By Randall Osborne

Two companies — one with multiple partnerships aimed at cloning human receptors for small molecule drugs, and the other banking on its patented system for growing bone marrow cells outside the body — are headed for the capital market.

Synaptic Pharmaceutical Corp., of Paramus, N.J., and Aastrom Biosciences Inc., of Ann Arbor, Mich., have registered with the Securities and Exchange Commission to offer 2.5 million shares and 1.5 million shares, respectively.

Based on Thursday's closing stock price of $14.250, Synaptic (NASDAQ:SNAP) would raise $35.625 million from its offering. Aastrom (NASDAQ:ASTM), which closed Monday at $7.625, would raise $11.437 million.

Synaptic, which clones human receptors for use as targets in the design of drugs, has collaborations with four pharmaceutical companies: Eli Lilly and Co., of Indianapolis, for acute migraine headache, migraine prophylaxis, smoking cessation, depression and obesity; Merck & Co. Inc., of Whitehouse Station, N.J., for benign prostatic hyperplasia; Novartis Pharma A.G., of Basel, Switzerland, for obesity; and Warner-Lambert Co., of Morris Plains, N.J., for obesity, diabetes, Alzheimer's disease, depression and pain.

The most recent pact was signed with Warner-Lambert in August 1997. Worth up to $34 million, the deal is for development of drugs based on Synaptic's work with receptors for galanin, a neurotransmitter thought to be associated with overeating.

All three of the earlier collaborators have extended their agreements.

As of June 30, Synaptic had $27.55 million in cash, with a net loss of $2.095 million for the first half of 1997.

Aastrom, the bone marrow cell-maker, said it will use the proceeds from its offering to further develop and manufacture its cell production system, which grows the bone marrow cells from a small amount of material outside the patient's body, retaining the stem and other key immune cells needed to restore tissues destroyed by aggressive cancer treatments.

The company's initial public offering was held in February and generated $21 million, after Aastrom lowered the number of shares for sale and their price.

Aastrom's technology uses as little as 10 ml of bone marrow to generate enough cells to rejuvenate a patient's blood and immune system. Current procedures require a quart of bone marrow, extracted in separate procedures, for a transplant. The company said its cell production system may be used to replicate other types of cells, such as T cells and solid tissue cells.

As of June 30, Aastrom had $17.007 million cash. For the fiscal year ending June 30, the company reported a net loss of $14.288 million. *