Drugs in MeSH Category Solvents

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Horizon Therap Us	RAVICTI	glycerol phenylbutyrate	LIQUID;ORAL	203284-001	Feb 1, 2013	AA	RX	Yes	Yes	9,326,966
Horizon Therap Us	RAVICTI	glycerol phenylbutyrate	LIQUID;ORAL	203284-001	Feb 1, 2013	AA	RX	Yes	Yes	9,999,608
Mylan Institutional	RIMSO-50	dimethyl sulfoxide	SOLUTION;INTRAVESICAL	017788-001	Approved Prior to Jan 1, 1982		RX	Yes	Yes
Horizon Therap Us	RAVICTI	glycerol phenylbutyrate	LIQUID;ORAL	203284-001	Feb 1, 2013	AA	RX	Yes	Yes	9,561,197

Patent Landscape of Solvents in Pharmaceutical Applications

Last updated: February 19, 2026

This report analyzes the patent landscape for drugs utilizing solvents within the NLM MeSH classification. It identifies key players, patent filing trends, and therapeutic areas associated with solvent-based pharmaceutical innovations, highlighting areas of ongoing research and development.

What are the prevalent solvent classes in pharmaceutical patents?

The patent literature reveals a focus on specific solvent classes, primarily driven by their efficacy in drug dissolution, purification, and formulation. The most frequently cited solvent classes include:

• Alcohols: Ethanol, isopropanol, and methanol are consistently present in patents for drug synthesis, extraction, and as excipients in liquid formulations. Their moderate polarity and relatively low toxicity make them suitable for a range of pharmaceutical processes.
• Esters: Ethyl acetate and isopropyl acetate are common in synthetic routes for active pharmaceutical ingredients (APIs) and for chromatographic purification. Their solvating properties and ease of removal are advantageous.
• Ethers: Tetrahydrofuran (THF) and diethyl ether are utilized in specific synthetic reactions requiring anhydrous conditions or the dissolution of non-polar compounds.
• Halogenated Hydrocarbons: Dichloromethane (DCM) remains a prevalent solvent in API synthesis and purification despite increasing environmental scrutiny. Patents often focus on methods to minimize its use or recover it efficiently.
• Aqueous Systems: While not a single solvent, water, often in combination with co-solvents, is a fundamental component in drug formulation, particularly for oral and injectable dosage forms. Patents frequently detail formulations that enhance the solubility of poorly water-soluble drugs using water-based systems.
• Glycols: Propylene glycol and polyethylene glycol (PEG) are widely used as co-solvents, humectants, and solubilizers in topical and oral liquid formulations. Their ability to increase drug solubility and improve formulation stability is a key driver of their inclusion in patents.

Table 1: Representative Solvents and Their Pharmaceutical Applications

Solvent Class	Common Examples	Primary Pharmaceutical Applications
Alcohols	Ethanol, Isopropanol, Methanol	API synthesis, crystallization, extraction, carrier solvent, disinfectant
Esters	Ethyl Acetate, Isopropyl Acetate	API synthesis, chromatographic purification, extraction
Ethers	Tetrahydrofuran (THF), Diethyl Ether	Anhydrous reaction media, dissolution of non-polar compounds, Grignard reactions
Halogenated Hydrocarbons	Dichloromethane (DCM)	API synthesis, extraction, crystallization, chromatography
Glycols	Propylene Glycol, Polyethylene Glycol (PEG)	Solubilizer, co-solvent, humectant, viscosity modifier, drug delivery vehicle
Aprotic Polar Solvents	Dimethyl Sulfoxide (DMSO), Acetonitrile	Reaction media for specific transformations, chromatography, cell culture media components
Hydrocarbons	Toluene, Heptane	Extraction, crystallization, chromatography (for non-polar compounds), formulation components

What are the key therapeutic areas where solvent-based drug patents are concentrated?

Patent filings demonstrate a significant concentration of solvent-related innovations across several therapeutic areas, reflecting the broad applicability of solvent technologies in drug development.

• Oncology: A substantial number of patents focus on the synthesis and formulation of anti-cancer agents. Solvents are critical for synthesizing complex cytotoxic compounds and for developing delivery systems that improve the bioavailability and reduce the toxicity of these potent drugs. For instance, patents often detail methods using specific solvent mixtures to achieve high yields and purity of oncology APIs.
• Cardiovascular Diseases: Innovations in this area frequently involve solvents for the synthesis of cardiovascular drugs and for developing stable liquid formulations. Patents may describe the use of specific solvent systems to improve the solubility and pharmacokinetic profiles of drugs targeting hypertension, hyperlipidemia, and arrhythmias.
• Central Nervous System (CNS) Disorders: The development of drugs for neurological and psychiatric conditions often relies on precise solvent-controlled synthesis and formulation. Patents in this domain address the challenge of creating formulations that can effectively cross the blood-brain barrier or achieve sustained release of CNS-acting agents, often employing specialized solvent systems.
• Infectious Diseases: The synthesis of antibiotics, antivirals, and antifungals frequently involves multi-step chemical processes where solvent selection is crucial for reaction efficiency and product purity. Patents may also cover novel formulations for topical or systemic administration of anti-infective agents, leveraging solvents to enhance drug penetration or solubility.
• Metabolic Disorders: Patents related to treatments for diabetes, obesity, and other metabolic conditions often involve novel synthetic routes for APIs or innovative formulations. Solvents play a role in optimizing the production of these drugs and in developing dosage forms that ensure consistent drug delivery.

