Alendronic acid

Absorption

Mean oral bioavailability of alendronic acid in women is 0.64% and in men is 0.59%. Bioavailability of alendronic acid decreases by up to 40% if it is taken within an hour of a meal.

Toxicity

In clinical studies, ≥3% of patients experience abdominal pain, acid regurgitation, constipation, diarrhea, dyspepsia, musculoskeletal pain, and nausea.
No information for treatment of overdose is available, however patients should be given milk or antacids to bind alendronic acid and vomiting should not be induced. Patients may experience hypocalcemia, hypophosphatemia, and upper gastrointestinal events..
There are currently no studies for safety and efficacy in pregnancy, though studies in pregnant rats show fetal and maternal complications at 4 times the clinical dose and pregnant rabbits do not show complications at as high as 10 times the clincal dose.
Excretion in breast milk, and therefore safety in lactation, is unknown.
Alendronic acid has been studied for use in pediatric patients. The oral bioavailability is similar to that in adult patients, but an increase in the portion of patients experiencing vomiting.
There is no significant difference in efficacy or safety of alendronic acid in geriatric populations, though there is potential for even greater sensitivity in patients at a further advanced age than those in the study.
Alendronic acid is not recommended for patients with creatinine clearance <35mL/min, but no dosage adjustment is necessary in hepatic impairment.

Originator

Adronat ,Neopharmed ,Italy

The Uses of Alendronic acid

Alendronate acid is an inhibitor of FDPS.

Background

Alendronic acid is a second generation bisphosphonate that is used for the treatment of some forms of osteoperosis and Paget's disease. It functions by preventing resorption of bone.

What are the applications of Application

Alendronate acid is an inhibitor of FDPS

Indications

Alendronic acid is indicated for the treatment and prevention of osteoporosis in men and postmenopausal women, treatment of glucocorticoid-induced osteoporosis, and Paget's disease of bone. However, alendronic acid is not indicated for use in pediatric populations or patients with a creatinine clearance <35mL/min.

Definition

ChEBI: A 1,1-bis(phosphonic acid) that is methanebis(phosphonic acid) in which the two methylene hydrogens are replaced by hydroxy and 3-aminopropyl groups.

Manufacturing Process

4-Amino-1-hydroxybutylidene-1,1-diphosphonic acid (ABDT).
Orthosphophorous acid (102.7 g; 1.25 moles) is introduced into a 2 liter-flask with condenser, stirrer and dropping funnel, placed on a thermostatized bath; the air is then removed with a nitrogen stream which is continued during all the reaction. The acid is melted by heating the bath to 95°C. When melting is complete, 4-aminobutyric acid (103.3; 1 mole) is added under stirring which is continued till obtaining a doughy fluid. Phosphorous trihalide (176 ml; 2 moles) is added dropwise causing the mixture to boil and evolution of gaseous hydrochloric acid which is damped by means of a suitable trap. The addition rate is adjusted so as to keep a constant reflux for about 60 minutes. When the addition is nearly over, the mixture swells, slowly hardening. Stirring is continued as long as possible, whereafter the mixture is heated for further 3 hours. Without cooling, but removing the bath, water (300 ml) is added, first slowly and then quickly. Heating and stirring are started again. Decolorizing charcoal is added and the mixture is boiled for about 5 minutes, then hotfiltered on paper and the filtrate is refluxed for 6 hours. After cooling is slowly poured in stirred methanol (1500 ml) causing thereby the separation of a white solid which collected and dried (161 g; 64.6%). The structure of ABDT is confirmed by IR spectrum, proton magnetic and nuclear magnetic resonance spectrum and elemental analysis.
The sodium salt of this acid may be prepared by adding of equivalent of sodium hydroxide.

Therapeutic Function

Antiosteoporotic

Hazard

A reproductive hazard.

Pharmacokinetics

Alendronic acid tablets have a very low oral bioavialability. After administration it distributes into soft tissue and bone or is excreted in the urine. Alendronic acid does not undergo metabolism.

Clinical Use

Bisphosphonate:
Treatment and prophylaxis of osteoporosis

Drug interactions

Potentially hazardous interactions with other drugs
Calcium salts: reduced absorption of alendronate.

Metabolism

Alendronate transiently distributes to soft tissues but is then rapidly redistributed to bone or excreted in the urine. There is no evidence that alendronate is metabolised in animals or humans. Following a single intravenous dose of [14C]-alendronate, approximately 50% of the radioactivity was excreted in the urine within 72 hours and little or no radioactivity was recovered in the faeces.

Metabolism

Urinary excretion is the sole method of elimination of alendronic acid and no metabolites are detected upon urine collection.