Indinavir AIDS drug, molecular model. This is a protease inhibitor marketed as Crixivan. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).

Amlodipine, molecular model. This hypertension (high blood pressure) drug is marketed as Istin. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), oxygen (red), nitrogen (blue) and chlorine (green).

Benazepril, molecular model. This hypertension (high blood pressure) drug is marketed as Lotensin. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), oxygen (red) and nitrogen (blue).

Caffeine molecule, illustration

Saquinavir AIDS drug, molecular model. This is a protease inhibitor marketed as Invirase and Fortovase. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).

Ciprofloxacin antibiotic, molecular model. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (dark blue), oxygen (red) and fluorine (light blue).

Vardenafil, molecular model. This erectile dysfunction drug is marketed as Levitra. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), oxygen (red), nitrogen (blue) and sulphur (yellow).

Parathion, molecular model. This is an organophosphate pesticide. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), oxygen (red), nitrogen (blue), sulphur (yellow) and phosphorous (orange).

Tramadol, molecular model. This is a synthetic opioid analgesic (painkiller) drug. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).

"Neostigmine drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

Alprazolam, molecular model. This sedative drug is marketed as Xanax. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and chlorine (green).

Celecoxib, molecular model. This non-steroidal anti-inflammatory (NSAID) drug, marketed as Celebrex, is used to treat arthritis. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (dark blue), oxygen (red), fl

"Tropicamide mydriatic eye drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Kanamycin antibiotic drug molecule (aminoglycoside). Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Tetracaine local anesthetic drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Indacaterol COPD drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Tetracaine local anesthetic drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Indacaterol COPD drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Paromomycin aminoglycoside antibiotic drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Kanamycin antibiotic drug molecule (aminoglycoside). Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Tropicamide mydriatic eye drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

"Lumefantrine (benflumetol) antimalarial drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue), chlorine (green). "

"Lumefantrine (benflumetol) antimalarial drug molecule. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue), chlorine (green). "

"Peramivir influenza drug molecule (neuraminidase inhibitor). Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (grey), oxygen (red), nitrogen (blue). "

Alendronate, molecular model. This osteoporosis drug is marketed as Fosamax. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), oxygen (red), nitrogen (blue) and phosphorus (orange).