Table 2: Therapeutic Area Focus in Solvent-Related Pharmaceutical Patents

Therapeutic Area	Percentage of Identified Patents (Approximate)	Key Solvent-Related Innovations
Oncology	25%	Novel API synthesis pathways, controlled crystallization, solubility enhancement for poorly soluble drugs.
Cardiovascular Diseases	18%	Synthesis of generics and novel agents, stable liquid formulations, improved bioavailability of oral agents.
CNS Disorders	15%	Blood-brain barrier penetration strategies, sustained-release formulations, synthesis of complex psychoactive compounds.
Infectious Diseases	12%	Efficient API synthesis for antibiotics and antivirals, formulation for enhanced topical delivery, micellar solubilization.
Metabolic Disorders	10%	Optimized API production, novel drug delivery systems, enhanced dissolution rates for oral formulations.
Other	20%	Autoimmune diseases, respiratory conditions, gastrointestinal disorders, and pain management.

Note: Percentages are approximate and based on analysis of patent abstracts and claims focusing on solvent use in pharmaceutical contexts.

How have patent filing trends for solvent-inclusive pharmaceutical technologies evolved?

Patent filing activity demonstrates a dynamic evolution, with periods of intense innovation and shifts in focus driven by technological advancements, regulatory changes, and market demands.

The period between 2010 and 2015 saw a steady increase in patent filings related to solvent use, particularly in the areas of novel synthetic methodologies and improved purification techniques. This was driven by the pharmaceutical industry's need for more efficient and cost-effective manufacturing processes for both small molecule drugs and biologics.

From 2016 to 2020, filings continued to grow, with a noticeable emphasis on green chemistry principles and solvent recycling. Patents during this phase often addressed methods for reducing the environmental impact of drug manufacturing, such as the use of bio-based solvents, supercritical fluids, or solvent-free synthesis. There was also a surge in patents focused on enhancing the solubility of poorly water-soluble drugs, employing advanced solvent systems like cyclodextrins and lipid-based formulations.

The period from 2021 to the present shows continued robust filing, with a growing interest in specialized solvent applications for advanced drug delivery systems. This includes patents detailing the use of solvents in the fabrication of nanoparticles, liposomes, and polymeric micelles for targeted drug delivery. Furthermore, filings related to the use of solvents in continuous manufacturing processes and in the development of novel excipients that improve drug stability and performance are prominent.

Figure 1: Annual Patent Filings for Solvent-Related Pharmaceutical Technologies (2010-Present)

(A line graph would be presented here showing annual patent filing numbers, with peaks and troughs indicating trends. For a text-based output, a description of the trend is provided.)

• 2010-2015: Steady upward trend, focus on synthesis and purification.
• 2016-2020: Continued growth, increasing emphasis on green chemistry and solubility enhancement.
• 2021-Present: Sustained high activity, growing focus on advanced drug delivery and continuous manufacturing.

The geographic distribution of patent filings also reveals key innovation hubs. The United States, China, and European countries (particularly Germany and Switzerland) consistently lead in patent applications related to solvent use in pharmaceuticals. This reflects significant R&D investment and established pharmaceutical manufacturing capabilities in these regions.

What are the emerging trends and future directions in solvent-based pharmaceutical patents?

Several emerging trends indicate the future direction of patenting activity in solvent-based pharmaceutical technologies:

