanol R. The colour becomes violet and then blue.

4. AMOBARBITAL Pemerian : A white or almost white, crystalline powder Kelarutan : very slightly soluble in water, freely soluble in alcohol, soluble in methylene chloride. It forms water-soluble compounds with alkali hydroxides and carbonates and with ammonia.

Identifikasi Determine the melting point of the substance to be examined. Mix equal parts of the substance to be examined and amobarbital CRS and determine the melting point of the mixture. The difference between the melting points (which are about 157 °C) is not greater than 2 °C. Examine by infrared absorption spectrophotometry comparing with the spectrum obtained with amobarbital CRS .

Identifikasi (Cont.) Examine by thin-layer chromatography, using silica gel GF254 R as the coating substance. Test solution : Dissolve 0.1 g of the substance to be examined in alcohol R and dilute to 100 ml with the same solvent. Reference solution : Dissolve 0.1 g of amobarbital CRS in alcohol R and dilute to 100 ml with the same solvent. Apply separately to the plate 10 μl of each solution. Develop over a path of 18 cm using the lower layer from a mixture of 5 volumes of concentrated ammonia R, 15 volumes of alcohol R and 80 volumes of chloroform R. Examine immediately in ultraviolet light at 254 nm. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with the reference solution. It gives the reaction of non-nitrogen substituted barbiturates

SPEKTRUM IR Fenobarbital

Spektrum IR Pentobarbital