ラクトース一水和物

定義

本品は、次の化学式で表される二糖類である。

解説

ラクトース

乳糖ともいう．D-グルコースの4位にD-ガラクトースがβ-グリコシド結合した還元性の二糖．すべてのほ乳動物の乳汁中に5％ 前後含まれており，モクセイ科植物，ナツメヤシなど2，3の植物にも存在する．牛乳から脂肪およびチーズをとった残りの乳清を濃縮して，結晶化させて製造する．α-アノマーの一水和物は融点202 ℃．＋85→＋52.6°(水)．β-アノマーは融点252 ℃．＋34.9→＋55.4°(水)．前者は常温で，後者は93 ℃ 以上で晶出させると得られる．生体中ではUDP-ガラクトースのガラクトシル基がグルコースに転移して合成される．特殊なラクトース酵母で発酵されて乳酸を生じ，各種の乳酸菌の栄養源となる．散薬の希釈剤や錠剤の賦形剤などの薬用，乳製品添加剤，乳酸発酵用などの食用として広く用いられる．

用途

培養基剤、食品添加物

化粧品の成分用途

保湿.湿潤剤

効能

錠・カプセル希釈剤

化学的特性

Anhydrous lactose occurs as white to off-white crystalline particles or powder. Several different brands of anhydrous lactose are commercially available which contain anhydrous b-lactose and anhydrous a-lactose. Anhydrous lactose typically contains 70–80% anhydrous b-lactose and 20–30% anhydrous a-lactose.

使用

Lactose is a disaccharide carbohydrate that occurs in mammalian milk except that of the whale and the hippopotamus. it is princi- pally obtained as a cows’ milk derivative. it is also termed milk sugar and it is a reducing sugar consisting of glucose and galactose. its most common commercial form is alpha-monohydrate, with the beta-anhydride form available to a lesser extent. all forms in solution will equilibrate to a beta:alpha ratio of 62.25:37.75 at 0°c. it is about one-sixth as sweet as sugar and is less soluble. it functions as a flow agent, humectant, crystallization control agent, and sweetener. it is used in baked goods for flavor, browning, and tenderizing and in dry mixes as an anticaking agent.

定義

A sugar found in milk. It is a disaccharide composed of glucose and galactose units.

調製方法

There are two anhydrous forms of lactose: a-lactose and b-lactose. The temperature of crystallization influences the ratio of a- and blactose. The anhydrous forms that are commercially available may exhibit hygroscopicity at high relative humidities. Anhydrous lactose is produced by roller drying a solution of lactose above 93.5°C. The resulting product is then milled and sieved. Two anhydrous a-lactoses can be prepared using special drying techniques: one is unstable and hygroscopic; the other exhibits good compaction properties. However, these materials are not commercially available.

生物活性

ラクトースの分解はラクターゼによって行われるが、一方、生合成は乳腺(にゅうせん)内でUDP（ウリジン二リン酸）-ガラクトースからガラクトースを転移する反応により生成される。この転移反応を触媒する酵素は、乳汁や乳腺中にみいだされるガラクトシルトランスフェラーゼで、アロステリックタンパク質の一種である。この酵素はα(アルファ)-ラクトアルブミン（血清タンパク質の一種）を結合するときにグルコースを受容体としてラクトースを合成するが、この酵素だけの場合はグルコースではなく、N-アセチルグルコサミンにガラクトースが転移されてN-アセチルラクトサミンが生成される。これは生物のもつ調節機構の一例であり、出産後にはα-ラクトアルブミンが増加して、乳児に必要なラクトースの合成が促進される。なお、ラクトースは腸のラクターゼによって加水分解されたのち吸収される。

一般的な説明

Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.

空気と水の反応

Water soluble.

反応プロフィール

Flammable and/or toxic gases are generated by the combination of alcohols with alkali metals, nitrides, and strong reducing agents. They react with oxoacids and carboxylic acids to form esters plus water. Oxidizing agents convert them to aldehydes or ketones. Alcohols exhibit both weak acid and weak base behavior. They may initiate the polymerization of isocyanates and epoxides.

健康ハザード

ACUTE/CHRONIC HAZARDS: Lactose should be considered toxic.

応用例（製薬）

Anhydrous lactose is widely used in direct compression tableting applications, and as a tablet and capsule filler and binder. Anhydrous lactose can be used with moisture-sensitive drugs due to its low moisture content. It may also be used in intravenous injections.

安全性

Lactose is widely used in pharmaceutical formulations as a diluent and filler-binder in oral capsule and tablet formulations. It may also be used in intravenous injections. Adverse reactions to lactose are largely due to lactose intolerance, which occurs in individuals with a deficiency of the intestinal enzyme lactase, and is associated with oral ingestion of amounts well over those found in solid dosage forms.

貯蔵

Mold growth may occur under humid conditions (80% RH and above). Lactose may develop a brown coloration on storage, the reaction being accelerated by warm, damp conditions. At 80°C and 80% RH, tablets containing anhydrous lactose have been shown to expand 1.2 times after one day.
Lactose anhydrous should be stored in a well-closed container in a cool, dry place.

純化方法

-Lactose crystallises from water below 93.5o as the hydrate which can be dried at 80o/14mm. [Horst Recl Trav Chim, Pays-Bas 72 878 1953, Beilst 17 III/IV 3066.]

不和合性

Lactose anhydrous is incompatible with strong oxidizers. When mixtures containing a hydrophobic leukotriene antagonist and anhydrous lactose or lactose monohydrate were stored for six weeks at 40°C and 75% RH, the mixture containing anhydrous lactose showed greater moisture uptake and drug degradation.
Studies have also shown that in blends of roxifiban acetate (DMP-754) and lactose anhydrous, the presence of lactose anhydrous accelerated the hydrolysis of the ester and amidine groups.
Lactose anhydrous is a reducing sugar with the potential to interact with primary and secondary amines (Maillard reaction) when stored under conditions of high humidity for extended periods.

規制状況(Regulatory Status)

GRAS listed. Included in the FDA Inactive Ingredients Database (IM, IV: powder for injection solution; IV and sublingual preparations; oral: capsules and tablets; powder for inhalation; vaginal). Included in nonparenteral and parenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.