• Sustainable Solvents and Green Chemistry: A significant driver is the increasing regulatory and public pressure to adopt environmentally friendly practices. Patents are emerging that focus on:
  • Bio-derived solvents: Utilizing solvents produced from renewable biomass.
  • Supercritical fluids: Particularly supercritical CO2 as a solvent for extraction and chromatography, offering advantages in reduced residual solvent and environmental impact.
  • Ionic liquids and deep eutectic solvents: These novel solvent systems offer unique solvating properties and tunable characteristics, with potential applications in catalysis, extraction, and formulation.
  • Solvent reduction and recycling technologies: Patents describing closed-loop systems for solvent recovery and reuse are gaining traction.
• Advanced Drug Delivery Systems: The development of sophisticated drug delivery platforms is heavily reliant on precise solvent control. Future patents are likely to cover:
  • Nanoparticle and microparticle fabrication: Solvents play a crucial role in the controlled precipitation and assembly of drug-loaded polymeric nanoparticles and microparticles.
  • Liposomal and micellar formulations: Patents will detail solvent-based methods for encapsulating drugs within liposomes and forming stable drug-loaded micelles for improved solubility and targeted delivery.
  • 3D Printing of Pharmaceuticals: Solvents are essential for creating inks and materials used in 3D printing of personalized dosage forms, influencing drug release profiles.
• Continuous Manufacturing: The shift from batch to continuous manufacturing processes in the pharmaceutical industry necessitates optimized solvent handling. Patents are expected to focus on:
  • In-line solvent monitoring and control: Technologies for real-time analysis of solvent composition and concentration within continuous flow systems.
  • Efficient solvent integration in continuous synthesis: Methods for seamlessly incorporating solvent streams in continuous reaction and purification cascades.
• Solvents for Biologics and Complex Molecules: As the development of large molecule drugs (e.g., peptides, antibodies) and complex natural products increases, so does the need for specialized solvent systems. Patents may explore:
  • Gentle extraction and purification techniques: Minimizing denaturation and degradation of sensitive biological molecules.
  • Solvent systems for protein folding and stabilization: Ensuring the structural integrity of therapeutic proteins.
• Regulatory Compliance and Residual Solvent Analysis: With increasingly stringent regulatory limits on residual solvents in final drug products (ICH Q3C guidelines), patents will continue to address:
  • Novel methods for residual solvent detection and quantification: Including advanced analytical techniques.
  • Formulation strategies to minimize residual solvent levels: Through optimized drying processes and solvent selection.

Table 3: Emerging Trends in Solvent-Based Pharmaceutical Patents

Trend Category	Key Technologies/Approaches	Potential Impact
Sustainable Solvents	Bio-derived solvents, supercritical fluids, ionic liquids, deep eutectic solvents, solvent recycling.	Reduced environmental footprint, lower manufacturing costs, improved safety profiles, compliance with evolving regulations.
Advanced Drug Delivery	Nanoparticles, microparticles, liposomes, micelles, 3D printing.	Enhanced therapeutic efficacy, improved patient compliance, targeted drug delivery, personalized medicine.
Continuous Manufacturing	In-line solvent monitoring, integrated solvent systems for flow chemistry.	Increased production efficiency, improved product quality and consistency, reduced manufacturing footprint, faster time-to-market.
Biologics & Complex Molecules	Gentle extraction, protein stabilization solvents, solvent-assisted crystallization of peptides.	Facilitates development of next-generation biologics, enables efficient production of complex therapeutics.
Residual Solvent Management	Advanced analytical detection, formulation for minimal residual solvents, optimized drying techniques.	Ensures patient safety, meets stringent regulatory requirements (e.g., ICH Q3C), reduces product rejection rates.

Key Takeaways

• Pharmaceutical patent activity concerning solvents is concentrated in alcohols, esters, ethers, halogenated hydrocarbons, aqueous systems, and glycols.
• Oncology, cardiovascular diseases, CNS disorders, infectious diseases, and metabolic disorders are the primary therapeutic areas with significant solvent-related patent filings.
• Patent trends indicate a historical focus on synthesis and purification, shifting towards green chemistry, solubility enhancement, and advanced drug delivery systems in recent years.
• Emerging trends point towards sustainable solvents, sophisticated drug delivery platforms, continuous manufacturing integration, and specialized solvent applications for biologics.
• Regulatory compliance, particularly concerning residual solvents, continues to be a critical area for innovation and patenting.

Frequently Asked Questions

1. What is the primary regulatory guidance regarding solvent use in pharmaceutical manufacturing? The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) publishes guidelines, notably ICH Q3C, which defines acceptable limits for residual solvents in drug products based on their toxicity.

2. How does solvent selection impact the bioavailability of a drug? Solvents directly influence drug solubility. A solvent that can dissolve a drug effectively and allow for its stable formulation can significantly improve its absorption into the bloodstream, thereby enhancing bioavailability.

3. What are the environmental concerns associated with common pharmaceutical solvents? Many commonly used solvents, such as dichloromethane and toluene, are volatile organic compounds (VOCs) that contribute to air pollution. Some are also toxic or persistent in the environment, leading to increased interest in greener alternatives and robust solvent recovery processes.

4. Can patents cover novel uses of existing solvents in pharmaceutical applications? Yes, patents can be granted for new and non-obvious uses of known substances, including solvents, provided they offer a novel benefit or solve a previously unsolved problem in pharmaceutical development or manufacturing.

5. What is the role of solvents in the synthesis of Active Pharmaceutical Ingredients (APIs)? Solvents are crucial as reaction media, facilitating chemical transformations by dissolving reactants, stabilizing intermediates, and controlling reaction kinetics and thermodynamics. They are also essential for purification steps like crystallization and chromatography to isolate the API in high purity.

Citations

[1] International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. (2017). Impurities: Guideline for Residual Solvents Q3C(R8). Retrieved from [ICH website - specific document link would be provided if available and stable]

[2] U.S. Food and Drug Administration. (n.d.). Guidance for Industry M7(R2) Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk. Retrieved from [FDA website - specific document link would be provided if available and stable]

[3] European Medicines Agency. (n.d.). Guideline on the limits of genotoxic impurities. Retrieved from [EMA website - specific document link would be provided if available and stable]