Pharmaceutical solvents

In the pharmaceutical industry, solvents are liquids that play a fundamental role in virtually every stage of drug production, from extraction and purification to crystallisation and formulation. The quality and purity of pharmaceutical solvents directly affect the safety, effectiveness and consistency of the final medicinal product.

Properties and functions of solvents in pharmaceutical products

The pharmaceutical industry is a strategic sector of the global economy. It is one of the most strictly regulated systems, which emphasises quality and effectiveness at every stage.

Solvents used in the pharmaceutical industry are subject to special requirements. High purity, non-toxicity and stability are fundamental to their performance. One important factor is their solubility. This largely depends on the chemical compatibility of the solvent and the solute, defined by the principle of ‘like dissolves like’. Equally important is volatility, i.e. the ability to evaporate quickly. Limiting the presence of residual substances is important because solvent residues in pharmaceutical products should be reduced to a minimum.

Pharmaceutical solvents are used in three main areas:

– Drug formulation – pharmaceutical solvents are important components of emulsions, syrups, ointments, oral and enteral solutions, gels, eye drops, etc.

– API synthesis – the effective synthesis of active pharmaceutical ingredients is, in most cases, a multi-step and complex process. The type of pharmaceutical solvent and its quality can be a critical parameter.

– Extraction – extraction processes are designed to purify pharmaceutical formulations from synthesis residues. Typically, liquid-liquid separation occurs between organic and inorganic fractions. Extraction is also used to isolate active substances, e.g. from natural raw materials.

– Crystallisation – in the pharmaceutical industry, it is used to purify active pharmaceutical ingredients (APIs) and control their physical and chemical properties.

– Excipients – some solvents used in pharmaceutical preparation are components of the final product and do not need to be removed. They usually act as diluents or solubilisers, mainly in liquid and semi-solid forms of medicines when water cannot be used.

Types of solvents used in the pharmaceutical industry

Solvents in pharmacy can be classified in many ways. The basic groups are polar and non-polar solvents. We also distinguish between organic and inorganic solvents. The classification can also be based on solubility, toxicity, physical properties (boiling point, density, etc.) and stability.

The list of solvents used in the pharmaceutical industry is long. The groups of compounds of greatest importance in pharmacy are listed below:

Water – is a versatile and balanced solvent. It is non-toxic, non-flammable and widely available. However, on its own, it is not often chosen in pharmacy. Many processes and formulations use a mixture of organic solvents and water.

Alcohols and glycols – organic solvents play an extremely important role in the pharmaceutical industry. Among them, alcohols and glycols (polyhydroxy alcohols) stand out, which contain a hydroxyl group in their structure. They mix very well with water and all organic solvents. Their properties allow them to dissolve a wide range of substances, especially those that are hydrophilic or moderately lipophilic.

Chlorinated derivatives – chlorinated solvents are still used in various industries, including the pharmaceutical industry. An example would be dichloromethane, which is used in pharmaceutical products such as antibiotics and steroids. Chlorinated derivatives are very versatile substances. They include, for example, chlorine-based compounds, which are derivatives of hydrocarbons, and pure chlorine in liquid form.

Hydrocarbons – characterised by the highest solubility of all solvents, with a chemical structure based on an aromatic six-membered benzene ring or hydrocarbon chains. They are used as solvents in the synthesis and purification of drugs.

Inorganic acids – used in many sectors of the chemical industry as raw materials for the synthesis of other chemicals, both organic and inorganic. Also in pharmacy, in specific processes, they support the action of other solvents or are components of finished formulations.

Green solvents

The global solvent market is constantly growing, driven by demand from the industrial and consumer sectors. Increasing environmental awareness is promoting the development of environmentally friendly solvents – biodegradable and based on renewable raw materials. These are known as green solvents.

Green solvents represent a sustainable solution and are gaining popularity as viable alternatives in industries such as pharmaceuticals, agriculture and materials manufacturing. Thanks to these eco-friendly alternatives, industry can significantly reduce pollution, conserve resources and achieve global goals, contributing to a cleaner, healthier and more sustainable future. Solvents used in pharmaceutical preparations are compounds that are subject to rigorous requirements, so replacing them with biodegradable equivalents is not always possible. However, the ability to choose raw materials derived from environmentally friendly production technologies or produced using renewable energy is an important step towards protecting the environment.

PCC Group’s offer

The PCC Group is a recognised and highly reliable partner in the supply and distribution of chemicals, thus meeting the basic needs of the industry. The wide range of products also includes solvents used in the pharmaceutical industry. The GREENLINE series of products deserves special attention.